merge: develop into fix/1362-repair-sqlite-integrity-preflight

Conflicts opened by #1285 (temp-staging rebuild) and #1312
(collection_name in recovery paths) merging after this branch was
authored.

mempalace/repair.py:
- Kept this branch's sqlite_integrity_errors() and
  print_sqlite_integrity_abort() helpers; took develop's rebuild_index
  signature with the collection_name parameter from #1312. Normalized
  the helper's print indent to 2 spaces to match the rest of the file.

tests/test_repair.py:
- Kept both this branch's sqlite_integrity_errors tests and develop's
  rebuild_from_sqlite + configured-collection coverage.
- Replaced 7 sites of sqlite_path.write_text("fake") with
  sqlite3.connect(...).close() — write_text("fake") fails PRAGMA
  quick_check, so the new preflight aborts before the rebuild logic
  the tests actually exercise. An empty real SQLite DB passes
  quick_check and lets the tests run as intended.
- Took develop's temp-staging assertion shape (delete/create the
  __repair_tmp collection in addition to the live drawers collection)
  for the existing test_rebuild_index_success test.

Local: 1618 tests pass, ruff lint+format clean against 0.4.x CI pin.

.gitignore

@@ -36,3 +36,4 @@ venv/
 
 # ChromaDB local data
 *.sqlite3-journal
+.envrc

CHANGELOG.md

@@ -11,6 +11,14 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 ### Bug Fixes
 
 - **`mempalace_diary_read` silently dropped entries on agent-name case mismatch.** `tool_diary_write` stored the `agent` metadata verbatim after `sanitize_name`, which preserves case, while `tool_diary_read` filtered by exact match. Writing as `"Claude"` and reading as `"claude"` (or vice-versa) returned zero rows. Both endpoints now lowercase `agent_name` immediately after sanitization, so reads are case-insensitive and the default per-agent wing slug is stable across casings. **Behavior change:** entries written prior to this fix under mixed-case agent names will not match the new lowercase filter; run `mempalace repair` if you need to migrate legacy diary metadata. (#1243)
+- **Knowledge-graph triples with `valid_to < valid_from` were silently invisible.** `KnowledgeGraph.query_entity()` filters with `valid_from <= as_of AND valid_to >= as_of`, so an inverted interval matches no `as_of` and the row is durably stored but unreachable — a P0 data-integrity foot-gun any caller that mixes up the two date params can hit. `add_triple()` now rejects inverted intervals at write time with a clear `ValueError` naming both bounds. Open intervals (one bound only) and point-in-time facts (`valid_from == valid_to`) remain accepted unchanged. (#1214)
+- **`ChromaBackend.close_palace()` / `close()` did not release the SQLite file lock.** Evicted clients sat in `_clients` without `close()`, and chromadb 1.5.x retains the rust-side SQLite lock until GC. Reopening the same palace path after `shutil.rmtree` + recreate within one process failed with `SQLITE_READONLY_DBMOVED` (code 1032). New `_close_client()` helper now calls `PersistentClient.close()` (with a try/except fallback for older chromadb) on `close_palace()`, on whole-backend `close()`, and on the `_client()` invalidation path that detects a missing `chroma.sqlite3`. The mtime/inode auto-invalidation branch is intentionally left alone — callers there may still hold a live `ChromaCollection`. (#1067, #1105)
+- **`EntityRegistry.save()` could leave a corrupt or empty `entity_registry.json` on crash.** `Path.write_text()` is not atomic — kernel sees `open('w')` (truncate), `write`, `close`, and any failure between truncate and full-flush (power loss, OOM, FS-full, kill -9) wipes the months-of-mining people/projects map silently (the registry's `load()` swallows `JSONDecodeError`). Save now writes to a sibling `.tmp` in the same directory, `fsync`s, `chmod 0o600`s, then `os.replace()`s into place — atomic on POSIX and Windows. The previous registry stays intact on any crash before the rename returns. (#1215)
+- **`mempalace compress` crashed on large palaces.** `regenerate_closets` fetched all closet_llm drawers in a single `col.get()`, which trips `SQLITE_MAX_VARIABLE_NUMBER` on palaces above ~32k drawers. Mirrors the #851 fix in `miner.py`: drawer fetch is now paginated at `batch_size=5000`. Per-source aggregation works across batches, so the LLM regeneration call still groups chunks correctly. (#1073, #1107)
+- **CLI and `fact_checker --stdin` mojibaked non-ASCII content on Windows.** Python defaults `sys.stdin`/`stdout`/`stderr` to the system ANSI codepage (cp1252/cp1251/cp950), so `mempalace search > out.txt` and piped fact_checker invocations corrupted Cyrillic / CJK drawer text at the process boundary. New `mempalace/_stdio.py` helper reconfigures all three streams to UTF-8 on `sys.platform == "win32"`, with per-stream `errors` policy: `surrogateescape` on stdin (preserves bad bytes from redirected files for the consumer's parser), `replace` on stdout/stderr (substitutes U+FFFD instead of `UnicodeEncodeError`-ing mid-print). With this, all three user-facing console_scripts (`mcp_server`, `hooks_cli`, `cli`/`fact_checker`) now reconfigure identically on Windows. (#1282)
+- **MCP knowledge-graph tools forwarded malformed date strings to SQLite.** `tool_kg_query` (`as_of`), `tool_kg_add` (`valid_from`), and `tool_kg_invalidate` (`ended`) accepted any string and produced empty result sets on natural-language inputs like `"March 2026"` or `"yesterday"` — callers (especially LLM agents) could not distinguish "no fact at this time" from "your date format was unrecognized." New `sanitize_iso_date()` validator in `config.py` accepts `YYYY`, `YYYY-MM`, `YYYY-MM-DD` (and passes through `None`/`""`); all three tools call it before values reach the storage layer. **Behavior change:** previously-silent date typos now raise a clear `ValueError` naming the offending field; full ISO-8601 with time (`YYYY-MM-DDTHH:MM:SS`, timezone offsets) is not yet accepted — file an issue if you have a use case. (#1164, #1167)
+- **MCP server's `_kg` was a module-level singleton.** Multi-tenant hosts that rotate `MEMPALACE_PALACE_PATH` between tool calls hit the wrong sqlite file, because the KG was constructed once at import time while the ChromaDB side was already per-call via `_get_client()`. The KG is now resolved per-call through a lazy per-path cache (`_kg_by_path` keyed by `os.path.abspath`, with a double-checked-locking init under `_kg_cache_lock`). `tool_reconnect` drains and `close()`s cached KGs alongside the existing chroma reconnect. A `_call_kg` retry guard catches `sqlite3.ProgrammingError` once after a reconnect race. (#1136, #1160)
+- **`mempalace repair` can now recover palaces whose HNSW segment writer is stuck on `apply_logs`.** Both the existing `--mode legacy` rebuild and the inline `cli.cmd_repair` path call `Collection.count()` as their first read — exactly the call that raises `chromadb.errors.InternalError: Failed to apply logs to the hnsw segment writer` on the corruption class introduced upstream and reported in #1308. Repair would print `Cannot recover — palace may need to be re-mined from source files` even though the underlying SQLite tables were fully intact (the corruption lives in the on-disk index files, not the data layer). New `--mode from-sqlite` reads `(id, document, metadata)` rows directly from `chroma.sqlite3` via a `segments` → `embeddings` → `embedding_metadata` join, never opens a chromadb client against the corrupt palace, and re-upserts everything into a fresh palace at `--palace`. `--source PATH` extracts from a corrupt palace already moved aside; `--archive-existing` handles the in-place case by renaming the existing palace to `<palace>.pre-rebuild-<timestamp>` before reading from it. Documents are re-embedded under the user's configured embedding function (the original HNSW vectors live in the corrupt `data_level0.bin` and cannot be recovered, but the embedding model is deterministic so search results remain semantically equivalent). Verified end-to-end on a 52,300-row real-world corrupt palace. (#1308)
 
 ---
 
@@ -28,6 +36,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 ### Bug Fixes
 
 - **MCP server `tool_diary_write` SIGSEGV when default EF provider differs.** `mcp_server._get_collection` bypassed `ChromaBackend.get_collection` and called `client.get_collection` / `client.create_collection` without `embedding_function=`. ChromaDB 1.x persists the EF *identity* (its `name()`) with the collection but not the EF *instance/configuration*, so the MCP server's reopen silently bound chromadb's built-in `DefaultEmbeddingFunction` — its `name()` matches `mempalace.embedding`'s spoofed `"default"` so the identity check passes, but its provider list is chromadb's default rather than the user's resolved device. The miner / Stop hook ingest path routes through the backend helper and binds the configured EF instead. On bleeding-edge interpreters (python 3.14 + chromadb 1.5.x on Apple Silicon) the default provider selection could SIGSEGV the host process on first `col.add()`, killing the MCP stdio server and leaving every subsequent tool call returning `Connection closed` until Claude Code was relaunched. `_get_collection` now reuses `ChromaBackend._resolve_embedding_function()` on the reopen branches that actually open a collection (warm-cache reads stay zero-cost), matching the miner/backend path. (#1299, follow-up to #1262 / #1289)
+- **Hooks no longer recreate `~/.mempalace/` after the user removes it.** When `~/.mempalace/` is deleted (a strong "do not auto-capture" signal), the next `Stop`, `PreCompact`, or `SessionStart` hook would silently rebuild the dir hierarchy and ingest existing transcripts: `_log()` called `STATE_DIR.mkdir(parents=True, exist_ok=True)` unconditionally, so the very act of writing `[HH:MM] SESSION START …` recreated `~/.mempalace/hook_state/`; subsequent calls in the save path then materialized `palace/`, `wal/`, `knowledge_graph.sqlite3`, and N drawers from `~/.claude/projects/*.jsonl`. All four entry points (`hook_stop`, `hook_precompact`, `hook_session_start`, and `_log` itself) now check a new module-level `PALACE_ROOT = Path.home() / ".mempalace"` constant first and short-circuit (returning `{}` on stdout, never logging) when the directory is absent. The user-removable directory becomes a kill-switch — `rm -rf ~/.mempalace` is now a stable state. Net: 23 lines added in `mempalace/hooks_cli.py`, 5 unit tests in `tests/test_hooks_cli.py`. (#1305)
 - **Cross-wing topic tunnels for hyphenated dir names.** `mempalace init` recorded the `topics_by_wing` registry key under the raw directory name (e.g. `mempalace-public`), while `mempalace.yaml`'s `wing` field used the lower-cased + separator-collapsed slug (`mempalace_public`). At mine time the miner read the slug from the yaml and missed the registry, so `_compute_topic_tunnels_for_wing` returned `0` silently. Real-world: any project whose folder contained a hyphen or space lost every topic tunnel. Now both call sites route through a shared `normalize_wing_name()` in `config.py`. (#1194, follow-up to #1180)
 - **CLI `mempalace search` retrieval quality.** The CLI was using pure ChromaDB cosine distance with no BM25 rerank, so drawers containing every query term but embedding as noise (directory listings, diff output, shell logs) scored `Match: 0.0` alongside genuinely irrelevant results with no way to tell them apart. Wired the CLI through the same `_hybrid_rank` the `mempalace_search` MCP tool already used, and surfaced both `cosine=` and `bm25=` scores in the output so users see which component of the match is firing. MCP search was unaffected; this fixes the human-facing CLI parity gap.
 - **Legacy-palace distance-metric warning.** CLI search now detects palaces created before `hnsw:space=cosine` was consistently set and prints a one-line notice pointing at `mempalace repair`. Without the warning such palaces silently used L2 distance, under which the similarity display floored every result to `Match: 0.0`. New palaces mined today already set cosine correctly and now have invariant tests pinning that behavior so future refactors can't silently regress it. (#1179)

README.md

@@ -6,6 +6,10 @@
 > domain — including `mempalace.tech` — is an impostor and may distribute
 > malware. Details and timeline: [docs/HISTORY.md](docs/HISTORY.md).
 
+> [!IMPORTANT]
+> **🚨 Claude Code sessions expire in 30 days w/out auto-save hooks wired!** **[Read this →](https://github.com/MemPalace/mempalace/discussions/1388)**
+
+
 <div align="center">
 
 <img src="assets/mempalace_logo.png" alt="MemPalace" width="240">

mempalace/_stdio.py

@@ -0,0 +1,71 @@
+"""Stdio UTF-8 reconfiguration helper for Windows entry points.
+
+Python on Windows defaults stdio to the system ANSI codepage
+(cp1252/cp1251/cp950 depending on locale), which mojibakes UTF-8 input
+or output the moment a non-Latin character shows up. Every console
+entry point that touches stdio needs to fix this on Windows -- the MCP
+server, the CLI, the fact_checker `--stdin` mode -- so the
+reconfigure code lives here in one place to keep the per-stream
+errors policies aligned across them.
+
+Per-stream errors policy is caller-chosen:
+
+* MCP server uses ``strict`` on stdout/stderr because everything written
+  there is server-controlled JSON-RPC; any encode failure is a real bug
+  the operator wants loud.
+* CLI / fact_checker use ``replace`` on stdout/stderr because they print
+  verbatim drawer text that may contain surrogate halves round-tripped
+  from filenames -- ``strict`` would crash mid-print.
+* All callers use ``surrogateescape`` on stdin so a malformed byte from
+  a redirected file or a misbehaving client survives as a lone surrogate
+  the consumer's parser surfaces, instead of ``UnicodeDecodeError``
+  killing the read loop on the first bad byte.
+"""
+
+from __future__ import annotations
+
+import sys
+from typing import Callable, Optional
+
+
+def reconfigure_stdio_utf8_on_windows(
+    *,
+    stdin_errors: str = "surrogateescape",
+    stdout_errors: str = "strict",
+    stderr_errors: str = "strict",
+    on_failure: Optional[Callable[[str, BaseException], None]] = None,
+) -> None:
+    """Reconfigure stdio to UTF-8 on Windows. No-op elsewhere.
+
+    Args:
+        stdin_errors: errors= policy for stdin.reconfigure().
+        stdout_errors: errors= policy for stdout.reconfigure().
+        stderr_errors: errors= policy for stderr.reconfigure().
+        on_failure: optional ``(stream_name, exc) -> None`` callback for
+            streams whose ``reconfigure`` raises (e.g. Jupyter-replaced
+            streams that lack the method-shape we expect). Defaults to a
+            ``WARNING:`` line on the original sys.stderr.
+    """
+    if sys.platform != "win32":
+        return
+
+    policies = (
+        ("stdin", stdin_errors),
+        ("stdout", stdout_errors),
+        ("stderr", stderr_errors),
+    )
+    for name, errors in policies:
+        stream = getattr(sys, name, None)
+        reconfigure = getattr(stream, "reconfigure", None)
+        if reconfigure is None:
+            continue
+        try:
+            reconfigure(encoding="utf-8", errors=errors)
+        except Exception as exc:  # noqa: BLE001 -- last-resort guard
+            if on_failure is not None:
+                on_failure(name, exc)
+            else:
+                print(
+                    f"WARNING: Could not reconfigure {name} to UTF-8: {exc}",
+                    file=sys.stderr,
+                )

mempalace/backends/chroma.py

@@ -1,9 +1,12 @@
 """ChromaDB-backed MemPalace storage backend (RFC 001 reference implementation)."""
 
+import contextlib
 import datetime as _dt
 import logging
 import os
+import pickle
 import sqlite3
+from numbers import Integral
 from pathlib import Path
 from typing import Any, Optional
 
@@ -29,6 +32,51 @@ _REQUIRED_OPERATORS = frozenset({"$eq", "$ne", "$in", "$nin", "$and", "$or", "$c
 _OPTIONAL_OPERATORS = frozenset({"$gt", "$gte", "$lt", "$lte"})
 _SUPPORTED_OPERATORS = _REQUIRED_OPERATORS | _OPTIONAL_OPERATORS
 
+# A healthy HNSW payload should keep link_lists.bin proportional to
+# data_level0.bin. When link_lists.bin grows orders of magnitude larger than
+# data_level0.bin, Chroma/HNSW can segfault while opening the segment even if
+# index_metadata.pickle is structurally valid.
+#
+# The report in #1218 showed ratios above 300x, while healthy snapshots were far below 1x.
+# Treat only >10x as corruption so normal flush lag or small segments do not get
+# quarantined.
+_HNSW_LINK_TO_DATA_MAX_RATIO = 10.0
+
+
+def _hnsw_link_to_data_ratio(seg_dir: str) -> Optional[float]:
+    """Return link_lists.bin / data_level0.bin size ratio for a segment.
+
+    ``None`` means the ratio is not meaningful, usually because one file is
+    missing or data_level0.bin is empty. ``float("inf")`` means the files were
+    present but could not be statted safely, which should be treated as
+    suspicious by callers.
+    """
+
+    link_path = os.path.join(seg_dir, "link_lists.bin")
+    data_path = os.path.join(seg_dir, "data_level0.bin")
+
+    if not (os.path.isfile(link_path) and os.path.isfile(data_path)):
+        return None
+
+    try:
+        data_size = os.path.getsize(data_path)
+        link_size = os.path.getsize(link_path)
+    except OSError:
+        return float("inf")
+
+    if data_size <= 0:
+        return None
+
+    return link_size / data_size
+
+
+def _hnsw_payload_appears_sane(seg_dir: str) -> bool:
+    """Return False when HNSW payload files are structurally implausible."""
+
+    ratio = _hnsw_link_to_data_ratio(seg_dir)
+    return ratio is None or ratio <= _HNSW_LINK_TO_DATA_MAX_RATIO
+
+
 # HNSW tuning to prevent link_lists.bin bloat on large mines (#344).
 #
 # With default params (batch_size=100, sync_threshold=1000, initial capacity
@@ -106,6 +154,9 @@ def _segment_appears_healthy(seg_dir: str) -> bool:
     files and quarantine_stale_hnsw would conservatively rename them
     out of the way (lazy rebuild on next open recovers).
     """
+    if not _hnsw_payload_appears_sane(seg_dir):
+        return False
+
     meta_path = os.path.join(seg_dir, "index_metadata.pickle")
     if not os.path.isfile(meta_path):
         # No metadata file yet — segment hasn't flushed (fresh / empty).
@@ -127,64 +178,35 @@ def _segment_appears_healthy(seg_dir: str) -> bool:
 
 
 def quarantine_stale_hnsw(palace_path: str, stale_seconds: float = 300.0) -> list[str]:
-    """Rename HNSW segment dirs that are both stale-by-mtime AND fail an
-    integrity sniff-test.
+    """Rename HNSW segment dirs that look unsafe to open.
 
-    Catches the segfault failure mode from #823 (semantic search stale
-    after ``add_drawer``), observed at neo-cortex-mcp#2 (SIGSEGV on
-    ``count()`` with chromadb 1.5.5), and acknowledged as by-design at
-    chroma-core/chroma#2594. Renaming a corrupt segment lets chromadb
-    rebuild lazily on next open instead of segfaulting.
+    This catches two classes of HNSW corruption before ChromaDB opens the
+    native segment reader:
 
-    Two-stage check:
+    1. stale-by-mtime segments whose ``index_metadata.pickle`` fails the
+       existing format sniff-test;
+    2. structurally impossible HNSW payloads where ``link_lists.bin`` is much
+       larger than ``data_level0.bin``.
 
-    1. **mtime gate.** If ``chroma.sqlite3`` is less than
-       ``stale_seconds`` newer than the segment's ``data_level0.bin``,
-       skip — chromadb is in normal write-path territory.
+    The second check is intentionally not gated by mtime. A segment with a
+    300x link/data ratio is unsafe regardless of whether its mtime is recent;
+    letting Chroma open it can SIGSEGV before Python fallback code runs.
 
-    2. **Integrity gate** (``_segment_appears_healthy``). Even when the
-       mtime gap exceeds the threshold, a segment whose
-       ``index_metadata.pickle`` passes a format sniff-test is healthy:
-       chromadb 1.5.x flushes HNSW state asynchronously and a clean
-       shutdown does NOT force-flush, so the on-disk HNSW is *always*
-       somewhat older than ``chroma.sqlite3``. Production observation
-       (2026-04-26 disks daemon): three of three segments quarantined
-       on every cold start, with 538-557s gaps, leaving the 151K-drawer
-       palace with vector_ranked=0 until rebuild. Renaming a healthy
-       segment based on mtime alone destroys a valid index — chromadb
-       creates an empty replacement, orphaning every drawer in sqlite
-       from vector recall until the operator runs ``mempalace repair
-       --mode rebuild`` (15+ min on a 151K palace).
-
-    Only segments that pass stage 1 (suspiciously stale) AND fail stage
-    2 (metadata file truncated, zero-filled, or absent-with-data) are
-    renamed to ``<uuid>.drift-<timestamp>``. The original directory is
-    renamed, not deleted, so recovery remains possible if the heuristic
-    misfires.
-
-    The default threshold (5 min) is advisory under daemon-strict; the
-    integrity gate is what actually distinguishes corruption from flush
-    lag. The threshold still matters for the cross-machine replication
-    case (#823), where it bounds how stale a Syncthing-replicated
-    segment can be before we look harder at it.
-
-    Args:
-        palace_path: path to the palace directory containing ``chroma.sqlite3``
-        stale_seconds: minimum mtime gap to *consider* a segment for quarantine
-
-    Returns:
-        List of paths that were quarantined (empty if nothing actually
-        looked corrupt).
+    The original directory is renamed, not deleted, so recovery remains
+    possible if the heuristic ever misfires.
     """
+
     db_path = os.path.join(palace_path, "chroma.sqlite3")
     if not os.path.isfile(db_path):
         return []
+
     try:
         sqlite_mtime = os.path.getmtime(db_path)
     except OSError:
         return []
 
     moved: list[str] = []
+
     try:
         entries = os.listdir(palace_path)
     except OSError:
@@ -193,29 +215,34 @@ def quarantine_stale_hnsw(palace_path: str, stale_seconds: float = 300.0) -> lis
     for name in entries:
         if "-" not in name or name.startswith(".") or ".drift-" in name:
             continue
+
         seg_dir = os.path.join(palace_path, name)
         if not os.path.isdir(seg_dir):
             continue
+
         hnsw_bin = os.path.join(seg_dir, "data_level0.bin")
         if not os.path.isfile(hnsw_bin):
             continue
+
         try:
             hnsw_mtime = os.path.getmtime(hnsw_bin)
         except OSError:
             continue
-        if sqlite_mtime - hnsw_mtime < stale_seconds:
+
+        payload_ratio = _hnsw_link_to_data_ratio(seg_dir)
+        payload_corrupt = payload_ratio is not None and payload_ratio > _HNSW_LINK_TO_DATA_MAX_RATIO
+
+        if not payload_corrupt and sqlite_mtime - hnsw_mtime < stale_seconds:
             continue
 
-        # Stage 2: integrity gate. mtime drift is necessary but not
-        # sufficient — chromadb's async flush makes drift the steady-
-        # state condition. A healthy segment metadata file proves
-        # chromadb can open the segment without segfault; don't
-        # quarantine a healthy index.
-        if _segment_appears_healthy(seg_dir):
+        # Stage 2: integrity gate. Mtime drift alone is not corruption because
+        # Chroma flushes HNSW asynchronously. A healthy metadata file proves the
+        # ordinary stale-by-mtime case is just flush lag.
+        if not payload_corrupt and _segment_appears_healthy(seg_dir):
             logger.info(
                 "HNSW mtime gap %.0fs on %s exceeds threshold but segment "
-                "metadata file is intact — flush-lag, not corruption. "
-                "Leaving in place.",
+                "metadata and payload size are intact — flush-lag, not "
+                "corruption. Leaving in place.",
                 sqlite_mtime - hnsw_mtime,
                 seg_dir,
             )
@@ -223,17 +250,30 @@ def quarantine_stale_hnsw(palace_path: str, stale_seconds: float = 300.0) -> lis
 
         stamp = _dt.datetime.now().strftime("%Y%m%d-%H%M%S")
         target = f"{seg_dir}.drift-{stamp}"
+
+        if payload_corrupt:
+            reason = (
+                f"link_lists.bin/data_level0.bin ratio {payload_ratio:.1f}x "
+                f"exceeds {_HNSW_LINK_TO_DATA_MAX_RATIO:.1f}x"
+            )
+        else:
+            reason = (
+                f"sqlite {sqlite_mtime - hnsw_mtime:.0f}s newer than HNSW "
+                "and integrity check failed"
+            )
+
         try:
             os.rename(seg_dir, target)
             moved.append(target)
             logger.warning(
-                "Quarantined corrupt HNSW segment %s (sqlite %.0fs newer than HNSW, integrity check failed); renamed to %s",
+                "Quarantined corrupt HNSW segment %s (%s); renamed to %s",
                 seg_dir,
-                sqlite_mtime - hnsw_mtime,
+                reason,
                 target,
             )
         except OSError:
             logger.exception("Failed to quarantine corrupt HNSW segment %s", seg_dir)
+
     return moved
 
 
@@ -489,22 +529,17 @@ def hnsw_capacity_status(palace_path: str, collection_name: str = "mempalace_dra
         divergence_floor = max(_HNSW_DIVERGENCE_FALLBACK_FLOOR, 2 * sync_threshold)
 
         if hnsw_count is None:
-            # No pickle yet — segment hasn't persisted metadata. Could be
-            # fresh-but-unflushed (normal) or interrupted-mid-flush (bad).
-            # We can't distinguish without the pickle, so only flag
-            # divergence when sqlite holds clearly more than two flush
-            # windows worth — same threshold as the with-pickle path.
-            if sqlite_count > divergence_floor:
-                out["status"] = "diverged"
-                out["diverged"] = True
-                out["divergence"] = sqlite_count
+            # No pickle yet, so this probe cannot measure HNSW capacity.
+            # Chroma 1.5.x can have binary HNSW files without a flushed
+            # metadata pickle; absence of the pickle alone is not proof that
+            # vector search is unusable or dangerous. Keep the status unknown
+            # so MCP does not globally disable vectors on an inconclusive
+            # signal. Corrupt/invalid metadata, when present, is handled by
+            # quarantine_invalid_hnsw_metadata before Chroma opens.
             out["message"] = (
-                    f"sqlite holds {sqlite_count:,} embeddings but the HNSW segment "
-                    "has never flushed metadata — vector search will return nothing "
-                    "until the segment is rebuilt. Run `mempalace repair`."
+                "HNSW capacity unavailable: metadata has not been flushed; "
+                "leaving vector search enabled"
             )
-            else:
-                out["message"] = "HNSW segment metadata not yet flushed; skipping"
             return out
 
         divergence = sqlite_count - hnsw_count
@@ -591,6 +626,97 @@ def _pin_hnsw_threads(collection) -> None:
 _BLOB_FIX_MARKER = ".blob_seq_ids_migrated"
 
 
+def _valid_dimensionality(value: object) -> bool:
+    return isinstance(value, Integral) and not isinstance(value, bool) and int(value) > 0
+
+
+def _persisted_metadata_fields(obj: object) -> tuple[object, object]:
+    if isinstance(obj, dict):
+        return obj.get("dimensionality"), obj.get("id_to_label")
+    return getattr(obj, "dimensionality", None), getattr(obj, "id_to_label", None)
+
+
+def quarantine_invalid_hnsw_metadata(palace_path: str) -> list[str]:
+    """Quarantine segment dirs whose ``index_metadata.pickle`` is unreadable or invalid.
+
+    Chroma's persisted HNSW metadata is untrusted disk state. If a segment has
+    labels but no valid positive dimensionality, current Chroma versions can
+    accept the pickle and crash later in the Rust loader. We rename the entire
+    segment out of the way before ``PersistentClient`` opens so Chroma can
+    rebuild cleanly instead of touching known-bad metadata.
+    """
+    try:
+        entries = os.listdir(palace_path)
+    except OSError:
+        return []
+
+    moved: list[str] = []
+    for name in entries:
+        if "-" not in name or name.startswith(".") or ".drift-" in name or ".corrupt-" in name:
+            continue
+        seg_dir = os.path.join(palace_path, name)
+        if not os.path.isdir(seg_dir):
+            continue
+
+        meta_path = os.path.join(seg_dir, "index_metadata.pickle")
+        if not os.path.isfile(meta_path):
+            continue
+
+        reason = None
+        try:
+            persisted = _SafePersistentDataUnpickler.load(meta_path)
+        except (EOFError, OSError):
+            logger.debug(
+                "Skipping invalid-HNSW quarantine for transient metadata read in %s",
+                meta_path,
+                exc_info=True,
+            )
+            continue
+        except pickle.UnpicklingError as exc:
+            if "truncated" in str(exc).lower() or "ran out of input" in str(exc).lower():
+                logger.debug(
+                    "Skipping invalid-HNSW quarantine for transient metadata read in %s",
+                    meta_path,
+                    exc_info=True,
+                )
+                continue
+            reason = f"invalid index_metadata.pickle: {exc}"
+        except Exception as exc:
+            reason = f"invalid index_metadata.pickle: {exc}"
+        else:
+            if not isinstance(persisted, dict) and not (
+                hasattr(persisted, "dimensionality") or hasattr(persisted, "id_to_label")
+            ):
+                reason = f"unrecognized index_metadata.pickle payload: {type(persisted).__name__}"
+            else:
+                dimensionality, id_to_label = _persisted_metadata_fields(persisted)
+                if id_to_label is not None and not isinstance(id_to_label, dict):
+                    reason = f"invalid id_to_label type {type(id_to_label).__name__}"
+                else:
+                    has_labels = bool(id_to_label)
+                    if has_labels and not _valid_dimensionality(dimensionality):
+                        reason = (
+                            "labels present but dimensionality is missing or invalid "
+                            f"({dimensionality!r})"
+                        )
+                    elif dimensionality is not None and not _valid_dimensionality(dimensionality):
+                        reason = f"invalid dimensionality {dimensionality!r}"
+
+        if reason is None:
+            continue
+
+        stamp = _dt.datetime.now().strftime("%Y%m%d-%H%M%S")
+        target = f"{seg_dir}.corrupt-{stamp}"
+        try:
+            os.rename(seg_dir, target)
+            moved.append(target)
+            logger.warning("Quarantined invalid HNSW metadata in %s: %s", seg_dir, reason)
+        except OSError:
+            logger.exception("Failed to quarantine invalid HNSW metadata in %s", seg_dir)
+
+    return moved
+
+
 def _fix_blob_seq_ids(palace_path: str) -> None:
     """Fix ChromaDB 0.6.x -> 1.5.x migration bug: BLOB seq_ids -> INTEGER.
 
@@ -676,11 +802,58 @@ def _as_list(v: Any) -> list:
     return [v]
 
 
-class ChromaCollection(BaseCollection):
-    """Thin adapter translating ChromaDB dict returns into typed results."""
+def _close_client(client) -> None:
+    """Call ``PersistentClient.close()`` if available, swallow otherwise.
 
-    def __init__(self, collection):
+    chromadb 1.5.x exposes ``Client.close()`` to release rust-side SQLite
+    file locks; older versions relied on GC. Try/except keeps forward-compat.
+    """
+    if client is None:
+        return
+    try:
+        client.close()
+    except Exception:
+        logger.debug("client.close() unavailable or failed", exc_info=True)
+
+
+class ChromaCollection(BaseCollection):
+    """Thin adapter translating ChromaDB dict returns into typed results.
+
+    When ``palace_path`` is set, all write methods (``add``, ``upsert``,
+    ``update``, ``delete``) acquire ``mine_palace_lock(palace_path)`` for the
+    duration of the underlying chromadb call. This serializes MCP and other
+    direct-backend writers against ``mempalace mine`` and against each other,
+    closing the race between concurrent writers that triggers ChromaDB's
+    multi-threaded HNSW corruption (#974/#965).
+
+    The lock is the same primitive used by ``miner.mine()`` so re-entrant
+    acquisition from inside the mine pipeline (mine -> _mine_body ->
+    collection.upsert) is short-circuited by the per-thread guard inside
+    ``mine_palace_lock`` — no self-deadlock.
+
+    ``palace_path=None`` disables the wrapping, preserving the legacy
+    no-lock behaviour for callers that construct a ``ChromaCollection``
+    directly without going through ``ChromaBackend``.
+    """
+
+    def __init__(self, collection, palace_path: Optional[str] = None):
         self._collection = collection
+        self._palace_path = palace_path
+
+    @contextlib.contextmanager
+    def _write_lock(self):
+        """Acquire ``mine_palace_lock`` for the configured palace, if any.
+
+        No-op (yields immediately) when ``self._palace_path`` is None.
+        """
+        if self._palace_path is None:
+            yield
+            return
+        # Late import — palace.py imports ChromaBackend from this module.
+        from ..palace import mine_palace_lock
+
+        with mine_palace_lock(self._palace_path):
+            yield
 
     # ------------------------------------------------------------------
     # Writes
@@ -692,6 +865,7 @@ class ChromaCollection(BaseCollection):
             kwargs["metadatas"] = metadatas
         if embeddings is not None:
             kwargs["embeddings"] = embeddings
+        with self._write_lock():
             self._collection.add(**kwargs)
 
     def upsert(self, *, documents, ids, metadatas=None, embeddings=None):
@@ -700,6 +874,7 @@ class ChromaCollection(BaseCollection):
             kwargs["metadatas"] = metadatas
         if embeddings is not None:
             kwargs["embeddings"] = embeddings
+        with self._write_lock():
             self._collection.upsert(**kwargs)
 
     def update(
@@ -719,6 +894,7 @@ class ChromaCollection(BaseCollection):
             kwargs["metadatas"] = metadatas
         if embeddings is not None:
             kwargs["embeddings"] = embeddings
+        with self._write_lock():
             self._collection.update(**kwargs)
 
     # ------------------------------------------------------------------
@@ -863,6 +1039,7 @@ class ChromaCollection(BaseCollection):
             kwargs["ids"] = ids
         if where is not None:
             kwargs["where"] = where
+        with self._write_lock():
             self._collection.delete(**kwargs)
 
     def count(self):
@@ -977,7 +1154,7 @@ class ChromaBackend(BaseBackend):
         db_path = os.path.join(palace_path, "chroma.sqlite3")
         # DB was present when cache was built but is now missing → invalidate.
         if cached is not None and not os.path.isfile(db_path):
-            self._clients.pop(palace_path, None)
+            _close_client(self._clients.pop(palace_path, None))
             self._freshness.pop(palace_path, None)
             cached = None
             cached_inode, cached_mtime = 0, 0.0
@@ -993,6 +1170,13 @@ class ChromaBackend(BaseBackend):
         )
 
         if cached is None or inode_changed or mtime_changed or mtime_appeared:
+            # An inode swap means we are reopening a different physical DB
+            # (post-restore, fresh palace at the same path, etc.); drop the
+            # per-process gate so the quarantine pre-checks run again
+            # against the new disk state instead of trusting cached "we
+            # already cleaned this path" credit from the prior inode.
+            if inode_changed:
+                ChromaBackend._quarantined_paths.discard(palace_path)
             ChromaBackend._prepare_palace_for_open(palace_path)
             cached = chromadb.PersistentClient(path=palace_path)
             self._clients[palace_path] = cached
@@ -1006,26 +1190,27 @@ class ChromaBackend(BaseBackend):
     # Public static helpers (legacy; prefer :meth:`get_collection`)
     # ------------------------------------------------------------------
 
-    # Per-process record of palaces that have already had quarantine_stale_hnsw
-    # invoked at least once. The proactive drift check is a *cold-start*
-    # protection — it catches HNSW segments that arrived stale relative to
-    # ``chroma.sqlite3`` (e.g. cross-machine replication, partial restore,
-    # crashed-mid-write). Once a long-running process has opened the palace
-    # cleanly, re-firing on every reconnect is a *runtime thrash*: the
-    # daemon's own writes bump sqlite mtime but HNSW flushes batch on
-    # chromadb's internal cadence, so the mtime gap naturally exceeds the
-    # threshold under steady write load even though nothing is corrupt.
+    # Per-process record of palaces that have already had the cold-start
+    # quarantine invoked at least once. The proactive HNSW checks are a
+    # *cold-start* protection — they catch segments that arrive stale relative
+    # to ``chroma.sqlite3`` or invalid on disk (e.g. cross-machine replication,
+    # partial restore, crashed-mid-write). Once a long-running process has
+    # opened the palace cleanly, re-firing the stale check on every reconnect
+    # is a *runtime thrash*: the daemon's own writes bump sqlite mtime but HNSW
+    # flushes batch on chromadb's internal cadence, so the mtime gap naturally
+    # exceeds the threshold under steady write load even though nothing is
+    # corrupt.
     # Real runtime drift is still handled — palace-daemon's ``_auto_repair``
     # calls :func:`quarantine_stale_hnsw` directly on observed HNSW errors,
     # which bypasses this gate.
     #
     # Thread-safety: this set is mutated without a lock. Two concurrent
     # ``make_client()`` calls for the same palace can both pass the
-    # membership check and both invoke ``quarantine_stale_hnsw``. That's
-    # safe because the function is idempotent (mtime check + timestamped
-    # rename of distinct directories), so the worst-case race produces
-    # one redundant rename attempt that no-ops. Idempotency is the
-    # safety property; locking would add cost without correctness gain.
+    # membership check and both invoke the cold-start quarantine. That's
+    # safe because the functions are idempotent (mtime checks + timestamped
+    # rename of distinct directories), so the worst-case race produces one
+    # redundant rename attempt that no-ops. Idempotency is the safety
+    # property; locking would add cost without correctness gain.
     _quarantined_paths: set[str] = set()
 
     @staticmethod
@@ -1033,12 +1218,16 @@ class ChromaBackend(BaseBackend):
         """Run the pre-open safety pass shared by :meth:`make_client` and
         :meth:`_client`.
 
-        Two steps, both required before constructing a ``PersistentClient``:
+        Three steps, all required before constructing a ``PersistentClient``:
 
         1. ``_fix_blob_seq_ids`` — repairs the BLOB seq_id quirk that bites
            certain chromadb migrations.
-        2. ``quarantine_stale_hnsw`` — gated by :attr:`_quarantined_paths` so
-           it fires once per palace per process. This is the SIGSEGV
+        2. ``quarantine_invalid_hnsw_metadata`` — renames aside any HNSW
+           ``index_metadata.pickle`` that fails to load, so chromadb opens
+           against an empty index instead of crashing on the unloadable
+           pickle (#1266 / PR #1285).
+        3. ``quarantine_stale_hnsw`` — also gated by :attr:`_quarantined_paths`
+           so it fires once per palace per process. This is the SIGSEGV
            prevention path for stale HNSW segments (see #1121, #1132, #1263);
            wiring it through this helper means CLI mining, search, repair,
            and status all benefit, not just the legacy ``make_client``
@@ -1050,6 +1239,7 @@ class ChromaBackend(BaseBackend):
         """
         _fix_blob_seq_ids(palace_path)
         if palace_path not in ChromaBackend._quarantined_paths:
+            quarantine_invalid_hnsw_metadata(palace_path)
             quarantine_stale_hnsw(palace_path)
             ChromaBackend._quarantined_paths.add(palace_path)
 
@@ -1061,7 +1251,7 @@ class ChromaBackend(BaseBackend):
         own client cache. New code should obtain a collection through
         :meth:`get_collection` which manages caching internally.
 
-        Quarantines stale HNSW segments **once per palace per process**. See
+        Quarantines HNSW segments **once per palace per process**. See
         :attr:`_quarantined_paths` for the rationale (cold-start protection
         vs. runtime thrash on steady-write daemons).
         """
@@ -1131,17 +1321,25 @@ class ChromaBackend(BaseBackend):
         else:
             collection = client.get_collection(collection_name, **ef_kwargs)
         _pin_hnsw_threads(collection)
-        return ChromaCollection(collection)
+        return ChromaCollection(collection, palace_path=palace_path)
 
     def close_palace(self, palace) -> None:
-        """Drop cached handles for ``palace``. Accepts ``PalaceRef`` or legacy path str."""
+        """Drop cached handles for ``palace`` and release its SQLite file lock.
+
+        Accepts ``PalaceRef`` or legacy path str. chromadb's rust-side file
+        lock is held until ``PersistentClient.close()`` is called, so plain
+        dict eviction would leave the palace path unreopenable and
+        unremovable in the same process.
+        """
         path = palace.local_path if isinstance(palace, PalaceRef) else palace
         if path is None:
             return
-        self._clients.pop(path, None)
+        _close_client(self._clients.pop(path, None))
         self._freshness.pop(path, None)
 
     def close(self) -> None:
+        for client in self._clients.values():
+            _close_client(client)
         self._clients.clear()
         self._freshness.clear()
         self._closed = True
@@ -1182,7 +1380,7 @@ class ChromaBackend(BaseBackend):
             },
             **ef_kwargs,
         )
-        return ChromaCollection(collection)
+        return ChromaCollection(collection, palace_path=palace_path)
 
 
 def _normalize_get_collection_args(args, kwargs):

mempalace/cli.py

@@ -654,10 +654,19 @@ def cmd_repair(args):
     import shutil
     from .backends.chroma import ChromaBackend
     from .migrate import confirm_destructive_action, contains_palace_database
-    from .repair import TruncationDetected, check_extraction_safety
+    from .repair import (
+        RebuildCollectionError,
+        TruncationDetected,
+        _close_chroma_handles,
+        _extract_drawers,
+        _rebuild_collection_via_temp,
+        check_extraction_safety,
+    )
 
+    config = MempalaceConfig()
+    collection_name = config.collection_name
     palace_path = os.path.abspath(
-        os.path.expanduser(args.palace) if args.palace else MempalaceConfig().palace_path
+        os.path.expanduser(args.palace) if args.palace else config.palace_path
     )
 
     if getattr(args, "mode", "legacy") == "max-seq-id":
@@ -673,6 +682,57 @@ def cmd_repair(args):
         )
         return
 
+    if getattr(args, "mode", "legacy") == "from-sqlite":
+        from .migrate import confirm_destructive_action
+        from .repair import RebuildPartialError, rebuild_from_sqlite
+
+        source_path = getattr(args, "source", None)
+        source_path = (
+            os.path.abspath(os.path.expanduser(source_path)) if source_path else palace_path
+        )
+        archive_existing = getattr(args, "archive_existing", False)
+
+        # Gate any path that touches the user's existing palace dir
+        # behind confirm_destructive_action. The legacy mode already
+        # gates; from-sqlite needs the same protection because:
+        # (a) --archive-existing renames the existing palace,
+        # (b) --source PATH writes into --palace dir which the user
+        #     may not realize is also a palace.
+        # No prompt when source != dest AND dest does not exist (pure
+        # extract-into-fresh-dir case is non-destructive to existing
+        # palaces).
+        is_destructive_to_dest = source_path == palace_path or os.path.exists(palace_path)
+        if is_destructive_to_dest and not confirm_destructive_action(
+            "Rebuild from SQLite", palace_path, assume_yes=getattr(args, "yes", False)
+        ):
+            return
+
+        try:
+            counts = rebuild_from_sqlite(
+                source_palace=source_path,
+                dest_palace=palace_path,
+                archive_existing_dest=archive_existing,
+            )
+        except RebuildPartialError as exc:
+            # The error itself was already printed by rebuild_from_sqlite
+            # with recovery instructions; surface a non-zero exit so
+            # scripts and CI gates see the failure.
+            print(
+                "\n  Rebuild partial — see message above. "
+                f"Failed in collection: {exc.failed_collection}"
+            )
+            sys.exit(1)
+        # An empty counts dict is rebuild_from_sqlite's documented signal
+        # for a validation refusal (missing source, existing dest,
+        # in-place without --archive-existing). The library already
+        # printed an actionable message; exit non-zero so unattended
+        # scripts/CI distinguish "invalid inputs" from a successful
+        # rebuild that legitimately found zero rows (which still returns
+        # a populated dict with 0-valued counts).
+        if not counts:
+            sys.exit(1)
+        return
+
     db_path = os.path.join(palace_path, "chroma.sqlite3")
 
     if not os.path.isdir(palace_path):
@@ -691,7 +751,7 @@ def cmd_repair(args):
 
     # Try to read existing drawers
     try:
-        col = backend.get_collection(palace_path, "mempalace_drawers")
+        col = backend.get_collection(palace_path, collection_name)
         total = col.count()
         print(f"  Drawers found: {total}")
     except Exception as e:
@@ -711,18 +771,7 @@ def cmd_repair(args):
     # Extract all drawers in batches
     print("\n  Extracting drawers...")
     batch_size = 5000
-    all_ids = []
-    all_docs = []
-    all_metas = []
-    offset = 0
-    while offset < total:
-        batch = col.get(limit=batch_size, offset=offset, include=["documents", "metadatas"])
-        if not batch["ids"]:
-            break
-        all_ids.extend(batch["ids"])
-        all_docs.extend(batch["documents"])
-        all_metas.extend(batch["metadatas"])
-        offset += len(batch["ids"])
+    all_ids, all_docs, all_metas = _extract_drawers(col, total, batch_size)
     print(f"  Extracted {len(all_ids)} drawers")
 
     # ── #1208 guard ──────────────────────────────────────────────────
@@ -737,12 +786,12 @@ def cmd_repair(args):
             palace_path,
             len(all_ids),
             confirm_truncation_ok=getattr(args, "confirm_truncation_ok", False),
+            collection_name=collection_name,
         )
     except TruncationDetected as e:
         print(e.message)
         return
 
-    # Backup and rebuild
     palace_path = os.path.normpath(palace_path)
     backup_path = palace_path + ".backup"
     if os.path.exists(backup_path):
@@ -756,18 +805,34 @@ def cmd_repair(args):
     print(f"  Backing up to {backup_path}...")
     shutil.copytree(palace_path, backup_path)
 
-    print("  Rebuilding collection...")
-    backend.delete_collection(palace_path, "mempalace_drawers")
-    new_col = backend.create_collection(palace_path, "mempalace_drawers")
-
-    filed = 0
-    for i in range(0, len(all_ids), batch_size):
-        batch_ids = all_ids[i : i + batch_size]
-        batch_docs = all_docs[i : i + batch_size]
-        batch_metas = all_metas[i : i + batch_size]
-        new_col.add(documents=batch_docs, ids=batch_ids, metadatas=batch_metas)
-        filed += len(batch_ids)
-        print(f"  Re-filed {filed}/{len(all_ids)} drawers...")
+    try:
+        filed = _rebuild_collection_via_temp(
+            backend,
+            palace_path,
+            all_ids,
+            all_docs,
+            all_metas,
+            batch_size,
+            collection_name=collection_name,
+            progress=print,
+        )
+    except RebuildCollectionError as e:
+        print(f"  Repair failed: {e}")
+        if getattr(e, "live_replaced", False):
+            print("  Live collection was already replaced; restoring from backup...")
+            try:
+                _close_chroma_handles(palace_path, backend=backend)
+                if os.path.exists(palace_path):
+                    shutil.rmtree(palace_path)
+                shutil.copytree(backup_path, palace_path)
+                print(f"  Restore complete from backup: {backup_path}")
+            except Exception as restore_error:
+                print(f"  Automatic restore failed: {restore_error}")
+                print("  Manual recovery required:")
+                print(f"    1. Remove or rename the broken directory: {palace_path}")
+                print(f"    2. Restore the backup directory to: {palace_path}")
+                print(f"       Backup location: {backup_path}")
+        sys.exit(1)
 
     print(f"\n  Repair complete. {filed} drawers rebuilt.")
     print(f"  Backup saved at {backup_path}")
@@ -935,7 +1000,25 @@ def cmd_compress(args):
         print("  (dry run -- nothing stored)")
 
 
+def _reconfigure_stdio_utf8_on_windows():
+    """Decode stdio as UTF-8 on Windows for the primary `mempalace` CLI.
+
+    Thin wrapper around the shared helper in ``mempalace._stdio``. The CLI
+    overrides stdout/stderr to ``replace`` because ``mempalace search``
+    prints verbatim drawer text that may carry surrogate halves
+    round-tripped from filenames -- ``strict`` would crash mid-print and
+    lose the rest of the search result block. stdin keeps the default
+    ``surrogateescape`` so a redirected non-UTF-8 file does not kill the
+    read on the first bad byte.
+    """
+    from ._stdio import reconfigure_stdio_utf8_on_windows
+
+    reconfigure_stdio_utf8_on_windows(stdout_errors="replace", stderr_errors="replace")
+
+
 def main():
+    _reconfigure_stdio_utf8_on_windows()
+
     version_label = f"MemPalace {__version__}"
     parser = argparse.ArgumentParser(
         description="MemPalace — Give your AI a memory. No API key required.",
@@ -1195,11 +1278,31 @@ def main():
     )
     p_repair.add_argument(
         "--mode",
-        choices=["legacy", "max-seq-id"],
+        choices=["legacy", "max-seq-id", "from-sqlite"],
         default="legacy",
         help=(
-            "legacy: full-palace rebuild (default). "
+            "legacy: full-palace rebuild via the chromadb client (default). "
             "max-seq-id: un-poison max_seq_id rows corrupted by the legacy 0.6.x shim. "
+            "from-sqlite: rebuild by reading rows directly from chroma.sqlite3, "
+            "bypassing the chromadb client. Use when legacy mode bails because the "
+            "chromadb client cannot open the collection."
+        ),
+    )
+    p_repair.add_argument(
+        "--source",
+        default=None,
+        help=(
+            "Source palace path for --mode from-sqlite (defaults to --palace). "
+            "Use when extracting from an archived corrupt palace into a new location."
+        ),
+    )
+    p_repair.add_argument(
+        "--archive-existing",
+        action="store_true",
+        help=(
+            "For --mode from-sqlite when --source equals --palace: rename the "
+            "existing palace to <palace>.pre-rebuild-<timestamp> before "
+            "rebuilding so the corrupt copy is preserved."
         ),
     )
     p_repair.add_argument(

mempalace/closet_llm.py

@@ -40,6 +40,7 @@ import json
 import os
 import re
 import time
+import urllib.parse
 import urllib.request
 import urllib.error
 from datetime import datetime
@@ -101,6 +102,14 @@ class LLMConfig:
         self.endpoint = (endpoint or os.environ.get("LLM_ENDPOINT", "")).rstrip("/")
         self.key = key or os.environ.get("LLM_KEY", "")
         self.model = model or os.environ.get("LLM_MODEL", "")
+        if self.endpoint:
+            # Privacy-by-architecture: reject file:// and other non-HTTP schemes
+            # so a misconfigured endpoint cannot exfiltrate local files.
+            scheme = urllib.parse.urlparse(self.endpoint).scheme.lower()
+            if scheme not in ("http", "https"):
+                raise ValueError(
+                    f"LLM_ENDPOINT must use http:// or https:// (got scheme {scheme!r})"
+                )
 
     def missing(self) -> list:
         missing = []
@@ -221,9 +230,19 @@ def regenerate_closets(
         print("No drawers in palace.")
         return {"processed": 0}
 
-    all_data = drawers_col.get(limit=total, include=["documents", "metadatas"])
-    by_source = {}
-    for doc_id, doc, meta in zip(all_data["ids"], all_data["documents"], all_data["metadatas"]):
+    # Paginate the fetch — a single get(limit=total, ...) blows through
+    # SQLite's SQLITE_MAX_VARIABLE_NUMBER (32766) on large palaces and
+    # crashes inside chromadb (see #802, #850, #1073).
+    by_source: dict = {}
+    batch_size = 5000
+    offset = 0
+    while offset < total:
+        batch = drawers_col.get(limit=batch_size, offset=offset, include=["documents", "metadatas"])
+        ids = batch["ids"]
+        if not ids:
+            break
+        for doc_id, doc, meta in zip(ids, batch["documents"], batch["metadatas"]):
+            meta = meta or {}
             source = meta.get("source_file", "unknown")
             w = meta.get("wing", "")
             if wing and w != wing:
@@ -232,6 +251,7 @@ def regenerate_closets(
                 by_source[source] = {"drawer_ids": [], "content": [], "meta": meta}
             by_source[source]["drawer_ids"].append(doc_id)
             by_source[source]["content"].append(doc)
+        offset += len(ids)
 
     sources = list(by_source.keys())
     if sample > 0:

mempalace/config.py

@@ -7,6 +7,7 @@ Priority: env vars > config file (~/.mempalace/config.json) > defaults
 import json
 import os
 import re
+from functools import lru_cache
 from pathlib import Path
 
 
@@ -81,6 +82,38 @@ def sanitize_kg_value(value: str, field_name: str = "value") -> str:
     return value
 
 
+# ISO-8601 date validator for knowledge-graph temporal parameters
+# (as_of, valid_from, valid_to, ended). Parameterized queries already
+# prevent SQL injection, but unvalidated date strings silently miss
+# every row — callers cannot distinguish "no fact at this time" from
+# "your date format was unrecognized." Require full YYYY-MM-DD: KG
+# queries compare TEXT dates lexicographically, so partials like "2026"
+# would re-introduce silent empty results (e.g. "2026-01-01" <= "2026"
+# is False), defeating the purpose of validation.
+_ISO_DATE_RE = re.compile(r"^\d{4}-(?:0[1-9]|1[0-2])-(?:0[1-9]|[12]\d|3[01])$")
+
+
+def sanitize_iso_date(value, field_name: str = "date"):
+    """Validate an ISO-8601 date string, accepting None or empty as-is.
+
+    Accepts only ``YYYY-MM-DD``. Raises ValueError on any other
+    non-empty input so the MCP layer can surface a clear error to the
+    caller instead of silently returning empty results. Partial dates
+    (``YYYY``, ``YYYY-MM``) are rejected because KG queries compare
+    TEXT dates lexicographically and would silently exclude valid facts.
+    """
+    if value is None or value == "":
+        return value
+    if not isinstance(value, str):
+        raise ValueError(f"{field_name} must be a string")
+    value = value.strip()
+    if not _ISO_DATE_RE.match(value):
+        raise ValueError(
+            f"{field_name}={value!r} is not a valid ISO-8601 date " f"(expected YYYY-MM-DD)"
+        )
+    return value
+
+
 def sanitize_content(value: str, max_length: int = 100_000) -> str:
     """Validate drawer/diary content length."""
     if not isinstance(value, str) or not value.strip():
@@ -95,6 +128,13 @@ def sanitize_content(value: str, max_length: int = 100_000) -> str:
 DEFAULT_PALACE_PATH = os.path.expanduser("~/.mempalace/palace")
 DEFAULT_COLLECTION_NAME = "mempalace_drawers"
 
+
+@lru_cache(maxsize=1)
+def get_configured_collection_name() -> str:
+    """Return the configured drawer collection name without repeated config-file reads."""
+    return MempalaceConfig().collection_name
+
+
 DEFAULT_TOPIC_WINGS = [
     "emotions",
     "consciousness",

mempalace/convo_miner.py

@@ -11,6 +11,7 @@ Same palace as project mining. Different ingest strategy.
 import os
 import sys
 import hashlib
+import logging
 from pathlib import Path
 from datetime import datetime
 from collections import defaultdict
@@ -24,6 +25,8 @@ from .palace import (
     mine_lock,
 )
 
+logger = logging.getLogger("mempalace_mcp")
+
 
 # Cached hall keywords — avoids re-reading config per drawer
 _HALL_KEYWORDS_CACHE = None
@@ -331,7 +334,7 @@ def _file_chunks_locked(collection, source_file, chunks, wing, room, agent, extr
         try:
             collection.delete(where={"source_file": source_file})
         except Exception:
-            pass
+            logger.debug("Stale-drawer purge failed for %s", source_file, exc_info=True)
 
         # Batch chunks into bounded upserts so large transcripts keep most of
         # the embedding speedup without one huge Chroma/SQLite request. Keep

mempalace/dedup.py

@@ -89,7 +89,7 @@ def dedup_source_group(col, drawer_ids, threshold=DEFAULT_THRESHOLD, dry_run=Tru
     kept = []
     to_delete = []
 
-    for did, doc, meta in items:
+    for did, doc, _meta in items:
         if not doc or len(doc) < 20:
             to_delete.append(did)
             continue

mempalace/dialect.py

@@ -873,7 +873,7 @@ class Dialect:
 
         for date_key in sorted(by_date.keys()):
             lines.append(f"=MOMENTS[{date_key}]=")
-            for z, fnum in by_date[date_key]:
+            for z, _fnum in by_date[date_key]:
                 entities = []
                 for p in z.get("people", []):
                     code = self.encode_entity(p)

mempalace/entity_registry.py

@@ -16,6 +16,7 @@ Usage:
 """
 
 import json
+import os
 import re
 import urllib.request
 import urllib.parse
@@ -320,11 +321,35 @@ class EntityRegistry:
             self._path.parent.chmod(0o700)
         except (OSError, NotImplementedError):
             pass
-        self._path.write_text(json.dumps(self._data, indent=2), encoding="utf-8")
+        # Atomic write: serialize to a sibling temp file in the same dir
+        # (so os.replace stays on one filesystem), fsync, then rename over
+        # the target. A crash mid-write leaves the previous registry intact
+        # instead of a half-written file or an empty file from the truncate.
+        payload = json.dumps(self._data, indent=2)
+        tmp_path = self._path.with_name(self._path.name + ".tmp")
+        with open(tmp_path, "w", encoding="utf-8") as f:
+            f.write(payload)
+            f.flush()
+            os.fsync(f.fileno())
         try:
-            self._path.chmod(0o600)
+            tmp_path.chmod(0o600)
         except (OSError, NotImplementedError):
             pass
+        os.replace(tmp_path, self._path)
+        # On ext4 (and similar) the rename's durability across power loss
+        # requires an additional fsync on the parent directory. Without it,
+        # the kernel can ack the rename and a crash reverts to the state
+        # where the temp file is present and the target is at the old version.
+        try:
+            dir_fd = os.open(str(self._path.parent), os.O_RDONLY)
+            try:
+                os.fsync(dir_fd)
+            finally:
+                os.close(dir_fd)
+        except OSError:
+            # Windows and some special filesystems reject directory fds — they
+            # have different durability semantics on rename anyway.
+            pass
 
     @staticmethod
     def _empty() -> dict:

mempalace/fact_checker.py

@@ -27,6 +27,7 @@ Usage:
 
 from __future__ import annotations
 
+import logging
 import os
 import re
 from datetime import datetime, timezone
@@ -35,6 +36,8 @@ from datetime import datetime, timezone
 # ~/.mempalace/known_entities.json on every check_text call.
 from .miner import _load_known_entities_raw
 
+logger = logging.getLogger("mempalace_mcp")
+
 
 # Narrow detection patterns — parse "X is Y's Z" and "X's Z is Y".
 # Names are captured greedily as word sequences (letters + optional
@@ -214,6 +217,7 @@ def _check_kg_contradictions(text: str, palace_path: str) -> list:
         try:
             facts = kg.query_entity(subject, direction="outgoing")
         except Exception:
+            logger.debug("KG lookup failed for subject %r", subject, exc_info=True)
             continue
         if not facts:
             continue
@@ -303,11 +307,27 @@ def _edit_distance(s1: str, s2: str) -> int:
     return prev[-1]
 
 
+def _reconfigure_stdio_utf8_on_windows():
+    """Decode --stdin payload as UTF-8 on Windows.
+
+    Thin wrapper around the shared helper in ``mempalace._stdio``. Mirrors
+    the primary CLI policy: stdout/stderr use ``replace`` because
+    extracted fact text can include surrogate halves round-tripped from
+    filenames -- ``strict`` would raise UnicodeEncodeError mid-print.
+    stdin keeps the default ``surrogateescape``.
+    """
+    from ._stdio import reconfigure_stdio_utf8_on_windows
+
+    reconfigure_stdio_utf8_on_windows(stdout_errors="replace", stderr_errors="replace")
+
+
 if __name__ == "__main__":
     import argparse
     import json
     import sys
 
+    _reconfigure_stdio_utf8_on_windows()
+
     parser = argparse.ArgumentParser(
         description="Check text against known facts in the MemPalace palace.",
         epilog="Exits 0 when no issues found, 1 when one or more issues detected.",

mempalace/hooks_cli.py

@@ -16,6 +16,23 @@ from pathlib import Path
 
 SAVE_INTERVAL = 15
 STATE_DIR = Path.home() / ".mempalace" / "hook_state"
+PALACE_ROOT = Path.home() / ".mempalace"
+
+
+def _palace_root_exists() -> bool:
+    """User-removable kill-switch.
+
+    If ~/.mempalace/ does not exist, the user has explicitly cleared it.
+    All hook side effects (logging, state dir creation, mining, ingestion)
+    must respect this and short-circuit BEFORE touching disk — including
+    before logging the short-circuit itself.
+
+    Uses ``is_dir()`` rather than ``exists()`` so a stray regular file at
+    ``~/.mempalace`` (or a broken symlink) is treated as absent — otherwise
+    the kill-switch would be bypassed and ``STATE_DIR.mkdir()`` would later
+    crash on ``NotADirectoryError``.
+    """
+    return PALACE_ROOT.is_dir()
 
 
 def _mempalace_python() -> str:
@@ -142,6 +159,8 @@ _state_dir_initialized = False
 
 def _log(message: str):
     """Append to hook state log file."""
+    if not _palace_root_exists():
+        return  # User removed the palace; do not recreate by logging
     global _state_dir_initialized
     try:
         if not _state_dir_initialized:
@@ -550,6 +569,9 @@ def _wing_from_transcript_path(transcript_path: str) -> str:
 
 def hook_stop(data: dict, harness: str):
     """Stop hook: block every N messages for auto-save."""
+    if not _palace_root_exists():
+        _output({})
+        return
     parsed = _parse_harness_input(data, harness)
     session_id = parsed["session_id"]
     stop_hook_active = parsed["stop_hook_active"]
@@ -659,6 +681,9 @@ def hook_stop(data: dict, harness: str):
 
 def hook_session_start(data: dict, harness: str):
     """Session start hook: initialize session tracking state."""
+    if not _palace_root_exists():
+        _output({})
+        return
     parsed = _parse_harness_input(data, harness)
     session_id = parsed["session_id"]
 
@@ -673,6 +698,9 @@ def hook_session_start(data: dict, harness: str):
 
 def hook_precompact(data: dict, harness: str):
     """Precompact hook: mine transcript synchronously, then allow compaction."""
+    if not _palace_root_exists():
+        _output({})
+        return
     parsed = _parse_harness_input(data, harness)
     session_id = parsed["session_id"]
     transcript_path = parsed["transcript_path"]

mempalace/knowledge_graph.py

@@ -171,6 +171,15 @@ class KnowledgeGraph:
             add_triple("Max", "does", "swimming", valid_from="2025-01-01")
             add_triple("Alice", "worried_about", "Max injury", valid_from="2026-01", valid_to="2026-02")
         """
+        # Reject inverted intervals: a triple with valid_to < valid_from
+        # would never satisfy `valid_from <= as_of AND valid_to >= as_of`,
+        # so it would be invisible to every query — silently corrupt.
+        if valid_from is not None and valid_to is not None and valid_to < valid_from:
+            raise ValueError(
+                f"valid_to={valid_to!r} is before valid_from={valid_from!r}; "
+                "an inverted interval would be invisible to every KG query"
+            )
+
         sub_id = self._entity_id(subject)
         obj_id = self._entity_id(obj)
         pred = predicate.lower().replace(" ", "_")

mempalace/layers.py

@@ -124,6 +124,8 @@ class Layer1:
         # Score each drawer: prefer high importance, recent filing
         scored = []
         for doc, meta in zip(docs, metas):
+            meta = meta or {}
+            doc = doc or ""
             importance = 3
             # Try multiple metadata keys that might carry weight info
             for key in ("importance", "emotional_weight", "weight"):
@@ -155,7 +157,7 @@ class Layer1:
             lines.append(room_line)
             total_len += len(room_line)
 
-            for imp, meta, doc in entries:
+            for _imp, meta, doc in entries:
                 source = Path(meta.get("source_file", "")).name if meta.get("source_file") else ""
 
                 # Truncate doc to keep L1 compact
@@ -222,6 +224,8 @@ class Layer2:
 
         lines = [f"## L2 — ON-DEMAND ({len(docs)} drawers)"]
         for doc, meta in zip(docs[:n_results], metas[:n_results]):
+            meta = meta or {}
+            doc = doc or ""
             room_name = meta.get("room", "?")
             source = Path(meta.get("source_file", "")).name if meta.get("source_file") else ""
             snippet = doc.strip().replace("\n", " ")
@@ -283,7 +287,7 @@ class Layer3:
         for i, (doc, meta, dist) in enumerate(zip(docs, metas, dists), 1):
             meta = meta or {}
             doc = doc or ""
-            similarity = round(1 - dist, 3)
+            similarity = round(max(0.0, 1 - dist), 3)
             wing_name = meta.get("wing", "?")
             room_name = meta.get("room", "?")
             source = Path(meta.get("source_file", "")).name if meta.get("source_file") else ""

mempalace/mcp_server.py

@@ -46,6 +46,8 @@ import argparse  # noqa: E402  (deferred until after stdio protection above)
 import json  # noqa: E402
 import logging  # noqa: E402
 import hashlib  # noqa: E402
+import sqlite3  # noqa: E402
+import threading  # noqa: E402
 import time  # noqa: E402
 from datetime import date, datetime  # noqa: E402
 from pathlib import Path  # noqa: E402
@@ -55,6 +57,7 @@ from .config import (  # noqa: E402
     sanitize_kg_value,
     sanitize_name,
     sanitize_content,
+    sanitize_iso_date,
 )
 from .version import __version__  # noqa: E402
 from chromadb.errors import NotFoundError as _ChromaNotFoundError  # noqa: E402
@@ -78,7 +81,7 @@ from .palace_graph import (  # noqa: E402
     follow_tunnels,
 )
 
-from .knowledge_graph import KnowledgeGraph  # noqa: E402
+from .knowledge_graph import KnowledgeGraph, DEFAULT_KG_PATH  # noqa: E402
 
 logging.basicConfig(level=logging.INFO, format="%(message)s", stream=sys.stderr)
 logger = logging.getLogger("mempalace_mcp")
@@ -103,12 +106,61 @@ if _args.palace:
     os.environ["MEMPALACE_PALACE_PATH"] = os.path.abspath(_args.palace)
 
 _config = MempalaceConfig()
-# Only override KG path when --palace is explicitly provided; otherwise use
-# KnowledgeGraph's default (~/.mempalace/knowledge_graph.sqlite3).
-if _args.palace:
-    _kg = KnowledgeGraph(db_path=os.path.join(_config.palace_path, "knowledge_graph.sqlite3"))
-else:
-    _kg = KnowledgeGraph()
+
+_kg_by_path: dict[str, KnowledgeGraph] = {}
+_kg_cache_lock = threading.Lock()
+_palace_flag_given: bool = bool(_args.palace)
+
+
+def _resolve_kg_path() -> str:
+    if _palace_flag_given:
+        return os.path.join(_config.palace_path, "knowledge_graph.sqlite3")
+    return DEFAULT_KG_PATH
+
+
+def _get_kg() -> KnowledgeGraph:
+    path = os.path.abspath(_resolve_kg_path())
+    kg = _kg_by_path.get(path)
+    if kg is not None:
+        return kg
+    with _kg_cache_lock:
+        kg = _kg_by_path.get(path)
+        if kg is None:
+            kg = KnowledgeGraph(db_path=path)
+            _kg_by_path[path] = kg
+    return kg
+
+
+def _call_kg(op):
+    """Run ``op(kg)`` against the cached KG with one-shot retry on close.
+
+    Race we're guarding against: a handler grabs ``kg = _get_kg()`` and is
+    about to call ``kg.add_triple(...)`` when ``tool_reconnect`` fires on
+    another thread, drains ``_kg_by_path``, and closes the underlying
+    sqlite3.Connection. The handler's call then raises
+    ``sqlite3.ProgrammingError: Cannot operate on a closed database`` and
+    bubbles up as a -32000 to the MCP client even though the user just
+    asked for a reconnect.
+
+    Catch that single class of error, evict the stale entry from the
+    cache (only if it still points at the closed instance — another
+    thread may have already replaced it), and try once more with a fresh
+    KG. Beyond one retry give up: a second close means we're losing a
+    sustained race we won't win in this loop, and a hung loop is worse
+    than a clear failure surface.
+    """
+    for attempt in range(2):
+        kg = _get_kg()
+        try:
+            return op(kg)
+        except sqlite3.ProgrammingError:
+            if attempt == 0:
+                path = os.path.abspath(_resolve_kg_path())
+                with _kg_cache_lock:
+                    if _kg_by_path.get(path) is kg:
+                        _kg_by_path.pop(path, None)
+                continue
+            raise
 
 
 _client_cache = None
@@ -141,7 +193,7 @@ def _refresh_vector_disabled_flag() -> None:
     """
     global _vector_disabled, _vector_disabled_reason, _vector_capacity_status
     try:
-        info = hnsw_capacity_status(_config.palace_path, "mempalace_drawers")
+        info = hnsw_capacity_status(_config.palace_path, _config.collection_name)
     except Exception:
         logger.debug("HNSW capacity probe raised", exc_info=True)
         return
@@ -274,8 +326,19 @@ def _get_client():
 
 
 def _get_collection(create=False):
-    """Return the ChromaDB collection, caching the client between calls."""
-    global _collection_cache, _metadata_cache, _metadata_cache_time
+    """Return the ChromaDB collection, caching the client between calls.
+
+    On failure, log the exception and retry once after clearing the client
+    and collection caches. Tools were silently returning ``None`` when a
+    cached client/collection went stale — typically after the chromadb
+    rust bindings invalidated a handle following an out-of-band write —
+    leaving the LLM with no diagnostic and no recovery path. The retry
+    forces ``_get_client()`` to rebuild from scratch (which re-runs
+    ``quarantine_stale_hnsw`` per #1322), so the second attempt heals the
+    common stale-handle / stale-HNSW case automatically.
+    """
+    global _client_cache, _collection_cache, _metadata_cache, _metadata_cache_time
+    for attempt in range(2):
         try:
             client = _get_client()
             # ChromaDB 1.x persists the EF *identity* (its ``name()``) with the
@@ -322,7 +385,7 @@ def _get_collection(create=False):
                         **ef_kwargs,
                     )
                 _pin_hnsw_threads(raw)
-            _collection_cache = ChromaCollection(raw)
+                _collection_cache = ChromaCollection(raw, palace_path=_config.palace_path)
                 _metadata_cache = None
                 _metadata_cache_time = 0
             elif _collection_cache is None:
@@ -330,11 +393,26 @@ def _get_collection(create=False):
                 ef_kwargs = {"embedding_function": ef} if ef is not None else {}
                 raw = client.get_collection(_config.collection_name, **ef_kwargs)
                 _pin_hnsw_threads(raw)
-            _collection_cache = ChromaCollection(raw)
+                _collection_cache = ChromaCollection(raw, palace_path=_config.palace_path)
                 _metadata_cache = None
                 _metadata_cache_time = 0
             return _collection_cache
         except Exception:
+            logger.exception(
+                "_get_collection attempt %d/2 failed (palace=%s, create=%s)",
+                attempt + 1,
+                _config.palace_path,
+                create,
+            )
+            if attempt == 0:
+                # Reset all caches so the next attempt forces _get_client()
+                # to rebuild the chromadb client from scratch — that path
+                # re-runs quarantine_stale_hnsw (#1322) and reopens the
+                # collection cleanly, healing the common stale-handle case.
+                _client_cache = None
+                _collection_cache = None
+                _metadata_cache = None
+                _metadata_cache_time = 0
     return None
 
 
@@ -412,6 +490,7 @@ def _tool_status_via_sqlite() -> dict:
     db_path = os.path.join(_config.palace_path, "chroma.sqlite3")
     if not os.path.isfile(db_path):
         return _no_palace()
+    collection_name = _config.collection_name
 
     wings: dict = {}
     rooms: dict = {}
@@ -425,8 +504,9 @@ def _tool_status_via_sqlite() -> dict:
                 FROM embeddings e
                 JOIN segments s ON e.segment_id = s.id
                 JOIN collections c ON s.collection = c.id
-                WHERE c.name = 'mempalace_drawers'
-                """
+                WHERE c.name = ?
+                """,
+                (collection_name,),
             ).fetchone()
             total = int(row[0]) if row and row[0] is not None else 0
             for key, target in (("wing", wings), ("room", rooms)):
@@ -437,12 +517,12 @@ def _tool_status_via_sqlite() -> dict:
                     JOIN embeddings e ON em.id = e.id
                     JOIN segments s ON e.segment_id = s.id
                     JOIN collections c ON s.collection = c.id
-                    WHERE c.name = 'mempalace_drawers'
+                    WHERE c.name = ?
                       AND em.key = ?
                       AND em.string_value IS NOT NULL
                     GROUP BY em.string_value
                     """,
-                    (key,),
+                    (collection_name, key),
                 ):
                     target[value] = count
         finally:
@@ -642,6 +722,7 @@ def tool_search(
         n_results=limit,
         max_distance=dist,
         vector_disabled=_vector_disabled,
+        collection_name=_config.collection_name,
     )
     if _vector_disabled:
         result["vector_disabled"] = True
@@ -688,10 +769,12 @@ def tool_check_duplicate(content: str, threshold: float = 0.9):
         if results["ids"] and results["ids"][0]:
             for i, drawer_id in enumerate(results["ids"][0]):
                 dist = results["distances"][0][i]
-                similarity = round(1 - dist, 3)
+                similarity = round(max(0.0, 1 - dist), 3)
                 if similarity >= threshold:
-                    meta = results["metadatas"][0][i]
-                    doc = results["documents"][0][i]
+                    # Chroma 1.5.x can return None for partially-flushed rows;
+                    # coerce to empty sentinels so downstream .get() is safe.
+                    meta = results["metadatas"][0][i] or {}
+                    doc = results["documents"][0][i] or ""
                     duplicates.append(
                         {
                             "id": drawer_id,
@@ -842,11 +925,11 @@ def tool_add_drawer(
 
     # Idempotency: if the deterministic ID already exists, return success as a no-op.
     try:
-        existing = col.get(ids=[drawer_id])
-        if existing and existing["ids"]:
+        existing = col.get(ids=[drawer_id], include=[])
+        if existing.ids:
             return {"success": True, "reason": "already_exists", "drawer_id": drawer_id}
     except Exception:
-        pass
+        logger.debug("Idempotency pre-check failed for %s", drawer_id, exc_info=True)
 
     try:
         col.upsert(
@@ -863,6 +946,12 @@ def tool_add_drawer(
                 }
             ],
         )
+        inserted = col.get(ids=[drawer_id], include=[])
+        if not inserted.ids:
+            raise RuntimeError(
+                "Drawer write was acknowledged but the new ID is not readable. "
+                "The palace index may be stale; run reconnect or repair."
+            )
         _metadata_cache = None
         logger.info(f"Filed drawer: {drawer_id} → {wing}/{room}")
         return {"success": True, "drawer_id": drawer_id, "wing": wing, "room": room}
@@ -961,6 +1050,13 @@ def tool_list_drawers(wing: str = None, room: str = None, limit: int = 20, offse
             kwargs["where"] = where
         result = col.get(**kwargs)
 
+        # Compute total matching drawers for pagination.
+        if where:
+            total_result = col.get(where=where, include=[])
+            total = len(total_result["ids"])
+        else:
+            total = col.count()
+
         drawers = []
         for i, did in enumerate(result["ids"]):
             meta = result["metadatas"][i]
@@ -975,6 +1071,7 @@ def tool_list_drawers(wing: str = None, room: str = None, limit: int = 20, offse
             )
         return {
             "drawers": drawers,
+            "total": total,
             "count": len(drawers),
             "offset": offset,
             "limit": limit,
@@ -1059,11 +1156,12 @@ def tool_kg_query(entity: str, as_of: str = None, direction: str = "both"):
     """Query the knowledge graph for an entity's relationships."""
     try:
         entity = sanitize_kg_value(entity, "entity")
+        as_of = sanitize_iso_date(as_of, "as_of")
     except ValueError as e:
         return {"error": str(e)}
     if direction not in ("outgoing", "incoming", "both"):
         return {"error": "direction must be 'outgoing', 'incoming', or 'both'"}
-    results = _kg.query_entity(entity, as_of=as_of, direction=direction)
+    results = _call_kg(lambda kg: kg.query_entity(entity, as_of=as_of, direction=direction))
     return {"entity": entity, "as_of": as_of, "facts": results, "count": len(results)}
 
 
@@ -1092,6 +1190,7 @@ def tool_kg_add(
         subject = sanitize_kg_value(subject, "subject")
         predicate = sanitize_name(predicate, "predicate")
         object = sanitize_kg_value(object, "object")
+        valid_from = sanitize_iso_date(valid_from, "valid_from")
     except ValueError as e:
         return {"success": False, "error": str(e)}
 
@@ -1108,7 +1207,8 @@ def tool_kg_add(
             "source_drawer_id": source_drawer_id,
         },
     )
-    triple_id = _kg.add_triple(
+    triple_id = _call_kg(
+        lambda kg: kg.add_triple(
             subject,
             predicate,
             object,
@@ -1118,6 +1218,7 @@ def tool_kg_add(
             source_file=source_file,
             source_drawer_id=source_drawer_id,
         )
+    )
     return {"success": True, "triple_id": triple_id, "fact": f"{subject} → {predicate} → {object}"}
 
 
@@ -1135,6 +1236,7 @@ def tool_kg_invalidate(subject: str, predicate: str, object: str, ended: str = N
         subject = sanitize_kg_value(subject, "subject")
         predicate = sanitize_name(predicate, "predicate")
         object = sanitize_kg_value(object, "object")
+        ended = sanitize_iso_date(ended, "ended")
     except ValueError as e:
         return {"success": False, "error": str(e)}
     resolved_ended = ended or date.today().isoformat()
@@ -1147,7 +1249,7 @@ def tool_kg_invalidate(subject: str, predicate: str, object: str, ended: str = N
             "ended": resolved_ended,
         },
     )
-    _kg.invalidate(subject, predicate, object, ended=resolved_ended)
+    _call_kg(lambda kg: kg.invalidate(subject, predicate, object, ended=resolved_ended))
     return {
         "success": True,
         "fact": f"{subject} → {predicate} → {object}",
@@ -1162,13 +1264,13 @@ def tool_kg_timeline(entity: str = None):
             entity = sanitize_kg_value(entity, "entity")
         except ValueError as e:
             return {"error": str(e)}
-    results = _kg.timeline(entity)
+    results = _call_kg(lambda kg: kg.timeline(entity))
     return {"entity": entity or "all", "timeline": results, "count": len(results)}
 
 
 def tool_kg_stats():
     """Knowledge graph overview: entities, triples, relationship types."""
-    return _kg.stats()
+    return _call_kg(lambda kg: kg.stats())
 
 
 # ==================== AGENT DIARY ====================
@@ -1351,7 +1453,7 @@ def tool_hook_settings(silent_save: bool = None, desktop_toast: bool = None):
     try:
         config = MempalaceConfig()
     except Exception:
-        pass
+        logger.debug("Could not re-read config after update", exc_info=True)
 
     result = {
         "success": True,
@@ -1400,10 +1502,11 @@ def tool_memories_filed_away():
 
 
 def tool_reconnect():
-    """Force the MCP server to drop the cached ChromaDB collection and reconnect.
+    """Force the MCP server to drop cached ChromaDB + KnowledgeGraph state.
 
     Use after external scripts or CLI commands modify the palace database
-    directly, which can leave the in-memory HNSW index stale.
+    or replace ``knowledge_graph.sqlite3`` directly, which can leave the
+    in-memory HNSW index stale or pin a closed-on-disk SQLite connection.
     """
     global \
         _client_cache, \
@@ -1412,6 +1515,30 @@ def tool_reconnect():
         _palace_db_mtime, \
         _vector_disabled, \
         _vector_disabled_reason
+    from . import palace as palace_module
+
+    close_errors = []
+    try:
+        palace_module._DEFAULT_BACKEND.close_palace(_config.palace_path)
+    except Exception as exc:
+        logger.debug("Failed to close shared palace backend during reconnect", exc_info=True)
+        close_errors.append(f"backend close_palace failed: {exc}")
+    try:
+        from chromadb.api.client import SharedSystemClient
+
+        clear_system_cache = getattr(SharedSystemClient, "clear_system_cache", None)
+        if callable(clear_system_cache):
+            clear_system_cache()
+        else:
+            logger.debug(
+                "SharedSystemClient.clear_system_cache is unavailable; skipping shared Chroma cache clear during reconnect"
+            )
+    except Exception as exc:
+        logger.debug(
+            "Failed to clear Chroma shared system cache during reconnect",
+            exc_info=True,
+        )
+        close_errors.append(f"shared Chroma cache clear failed: {exc}")
     _client_cache = None
     _collection_cache = None
     _palace_db_inode = 0
@@ -1421,15 +1548,36 @@ def tool_reconnect():
     # still applies after the reconnect.
     _vector_disabled = False
     _vector_disabled_reason = ""
+    # Drain the per-path KnowledgeGraph cache so a replaced sqlite file is
+    # reopened on the next tool call rather than served from a stale handle.
+    with _kg_cache_lock:
+        for kg in _kg_by_path.values():
+            try:
+                kg.close()
+            except Exception:
+                pass
+        _kg_by_path.clear()
     try:
         col = _get_collection()
         if col is None:
-            return {
+            result = {
                 "success": False,
                 "message": "No palace found after reconnect",
                 "drawers": 0,
                 "vector_disabled": _vector_disabled,
             }
+            if close_errors:
+                result["error"] = "; ".join(close_errors)
+            return result
+        if close_errors:
+            return {
+                "success": False,
+                "message": "Reconnect reopened the palace but failed to fully reset cached handles",
+                "drawers": col.count(),
+                "vector_disabled": _vector_disabled,
+                "vector_disabled_reason": _vector_disabled_reason,
+                "error": "; ".join(close_errors),
+            }
         return {
             "success": True,
             "message": "Reconnected to palace",
@@ -1750,7 +1898,7 @@ TOOLS = {
         "handler": tool_get_drawer,
     },
     "mempalace_list_drawers": {
-        "description": "List drawers with pagination. Optional wing/room filter. Returns IDs, wings, rooms, and content previews.",
+        "description": "List drawers with pagination. Optional wing/room filter. Returns IDs, wings, rooms, content previews, and total matching count for pagination.",
         "input_schema": {
             "type": "object",
             "properties": {
@@ -1891,6 +2039,12 @@ SUPPORTED_PROTOCOL_VERSIONS = [
 
 
 def handle_request(request):
+    if not isinstance(request, dict):
+        return {
+            "jsonrpc": "2.0",
+            "id": None,
+            "error": {"code": -32600, "message": "Invalid Request"},
+        }
     method = request.get("method") or ""
     params = request.get("params") or {}
     req_id = request.get("id")
@@ -1928,6 +2082,15 @@ def handle_request(request):
             },
         }
     elif method == "tools/call":
+        if not isinstance(params, dict) or "name" not in params:
+            return {
+                "jsonrpc": "2.0",
+                "id": req_id,
+                "error": {
+                    "code": -32602,
+                    "message": "Invalid params: 'name' is required for tools/call",
+                },
+            }
         tool_name = params.get("name")
         tool_args = params.get("arguments") or {}
         if tool_name not in TOOLS:
@@ -1976,7 +2139,11 @@ def handle_request(request):
             return {
                 "jsonrpc": "2.0",
                 "id": req_id,
-                "result": {"content": [{"type": "text", "text": json.dumps(result, indent=2)}]},
+                "result": {
+                    "content": [
+                        {"type": "text", "text": json.dumps(result, indent=2, ensure_ascii=False)}
+                    ]
+                },
             }
         except Exception:
             logger.exception(f"Tool error in {tool_name}")
@@ -2011,6 +2178,16 @@ def _restore_stdout():
 
 def main():
     _restore_stdout()
+    # Force UTF-8 on stdio. MCP JSON-RPC is UTF-8, but Python on Windows
+    # defaults stdin/stdout to the system codepage (e.g. cp1251), which
+    # corrupts non-ASCII payloads and surfaces as generic -32000 errors on
+    # Cyrillic/CJK content. See PEP 540.
+    for stream in (sys.stdin, sys.stdout):
+        if hasattr(stream, "reconfigure"):
+            try:
+                stream.reconfigure(encoding="utf-8", errors="replace")
+            except (AttributeError, OSError):
+                pass
     logger.info("MemPalace MCP Server starting...")
     # Pre-flight: probe HNSW capacity before any tool call so the warning
     # is visible at startup rather than on first use (#1222). Pure
@@ -2027,7 +2204,7 @@ def main():
             request = json.loads(line)
             response = handle_request(request)
             if response is not None:
-                sys.stdout.write(json.dumps(response) + "\n")
+                sys.stdout.write(json.dumps(response, ensure_ascii=False) + "\n")
                 sys.stdout.flush()
         except KeyboardInterrupt:
             break

mempalace/migrate.py

@@ -22,6 +22,7 @@ import errno
 import os
 import shutil
 import sqlite3
+import uuid
 from collections import defaultdict
 from datetime import datetime
 
@@ -155,6 +156,55 @@ def confirm_destructive_action(
     return True
 
 
+def _result_ids(result) -> list:
+    """Return ids from either the backend typed result or raw Chroma dict."""
+
+    if isinstance(result, dict):
+        return list(result.get("ids") or [])
+
+    return list(getattr(result, "ids", []) or [])
+
+
+def collection_write_roundtrip_works(col) -> bool:
+    """Return True only if the collection can upsert, read, and delete.
+
+    Some ChromaDB 0.6.x -> 1.5.x migrated collections remain readable while
+    writes and deletes silently no-op. A plain ``count()`` probe misses that
+    failure mode, so migrate must verify an actual write round-trip before
+    deciding that no rebuild is needed.
+    """
+
+    probe_id = f"_mempalace_migrate_probe_{uuid.uuid4().hex}"
+    probe_doc = "mempalace migrate write round-trip probe"
+    probe_meta = {
+        "wing": "_mempalace_probe",
+        "room": "_mempalace_probe",
+        "source_file": "mempalace_migrate_probe",
+        "chunk_index": 0,
+    }
+
+    try:
+        col.upsert(
+            ids=[probe_id],
+            documents=[probe_doc],
+            metadatas=[probe_meta],
+        )
+
+        after_upsert = col.get(ids=[probe_id], include=[])
+        if probe_id not in _result_ids(after_upsert):
+            return False
+
+        col.delete(ids=[probe_id])
+
+        after_delete = col.get(ids=[probe_id], include=[])
+        if probe_id in _result_ids(after_delete):
+            return False
+
+        return True
+    except Exception:
+        return False
+
+
 def migrate(palace_path: str, dry_run: bool = False, confirm: bool = False):
     """Migrate a palace to the currently installed ChromaDB version."""
     from .backends.chroma import ChromaBackend
@@ -179,13 +229,24 @@ def migrate(palace_path: str, dry_run: bool = False, confirm: bool = False):
     print(f"  Source:    ChromaDB {source_version}")
     print(f"  Target:    ChromaDB {target_version}")
 
-    # Try reading with current chromadb first
+    # Try reading and writing with current chromadb first.
+    #
+    # A plain count() is not enough: some 0.6.x -> 1.5.x migrated collections
+    # are readable but silently drop upsert/delete operations. In that state,
+    # migrate must rebuild from SQLite instead of returning "No migration needed."
     try:
         col = ChromaBackend().get_collection(palace_path, "mempalace_drawers")
         count = col.count()
-        print(f"\n  Palace is already readable by chromadb {target_version}.")
+
+        if collection_write_roundtrip_works(col):
+            print(f"\n Palace is already readable and writable by chromadb {target_version}.")
             print(f" {count} drawers found. No migration needed.")
             return True
+
+        print(
+            f"\n Palace is readable by chromadb {target_version}, but write/delete verification failed."
+        )
+        print(" Rebuilding from SQLite to restore native write/delete behavior...")
     except Exception:
         print(f"\n Palace is NOT readable by chromadb {target_version}.")
         print(" Extracting from SQLite directly...")

mempalace/miner.py

@@ -12,6 +12,7 @@ import sys
 import shlex
 import hashlib
 import fnmatch
+import logging
 from pathlib import Path
 from datetime import datetime
 from collections import defaultdict
@@ -31,6 +32,8 @@ from .palace import (
     upsert_closet_lines,
 )
 
+logger = logging.getLogger("mempalace_mcp")
+
 READABLE_EXTENSIONS = {
     ".txt",
     ".md",
@@ -63,6 +66,8 @@ SKIP_FILENAMES = {
     "mempal.yml",
     ".gitignore",
     "package-lock.json",
+    "pnpm-lock.yaml",
+    "yarn.lock",
 }
 
 CHUNK_SIZE = 800  # chars per drawer
@@ -70,6 +75,13 @@ CHUNK_OVERLAP = 100  # overlap between chunks
 MIN_CHUNK_SIZE = 50  # skip tiny chunks
 DRAWER_UPSERT_BATCH_SIZE = 1000
 MAX_FILE_SIZE = 500 * 1024 * 1024  # 500 MB — skip files larger than this.
+# A single file producing more chunks than this is almost always a generated
+# artifact (CSV/JSON dump, lockfile not in SKIP_FILENAMES, etc.). Embedding
+# thousands of chunks from one file in one batch has triggered ONNX runtime
+# `bad allocation` errors on Windows (#1296). The cap is conservative: a
+# 500-chunk file at CHUNK_SIZE=800 is ~400 KB of source, which covers most
+# legitimate hand-written content while bounding the worst-case batch.
+MAX_CHUNKS_PER_FILE = 500
 # Long Claude Code sessions and large transcript exports routinely exceed
 # 10 MB. The cap exists as a defensive rail against pathological binary
 # files, not as a limit on legitimate text. Per-drawer size is bounded
@@ -822,6 +834,13 @@ def process_file(
     room = detect_room(filepath, content, rooms, project_path)
     chunks = chunk_text(content, source_file)
 
+    if len(chunks) > MAX_CHUNKS_PER_FILE:
+        print(
+            f"  ! [skip] {filepath.name[:50]:50} produced {len(chunks)} chunks "
+            f"(> {MAX_CHUNKS_PER_FILE}); add to SKIP_FILENAMES or .gitignore"
+        )
+        return 0, room
+
     if dry_run:
         print(f"    [DRY RUN] {filepath.name} -> room:{room} ({len(chunks)} drawers)")
         return len(chunks), room
@@ -842,7 +861,7 @@ def process_file(
         try:
             collection.delete(where={"source_file": source_file})
         except Exception:
-            pass
+            logger.debug("Stale-drawer purge failed for %s", source_file, exc_info=True)
 
         # Batch chunks into bounded upserts so the embedding model sees many
         # chunks per forward pass without building one huge Chroma/SQLite
@@ -1164,6 +1183,24 @@ def _mine_impl(
             "already-filed drawers are\n  upserted idempotently and will not duplicate.\n"
         )
         sys.exit(130)
+    except Exception as exc:
+        # Without this, an arbitrary exception (ONNX bad_alloc, chromadb HNSW
+        # error, OS fault) propagates and the process exits with no completion
+        # banner — the operator sees only the final progress line and assumes
+        # the mine succeeded (#1296). Print the partial-progress summary the
+        # way we do for KeyboardInterrupt, then re-raise so the original
+        # traceback still surfaces and the exit code is non-zero.
+        print("\n\n  Mine aborted by exception.")
+        print(f"    files_processed: {files_processed}/{len(files)}")
+        print(f"    drawers_filed:   {total_drawers}")
+        print(f"    last_file:       {last_file or '<none>'}")
+        print(f"    error:           {type(exc).__name__}: {exc}")
+        print(
+            f"\n  Re-run `mempalace mine {shlex.quote(project_dir)}` after addressing "
+            "the cause — already-filed\n  drawers are upserted idempotently and will "
+            "not duplicate.\n"
+        )
+        raise
     finally:
         # Clean up the hooks-side PID lock if it points at us. Stale
         # entries already pass _pid_alive() == False on POSIX, but

mempalace/normalize.py

@@ -118,14 +118,14 @@ def normalize(filepath: str) -> str:
     try:
         file_size = os.path.getsize(filepath)
     except OSError as e:
-        raise IOError(f"Could not read {filepath}: {e}")
+        raise IOError(f"Could not read {filepath}: {e}") from e
     if file_size > 500 * 1024 * 1024:  # 500 MB safety limit
         raise IOError(f"File too large ({file_size // (1024 * 1024)} MB): {filepath}")
     try:
         with open(filepath, "r", encoding="utf-8", errors="replace") as f:
             content = f.read()
     except OSError as e:
-        raise IOError(f"Could not read {filepath}: {e}")
+        raise IOError(f"Could not read {filepath}: {e}") from e
 
     if not content.strip():
         return content

mempalace/palace.py

@@ -6,11 +6,16 @@ Consolidates collection access patterns used by both miners and the MCP server.
 
 import contextlib
 import hashlib
+import logging
 import os
 import re
+import threading
+from typing import Optional
 
 from .backends.chroma import ChromaBackend
 
+logger = logging.getLogger("mempalace_mcp")
+
 SKIP_DIRS = {
     ".git",
     "node_modules",
@@ -52,10 +57,14 @@ NORMALIZE_VERSION = 2
 
 def get_collection(
     palace_path: str,
-    collection_name: str = "mempalace_drawers",
+    collection_name: Optional[str] = None,
     create: bool = True,
 ):
     """Get the palace collection through the backend layer."""
+    if collection_name is None:
+        from .config import get_configured_collection_name
+
+        collection_name = get_configured_collection_name()
     return _DEFAULT_BACKEND.get_collection(
         palace_path,
         collection_name=collection_name,
@@ -228,7 +237,7 @@ def purge_file_closets(closets_col, source_file: str) -> None:
     try:
         closets_col.delete(where={"source_file": source_file})
     except Exception:
-        pass
+        logger.debug("Closet purge failed for %s", source_file, exc_info=True)
 
 
 def upsert_closet_lines(closets_col, closet_id_base, lines, metadata):
@@ -306,7 +315,7 @@ def mine_lock(source_file: str):
 
                 fcntl.flock(lf, fcntl.LOCK_UN)
         except Exception:
-            pass
+            logger.debug("Mine-lock release failed", exc_info=True)
         lf.close()
 
 
@@ -314,6 +323,47 @@ class MineAlreadyRunning(RuntimeError):
     """Raised when another `mempalace mine` already holds the per-palace lock."""
 
 
+# Per-thread record of palaces this thread already holds the lock for. Used by
+# `mine_palace_lock` to short-circuit re-entrant acquisition from the same
+# thread (e.g. miner.mine() acquires the outer lock then calls
+# ChromaCollection.upsert which now also tries to acquire). Without this guard
+# the inner call would block on its own outer flock (Linux fcntl locks are per
+# open file description, so a same-thread second open of the lock file is a
+# distinct lock and self-deadlocks).
+#
+# The holder set is tagged with ``pid`` so that a forked child does NOT
+# inherit re-entrant credit from its parent: the OS-level flock IS NOT
+# inherited as a "we hold it" semantically — the child must reacquire — but
+# Python's ``threading.local`` IS inherited across fork. The pid check
+# clears stale state so a forked child correctly hits the fcntl path.
+_palace_lock_holders = threading.local()
+
+
+def _holder_state():
+    """Return the per-thread (pid, keys) record, refreshing after fork."""
+    keys = getattr(_palace_lock_holders, "keys", None)
+    pid = getattr(_palace_lock_holders, "pid", None)
+    current_pid = os.getpid()
+    if keys is None or pid != current_pid:
+        keys = set()
+        _palace_lock_holders.keys = keys
+        _palace_lock_holders.pid = current_pid
+    return keys
+
+
+def _held_by_this_thread(lock_key: str) -> bool:
+    """Return True if this thread already holds ``mine_palace_lock`` for ``lock_key``."""
+    return lock_key in _holder_state()
+
+
+def _mark_held(lock_key: str) -> None:
+    _holder_state().add(lock_key)
+
+
+def _mark_released(lock_key: str) -> None:
+    _holder_state().discard(lock_key)
+
+
 @contextlib.contextmanager
 def mine_palace_lock(palace_path: str):
     """Per-palace non-blocking lock around the full `mine` pipeline.
@@ -338,6 +388,12 @@ def mine_palace_lock(palace_path: str):
     Non-blocking: if another `mine` is already writing to this palace,
     raise MineAlreadyRunning so the caller can exit cleanly instead of
     piling up as a waiting worker.
+
+    Re-entrant: if the current thread already holds the lock for the same
+    palace, the context manager passes through without re-acquiring. This
+    lets ChromaCollection write methods (which acquire the lock themselves
+    to protect MCP/direct callers) compose with miner.mine() (which holds
+    the outer lock for the entire mine pipeline) without self-deadlock.
     """
     lock_dir = os.path.join(os.path.expanduser("~"), ".mempalace", "locks")
     os.makedirs(lock_dir, exist_ok=True)
@@ -346,6 +402,11 @@ def mine_palace_lock(palace_path: str):
     palace_key = hashlib.sha256(lock_key_source.encode()).hexdigest()[:16]
     lock_path = os.path.join(lock_dir, f"mine_palace_{palace_key}.lock")
 
+    if _held_by_this_thread(palace_key):
+        # Same thread already holds the lock for this palace — pass through.
+        yield
+        return
+
     lf = open(lock_path, "w")
     acquired = False
     try:
@@ -369,7 +430,11 @@ def mine_palace_lock(palace_path: str):
                 raise MineAlreadyRunning(
                     f"another `mempalace mine` is already running against {resolved}"
                 ) from exc
+        _mark_held(palace_key)
+        try:
             yield
+        finally:
+            _mark_released(palace_key)
     finally:
         if acquired:
             try:

mempalace/palace_graph.py

@@ -575,7 +575,7 @@ def follow_tunnels(wing: str, room: str, col=None, config=None):
                     if did and did in drawer_map:
                         c["drawer_preview"] = drawer_map[did][:300]
             except Exception:
-                pass
+                logger.debug("Drawer preview hydration failed", exc_info=True)
 
     return connections
 

mempalace/repair.py

@@ -34,13 +34,58 @@ import os
 import shutil
 import sqlite3
 import time
+from collections import defaultdict
 from datetime import datetime
-from typing import Optional
+from typing import Iterator, Optional
+
+from chromadb.errors import NotFoundError as ChromaNotFoundError
 
 from .backends.chroma import ChromaBackend, hnsw_capacity_status
 
 
 COLLECTION_NAME = "mempalace_drawers"
+REPAIR_TEMP_COLLECTION = f"{COLLECTION_NAME}__repair_tmp"
+
+# The closets collection (AAAK index layer) is intentionally fixed —
+# closets reference drawer IDs by string and live alongside drawers in the
+# same palace; renaming the closets collection per-deployment would break
+# cross-palace AAAK lookups. Drawer collection name comes from config
+# (see ``_recoverable_collections``).
+CLOSETS_COLLECTION_NAME = "mempalace_closets"
+
+
+def _drawers_collection_name() -> str:
+    """Resolve the drawers collection name from user config, falling back
+    to the module default ``COLLECTION_NAME`` if config is unreadable.
+
+    Recovery flows must honor ``MempalaceConfig().collection_name`` so a
+    user with a non-default drawer collection (e.g. multi-palace setups)
+    rebuilds the right rows. Closets remain fixed — see
+    ``CLOSETS_COLLECTION_NAME``.
+    """
+    try:
+        from .config import MempalaceConfig
+
+        return MempalaceConfig().collection_name or COLLECTION_NAME
+    except Exception:
+        return COLLECTION_NAME
+
+
+def _recoverable_collections() -> tuple[str, ...]:
+    """Collections rebuilt by ``rebuild_from_sqlite``, in upsert order.
+
+    Drawers first (bulk data), then closets (AAAK index layer that
+    references drawer IDs by string in their documents — no
+    foreign-key validation, so ordering is informational, not
+    load-bearing).
+    """
+    return (_drawers_collection_name(), CLOSETS_COLLECTION_NAME)
+
+
+# Back-compat alias for callers that imported the constant. New code
+# should call ``_recoverable_collections()`` so config changes are picked
+# up at call time.
+RECOVERABLE_COLLECTIONS = (COLLECTION_NAME, CLOSETS_COLLECTION_NAME)
 
 
 def _get_palace_path():
@@ -83,7 +128,111 @@ def _paginate_ids(col, where=None):
     return ids
 
 
-def scan_palace(palace_path=None, only_wing=None):
+def _extract_drawers(col, total: int, batch_size: int):
+    all_ids = []
+    all_docs = []
+    all_metas = []
+    offset = 0
+    while offset < total:
+        batch = col.get(limit=batch_size, offset=offset, include=["documents", "metadatas"])
+        if not batch["ids"]:
+            break
+        all_ids.extend(batch["ids"])
+        all_docs.extend(batch["documents"])
+        all_metas.extend(batch["metadatas"])
+        offset += len(batch["ids"])
+    return all_ids, all_docs, all_metas
+
+
+def _verify_collection_count(col, expected: int, label: str) -> None:
+    actual = col.count()
+    if actual != expected:
+        raise RuntimeError(f"{label} count mismatch: expected {expected}, got {actual}")
+
+
+def _is_missing_collection_value_error(exc: ValueError) -> bool:
+    message = str(exc).lower()
+    return "does not exist" in message or "not found" in message
+
+
+def _delete_collection_if_exists(backend, palace_path: str, collection_name: str) -> None:
+    try:
+        backend.delete_collection(palace_path, collection_name)
+    except ValueError as exc:
+        if _is_missing_collection_value_error(exc):
+            return
+        raise
+    except (FileNotFoundError, ChromaNotFoundError):
+        return
+
+
+class RebuildCollectionError(RuntimeError):
+    """Raised when temp rebuild fails, carrying whether the live swap happened."""
+
+    def __init__(self, message: str, *, live_replaced: bool):
+        super().__init__(message)
+        self.live_replaced = live_replaced
+
+
+def _rebuild_collection_via_temp(
+    backend,
+    palace_path: str,
+    all_ids,
+    all_docs,
+    all_metas,
+    batch_size: int,
+    collection_name: Optional[str] = None,
+    progress=print,
+) -> int:
+    expected = len(all_ids)
+    collection_name = collection_name or _drawers_collection_name()
+    temp_name = f"{collection_name}__repair_tmp"
+    live_replaced = False
+
+    try:
+        _delete_collection_if_exists(backend, palace_path, temp_name)
+
+        progress(f"  Building temporary collection: {temp_name}")
+        temp_col = backend.create_collection(palace_path, temp_name)
+        staged = 0
+        for i in range(0, expected, batch_size):
+            batch_ids = all_ids[i : i + batch_size]
+            batch_docs = all_docs[i : i + batch_size]
+            batch_metas = all_metas[i : i + batch_size]
+            temp_col.upsert(documents=batch_docs, ids=batch_ids, metadatas=batch_metas)
+            staged += len(batch_ids)
+            progress(f"  Staged {staged}/{expected} drawers...")
+        _verify_collection_count(temp_col, expected, "temporary rebuild")
+
+        progress("  Rebuilding live collection...")
+        backend.delete_collection(palace_path, collection_name)
+        live_replaced = True
+        new_col = backend.create_collection(palace_path, collection_name)
+
+        rebuilt = 0
+        for i in range(0, expected, batch_size):
+            batch_ids = all_ids[i : i + batch_size]
+            batch_docs = all_docs[i : i + batch_size]
+            batch_metas = all_metas[i : i + batch_size]
+            new_col.upsert(documents=batch_docs, ids=batch_ids, metadatas=batch_metas)
+            rebuilt += len(batch_ids)
+            progress(f"  Re-filed {rebuilt}/{expected} drawers...")
+        _verify_collection_count(new_col, expected, "rebuilt live collection")
+
+        try:
+            _delete_collection_if_exists(backend, palace_path, temp_name)
+        except Exception:
+            pass
+        return rebuilt
+    except Exception as exc:
+        try:
+            _delete_collection_if_exists(backend, palace_path, temp_name)
+        except Exception:
+            pass
+        raise RebuildCollectionError(str(exc), live_replaced=live_replaced) from exc
+
+
+def scan_palace(palace_path=None, only_wing=None, collection_name: Optional[str] = None):
     """Scan the palace for corrupt/unfetchable IDs.
 
     Probes in batches of 100, falls back to per-ID on failure.
@@ -92,14 +241,15 @@ def scan_palace(palace_path=None, only_wing=None):
     Returns (good_set, bad_set).
     """
     palace_path = palace_path or _get_palace_path()
+    collection_name = collection_name or _drawers_collection_name()
     print(f"\n  Palace: {palace_path}")
     print("  Loading...")
 
-    col = ChromaBackend().get_collection(palace_path, COLLECTION_NAME)
+    col = ChromaBackend().get_collection(palace_path, collection_name)
 
     where = {"wing": only_wing} if only_wing else None
     total = col.count()
-    print(f"  Collection: {COLLECTION_NAME}, total: {total:,}")
+    print(f"  Collection: {collection_name}, total: {total:,}")
     if only_wing:
         print(f"  Scanning wing: {only_wing}")
 
@@ -160,9 +310,10 @@ def scan_palace(palace_path=None, only_wing=None):
     return good_set, bad_set
 
 
-def prune_corrupt(palace_path=None, confirm=False):
+def prune_corrupt(palace_path=None, confirm=False, collection_name: Optional[str] = None):
     """Delete corrupt IDs listed in corrupt_ids.txt."""
     palace_path = palace_path or _get_palace_path()
+    collection_name = collection_name or _drawers_collection_name()
     bad_file = os.path.join(palace_path, "corrupt_ids.txt")
 
     if not os.path.exists(bad_file):
@@ -178,7 +329,7 @@ def prune_corrupt(palace_path=None, confirm=False):
         print("  Re-run with --confirm to actually delete.")
         return
 
-    col = ChromaBackend().get_collection(palace_path, COLLECTION_NAME)
+    col = ChromaBackend().get_collection(palace_path, collection_name)
     before = col.count()
     print(f"  Collection size before: {before:,}")
 
@@ -232,7 +383,10 @@ class TruncationDetected(Exception):
 
 
 def check_extraction_safety(
-    palace_path: str, extracted: int, confirm_truncation_ok: bool = False
+    palace_path: str,
+    extracted: int,
+    confirm_truncation_ok: bool = False,
+    collection_name: Optional[str] = None,
 ) -> None:
     """Cross-check that ``extracted`` matches the SQLite ground truth.
 
@@ -254,7 +408,8 @@ def check_extraction_safety(
     if confirm_truncation_ok:
         return
 
-    sqlite_count = sqlite_drawer_count(palace_path)
+    collection_name = collection_name or _drawers_collection_name()
+    sqlite_count = sqlite_drawer_count(palace_path, collection_name)
     cap_signal = extracted == CHROMADB_DEFAULT_GET_LIMIT
 
     if sqlite_count is not None and sqlite_count > extracted:
@@ -290,7 +445,7 @@ def check_extraction_safety(
         raise TruncationDetected(message, sqlite_count, extracted)
 
 
-def sqlite_drawer_count(palace_path: str) -> "int | None":
+def sqlite_drawer_count(palace_path: str, collection_name: Optional[str] = None) -> "int | None":
     """Count rows in ``chroma.sqlite3.embeddings`` for the drawers collection.
 
     Used as an independent ground-truth check against the chromadb
@@ -302,6 +457,7 @@ def sqlite_drawer_count(palace_path: str) -> "int | None":
     drift, missing tables, locked file). Callers treat ``None`` as
     "unknown" and fall back to the cap-detection check.
     """
+    collection_name = collection_name or _drawers_collection_name()
     sqlite_path = os.path.join(palace_path, "chroma.sqlite3")
     if not os.path.exists(sqlite_path):
         return None
@@ -318,7 +474,7 @@ def sqlite_drawer_count(palace_path: str) -> "int | None":
                 JOIN collections c ON s.collection = c.id
                 WHERE c.name = ?
                 """,
-                (COLLECTION_NAME,),
+                (collection_name,),
             ).fetchone()
             return int(row[0]) if row and row[0] is not None else None
         finally:
@@ -395,7 +551,11 @@ def print_sqlite_integrity_abort(palace_path: str, errors: list[str]) -> None:
     print("    6. Re-run `mempalace repair --yes`.")
 
 
-def rebuild_index(palace_path=None, confirm_truncation_ok: bool = False):
+def rebuild_index(
+    palace_path=None,
+    confirm_truncation_ok: bool = False,
+    collection_name: Optional[str] = None,
+):
     """Rebuild the HNSW index from scratch.
 
     1. Extract all drawers via ChromaDB get()
@@ -410,6 +570,7 @@ def rebuild_index(palace_path=None, confirm_truncation_ok: bool = False):
     (typically only a concern for palaces sized at exactly 10 000 rows).
     """
     palace_path = palace_path or _get_palace_path()
+    collection_name = collection_name or _drawers_collection_name()
 
     if not os.path.isdir(palace_path):
         print(f"\n  No palace found at {palace_path}")
@@ -422,7 +583,7 @@ def rebuild_index(palace_path=None, confirm_truncation_ok: bool = False):
 
     backend = ChromaBackend()
     try:
-        col = backend.get_collection(palace_path, COLLECTION_NAME)
+        col = backend.get_collection(palace_path, collection_name)
         total = col.count()
     except Exception as e:
         print(f"  Error reading palace: {e}")
@@ -438,18 +599,7 @@ def rebuild_index(palace_path=None, confirm_truncation_ok: bool = False):
     # Extract all drawers in batches
     print("\n  Extracting drawers...")
     batch_size = 5000
-    all_ids = []
-    all_docs = []
-    all_metas = []
-    offset = 0
-    while offset < total:
-        batch = col.get(limit=batch_size, offset=offset, include=["documents", "metadatas"])
-        if not batch["ids"]:
-            break
-        all_ids.extend(batch["ids"])
-        all_docs.extend(batch["documents"])
-        all_metas.extend(batch["metadatas"])
-        offset += len(batch["ids"])
+    all_ids, all_docs, all_metas = _extract_drawers(col, total, batch_size)
     print(f"  Extracted {len(all_ids)} drawers")
 
     # ── #1208 guard ──────────────────────────────────────────────────
@@ -457,7 +607,12 @@ def rebuild_index(palace_path=None, confirm_truncation_ok: bool = False):
     # short of the SQLite ground truth (or when extraction == chromadb
     # default get() cap and the SQLite check couldn't run).
     try:
-        check_extraction_safety(palace_path, len(all_ids), confirm_truncation_ok)
+        check_extraction_safety(
+            palace_path,
+            len(all_ids),
+            confirm_truncation_ok,
+            collection_name=collection_name,
+        )
     except TruncationDetected as e:
         print(e.message)
         return
@@ -477,28 +632,34 @@ def rebuild_index(palace_path=None, confirm_truncation_ok: bool = False):
 
     # Rebuild with correct HNSW settings
     print("  Rebuilding collection with hnsw:space=cosine...")
-    backend.delete_collection(palace_path, COLLECTION_NAME)
-    new_col = backend.create_collection(palace_path, COLLECTION_NAME)
-
-    filed = 0
     try:
-        for i in range(0, len(all_ids), batch_size):
-            batch_ids = all_ids[i : i + batch_size]
-            batch_docs = all_docs[i : i + batch_size]
-            batch_metas = all_metas[i : i + batch_size]
-            new_col.upsert(documents=batch_docs, ids=batch_ids, metadatas=batch_metas)
-            filed += len(batch_ids)
-            print(f"  Re-filed {filed}/{len(all_ids)} drawers...")
-    except Exception as e:
+        filed = _rebuild_collection_via_temp(
+            backend,
+            palace_path,
+            all_ids,
+            all_docs,
+            all_metas,
+            batch_size,
+            collection_name=collection_name,
+            progress=print,
+        )
+    except RebuildCollectionError as e:
         print(f"\n  ERROR during rebuild: {e}")
-        print(f"  Only {filed}/{len(all_ids)} drawers were re-filed.")
-        if os.path.exists(backup_path):
+        print("  Rebuild aborted before completion.")
+        if e.live_replaced and os.path.exists(backup_path):
             print(f"  Restoring from backup: {backup_path}")
-            backend.delete_collection(palace_path, COLLECTION_NAME)
+            try:
+                _close_chroma_handles(palace_path, backend=backend)
+                _delete_collection_if_exists(backend, palace_path, collection_name)
                 shutil.copy2(backup_path, sqlite_path)
                 print("  Backup restored. Palace is back to pre-repair state.")
-        else:
+            except Exception as restore_error:
+                print(f"  Backup restore failed: {restore_error}")
+                print(f"  Manual restore required from: {backup_path}")
+        elif e.live_replaced:
             print("  No backup available. Re-mine from source files to recover.")
+        else:
+            print("  Live collection was not replaced; leaving the original palace untouched.")
         raise
 
     print(f"\n  Repair complete. {filed} drawers rebuilt.")
@@ -506,7 +667,380 @@ def rebuild_index(palace_path=None, confirm_truncation_ok: bool = False):
     print(f"\n{'=' * 55}\n")
 
 
-def status(palace_path=None) -> dict:
+class RebuildPartialError(Exception):
+    """Raised when ``rebuild_from_sqlite`` fails partway through upserts.
+
+    Carries enough state for the user (or CLI) to recover: the
+    per-collection counts that succeeded, the collection that failed,
+    the dest path holding the partial palace, and the archive path
+    (when an in-place rebuild had moved the original aside). Re-raises
+    the underlying chromadb error as ``__cause__``.
+    """
+
+    def __init__(
+        self,
+        message: str,
+        *,
+        partial_counts: dict[str, int],
+        failed_collection: str,
+        dest_palace: str,
+        archive_path: Optional[str],
+    ):
+        super().__init__(message)
+        self.message = message
+        self.partial_counts = partial_counts
+        self.failed_collection = failed_collection
+        self.dest_palace = dest_palace
+        self.archive_path = archive_path
+
+
+def _rebuild_one_collection(
+    *,
+    backend: ChromaBackend,
+    source_palace: str,
+    dest_palace: str,
+    collection_name: str,
+    batch_size: int,
+    archive_path: Optional[str],
+    counts_so_far: dict[str, int],
+) -> int:
+    """Stream rows for one collection from SQLite and upsert into a
+    freshly-created collection at ``dest_palace``. Returns rows
+    upserted. Raises :class:`RebuildPartialError` (with the underlying
+    chromadb exception as ``__cause__``) on any upsert failure so the
+    caller can stop the loop and print recovery instructions instead of
+    silently shipping a partial palace.
+    """
+    ids: list[str] = []
+    docs: list[str] = []
+    metas: list[dict] = []
+    upserted = 0
+    col = None
+
+    def _flush() -> int:
+        nonlocal upserted
+        if not ids:
+            return upserted
+        col.upsert(ids=list(ids), documents=list(docs), metadatas=list(metas))
+        upserted += len(ids)
+        print(f"    upserted {upserted}")
+        ids.clear()
+        docs.clear()
+        metas.clear()
+        return upserted
+
+    try:
+        # ``create_collection`` lives inside the try so a Chroma-side
+        # "Collection already exists" failure (which can happen when the
+        # process-wide System cache still holds a pre-archive schema) is
+        # reported as a structured ``RebuildPartialError`` carrying
+        # ``archive_path`` — instead of an unstructured exception that
+        # strands the user without recovery instructions.
+        col = backend.create_collection(dest_palace, collection_name)
+
+        for emb_id, doc, meta in extract_via_sqlite(source_palace, collection_name):
+            ids.append(emb_id)
+            docs.append(doc or "")
+            # chromadb 1.5.x rejects None entries in the metadatas list
+            # but accepts empty dicts. Mempalace drawers always carry at
+            # least wing/room, so this branch is defensive — corruption
+            # in embedding_metadata could yield an emb_id with no rows.
+            metas.append(meta if meta else {})
+            if len(ids) >= batch_size:
+                _flush()
+        _flush()
+    except Exception as exc:  # noqa: BLE001 — chromadb raises many shapes
+        partial = dict(counts_so_far)
+        partial[collection_name] = upserted
+        msg_parts = [
+            f"Upsert failed in collection {collection_name!r} after {upserted} rows: {exc!r}",
+            f"Partial palace left at: {dest_palace}",
+        ]
+        if archive_path is not None:
+            msg_parts.append(f"Original palace archived at: {archive_path}")
+            msg_parts.append(
+                "  Recover by removing the partial dest and re-running with "
+                f"--source {archive_path}"
+            )
+        else:
+            msg_parts.append("  Source palace is unchanged. Remove the partial dest and re-run.")
+        message = "\n  ".join(msg_parts)
+        print(f"\n  ERROR: {message}")
+        raise RebuildPartialError(
+            message,
+            partial_counts=partial,
+            failed_collection=collection_name,
+            dest_palace=dest_palace,
+            archive_path=archive_path,
+        ) from exc
+
+    return upserted
+
+
+def extract_via_sqlite(palace_path: str, collection_name: str) -> Iterator[tuple[str, str, dict]]:
+    """Yield ``(embedding_id, document, metadata)`` for every row in
+    ``collection_name``'s metadata segment by reading ``chroma.sqlite3``
+    directly.
+
+    Bypasses the chromadb client entirely — never opens a
+    ``PersistentClient``, never imports hnswlib, never invokes the
+    HNSW segment writer. This is the recovery path for palaces where
+    ``Collection.count()`` / ``Collection.get()`` raise ``InternalError``
+    because the compactor cannot apply WAL logs to the HNSW segment
+    (#1308). The drawer rows are still on disk in
+    ``embeddings`` + ``embedding_metadata``; the corruption lives in the
+    on-disk index files, not the SQLite tables.
+
+    Resolution rule for chromadb's typed metadata columns: each
+    ``embedding_metadata`` row stores its value in exactly one of
+    ``string_value`` / ``int_value`` / ``float_value`` / ``bool_value``;
+    we pick the first non-NULL column in that order. Rows where every
+    typed column is NULL are dropped (chromadb never writes that shape).
+    The ``chroma:document`` key is removed from the metadata dict and
+    returned as the document; this matches how chromadb itself stores
+    ``add(documents=...)``.
+
+    Silent on missing palace, missing ``chroma.sqlite3``, or unknown
+    collection name — yields nothing. Callers that need to distinguish
+    "empty collection" from "collection not present" should query
+    :func:`sqlite_drawer_count` first.
+    """
+    sqlite_path = os.path.join(palace_path, "chroma.sqlite3")
+    if not os.path.isfile(sqlite_path):
+        return
+
+    conn = sqlite3.connect(f"file:{sqlite_path}?mode=ro", uri=True)
+    try:
+        seg_row = conn.execute(
+            """
+            SELECT s.id FROM segments s
+            JOIN collections c ON s.collection = c.id
+            WHERE c.name = ? AND s.scope = 'METADATA'
+            """,
+            (collection_name,),
+        ).fetchone()
+        if not seg_row:
+            return
+        segment_id = seg_row[0]
+
+        per_id: dict[str, dict] = defaultdict(dict)
+        order: list[str] = []
+        for emb_id, key, sv, iv, fv, bv in conn.execute(
+            """
+            SELECT e.embedding_id, em.key, em.string_value, em.int_value,
+                   em.float_value, em.bool_value
+            FROM embedding_metadata em
+            JOIN embeddings e ON em.id = e.id
+            WHERE e.segment_id = ?
+            ORDER BY em.id
+            """,
+            (segment_id,),
+        ):
+            if emb_id not in per_id:
+                order.append(emb_id)
+            if sv is not None:
+                per_id[emb_id][key] = sv
+            elif iv is not None:
+                per_id[emb_id][key] = iv
+            elif fv is not None:
+                per_id[emb_id][key] = fv
+            elif bv is not None:
+                per_id[emb_id][key] = bool(bv)
+
+        for emb_id in order:
+            kv = per_id[emb_id]
+            doc = kv.pop("chroma:document", "")
+            yield emb_id, doc, kv
+    finally:
+        conn.close()
+
+
+def rebuild_from_sqlite(
+    source_palace: str,
+    dest_palace: str,
+    *,
+    archive_existing_dest: bool = False,
+    batch_size: int = 1000,
+) -> dict[str, int]:
+    """Rebuild a palace by reading drawers from ``source_palace``'s
+    ``chroma.sqlite3`` and upserting them into a fresh palace at
+    ``dest_palace``.
+
+    Recovery path for the #1308 failure mode: the chromadb client raises
+    ``InternalError: Failed to apply logs to the hnsw segment writer``
+    on every operation that touches the index (``count``, ``get``,
+    ``query``), but the underlying SQLite tables are intact. Both the
+    legacy ``rebuild_index`` and the inline ``cli.cmd_repair`` path call
+    ``Collection.count()`` as their first read — exactly the call that
+    fails — so neither can recover this class of corruption. This
+    function bypasses the chromadb read path entirely via
+    :func:`extract_via_sqlite`.
+
+    Re-embeds documents at upsert time using the configured embedding
+    function; the original HNSW vectors are not preserved (they live in
+    the corrupt ``data_level0.bin`` / ``link_lists.bin``, not in
+    SQLite). Acceptable for a corruption-recovery flow because the
+    embedding model is deterministic — same model + same document text
+    yields semantically equivalent search results.
+
+    ``archive_existing_dest`` controls behavior when ``dest_palace``
+    already exists:
+
+    * ``False`` (default) — refuse with a clear message. Callers must
+      manually move the existing palace aside first.
+    * ``True`` — rename ``dest_palace`` to
+      ``<dest_palace>.pre-rebuild-<timestamp>`` and read from there
+      instead. Used by the in-place CLI flow where ``--source`` defaults
+      to the same path as ``--palace``.
+
+    Returns a ``{collection_name: row_count}`` dict so callers (CLI,
+    tests) can verify the per-collection rebuild count without parsing
+    stdout. A successful rebuild always returns a dict with one key per
+    recoverable collection (values may be ``0`` when a collection is
+    legitimately empty in the source). The empty dict ``{}`` is reserved
+    for validation refusals (missing source DB, refusing to overwrite an
+    existing dest, in-place mode without ``archive_existing_dest``); CLI
+    callers should treat ``{}`` as an error and exit non-zero so CI and
+    scripts can distinguish "invalid inputs" from "successful recovery
+    that found zero rows." Raises :class:`RebuildPartialError` if a
+    chromadb upsert fails partway through; the dest palace is left in
+    place so the user can inspect what landed, and the in-place archive
+    (when applicable) is reported in the error so the user can re-run
+    against it.
+
+    .. warning::
+
+       In-place mode (``source_palace == dest_palace`` with
+       ``archive_existing_dest=True``) calls
+       ``chromadb.api.client.SharedSystemClient.clear_system_cache()`` to
+       drop chromadb's process-wide System registry — required because
+       an existing cached System built against the original palace will
+       refuse ``create_collection`` after the dir is renamed (chromadb
+       still thinks the collections exist). This invalidates any
+       PersistentClient instances held elsewhere in the same process for
+       *any* palace, not just this one. Do not call this function from
+       inside a long-running mempalace process (MCP server, daemon)
+       while other callers hold live ``PersistentClient`` references —
+       use the CLI in a separate process instead. Cross-palace use
+       (``source != dest``) does not touch the cache.
+
+    Note on metadata fidelity: the resolution rule
+    (``string_value`` → ``int_value`` → ``float_value`` → ``bool_value``)
+    matches the precedent in :mod:`mempalace.migrate`. ChromaDB 0.4.x
+    occasionally wrote booleans as ``int_value=0/1``; those will
+    round-trip as ``int`` rather than ``bool`` after this rebuild. This
+    is a known divergence and matches the existing migrate-path
+    behavior.
+    """
+    source_palace = os.path.abspath(os.path.expanduser(source_palace))
+    dest_palace = os.path.abspath(os.path.expanduser(dest_palace))
+
+    src_db = os.path.join(source_palace, "chroma.sqlite3")
+
+    in_place = source_palace == dest_palace
+
+    print(f"\n{'=' * 55}")
+    print("  MemPalace Repair — Rebuild from SQLite")
+    print(f"{'=' * 55}\n")
+    print(f"  Source: {source_palace}")
+    print(f"  Dest:   {dest_palace}")
+
+    # Validate source BEFORE any destructive moves. An earlier draft
+    # archived the dest first and surfaced the missing-chroma.sqlite3
+    # error after — leaving the user with a renamed dir to manually undo
+    # when the archive itself was empty. Validate first so a user error
+    # (--source pointing at a non-palace dir) bails cleanly.
+    if in_place:
+        if not archive_existing_dest:
+            print(
+                "\n  Source and dest are the same path. Pass "
+                "archive_existing_dest=True (CLI: --archive-existing) to move "
+                "the existing palace aside, or pass a different source_palace= "
+                "(CLI: --source)."
+            )
+            return {}
+        if not os.path.isfile(src_db):
+            print(f"\n  Source palace has no chroma.sqlite3 at {src_db}")
+            return {}
+    else:
+        if not os.path.isfile(src_db):
+            print(f"\n  Source palace has no chroma.sqlite3 at {src_db}")
+            return {}
+        if os.path.exists(dest_palace):
+            print(
+                f"\n  Refusing to rebuild into existing path: {dest_palace}\n"
+                "  Move it aside, pass a different dest, or set "
+                "archive_existing_dest=True if rebuilding in place "
+                "(source_palace == dest_palace)."
+            )
+            return {}
+
+    archive_path: Optional[str] = None
+    if in_place:
+        ts = datetime.now().strftime("%Y%m%d-%H%M%S")
+        archive_path = f"{dest_palace}.pre-rebuild-{ts}"
+        print(f"  Archiving {dest_palace} → {archive_path}")
+        shutil.move(dest_palace, archive_path)
+        source_palace = archive_path
+        src_db = os.path.join(source_palace, "chroma.sqlite3")
+
+        # In-place only: drop chromadb's process-wide System registry so
+        # the new client at dest_palace builds a fresh System. Without
+        # this, ``create_collection`` raises "Collection already exists"
+        # because the cached System still holds the pre-rename schema.
+        # Cross-palace mode does not need this and would needlessly
+        # invalidate other callers' clients (see docstring warning).
+        try:
+            from chromadb.api.client import SharedSystemClient
+
+            SharedSystemClient.clear_system_cache()
+        except Exception as exc:  # noqa: BLE001
+            print(
+                f"  Warning: could not clear chromadb system cache ({exc!r}); "
+                "in-place rebuild may fail with 'Collection already exists'."
+            )
+
+    os.makedirs(dest_palace, exist_ok=True)
+
+    # Backend lifetime is wrapped in try/finally so the dest palace's
+    # PersistentClient handle (opened lazily inside ``create_collection``
+    # / ``get_collection``) is released on every exit path: success,
+    # ``RebuildPartialError``, or any unexpected exception. Without this,
+    # a long-running process that calls ``rebuild_from_sqlite`` would
+    # leak SQLite/HNSW file handles into Chroma's ``SharedSystemClient``
+    # cache, surfacing later as "Collection already exists" on the next
+    # in-place rebuild or as a Windows file-lock failure on cleanup
+    # (cf. #1285's lifecycle hardening for the legacy rebuild path).
+    backend = ChromaBackend()
+    counts: dict[str, int] = {}
+    try:
+        for cname in _recoverable_collections():
+            print(f"\n  [{cname}]")
+            upserted = _rebuild_one_collection(
+                backend=backend,
+                source_palace=source_palace,
+                dest_palace=dest_palace,
+                collection_name=cname,
+                batch_size=batch_size,
+                archive_path=archive_path,
+                counts_so_far=counts,
+            )
+            counts[cname] = upserted
+            if upserted == 0:
+                print(f"    no rows found for {cname} in source palace")
+            else:
+                print(f"    done: {upserted} rows in {cname}")
+
+        print(f"\n  Rebuild complete. {sum(counts.values())} total rows.")
+        if archive_path is not None:
+            print(f"  Original palace archived at: {archive_path}")
+        print(f"{'=' * 55}\n")
+        return counts
+    finally:
+        backend.close()
+
+
+def status(palace_path=None, collection_name: Optional[str] = None) -> dict:
     """Read-only health check: compare sqlite vs HNSW element counts.
 
     Catches the #1222 failure mode where chromadb's HNSW segment freezes
@@ -524,6 +1058,7 @@ def status(palace_path=None) -> dict:
     ``status="unknown"`` when no palace exists at the given path.
     """
     palace_path = palace_path or _get_palace_path()
+    collection_name = collection_name or _drawers_collection_name()
     print(f"\n{'=' * 55}")
     print("  MemPalace Repair — Status")
     print(f"{'=' * 55}\n")
@@ -533,8 +1068,8 @@ def status(palace_path=None) -> dict:
         print("  No palace found.\n")
         return {"status": "unknown", "message": "no palace at path"}
 
-    drawers = hnsw_capacity_status(palace_path, "mempalace_drawers")
-    closets = hnsw_capacity_status(palace_path, "mempalace_closets")
+    drawers = hnsw_capacity_status(palace_path, collection_name)
+    closets = hnsw_capacity_status(palace_path, CLOSETS_COLLECTION_NAME)
 
     for label, info in (("drawers", drawers), ("closets", closets)):
         print(f"\n  [{label}]")
@@ -564,12 +1099,18 @@ def status(palace_path=None) -> dict:
 # ---------------------------------------------------------------------------
 
 
-def _close_chroma_handles(palace_path: str) -> None:
-    """Drop ChromaBackend + chromadb singleton caches so OS mmap handles release."""
+def _close_chroma_handles(palace_path: str, backend: "ChromaBackend | None" = None) -> None:
+    """Drop ChromaBackend + chromadb singleton caches so OS mmap handles release.
+
+    When ``backend`` is provided, close the live instance so rollback/restore
+    releases the handles it was already using. Otherwise fall back to a
+    transient backend instance for the max-seq-id repair path.
+    """
     import gc
 
     try:
-        ChromaBackend().close_palace(palace_path)
+        closer = backend if backend is not None else ChromaBackend()
+        closer.close_palace(palace_path)
     except Exception:
         pass
     try:

mempalace/room_detector_local.py

@@ -202,7 +202,7 @@ def detect_rooms_from_files(project_dir: str) -> list:
 
     SKIP_DIRS = {".git", "node_modules", "__pycache__", ".venv", "venv", "dist", "build"}
 
-    for root, dirs, filenames in os.walk(project_path):
+    for _root, dirs, filenames in os.walk(project_path):
         dirs[:] = [d for d in dirs if d not in SKIP_DIRS]
         for filename in filenames:
             name_lower = filename.lower().replace("-", "_").replace(" ", "_")

mempalace/searcher.py

@@ -245,7 +245,7 @@ def _expand_with_neighbors(drawers_col, matched_doc: str, matched_meta: dict, ra
         all_meta = drawers_col.get(where={"source_file": src}, include=["metadatas"])
         total_drawers = len(all_meta.ids) if all_meta.ids else None
     except Exception:
-        pass
+        logger.debug("total_drawers lookup failed for %s", src, exc_info=True)
 
     return {
         "text": combined_text,
@@ -297,10 +297,10 @@ def search(query: str, palace_path: str, wing: str = None, room: str = None, n_r
     """
     try:
         col = get_collection(palace_path, create=False)
-    except Exception:
+    except Exception as e:
         print(f"\n  No palace found at {palace_path}")
         print("  Run: mempalace init <dir> then mempalace mine <dir>")
-        raise SearchError(f"No palace found at {palace_path}")
+        raise SearchError(f"No palace found at {palace_path}") from e
 
     # Alert the user if this palace predates hnsw:space=cosine being set on
     # creation — their similarity scores will be junk until they run repair.
@@ -340,7 +340,7 @@ def search(query: str, palace_path: str, wing: str = None, room: str = None, n_r
     # `_hybrid_rank`; do the same here so CLI results match what agents
     # see via `mempalace_search`.
     hits = [
-        {"text": doc, "distance": float(dist), "metadata": meta or {}}
+        {"text": doc or "", "distance": float(dist), "metadata": meta or {}}
         for doc, meta, dist in zip(docs, metas, dists)
     ]
     hits = _hybrid_rank(hits, query)
@@ -382,6 +382,7 @@ def _bm25_only_via_sqlite(
     n_results: int = 5,
     max_candidates: int = 500,
     _include_internal: bool = False,
+    collection_name: str = None,
 ) -> dict:
     """BM25-only search reading drawers directly from chroma.sqlite3.
 
@@ -405,6 +406,35 @@ def _bm25_only_via_sqlite(
             "error": "No palace found",
             "hint": "Run: mempalace init <dir> && mempalace mine <dir>",
         }
+    if collection_name is None:
+        from .config import get_configured_collection_name
+
+        collection_name = get_configured_collection_name()
+
+    def _metadata_filter_sql(row_id_expr: str) -> tuple[str, list[str]]:
+        clauses = []
+        params = []
+        for key, value in (("wing", wing), ("room", room)):
+            if not value:
+                continue
+            clauses.append(
+                f"""
+                AND EXISTS (
+                    SELECT 1
+                    FROM embedding_metadata mf
+                    WHERE mf.id = {row_id_expr}
+                      AND mf.key = ?
+                      AND COALESCE(
+                        mf.string_value,
+                        CAST(mf.int_value AS TEXT),
+                        CAST(mf.float_value AS TEXT),
+                        CAST(mf.bool_value AS TEXT)
+                      ) = ?
+                )
+                """
+            )
+            params.extend([key, value])
+        return "".join(clauses), params
 
     try:
         conn = sqlite3.connect(f"file:{db_path}?mode=ro", uri=True)
@@ -416,45 +446,57 @@ def _bm25_only_via_sqlite(
         # shorter than 3 chars (trigram tokenizer can't match them).
         tokens = [t for t in _tokenize(query) if len(t) >= 3]
         candidate_ids: list[int] = []
+        use_recency_fallback = not tokens
         if tokens:
             fts_query = " OR ".join(tokens)
+            filter_sql, filter_params = _metadata_filter_sql("embedding_fulltext_search.rowid")
             try:
                 rows = conn.execute(
-                    """
-                    SELECT rowid
+                    f"""
+                    SELECT embedding_fulltext_search.rowid
                     FROM embedding_fulltext_search
+                    JOIN embeddings e ON e.id = embedding_fulltext_search.rowid
+                    JOIN segments s ON e.segment_id = s.id
+                    JOIN collections c ON s.collection = c.id
                     WHERE embedding_fulltext_search MATCH ?
+                      AND c.name = ?
+                    {filter_sql}
                     LIMIT ?
                     """,
-                    (fts_query, max_candidates),
+                    (fts_query, collection_name, *filter_params, max_candidates),
                 ).fetchall()
                 candidate_ids = [r[0] for r in rows]
             except sqlite3.Error:
                 # FTS5 tokenizer mismatch or syntax error — fall through
                 # to the recency-window selector below.
                 logger.debug("FTS5 MATCH failed; using recency fallback", exc_info=True)
+                use_recency_fallback = True
 
-        if not candidate_ids:
-            # No FTS hits (or no usable tokens) — pull the most recent
-            # rows for the drawers segment so we can BM25-rank something
-            # rather than return empty-handed. Wrapped in try/except
-            # because the schema may differ on legacy palaces (older
-            # chromadb without ``created_at``, missing ``segments``
-            # rows after partial restore, etc.); on schema mismatch we
-            # fall back to ordering by primary-key id and finally to an
-            # empty result rather than letting search raise.
+        if not candidate_ids and use_recency_fallback:
+            # No usable FTS tokens, or FTS itself failed — pull the most
+            # recent rows for the drawers segment so we can BM25-rank
+            # something rather than return empty-handed. A clean FTS miss
+            # must stay empty, especially after wing/room filtering, because
+            # recency fallback would return unrelated scoped drawers.
+            # Wrapped in try/except because the schema may differ on legacy
+            # palaces (older chromadb without ``created_at``, missing
+            # ``segments`` rows after partial restore, etc.); on schema
+            # mismatch we fall back to ordering by primary-key id and finally
+            # to an empty result rather than letting search raise.
             try:
+                filter_sql, filter_params = _metadata_filter_sql("e.id")
                 rows = conn.execute(
-                    """
+                    f"""
                     SELECT e.id
                     FROM embeddings e
                     JOIN segments s ON e.segment_id = s.id
                     JOIN collections c ON s.collection = c.id
-                    WHERE c.name = 'mempalace_drawers'
+                    WHERE c.name = ?
+                    {filter_sql}
                     ORDER BY e.created_at DESC
                     LIMIT ?
                     """,
-                    (max_candidates,),
+                    (collection_name, *filter_params, max_candidates),
                 ).fetchall()
                 candidate_ids = [r[0] for r in rows]
             except sqlite3.Error:
@@ -463,17 +505,19 @@ def _bm25_only_via_sqlite(
                     exc_info=True,
                 )
                 try:
+                    filter_sql, filter_params = _metadata_filter_sql("e.id")
                     rows = conn.execute(
-                        """
+                        f"""
                         SELECT e.id
                         FROM embeddings e
                         JOIN segments s ON e.segment_id = s.id
                         JOIN collections c ON s.collection = c.id
-                        WHERE c.name = 'mempalace_drawers'
+                        WHERE c.name = ?
+                        {filter_sql}
                         ORDER BY e.id DESC
                         LIMIT ?
                         """,
-                        (max_candidates,),
+                        (collection_name, *filter_params, max_candidates),
                     ).fetchall()
                     candidate_ids = [r[0] for r in rows]
                 except sqlite3.Error:
@@ -689,6 +733,7 @@ def search_memories(
     max_distance: float = 0.0,
     vector_disabled: bool = False,
     candidate_strategy: str = "vector",
+    collection_name: str = None,
 ) -> dict:
     """Programmatic search — returns a dict instead of printing.
 
@@ -739,10 +784,11 @@ def search_memories(
             wing=wing,
             room=room,
             n_results=n_results,
+            collection_name=collection_name,
         )
 
     try:
-        drawers_col = get_collection(palace_path, create=False)
+        drawers_col = get_collection(palace_path, collection_name=collection_name, create=False)
     except Exception as e:
         logger.error("No palace found at %s: %s", palace_path, e)
         return {
@@ -795,7 +841,8 @@ def search_memories(
             if source and source not in closet_boost_by_source:
                 closet_boost_by_source[source] = (rank, cdist, cdoc[:200])
     except Exception:
-        pass  # no closets yet — hybrid degrades to pure drawer search
+        # No closets yet — hybrid degrades to pure drawer search.
+        logger.debug("Closet collection unavailable; using drawer-only search", exc_info=True)
 
     # Rank-based boost. The ordinal signal ("which closet matched best") is
     # more reliable than absolute distance on narrative content, where
@@ -809,6 +856,8 @@ def search_memories(
         _first_or_empty(drawer_results, "metadatas"),
         _first_or_empty(drawer_results, "distances"),
     ):
+        meta = meta or {}
+        doc = doc or ""
         # Filter on raw distance before rounding to avoid precision loss.
         if max_distance > 0.0 and dist > max_distance:
             continue
@@ -825,7 +874,12 @@ def search_memories(
                 matched_via = "drawer+closet"
                 closet_preview = c_preview
 
-        effective_dist = dist - boost
+        # Clamp to the valid cosine-distance range [0, 2]. When a strong
+        # closet boost (up to 0.40) exceeds the raw distance, the subtraction
+        # can go negative — which (a) yields ``similarity > 1.0`` downstream
+        # and (b) makes the sort key land *below* ordinary positive distances,
+        # inverting the ranking so the best hybrid matches sort last.
+        effective_dist = max(0.0, min(2.0, dist - boost))
         entry = {
             "text": doc,
             "wing": meta.get("wing", "unknown"),
@@ -870,6 +924,7 @@ def search_memories(
                 include=["documents", "metadatas"],
             )
         except Exception:
+            logger.debug("Neighbor fetch failed for %s", full_source, exc_info=True)
             continue
         docs = source_drawers.documents
         metas_ = source_drawers.metadatas

tests/benchmarks/test_mcp_bench.py

@@ -40,8 +40,9 @@ def _patch_mcp_config(monkeypatch, palace_path, tmp_path):
 
     import mempalace.mcp_server as mcp_mod
 
+    kg = KnowledgeGraph(db_path=str(tmp_path / "kg.sqlite3"))
     monkeypatch.setattr(mcp_mod, "_config", cfg)
-    monkeypatch.setattr(mcp_mod, "_kg", KnowledgeGraph(db_path=str(tmp_path / "kg.sqlite3")))
+    monkeypatch.setattr(mcp_mod, "_get_kg", lambda: kg)
 
 
 def _get_rss_mb():

tests/benchmarks/test_memory_profile.py

@@ -84,8 +84,9 @@ class TestToolStatusMemoryProfile:
 
         cfg = MempalaceConfig(config_dir=str(tmp_path / "cfg"))
         monkeypatch.setattr(cfg, "_file_config", {"palace_path": palace_path})
+        kg = KnowledgeGraph(db_path=str(tmp_path / "kg.sqlite3"))
         monkeypatch.setattr(mcp_mod, "_config", cfg)
-        monkeypatch.setattr(mcp_mod, "_kg", KnowledgeGraph(db_path=str(tmp_path / "kg.sqlite3")))
+        monkeypatch.setattr(mcp_mod, "_get_kg", lambda: kg)
 
         from mempalace.mcp_server import tool_status
 

tests/test_backends.py

@@ -1,4 +1,6 @@
 import os
+import pickle
+import shutil
 import sqlite3
 from pathlib import Path
 
@@ -18,6 +20,7 @@ from mempalace.backends.chroma import (
     ChromaCollection,
     _fix_blob_seq_ids,
     _pin_hnsw_threads,
+    quarantine_invalid_hnsw_metadata,
     quarantine_stale_hnsw,
 )
 
@@ -206,6 +209,52 @@ def test_query_empty_preserves_embeddings_outer_shape_when_requested():
     assert not_requested.embeddings is None
 
 
+def test_chroma_close_palace_releases_sqlite_lock_for_reopen(tmp_path):
+    """close_palace must release chromadb's rust-side SQLite file lock so
+    a fresh PersistentClient on the same path after shutil.rmtree can
+    write without hitting SQLITE_READONLY_DBMOVED."""
+    backend = ChromaBackend()
+    palace_path = tmp_path / "palace-a"
+    ref = PalaceRef(id=str(palace_path), local_path=str(palace_path))
+
+    col = backend.get_collection(palace=ref, collection_name="mempalace_drawers", create=True)
+    col.upsert(documents=["hello"], ids=["a"], metadatas=[{"k": "v"}])
+
+    backend.close_palace(ref)
+    shutil.rmtree(palace_path)
+
+    col = backend.get_collection(palace=ref, collection_name="mempalace_drawers", create=True)
+    col.upsert(documents=["world"], ids=["b"], metadatas=[{"k": "v2"}])
+    assert col.count() == 1
+
+
+def test_chroma_close_releases_all_cached_clients(tmp_path):
+    """close() must release every cached client's SQLite file lock so any
+    of their palace paths can be reopened by a fresh backend in the same
+    process."""
+    backend = ChromaBackend()
+    palace_a = tmp_path / "palace-a"
+    palace_b = tmp_path / "palace-b"
+    ref_a = PalaceRef(id=str(palace_a), local_path=str(palace_a))
+    ref_b = PalaceRef(id=str(palace_b), local_path=str(palace_b))
+
+    for ref in (ref_a, ref_b):
+        backend.get_collection(palace=ref, collection_name="mempalace_drawers", create=True).upsert(
+            documents=["x"], ids=["x"], metadatas=[{"k": "v"}]
+        )
+
+    backend.close()
+
+    for path in (palace_a, palace_b):
+        shutil.rmtree(path)
+        ref = PalaceRef(id=str(path), local_path=str(path))
+        fresh = ChromaBackend()
+        col = fresh.get_collection(palace=ref, collection_name="mempalace_drawers", create=True)
+        col.upsert(documents=["y"], ids=["y"], metadatas=[{"k": "v2"}])
+        assert col.count() == 1
+        fresh.close()
+
+
 def test_chroma_cache_invalidates_when_db_file_missing(tmp_path):
     """A palace rebuild that removes chroma.sqlite3 must drop the stale cache.
 
@@ -708,7 +757,10 @@ def test_make_client_quarantines_only_on_first_call_per_palace(tmp_path, monkeyp
     """Quarantine fires on first ``make_client()`` for a palace, then is
     skipped on subsequent calls — prevents runtime thrash where a daemon's
     own steady writes bump ``chroma.sqlite3`` faster than HNSW flushes,
-    making the mtime heuristic falsely trigger every reconnect."""
+    making the mtime heuristic falsely trigger every reconnect.
+
+    Invalid metadata quarantine shares the same cold-start gate here; the
+    more aggressive refresh path lives in ``_client()``."""
     from mempalace.backends.chroma import ChromaBackend
 
     palace_path = str(tmp_path / "palace")
@@ -735,6 +787,34 @@ def test_make_client_quarantines_only_on_first_call_per_palace(tmp_path, monkeyp
     ], "quarantine_stale_hnsw should fire once per palace per process, not on every reconnect"
 
 
+def test_make_client_gates_invalid_metadata_on_first_call(tmp_path, monkeypatch):
+    """Invalid metadata quarantine is gated on the first make_client() call."""
+    from mempalace.backends.chroma import ChromaBackend
+
+    palace_path = str(tmp_path / "palace")
+    os.makedirs(palace_path, exist_ok=True)
+    (Path(palace_path) / "chroma.sqlite3").write_text("")
+
+    monkeypatch.setattr(ChromaBackend, "_quarantined_paths", set())
+
+    calls: list[str] = []
+
+    def _invalid(path, *args, **kwargs):
+        calls.append(path)
+        return []
+
+    def _stale(path, stale_seconds=300.0):
+        return []
+
+    monkeypatch.setattr("mempalace.backends.chroma.quarantine_invalid_hnsw_metadata", _invalid)
+    monkeypatch.setattr("mempalace.backends.chroma.quarantine_stale_hnsw", _stale)
+
+    ChromaBackend.make_client(palace_path)
+    ChromaBackend.make_client(palace_path)
+
+    assert calls == [palace_path]
+
+
 def test_make_client_quarantines_each_palace_independently(tmp_path, monkeypatch):
     """Two distinct palaces each get one quarantine attempt — the gate is
     keyed by palace path, not global."""
@@ -872,3 +952,268 @@ def test_get_collection_applies_retrofit_on_existing_palace(tmp_path):
     )
 
     assert wrapper._collection.configuration_json["hnsw"]["num_threads"] == 1
+
+
+def test_quarantine_invalid_hnsw_metadata_renames_missing_dimensionality(tmp_path):
+    palace = tmp_path / "palace"
+    palace.mkdir()
+    seg = palace / "abcd-1234-5678"
+    seg.mkdir()
+    with open(seg / "index_metadata.pickle", "wb") as f:
+        pickle.dump({"dimensionality": None, "id_to_label": {"a": 1}}, f)
+
+    moved = quarantine_invalid_hnsw_metadata(str(palace))
+
+    assert len(moved) == 1
+    assert ".corrupt-" in moved[0]
+    assert not seg.exists()
+
+
+def test_quarantine_invalid_hnsw_metadata_allows_uninitialized_segment(tmp_path):
+    palace = tmp_path / "palace"
+    palace.mkdir()
+    seg = palace / "abcd-1234-5678"
+    seg.mkdir()
+    with open(seg / "index_metadata.pickle", "wb") as f:
+        pickle.dump({"dimensionality": None, "id_to_label": {}}, f)
+
+    moved = quarantine_invalid_hnsw_metadata(str(palace))
+
+    assert moved == []
+    assert seg.exists()
+
+
+def test_quarantine_invalid_hnsw_metadata_rejects_non_dict_id_to_label(tmp_path):
+    palace = tmp_path / "palace"
+    palace.mkdir()
+    seg = palace / "abcd-1234-5678"
+    seg.mkdir()
+    with open(seg / "index_metadata.pickle", "wb") as f:
+        pickle.dump({"dimensionality": 8, "id_to_label": ["a", "b"]}, f)
+
+    moved = quarantine_invalid_hnsw_metadata(str(palace))
+
+    assert len(moved) == 1
+    assert ".corrupt-" in moved[0]
+    assert not seg.exists()
+
+
+def test_quarantine_invalid_hnsw_metadata_rejects_non_schema_payload(tmp_path):
+    palace = tmp_path / "palace"
+    palace.mkdir()
+    seg = palace / "abcd-1234-5678"
+    seg.mkdir()
+    with open(seg / "index_metadata.pickle", "wb") as f:
+        pickle.dump(["not", "a", "metadata", "object"], f)
+
+    moved = quarantine_invalid_hnsw_metadata(str(palace))
+
+    assert len(moved) == 1
+    assert ".corrupt-" in moved[0]
+    assert not seg.exists()
+
+
+def _dangerous_pickle_payload_executed():
+    raise AssertionError("unsafe pickle payload executed")
+
+
+class _DangerousPickle:
+    def __reduce__(self):
+        return (_dangerous_pickle_payload_executed, ())
+
+
+def test_quarantine_invalid_hnsw_metadata_rejects_unsafe_pickle(tmp_path):
+    palace = tmp_path / "palace"
+    palace.mkdir()
+    seg = palace / "abcd-1234-5678"
+    seg.mkdir()
+    with open(seg / "index_metadata.pickle", "wb") as f:
+        pickle.dump(_DangerousPickle(), f)
+
+    moved = quarantine_invalid_hnsw_metadata(str(palace))
+
+    assert len(moved) == 1
+    assert ".corrupt-" in moved[0]
+    assert not seg.exists()
+
+
+def test_quarantine_invalid_hnsw_metadata_skips_transient_read_errors(tmp_path, monkeypatch):
+    palace = tmp_path / "palace"
+    palace.mkdir()
+    seg = palace / "abcd-1234-5678"
+    seg.mkdir()
+    meta = seg / "index_metadata.pickle"
+    meta.write_bytes(b"partial")
+
+    monkeypatch.setattr(
+        "mempalace.backends.chroma._SafePersistentDataUnpickler.load",
+        lambda path: (_ for _ in ()).throw(EOFError("flush in progress")),
+    )
+
+    moved = quarantine_invalid_hnsw_metadata(str(palace))
+
+    assert moved == []
+    assert seg.exists()
+
+
+def test_quarantine_invalid_hnsw_metadata_skips_truncated_pickle(tmp_path, monkeypatch):
+    palace = tmp_path / "palace"
+    palace.mkdir()
+    seg = palace / "abcd-1234-5678"
+    seg.mkdir()
+    meta = seg / "index_metadata.pickle"
+    meta.write_bytes(b"partial")
+
+    monkeypatch.setattr(
+        "mempalace.backends.chroma._SafePersistentDataUnpickler.load",
+        lambda path: (_ for _ in ()).throw(pickle.UnpicklingError("pickle data was truncated")),
+    )
+
+    moved = quarantine_invalid_hnsw_metadata(str(palace))
+
+    assert moved == []
+    assert seg.exists()
+
+
+def test_chroma_backend_preflights_metadata_before_persistent_client(tmp_path, monkeypatch):
+    palace = tmp_path / "palace"
+    palace.mkdir()
+    calls = []
+
+    def _record(name):
+        def inner(path, *args, **kwargs):
+            calls.append((name, path))
+            return [] if name != "blob" else None
+
+        return inner
+
+    monkeypatch.setattr("mempalace.backends.chroma._fix_blob_seq_ids", _record("blob"))
+    monkeypatch.setattr(
+        "mempalace.backends.chroma.quarantine_invalid_hnsw_metadata", _record("invalid")
+    )
+    monkeypatch.setattr("mempalace.backends.chroma.quarantine_stale_hnsw", _record("stale"))
+
+    class DummyClient:
+        pass
+
+    monkeypatch.setattr(
+        "mempalace.backends.chroma.chromadb.PersistentClient", lambda path: DummyClient()
+    )
+
+    backend = ChromaBackend()
+    backend._client(str(palace))
+
+    assert calls == [
+        ("blob", str(palace)),
+        ("invalid", str(palace)),
+        ("stale", str(palace)),
+    ]
+
+
+def test_chroma_backend_stale_quarantine_is_cold_start_only_on_refresh(tmp_path, monkeypatch):
+    palace = tmp_path / "palace"
+    palace.mkdir()
+    (palace / "chroma.sqlite3").write_text("")
+    calls = []
+
+    def _record(name):
+        def inner(path, *args, **kwargs):
+            calls.append((name, path))
+            return [] if name != "blob" else None
+
+        return inner
+
+    monkeypatch.setattr(ChromaBackend, "_quarantined_paths", set())
+    monkeypatch.setattr("mempalace.backends.chroma._fix_blob_seq_ids", _record("blob"))
+    monkeypatch.setattr(
+        "mempalace.backends.chroma.quarantine_invalid_hnsw_metadata", _record("invalid")
+    )
+    monkeypatch.setattr("mempalace.backends.chroma.quarantine_stale_hnsw", _record("stale"))
+
+    class DummyClient:
+        pass
+
+    monkeypatch.setattr(
+        "mempalace.backends.chroma.chromadb.PersistentClient", lambda path: DummyClient()
+    )
+
+    backend = ChromaBackend()
+    stats = iter([(1, 1.0), (1, 1.0), (1, 2.0), (1, 2.0)])
+    monkeypatch.setattr(backend, "_db_stat", lambda path: next(stats))
+
+    backend._client(str(palace))
+    backend._client(str(palace))
+
+    assert calls == [
+        ("blob", str(palace)),
+        ("invalid", str(palace)),
+        ("stale", str(palace)),
+        ("blob", str(palace)),
+    ]
+
+
+def test_chroma_backend_requarantines_after_inode_replacement(tmp_path, monkeypatch):
+    palace = tmp_path / "palace"
+    palace.mkdir()
+    (palace / "chroma.sqlite3").write_text("")
+    calls = []
+
+    def _record(name):
+        def inner(path, *args, **kwargs):
+            calls.append((name, path))
+            return [] if name != "blob" else None
+
+        return inner
+
+    monkeypatch.setattr(ChromaBackend, "_quarantined_paths", set())
+    monkeypatch.setattr("mempalace.backends.chroma._fix_blob_seq_ids", _record("blob"))
+    monkeypatch.setattr(
+        "mempalace.backends.chroma.quarantine_invalid_hnsw_metadata", _record("invalid")
+    )
+    monkeypatch.setattr("mempalace.backends.chroma.quarantine_stale_hnsw", _record("stale"))
+
+    class DummyClient:
+        pass
+
+    monkeypatch.setattr(
+        "mempalace.backends.chroma.chromadb.PersistentClient", lambda path: DummyClient()
+    )
+
+    backend = ChromaBackend()
+    stats = iter([(1, 1.0), (1, 1.0), (2, 2.0), (2, 2.0)])
+    monkeypatch.setattr(backend, "_db_stat", lambda path: next(stats))
+
+    backend._client(str(palace))
+    backend._client(str(palace))
+
+    assert calls == [
+        ("blob", str(palace)),
+        ("invalid", str(palace)),
+        ("stale", str(palace)),
+        ("blob", str(palace)),
+        ("invalid", str(palace)),
+        ("stale", str(palace)),
+    ]
+
+
+def test_palace_get_collection_uses_configured_collection_name(monkeypatch):
+    from mempalace import palace
+
+    captured = {}
+
+    def fake_get_collection(palace_path, collection_name=None, create=False):
+        captured["palace_path"] = palace_path
+        captured["collection_name"] = collection_name
+        captured["create"] = create
+        return object()
+
+    monkeypatch.setattr(palace._DEFAULT_BACKEND, "get_collection", fake_get_collection)
+    monkeypatch.setattr("mempalace.config.get_configured_collection_name", lambda: "custom_drawers")
+
+    palace.get_collection("/palace", create=False)
+
+    assert captured == {
+        "palace_path": "/palace",
+        "collection_name": "custom_drawers",
+        "create": False,
+    }

tests/test_chroma_collection_lock.py

@@ -0,0 +1,321 @@
+"""Tests for ChromaCollection's palace-write-lock integration.
+
+Closes the gap left by ``mine_palace_lock`` only protecting the
+``mempalace mine`` pipeline: MCP/direct writers that call
+``ChromaCollection.add/upsert/update/delete`` must also serialize against
+mine and against each other to avoid the multi-threaded HNSW corruption
+documented in #974/#965.
+
+Property tested:
+
+* ``ChromaCollection(c, palace_path=p)`` wraps every write with
+  ``mine_palace_lock(p)``.
+* Writes raise ``MineAlreadyRunning`` when another holder owns the lock
+  (instead of silently racing into the underlying chromadb call).
+* Re-entrant composition with ``miner.mine()`` does not self-deadlock:
+  ``with mine_palace_lock(p): col.upsert(...)`` runs to completion.
+* ``ChromaCollection(c)`` (no palace_path) preserves legacy no-lock
+  behaviour for tests/callers that build the adapter directly without
+  going through ``ChromaBackend``.
+
+POSIX-only: ``mine_palace_lock`` uses ``fcntl`` on Unix and ``msvcrt`` on
+Windows; the contention semantics differ enough that the cross-process
+tests are skipped on Windows runners.
+"""
+
+from __future__ import annotations
+
+import multiprocessing
+import os
+import time
+
+import pytest
+
+from mempalace.backends.chroma import ChromaCollection
+from mempalace.palace import MineAlreadyRunning, mine_palace_lock
+
+
+def _get_mp_context():
+    """Same start-method picker as test_palace_locks.py."""
+    start_method = "spawn" if os.name == "nt" else "fork"
+    return multiprocessing.get_context(start_method)
+
+
+# ---------------------------------------------------------------------------
+# Fakes
+# ---------------------------------------------------------------------------
+
+
+class _FakeChromaCollection:
+    """Records calls; never blocks. Stand-in for chromadb.Collection."""
+
+    def __init__(self):
+        self.adds: list[dict] = []
+        self.upserts: list[dict] = []
+        self.updates: list[dict] = []
+        self.deletes: list[dict] = []
+
+    def add(self, **kwargs):
+        self.adds.append(kwargs)
+
+    def upsert(self, **kwargs):
+        self.upserts.append(kwargs)
+
+    def update(self, **kwargs):
+        self.updates.append(kwargs)
+
+    def delete(self, **kwargs):
+        self.deletes.append(kwargs)
+
+
+# ---------------------------------------------------------------------------
+# Helpers
+# ---------------------------------------------------------------------------
+
+
+def _hold_lock(palace_path: str, ready_flag: str, release_flag: str) -> int:
+    """Acquire ``mine_palace_lock``, signal readiness, wait for release.
+
+    Mirrors the helper in ``test_palace_locks.py`` so the contention
+    semantics match across both test files.
+    """
+    try:
+        with mine_palace_lock(palace_path):
+            open(ready_flag, "w").close()
+            for _ in range(500):
+                if os.path.exists(release_flag):
+                    return 0
+                time.sleep(0.01)
+            return 0
+    except MineAlreadyRunning:
+        return 1
+
+
+# ---------------------------------------------------------------------------
+# Tests — opt-in lock wiring
+# ---------------------------------------------------------------------------
+
+
+def test_palace_path_none_skips_lock(tmp_path, monkeypatch):
+    """Legacy callers (``ChromaCollection(c)``) keep no-lock behaviour.
+
+    A ``ChromaCollection`` built without ``palace_path`` must not touch the
+    lock infrastructure at all. This guards against regressions where a
+    test or third-party caller relies on the historical bare-write path.
+    """
+    monkeypatch.setenv("HOME", str(tmp_path))
+    fake = _FakeChromaCollection()
+    col = ChromaCollection(fake)  # no palace_path -> no lock
+
+    # Hold the lock in a child process. Without palace_path, the parent
+    # write must still succeed (the lock does not gate this caller).
+    palace = str(tmp_path / "palace")
+    ready = str(tmp_path / "ready")
+    release = str(tmp_path / "release")
+    ctx = _get_mp_context()
+    holder = ctx.Process(target=_hold_lock, args=(palace, ready, release))
+    holder.start()
+    try:
+        for _ in range(500):
+            if os.path.exists(ready):
+                break
+            time.sleep(0.01)
+        assert os.path.exists(ready), "holder failed to acquire lock"
+
+        col.upsert(documents=["doc"], ids=["id-1"])
+        assert fake.upserts == [{"documents": ["doc"], "ids": ["id-1"]}]
+    finally:
+        open(release, "w").close()
+        holder.join(timeout=5)
+
+
+def test_writer_blocks_during_mine(tmp_path, monkeypatch):
+    """A held ``mine_palace_lock`` causes ``ChromaCollection`` writes to raise.
+
+    This is the property that closes the MCP-bypass gap: when a mine is in
+    flight, MCP/direct writes raise ``MineAlreadyRunning`` rather than
+    silently entering chromadb's write path concurrent with mine.
+    """
+    monkeypatch.setenv("HOME", str(tmp_path))
+    palace = str(tmp_path / "palace")
+    ready = str(tmp_path / "ready")
+    release = str(tmp_path / "release")
+
+    ctx = _get_mp_context()
+    holder = ctx.Process(target=_hold_lock, args=(palace, ready, release))
+    holder.start()
+    try:
+        for _ in range(500):
+            if os.path.exists(ready):
+                break
+            time.sleep(0.01)
+        assert os.path.exists(ready), "holder failed to acquire lock"
+
+        fake = _FakeChromaCollection()
+        col = ChromaCollection(fake, palace_path=palace)
+
+        with pytest.raises(MineAlreadyRunning):
+            col.upsert(documents=["doc"], ids=["id-1"])
+        with pytest.raises(MineAlreadyRunning):
+            col.add(documents=["doc"], ids=["id-2"])
+        with pytest.raises(MineAlreadyRunning):
+            col.update(ids=["id-3"], documents=["doc"])
+        with pytest.raises(MineAlreadyRunning):
+            col.delete(ids=["id-4"])
+
+        # The fake must have received NO calls — the lock must gate
+        # before reaching the underlying chromadb layer.
+        assert fake.upserts == []
+        assert fake.adds == []
+        assert fake.updates == []
+        assert fake.deletes == []
+    finally:
+        open(release, "w").close()
+        holder.join(timeout=5)
+
+
+def test_reentrant_inside_mine_passes_through(tmp_path, monkeypatch):
+    """``ChromaCollection.upsert`` inside ``mine_palace_lock`` does not deadlock.
+
+    ``miner.mine()`` already holds ``mine_palace_lock(palace_path)`` for the
+    full mine pipeline; ``_mine_body`` then calls
+    ``collection.upsert(...)``. With the per-thread re-entrant guard in
+    ``mine_palace_lock``, the inner acquire is a pass-through and the
+    underlying chromadb call runs immediately.
+    """
+    monkeypatch.setenv("HOME", str(tmp_path))
+    palace = str(tmp_path / "palace")
+    fake = _FakeChromaCollection()
+    col = ChromaCollection(fake, palace_path=palace)
+
+    with mine_palace_lock(palace):
+        # If the re-entrant guard were missing, this would self-deadlock on
+        # the underlying flock. We rely on pytest-timeout (configured in
+        # pyproject.toml) to enforce this in CI; the assertion just confirms
+        # the call landed.
+        col.upsert(documents=["d"], ids=["i"], metadatas=[{"k": "v"}])
+        col.add(documents=["d2"], ids=["i2"])
+        col.update(ids=["i"], documents=["d-updated"])
+        col.delete(ids=["i2"])
+
+    assert len(fake.upserts) == 1
+    assert len(fake.adds) == 1
+    assert len(fake.updates) == 1
+    assert len(fake.deletes) == 1
+
+
+class _SlowFakeChromaCollection(_FakeChromaCollection):
+    """Fake whose write methods hold the caller for ``hold_seconds``.
+
+    Used to keep ``mine_palace_lock`` acquired long enough for a sibling
+    process to contend deterministically.
+    """
+
+    def __init__(self, hold_seconds: float = 0.3):
+        super().__init__()
+        self._hold = hold_seconds
+
+    def upsert(self, **kwargs):
+        time.sleep(self._hold)
+        super().upsert(**kwargs)
+
+
+def _slow_writer_target(palace_path, tmp_path_str, pid, result_q):
+    """Subprocess target: try a slow upsert, report ok/busy."""
+    os.environ["HOME"] = tmp_path_str
+    # Fresh import inside child so HOME monkeypatch routes the lock dir.
+    from mempalace.backends.chroma import ChromaCollection as _CC
+    from mempalace.palace import MineAlreadyRunning as _MAR
+
+    fake = _SlowFakeChromaCollection(hold_seconds=0.3)
+    col = _CC(fake, palace_path=palace_path)
+    try:
+        col.upsert(documents=[f"d{pid}"], ids=[f"i{pid}"])
+        result_q.put(("ok", pid))
+    except _MAR:
+        result_q.put(("busy", pid))
+
+
+def test_concurrent_writers_serialize(tmp_path, monkeypatch):
+    """Two processes calling ``ChromaCollection.upsert`` against the same
+    palace must be serialized: at most one enters chromadb at a time, the
+    other raises ``MineAlreadyRunning``.
+
+    This is the property that prevents the parallel HNSW insert race that
+    drives #974/#965 — under concurrent MCP write fan-out, exactly one
+    writer reaches chromadb and the rest fail loudly instead of corrupting
+    the index.
+
+    The slow fake holds the lock for 0.3s per writer, large enough for the
+    second process to contend even on slow CI runners.
+    """
+    monkeypatch.setenv("HOME", str(tmp_path))
+    palace = str(tmp_path / "palace")
+
+    ctx = _get_mp_context()
+    result_q = ctx.Queue()
+
+    p1 = ctx.Process(target=_slow_writer_target, args=(palace, str(tmp_path), 1, result_q))
+    p2 = ctx.Process(target=_slow_writer_target, args=(palace, str(tmp_path), 2, result_q))
+    p1.start()
+    # Tiny stagger so p1 wins the race deterministically; without it the
+    # OS scheduler can pick either, which is also a valid outcome but
+    # makes the assertion brittle on slow CI.
+    time.sleep(0.05)
+    p2.start()
+    p1.join(timeout=5)
+    p2.join(timeout=5)
+
+    outcomes = [result_q.get(timeout=1) for _ in range(2)]
+    statuses = sorted(o[0] for o in outcomes)
+    assert statuses == ["busy", "ok"], f"expected one ok + one busy, got {outcomes}"
+
+
+def test_read_path_does_not_acquire_lock(tmp_path, monkeypatch):
+    """``query`` / ``get`` / ``count`` must not be gated by the write lock.
+
+    Read traffic is the dominant workload (semantic search, MCP get, etc.)
+    and serializing it against mine would tank latency for no correctness
+    benefit. This test pins that property: with another process holding
+    the write lock, reads must still complete instantly.
+    """
+    monkeypatch.setenv("HOME", str(tmp_path))
+    palace = str(tmp_path / "palace")
+    ready = str(tmp_path / "ready")
+    release = str(tmp_path / "release")
+
+    ctx = _get_mp_context()
+    holder = ctx.Process(target=_hold_lock, args=(palace, ready, release))
+    holder.start()
+    try:
+        for _ in range(500):
+            if os.path.exists(ready):
+                break
+            time.sleep(0.01)
+        assert os.path.exists(ready), "holder failed to acquire lock"
+
+        # _FakeChromaCollection doesn't implement query/get/count; we only
+        # need to confirm the wrapper does not call into mine_palace_lock
+        # for reads, which we assert by observing the wrapped methods are
+        # NOT in ChromaCollection's _write_lock path. A direct check via
+        # source inspection is more honest than mocking the entire chroma
+        # surface here.
+        import inspect
+
+        from mempalace.backends.chroma import ChromaCollection as _CC
+
+        for write_attr in ("add", "upsert", "update", "delete"):
+            src = inspect.getsource(getattr(_CC, write_attr))
+            assert "_write_lock" in src, f"{write_attr} should acquire write lock"
+
+        for read_attr in ("query", "get", "count"):
+            method = getattr(_CC, read_attr, None)
+            if method is None:
+                continue
+            src = inspect.getsource(method)
+            assert (
+                "_write_lock" not in src
+            ), f"{read_attr} must NOT acquire the write lock (read path)"
+    finally:
+        open(release, "w").close()
+        holder.join(timeout=5)

tests/test_cli.py

@@ -4,7 +4,7 @@ import argparse
 import shlex
 import sys
 from pathlib import Path
-from unittest.mock import MagicMock, patch
+from unittest.mock import MagicMock, call, patch
 
 import pytest
 
@@ -776,6 +776,7 @@ def test_cmd_repair_error_reading(mock_config_cls, tmp_path, capsys):
     palace_dir.mkdir()
     (palace_dir / "chroma.sqlite3").write_text("db")
     mock_config_cls.return_value.palace_path = str(palace_dir)
+    mock_config_cls.return_value.collection_name = "mempalace_drawers"
     args = argparse.Namespace(palace=None)
     mock_backend = MagicMock()
     mock_backend.get_collection.side_effect = Exception("corrupt db")
@@ -791,6 +792,7 @@ def test_cmd_repair_zero_drawers(mock_config_cls, tmp_path, capsys):
     palace_dir.mkdir()
     (palace_dir / "chroma.sqlite3").write_text("db")
     mock_config_cls.return_value.palace_path = str(palace_dir)
+    mock_config_cls.return_value.collection_name = "mempalace_drawers"
     args = argparse.Namespace(palace=None)
     mock_col = MagicMock()
     mock_col.count.return_value = 0
@@ -807,6 +809,7 @@ def test_cmd_repair_success(mock_config_cls, tmp_path, capsys):
     palace_dir.mkdir()
     (palace_dir / "chroma.sqlite3").write_text("db")
     mock_config_cls.return_value.palace_path = str(palace_dir)
+    mock_config_cls.return_value.collection_name = "mempalace_drawers"
     args = argparse.Namespace(palace=None, yes=True)
     mock_col = MagicMock()
     mock_col.count.return_value = 2
@@ -815,13 +818,98 @@ def test_cmd_repair_success(mock_config_cls, tmp_path, capsys):
         "documents": ["doc1", "doc2"],
         "metadatas": [{"wing": "a"}, {"wing": "b"}],
     }
+    mock_temp_col = MagicMock()
+    mock_temp_col.count.return_value = 2
     mock_new_col = MagicMock()
+    mock_new_col.count.return_value = 2
     mock_backend = _mock_backend_for(col=mock_col, new_col=mock_new_col)
+    mock_backend.create_collection.side_effect = [mock_temp_col, mock_new_col]
     with patch("mempalace.backends.chroma.ChromaBackend", return_value=mock_backend):
         cmd_repair(args)
     out = capsys.readouterr().out
     assert "Repair complete" in out
     assert "2 drawers rebuilt" in out
+    assert mock_backend.delete_collection.call_args_list == [
+        call(str(palace_dir), "mempalace_drawers__repair_tmp"),
+        call(str(palace_dir), "mempalace_drawers"),
+        call(str(palace_dir), "mempalace_drawers__repair_tmp"),
+    ]
+    mock_temp_col.upsert.assert_called_once()
+    mock_new_col.upsert.assert_called_once()
+    mock_new_col.add.assert_not_called()
+
+
+@patch("mempalace.cli.MempalaceConfig")
+def test_cmd_repair_uses_configured_collection(mock_config_cls, tmp_path, capsys):
+    palace_dir = tmp_path / "palace"
+    palace_dir.mkdir()
+    (palace_dir / "chroma.sqlite3").write_text("db")
+    mock_config_cls.return_value.palace_path = str(palace_dir)
+    mock_config_cls.return_value.collection_name = "custom_drawers"
+    args = argparse.Namespace(palace=None, yes=True)
+    mock_col = MagicMock()
+    mock_col.count.return_value = 2
+    mock_col.get.return_value = {
+        "ids": ["id1", "id2"],
+        "documents": ["doc1", "doc2"],
+        "metadatas": [{"wing": "a"}, {"wing": "b"}],
+    }
+    mock_temp_col = MagicMock()
+    mock_temp_col.count.return_value = 2
+    mock_new_col = MagicMock()
+    mock_new_col.count.return_value = 2
+    mock_backend = _mock_backend_for(col=mock_col, new_col=mock_new_col)
+    mock_backend.create_collection.side_effect = [mock_temp_col, mock_new_col]
+
+    with patch("mempalace.backends.chroma.ChromaBackend", return_value=mock_backend):
+        cmd_repair(args)
+
+    out = capsys.readouterr().out
+    assert "Repair complete" in out
+    mock_backend.get_collection.assert_called_once_with(str(palace_dir), "custom_drawers")
+    assert mock_backend.create_collection.call_args_list == [
+        call(str(palace_dir), "custom_drawers__repair_tmp"),
+        call(str(palace_dir), "custom_drawers"),
+    ]
+    assert mock_backend.delete_collection.call_args_list == [
+        call(str(palace_dir), "custom_drawers__repair_tmp"),
+        call(str(palace_dir), "custom_drawers"),
+        call(str(palace_dir), "custom_drawers__repair_tmp"),
+    ]
+
+
+@patch("mempalace.cli.MempalaceConfig")
+def test_cmd_repair_restores_backup_on_live_rebuild_failure(mock_config_cls, tmp_path, capsys):
+    palace_dir = tmp_path / "palace"
+    palace_dir.mkdir()
+    (palace_dir / "chroma.sqlite3").write_text("db")
+    mock_config_cls.return_value.palace_path = str(palace_dir)
+    mock_config_cls.return_value.collection_name = "mempalace_drawers"
+    args = argparse.Namespace(palace=None, yes=True)
+    mock_col = MagicMock()
+    mock_col.count.return_value = 2
+    mock_col.get.return_value = {
+        "ids": ["id1", "id2"],
+        "documents": ["doc1", "doc2"],
+        "metadatas": [{"wing": "a"}, {"wing": "b"}],
+    }
+    mock_temp_col = MagicMock()
+    mock_temp_col.count.return_value = 2
+    mock_backend = _mock_backend_for(col=mock_col)
+    mock_backend.create_collection.side_effect = [mock_temp_col, RuntimeError("live build failed")]
+    with patch("mempalace.backends.chroma.ChromaBackend", return_value=mock_backend):
+        with pytest.raises(SystemExit) as excinfo:
+            cmd_repair(args)
+    out = capsys.readouterr().out
+    assert excinfo.value.code == 1
+    assert "Repair failed" in out
+    assert "restoring from backup" in out
+    mock_backend.close_palace.assert_called_once_with(str(palace_dir))
+    assert mock_backend.delete_collection.call_args_list == [
+        call(str(palace_dir), "mempalace_drawers__repair_tmp"),
+        call(str(palace_dir), "mempalace_drawers"),
+        call(str(palace_dir), "mempalace_drawers__repair_tmp"),
+    ]
 
 
 @patch("mempalace.cli.MempalaceConfig")
@@ -830,6 +918,7 @@ def test_cmd_repair_aborts_without_confirmation(mock_config_cls, tmp_path, capsy
     palace_dir.mkdir()
     (palace_dir / "chroma.sqlite3").write_text("db")
     mock_config_cls.return_value.palace_path = str(palace_dir)
+    mock_config_cls.return_value.collection_name = "mempalace_drawers"
     args = argparse.Namespace(palace=None)
     mock_col = MagicMock()
     mock_col.count.return_value = 1
@@ -1042,3 +1131,119 @@ def test_cmd_repair_trailing_slash_does_not_recurse():
     palace_path = os.path.expanduser(args.palace).rstrip(os.sep)
     backup_path = palace_path + ".backup"
     assert not backup_path.startswith(palace_path + os.sep)
+
+
+# ── stdio reconfigure on Windows ─────────────────────────────────────
+
+
+class _ReconfigurableStringIO:
+    def __init__(self):
+        self.reconfigure_calls = []
+
+    def reconfigure(self, **kwargs):
+        self.reconfigure_calls.append(kwargs)
+
+
+def test_reconfigures_stdio_to_utf8_on_windows():
+    """Windows `mempalace` CLI must decode/encode stdio as UTF-8.
+
+    Without this, piped non-ASCII input (`mempalace search ... < q.txt`)
+    or piped non-ASCII output (`mempalace search "..." > out.txt`) is
+    mojibaked through the system ANSI codepage on non-Latin Windows
+    locales (cp1252/cp1251/cp950).
+    """
+    from mempalace.cli import _reconfigure_stdio_utf8_on_windows
+
+    stdin = _ReconfigurableStringIO()
+    stdout = _ReconfigurableStringIO()
+    stderr = _ReconfigurableStringIO()
+    with (
+        patch.object(sys, "platform", "win32"),
+        patch.object(sys, "stdin", stdin),
+        patch.object(sys, "stdout", stdout),
+        patch.object(sys, "stderr", stderr),
+    ):
+        _reconfigure_stdio_utf8_on_windows()
+
+    # Per-stream errors policy: stdin survives bad bytes via
+    # surrogateescape so a redirected non-UTF-8 file does not crash
+    # the read; stdout/stderr use replace so a drawer carrying a
+    # round-tripped surrogate half does not crash mid-print.
+    assert stdin.reconfigure_calls == [{"encoding": "utf-8", "errors": "surrogateescape"}]
+    assert stdout.reconfigure_calls == [{"encoding": "utf-8", "errors": "replace"}]
+    assert stderr.reconfigure_calls == [{"encoding": "utf-8", "errors": "replace"}]
+
+
+def test_reconfigure_stdio_is_noop_off_windows():
+    """Linux/macOS already default to UTF-8 stdio -- helper must not touch streams."""
+    from mempalace.cli import _reconfigure_stdio_utf8_on_windows
+
+    stdin = _ReconfigurableStringIO()
+    with (
+        patch.object(sys, "platform", "linux"),
+        patch.object(sys, "stdin", stdin),
+    ):
+        _reconfigure_stdio_utf8_on_windows()
+
+    assert stdin.reconfigure_calls == []
+
+
+# ── cmd_repair: from-sqlite mode exit codes ──────────────────────────
+
+
+@patch("mempalace.cli.MempalaceConfig")
+def test_cmd_repair_from_sqlite_validation_refusal_exits_nonzero(mock_config_cls, tmp_path, capsys):
+    """When ``rebuild_from_sqlite`` returns ``{}`` for a validation
+    refusal (missing source DB, in-place without --archive-existing,
+    refusing to overwrite an existing dest), the CLI must surface a
+    non-zero exit so unattended scripts and CI distinguish "invalid
+    inputs" from "successful recovery that found zero rows."
+
+    Catches: a regression where the CLI treats the validation-refusal
+    sentinel as success, leaving CI green on a no-op repair that should
+    have alerted an operator.
+    """
+    palace_dir = tmp_path / "palace"
+    palace_dir.mkdir()
+    mock_config_cls.return_value.palace_path = str(palace_dir)
+
+    args = argparse.Namespace(
+        palace=str(palace_dir),
+        mode="from-sqlite",
+        source=None,
+        archive_existing=False,
+        yes=True,
+    )
+    with patch("mempalace.repair.rebuild_from_sqlite", return_value={}):
+        with pytest.raises(SystemExit) as excinfo:
+            cmd_repair(args)
+    assert excinfo.value.code == 1
+
+
+@patch("mempalace.cli.MempalaceConfig")
+def test_cmd_repair_from_sqlite_success_does_not_exit(mock_config_cls, tmp_path):
+    """A successful from-sqlite rebuild — even one that finds zero rows
+    in a legitimately empty source palace — must NOT call ``sys.exit``.
+    A populated counts dict (with ``0`` values) is the success signal;
+    only the empty dict ``{}`` is reserved for validation refusal.
+
+    Catches: a regression where ``if not counts`` is replaced by
+    ``if not sum(counts.values())`` or similar, conflating "empty source"
+    with "validation refused" and breaking idempotent recovery scripts.
+    """
+    palace_dir = tmp_path / "palace"
+    palace_dir.mkdir()
+    mock_config_cls.return_value.palace_path = str(palace_dir)
+
+    args = argparse.Namespace(
+        palace=str(palace_dir),
+        mode="from-sqlite",
+        source=None,
+        archive_existing=False,
+        yes=True,
+    )
+    # Zero rows but per-collection keys present → success, no exit.
+    fake_counts = {"mempalace_drawers": 0, "mempalace_closets": 0}
+    with patch("mempalace.repair.rebuild_from_sqlite", return_value=fake_counts):
+        # Should return cleanly; no SystemExit raised.
+        cmd_repair(args)

tests/test_closet_llm.py

@@ -296,6 +296,182 @@ class TestRegenerateClosets:
             assert meta.get("generated_by", "").startswith("llm:")
             assert meta.get("normalize_version") == NORMALIZE_VERSION
 
+    def test_regen_paginates_drawer_fetch(self, tmp_path):
+        """Regression for #1073: drawers_col.get must be paginated at
+        batch_size=5000. A single get(limit=total, ...) on a palace with
+        more than SQLite's SQLITE_MAX_VARIABLE_NUMBER (32766) drawers
+        blows up inside chromadb. Matches the miner.status pattern
+        introduced in #851 (see #802, #850, #1073)."""
+        from mempalace import closet_llm as closet_llm_mod
+
+        palace = str(tmp_path / "palace")
+
+        # Build a fake collection: 12_000 drawers across 3 source files,
+        # enough to force 3 batches of batch_size=5000 (5000 + 5000 + 2000).
+        n_drawers = 12_000
+        ids = [f"d{i:05d}" for i in range(n_drawers)]
+        docs = [f"doc body {i}" for i in range(n_drawers)]
+        metas = [
+            {
+                "wing": "w",
+                "room": "r",
+                "source_file": f"/src/file_{i % 3}.md",
+                "entities": "",
+            }
+            for i in range(n_drawers)
+        ]
+
+        get_calls: list = []
+
+        class FakeDrawersCol:
+            def count(self):
+                return n_drawers
+
+            def get(self, limit=None, offset=0, include=None, **kwargs):
+                get_calls.append({"limit": limit, "offset": offset, "include": include})
+                end = min(offset + (limit or n_drawers), n_drawers)
+                return {
+                    "ids": ids[offset:end],
+                    "documents": docs[offset:end],
+                    "metadatas": metas[offset:end],
+                }
+
+        class FakeClosetsCol:
+            """Accept the purge + upsert calls the success path makes."""
+
+            def get(self, *a, **kw):
+                return {"ids": [], "documents": [], "metadatas": []}
+
+            def delete(self, *a, **kw):
+                return None
+
+            def upsert(self, *a, **kw):
+                return None
+
+        fake_drawers = FakeDrawersCol()
+        fake_closets = FakeClosetsCol()
+
+        def fake_urlopen(req, timeout=None):
+            return _FakeResp(
+                {
+                    "choices": [
+                        {"message": {"content": '{"topics":["t1"],"quotes":[],"summary":""}'}}
+                    ],
+                    "usage": {"prompt_tokens": 1, "completion_tokens": 1},
+                }
+            )
+
+        cfg = LLMConfig(endpoint="http://local/v1", model="m")
+
+        with (
+            patch.object(closet_llm_mod, "get_collection", return_value=fake_drawers),
+            patch.object(closet_llm_mod, "get_closets_collection", return_value=fake_closets),
+            patch.object(closet_llm_mod, "purge_file_closets", return_value=None),
+            patch.object(closet_llm_mod, "upsert_closet_lines", return_value=None),
+            patch("urllib.request.urlopen", side_effect=fake_urlopen),
+        ):
+            result = regenerate_closets(palace, cfg=cfg, dry_run=True)
+
+        # Three paginated calls: (limit=5000, offset=0), (5000, 5000), (5000, 10000).
+        assert len(get_calls) == 3, f"expected 3 batched fetches, got {len(get_calls)}"
+        for call in get_calls:
+            assert (
+                call["limit"] == 5000
+            ), f"batch must be 5000 — got {call['limit']} (would risk SQLITE_MAX_VARIABLE_NUMBER)"
+            # include must still request both documents and metadatas
+            assert "documents" in call["include"]
+            assert "metadatas" in call["include"]
+        assert [c["offset"] for c in get_calls] == [0, 5000, 10_000]
+
+        # by_source aggregation must be preserved exactly across batches:
+        # 12_000 drawers, 3 source files → 4_000 drawers each.
+        # dry_run=True short-circuits LLM calls but still walks by_source.
+        assert result.get("processed", 0) == 0  # dry_run
+        # Verify no single call tried to pull more than batch_size.
+        assert max(c["limit"] for c in get_calls) <= 5000
+
+    def test_regen_by_source_aggregates_across_batches(self, tmp_path):
+        """Pagination must not change the by_source grouping — drawers for
+        the same source_file split across batches still land in one group."""
+        from mempalace import closet_llm as closet_llm_mod
+
+        palace = str(tmp_path / "palace")
+
+        # 7_500 drawers, alternating between two source files → forces
+        # splits across the 5000/2500 boundary. Each source ends up with
+        # 3_750 drawers after regrouping.
+        n_drawers = 7_500
+        ids = [f"d{i:05d}" for i in range(n_drawers)]
+        docs = [f"body-{i}" for i in range(n_drawers)]
+        metas = [
+            {
+                "wing": "w",
+                "room": "r",
+                "source_file": f"/src/file_{i % 2}.md",
+                "entities": "",
+            }
+            for i in range(n_drawers)
+        ]
+
+        captured_sources: dict = {}
+
+        class FakeDrawersCol:
+            def count(self):
+                return n_drawers
+
+            def get(self, limit=None, offset=0, include=None, **kwargs):
+                end = min(offset + (limit or n_drawers), n_drawers)
+                return {
+                    "ids": ids[offset:end],
+                    "documents": docs[offset:end],
+                    "metadatas": metas[offset:end],
+                }
+
+        class FakeClosetsCol:
+            def get(self, *a, **kw):
+                return {"ids": [], "documents": [], "metadatas": []}
+
+            def delete(self, *a, **kw):
+                return None
+
+            def upsert(self, *a, **kw):
+                return None
+
+        # Hook _call_llm to inspect what regenerate_closets aggregated
+        # per source before the HTTP boundary.
+        real_call_llm = closet_llm_mod._call_llm
+
+        def spying_call_llm(cfg, source_file, wing, room, content):
+            captured_sources[source_file] = content
+            return (
+                {"topics": ["t"], "quotes": [], "summary": ""},
+                {"prompt_tokens": 1, "completion_tokens": 1},
+            )
+
+        cfg = LLMConfig(endpoint="http://local/v1", model="m")
+
+        with (
+            patch.object(closet_llm_mod, "get_collection", return_value=FakeDrawersCol()),
+            patch.object(closet_llm_mod, "get_closets_collection", return_value=FakeClosetsCol()),
+            patch.object(closet_llm_mod, "purge_file_closets", return_value=None),
+            patch.object(closet_llm_mod, "upsert_closet_lines", return_value=None),
+            patch.object(closet_llm_mod, "_call_llm", side_effect=spying_call_llm),
+        ):
+            regenerate_closets(palace, cfg=cfg)
+
+        # Both sources survived the pagination boundary.
+        assert set(captured_sources.keys()) == {"/src/file_0.md", "/src/file_1.md"}
+        # Each source accumulated exactly 3_750 drawer bodies, concatenated
+        # with the "\n\n" separator the regenerate path uses.
+        for source, content in captured_sources.items():
+            assert content.count("\n\n") == 3_749, (
+                f"{source}: expected 3_750 chunks joined (3_749 separators), "
+                f"got {content.count(chr(10) + chr(10)) + 1}"
+            )
+
+        # Silence unused-var lint.
+        assert real_call_llm is not None
+
     def test_regen_uses_basename_not_split_slash(self, tmp_path, monkeypatch):
         """Regression: the old closet_id base used ``source.split('/')[-1]``
         which silently degrades on Windows paths (``C:\\proj\\a.md`` →

tests/test_config.py

@@ -3,7 +3,13 @@ import json
 import tempfile
 
 import pytest
-from mempalace.config import MempalaceConfig, normalize_wing_name, sanitize_kg_value, sanitize_name
+from mempalace.config import (
+    MempalaceConfig,
+    normalize_wing_name,
+    sanitize_iso_date,
+    sanitize_kg_value,
+    sanitize_name,
+)
 
 
 def test_default_config():
@@ -212,3 +218,69 @@ def test_kg_value_rejects_null_bytes():
 def test_kg_value_rejects_over_length():
     with pytest.raises(ValueError):
         sanitize_kg_value("a" * 129)
+
+
+# --- sanitize_iso_date ---
+
+
+def test_iso_date_rejects_year_only():
+    # Partial dates re-introduce silent empty result sets via lexicographic
+    # TEXT comparison in KG queries (e.g. "2026-01-01" <= "2026" is False).
+    with pytest.raises(ValueError):
+        sanitize_iso_date("2026")
+
+
+def test_iso_date_rejects_year_month():
+    with pytest.raises(ValueError):
+        sanitize_iso_date("2026-03")
+
+
+def test_iso_date_accepts_full_date():
+    assert sanitize_iso_date("2026-03-15") == "2026-03-15"
+
+
+def test_iso_date_passes_through_none():
+    assert sanitize_iso_date(None) is None
+
+
+def test_iso_date_passes_through_empty_string():
+    assert sanitize_iso_date("") == ""
+
+
+def test_iso_date_strips_whitespace():
+    assert sanitize_iso_date("  2026-03-15  ") == "2026-03-15"
+
+
+def test_iso_date_rejects_natural_language():
+    with pytest.raises(ValueError):
+        sanitize_iso_date("March 2026")
+
+
+def test_iso_date_rejects_abbreviated_month():
+    with pytest.raises(ValueError):
+        sanitize_iso_date("Jan 2025")
+
+
+def test_iso_date_rejects_us_format():
+    with pytest.raises(ValueError):
+        sanitize_iso_date("03/15/2026")
+
+
+def test_iso_date_rejects_invalid_month():
+    with pytest.raises(ValueError):
+        sanitize_iso_date("2026-13")
+
+
+def test_iso_date_rejects_invalid_day():
+    with pytest.raises(ValueError):
+        sanitize_iso_date("2026-02-32")
+
+
+def test_iso_date_rejects_non_string():
+    with pytest.raises(ValueError):
+        sanitize_iso_date(20260315)
+
+
+def test_iso_date_error_names_field():
+    with pytest.raises(ValueError, match="valid_from"):
+        sanitize_iso_date("yesterday", "valid_from")

tests/test_entity_registry.py

@@ -2,6 +2,8 @@
 
 from unittest.mock import patch
 
+import pytest
+
 from mempalace.entity_registry import (
     COMMON_ENGLISH_WORDS,
     PERSON_CONTEXT_PATTERNS,
@@ -71,6 +73,50 @@ def test_save_creates_file(tmp_path):
     assert (tmp_path / "entity_registry.json").exists()
 
 
+def test_save_is_atomic_does_not_leave_tmp(tmp_path):
+    # Atomic write must not leave the .tmp sidecar file after a successful save.
+    registry = EntityRegistry.load(config_dir=tmp_path)
+    registry.save()
+    leftover = list(tmp_path.glob("entity_registry.json.tmp*"))
+    assert leftover == [], f"atomic write leaked tmp file(s): {leftover}"
+
+
+def test_save_preserves_previous_on_serialization_failure(tmp_path, monkeypatch):
+    # If serialization fails mid-write, the previous registry must remain
+    # intact — this is the whole point of atomic write vs truncating in place.
+    registry = EntityRegistry.load(config_dir=tmp_path)
+    registry.seed(
+        mode="personal",
+        people=[{"name": "Alice", "relationship": "friend", "context": "personal"}],
+        projects=[],
+    )
+    registry.save()
+    target = tmp_path / "entity_registry.json"
+    original = target.read_text(encoding="utf-8")
+
+    # Force os.replace to raise — simulates filesystem full / permission flip
+    # AFTER the temp file is written but BEFORE the rename completes.
+    import os as _os
+
+    real_replace = _os.replace
+
+    def boom(src, dst):
+        raise OSError("simulated rename failure")
+
+    monkeypatch.setattr(_os, "replace", boom)
+    with pytest.raises(OSError):
+        registry.seed(
+            mode="personal",
+            people=[{"name": "Bob", "relationship": "friend", "context": "personal"}],
+            projects=[],
+        )
+        registry.save()
+
+    # Restore os.replace before reading so the assertion can rely on it.
+    monkeypatch.setattr(_os, "replace", real_replace)
+    assert target.read_text(encoding="utf-8") == original
+
+
 # ── seed ────────────────────────────────────────────────────────────────
 
 

tests/test_fact_checker.py

@@ -286,3 +286,66 @@ class TestCLI:
         assert "similar_name" in out
         # Silence unused import warning.
         _ = (MagicMock, patch, fact_checker)
+
+    def test_reconfigures_stdio_to_utf8_on_windows(self):
+        """Windows fact_checker --stdin must decode payload as UTF-8.
+
+        Without this, Python defaults stdio to the system ANSI codepage
+        (cp1252/cp1251/cp950), which mojibakes non-ASCII text before
+        pattern parsing sees it.
+        """
+        import io
+        import sys
+
+        from mempalace.fact_checker import _reconfigure_stdio_utf8_on_windows
+
+        class _ReconfigurableStringIO(io.StringIO):
+            def __init__(self, initial_value=""):
+                super().__init__(initial_value)
+                self.reconfigure_calls = []
+
+            def reconfigure(self, **kwargs):
+                self.reconfigure_calls.append(kwargs)
+
+        stdin = _ReconfigurableStringIO()
+        stdout = _ReconfigurableStringIO()
+        stderr = _ReconfigurableStringIO()
+        with (
+            patch.object(sys, "platform", "win32"),
+            patch.object(sys, "stdin", stdin),
+            patch.object(sys, "stdout", stdout),
+            patch.object(sys, "stderr", stderr),
+        ):
+            _reconfigure_stdio_utf8_on_windows()
+
+        # Per-stream errors policy: stdin uses surrogateescape so a stray
+        # malformed byte from a redirected file does not crash the read,
+        # stdout/stderr use replace so an extracted fact carrying a
+        # surrogate half does not crash mid-print.
+        assert stdin.reconfigure_calls == [{"encoding": "utf-8", "errors": "surrogateescape"}]
+        assert stdout.reconfigure_calls == [{"encoding": "utf-8", "errors": "replace"}]
+        assert stderr.reconfigure_calls == [{"encoding": "utf-8", "errors": "replace"}]
+
+    def test_reconfigure_stdio_is_noop_off_windows(self):
+        """Linux/macOS already default to UTF-8 stdio -- helper must not touch streams."""
+        import io
+        import sys
+
+        from mempalace.fact_checker import _reconfigure_stdio_utf8_on_windows
+
+        class _ReconfigurableStringIO(io.StringIO):
+            def __init__(self):
+                super().__init__()
+                self.reconfigure_calls = []
+
+            def reconfigure(self, **kwargs):
+                self.reconfigure_calls.append(kwargs)
+
+        stdin = _ReconfigurableStringIO()
+        with (
+            patch.object(sys, "platform", "linux"),
+            patch.object(sys, "stdin", stdin),
+        ):
+            _reconfigure_stdio_utf8_on_windows()
+
+        assert stdin.reconfigure_calls == []

tests/test_hnsw_capacity.py

@@ -238,14 +238,40 @@ def test_capacity_status_tolerates_flush_lag(tmp_path):
     assert info["status"] == "ok"
 
 
-def test_capacity_status_flags_unflushed_with_large_sqlite(tmp_path):
-    """No pickle + many sqlite rows is its own divergence signal."""
+def test_capacity_status_does_not_flag_unflushed_with_large_sqlite(tmp_path):
+    """No pickle + many sqlite rows is inconclusive, not divergence."""
     seg = "seg-noflush"
     _seed_chroma_db(str(tmp_path), sqlite_count=10_000, segment_id=seg)
     info = hnsw_capacity_status(str(tmp_path), COLLECTION)
-    assert info["diverged"] is True
+    assert info["diverged"] is False
+    assert info["status"] == "unknown"
+    assert info["divergence"] is None
     assert info["hnsw_count"] is None
-    assert "never flushed" in info["message"]
+    assert "capacity unavailable" in info["message"]
+    assert "leaving vector search enabled" in info["message"]
+
+
+def test_mcp_probe_does_not_disable_vectors_for_unflushed_metadata(tmp_path, monkeypatch):
+    """The MCP preflight must not route all searches to BM25 on this signal."""
+    from mempalace import mcp_server
+
+    seg = "seg-mcp-noflush"
+    _seed_chroma_db(str(tmp_path), sqlite_count=10_000, segment_id=seg)
+
+    class _Cfg:
+        palace_path = str(tmp_path)
+        collection_name = "mempalace_drawers"
+
+    monkeypatch.setattr(mcp_server, "_config", _Cfg())
+    monkeypatch.setattr(mcp_server, "_vector_disabled", True)
+    monkeypatch.setattr(mcp_server, "_vector_disabled_reason", "old divergence")
+
+    mcp_server._refresh_vector_disabled_flag()
+
+    assert mcp_server._vector_disabled is False
+    assert mcp_server._vector_disabled_reason == ""
+    assert mcp_server._vector_capacity_status["status"] == "unknown"
+    assert "leaving vector search enabled" in mcp_server._vector_capacity_status["message"]
 
 
 def test_capacity_status_quiet_for_empty_palace(tmp_path):
@@ -372,6 +398,17 @@ def _seed_drawers(palace: str, segment_id: str, drawers: list[tuple[str, dict, s
         conn.close()
 
 
+def _set_drawer_created_at(palace: str, timestamps: dict[int, str]) -> None:
+    db_path = os.path.join(palace, "chroma.sqlite3")
+    conn = sqlite3.connect(db_path)
+    try:
+        for emb_id, created_at in timestamps.items():
+            conn.execute("UPDATE embeddings SET created_at = ? WHERE id = ?", (created_at, emb_id))
+        conn.commit()
+    finally:
+        conn.close()
+
+
 @pytest.fixture
 def palace_with_drawers(tmp_path):
     seg = "seg-bm25"
@@ -417,6 +454,122 @@ def test_bm25_fallback_filters_by_wing(palace_with_drawers):
     assert all(r["wing"] == "design" for r in out["results"])
 
 
+def test_bm25_fallback_applies_wing_before_fts_candidate_limit(tmp_path):
+    seg = "seg-bm25-fts-limit"
+    _seed_chroma_db(str(tmp_path), sqlite_count=0, segment_id=seg)
+    _seed_drawers(
+        str(tmp_path),
+        seg,
+        [
+            (
+                "shared token outside target wing",
+                {"wing": "ops", "room": "incidents", "source_file": "/x/ops.md"},
+                "d-1",
+            ),
+            (
+                "shared token inside target wing",
+                {"wing": "project", "room": "diary", "source_file": "/x/project.md"},
+                "d-2",
+            ),
+        ],
+    )
+
+    out = _bm25_only_via_sqlite("shared token", str(tmp_path), wing="project", max_candidates=1)
+
+    assert out["total_before_filter"] == 1
+    assert len(out["results"]) == 1
+    assert out["results"][0]["wing"] == "project"
+
+
+def test_bm25_fallback_applies_room_before_fts_candidate_limit(tmp_path):
+    seg = "seg-bm25-room-limit"
+    _seed_chroma_db(str(tmp_path), sqlite_count=0, segment_id=seg)
+    _seed_drawers(
+        str(tmp_path),
+        seg,
+        [
+            (
+                "shared token wrong room",
+                {"wing": "project", "room": "scratch", "source_file": "/x/scratch.md"},
+                "d-1",
+            ),
+            (
+                "shared token right room",
+                {"wing": "project", "room": "diary", "source_file": "/x/diary.md"},
+                "d-2",
+            ),
+        ],
+    )
+
+    out = _bm25_only_via_sqlite(
+        "shared token",
+        str(tmp_path),
+        wing="project",
+        room="diary",
+        max_candidates=1,
+    )
+
+    assert out["total_before_filter"] == 1
+    assert len(out["results"]) == 1
+    assert out["results"][0]["wing"] == "project"
+    assert out["results"][0]["room"] == "diary"
+
+
+def test_bm25_fallback_applies_wing_before_recency_candidate_limit(tmp_path):
+    seg = "seg-bm25-recency-limit"
+    _seed_chroma_db(str(tmp_path), sqlite_count=0, segment_id=seg)
+    _seed_drawers(
+        str(tmp_path),
+        seg,
+        [
+            (
+                "target drawer for short query",
+                {"wing": "project", "room": "diary", "source_file": "/x/project.md"},
+                "d-1",
+            ),
+            (
+                "newer drawer outside target wing",
+                {"wing": "ops", "room": "incidents", "source_file": "/x/ops.md"},
+                "d-2",
+            ),
+        ],
+    )
+    _set_drawer_created_at(
+        str(tmp_path),
+        {
+            1: "2026-01-01 00:00:00",
+            2: "2026-02-01 00:00:00",
+        },
+    )
+
+    out = _bm25_only_via_sqlite("a", str(tmp_path), wing="project", max_candidates=1)
+
+    assert out["total_before_filter"] == 1
+    assert len(out["results"]) == 1
+    assert out["results"][0]["wing"] == "project"
+
+
+def test_bm25_fallback_returns_empty_when_filtered_wing_has_no_candidates(tmp_path):
+    seg = "seg-bm25-empty-filter"
+    _seed_chroma_db(str(tmp_path), sqlite_count=0, segment_id=seg)
+    _seed_drawers(
+        str(tmp_path),
+        seg,
+        [
+            (
+                "shared token outside target wing",
+                {"wing": "ops", "room": "incidents", "source_file": "/x/ops.md"},
+                "d-1",
+            ),
+        ],
+    )
+
+    out = _bm25_only_via_sqlite("shared token", str(tmp_path), wing="project", max_candidates=1)
+
+    assert out["total_before_filter"] == 0
+    assert out["results"] == []
+
+
 def test_bm25_fallback_no_palace(tmp_path):
     out = _bm25_only_via_sqlite("anything", str(tmp_path))
     assert "error" in out
@@ -473,6 +626,7 @@ def test_tool_status_via_sqlite_returns_breakdown(palace_with_drawers, monkeypat
     # MempalaceConfig.
     class _Cfg:
         palace_path = str(palace_with_drawers)
+        collection_name = "mempalace_drawers"
 
     monkeypatch.setattr(mcp_server, "_config", _Cfg())
     monkeypatch.setattr(mcp_server, "_vector_disabled", True)

tests/test_hnsw_payload_health.py

@@ -0,0 +1,113 @@
+import os
+from pathlib import Path
+
+from mempalace.backends.chroma import (
+    _HNSW_LINK_TO_DATA_MAX_RATIO,
+    _hnsw_link_to_data_ratio,
+    _segment_appears_healthy,
+    quarantine_stale_hnsw,
+)
+
+
+def _write_segment(
+    seg_dir: Path,
+    *,
+    data_size: int = 100,
+    link_size: int = 100,
+    write_metadata: bool = True,
+) -> None:
+    seg_dir.mkdir(parents=True, exist_ok=True)
+    (seg_dir / "data_level0.bin").write_bytes(b"\0" * data_size)
+    (seg_dir / "link_lists.bin").write_bytes(b"\0" * link_size)
+
+    if write_metadata:
+        # Enough bytes to pass the existing pickle envelope sniff-test:
+        # starts with pickle protocol marker 0x80 and ends with STOP 0x2e.
+        (seg_dir / "index_metadata.pickle").write_bytes(b"\x80" + b"x" * 16 + b"\x2e")
+
+
+def test_hnsw_link_to_data_ratio_reports_payload_size_ratio(tmp_path):
+    seg_dir = tmp_path / "11111111-2222-3333-4444-555555555555"
+    _write_segment(seg_dir, data_size=100, link_size=250)
+
+    assert _hnsw_link_to_data_ratio(str(seg_dir)) == 2.5
+
+
+def test_segment_health_rejects_exploded_link_lists_even_with_valid_pickle(tmp_path):
+    seg_dir = tmp_path / "11111111-2222-3333-4444-555555555555"
+    _write_segment(
+        seg_dir,
+        data_size=100,
+        link_size=int(100 * (_HNSW_LINK_TO_DATA_MAX_RATIO + 1)),
+        write_metadata=True,
+    )
+
+    assert not _segment_appears_healthy(str(seg_dir))
+
+
+def test_segment_health_keeps_reasonable_payload_with_valid_pickle(tmp_path):
+    seg_dir = tmp_path / "11111111-2222-3333-4444-555555555555"
+    _write_segment(
+        seg_dir,
+        data_size=100,
+        link_size=int(100 * _HNSW_LINK_TO_DATA_MAX_RATIO),
+        write_metadata=True,
+    )
+
+    assert _segment_appears_healthy(str(seg_dir))
+
+
+def test_quarantine_catches_link_bloat_without_mtime_drift(tmp_path):
+    palace = tmp_path / "palace"
+    palace.mkdir()
+
+    db_path = palace / "chroma.sqlite3"
+    db_path.write_text("sqlite placeholder")
+
+    seg_dir = palace / "11111111-2222-3333-4444-555555555555"
+    _write_segment(
+        seg_dir,
+        data_size=100,
+        link_size=int(100 * (_HNSW_LINK_TO_DATA_MAX_RATIO + 1)),
+        write_metadata=True,
+    )
+
+    # Make sqlite and HNSW mtimes identical. The old mtime-only gate would
+    # skip this segment even though the payload is structurally corrupt.
+    same_time = 1_700_000_000
+    os.utime(db_path, (same_time, same_time))
+    os.utime(seg_dir / "data_level0.bin", (same_time, same_time))
+
+    moved = quarantine_stale_hnsw(str(palace), stale_seconds=999_999)
+
+    assert len(moved) == 1
+    assert not seg_dir.exists()
+
+    moved_path = Path(moved[0])
+    assert moved_path.exists()
+    assert moved_path.name.startswith("11111111-2222-3333-4444-555555555555.drift-")
+
+
+def test_quarantine_leaves_reasonable_payload_in_place(tmp_path):
+    palace = tmp_path / "palace"
+    palace.mkdir()
+
+    db_path = palace / "chroma.sqlite3"
+    db_path.write_text("sqlite placeholder")
+
+    seg_dir = palace / "11111111-2222-3333-4444-555555555555"
+    _write_segment(
+        seg_dir,
+        data_size=100,
+        link_size=100,
+        write_metadata=True,
+    )
+
+    same_time = 1_700_000_000
+    os.utime(db_path, (same_time, same_time))
+    os.utime(seg_dir / "data_level0.bin", (same_time, same_time))
+
+    moved = quarantine_stale_hnsw(str(palace), stale_seconds=999_999)
+
+    assert moved == []
+    assert seg_dir.exists()

tests/test_hooks_cli.py

@@ -8,6 +8,7 @@ from unittest.mock import MagicMock, patch
 
 import pytest
 
+import mempalace.hooks_cli as hooks_cli_mod
 from mempalace.hooks_cli import (
     SAVE_INTERVAL,
     _count_human_messages,
@@ -959,3 +960,108 @@ def test_stop_hook_rejects_injected_stop_hook_active(tmp_path):
     # The injected value is not "true"/"1"/"yes", so the hook should NOT pass through.
     # Save must have been attempted.
     assert mock_save.called
+
+
+# --- Absent palace root: hooks must not recreate ~/.mempalace ---
+#
+# When the user removes ~/.mempalace (e.g. `rm -rf`), that is the strongest
+# possible "do not auto-capture" signal. Hooks must short-circuit BEFORE
+# touching disk — including before the log-line that previously triggered
+# STATE_DIR.mkdir() on its own.
+
+
+def _redirect_palace_root(monkeypatch, tmp_path):
+    """Point PALACE_ROOT and STATE_DIR at a tmp location that does NOT exist."""
+    fake_root = tmp_path / "absent-mempalace"
+    monkeypatch.setattr(hooks_cli_mod, "PALACE_ROOT", fake_root)
+    monkeypatch.setattr(hooks_cli_mod, "STATE_DIR", fake_root / "hook_state")
+    monkeypatch.setattr(hooks_cli_mod, "_state_dir_initialized", False)
+    return fake_root
+
+
+def test_hook_stop_does_not_create_palace_dir_when_absent(tmp_path, monkeypatch):
+    fake_root = _redirect_palace_root(monkeypatch, tmp_path)
+    transcript = tmp_path / "t.jsonl"
+    transcript.write_text("")
+    buf = io.StringIO()
+    with contextlib.redirect_stdout(buf):
+        hook_stop(
+            {"session_id": "absent", "transcript_path": str(transcript), "stop_hook_active": False},
+            "claude-code",
+        )
+    assert json.loads(buf.getvalue() or "{}") == {}
+    assert not fake_root.exists()
+
+
+def test_hook_precompact_does_not_create_palace_dir_when_absent(tmp_path, monkeypatch):
+    fake_root = _redirect_palace_root(monkeypatch, tmp_path)
+    transcript = tmp_path / "t.jsonl"
+    transcript.write_text("")
+    buf = io.StringIO()
+    with contextlib.redirect_stdout(buf):
+        hook_precompact(
+            {"session_id": "absent", "transcript_path": str(transcript)},
+            "claude-code",
+        )
+    assert json.loads(buf.getvalue() or "{}") == {}
+    assert not fake_root.exists()
+
+
+def test_hook_session_start_does_not_create_palace_dir_when_absent(tmp_path, monkeypatch):
+    fake_root = _redirect_palace_root(monkeypatch, tmp_path)
+    buf = io.StringIO()
+    with contextlib.redirect_stdout(buf):
+        hook_session_start({"session_id": "absent"}, "claude-code")
+    assert json.loads(buf.getvalue() or "{}") == {}
+    assert not fake_root.exists()
+
+
+def test_log_does_not_create_palace_dir_when_absent(tmp_path, monkeypatch):
+    fake_root = _redirect_palace_root(monkeypatch, tmp_path)
+    _log("test message")
+    assert not fake_root.exists()
+
+
+def test_existing_dir_proceeds_normally(tmp_path, monkeypatch):
+    """Regression: when PALACE_ROOT exists, hooks must proceed (no short-circuit)."""
+    fake_root = tmp_path / "present-mempalace"
+    fake_root.mkdir()
+    monkeypatch.setattr(hooks_cli_mod, "PALACE_ROOT", fake_root)
+    monkeypatch.setattr(hooks_cli_mod, "STATE_DIR", fake_root / "hook_state")
+    monkeypatch.setattr(hooks_cli_mod, "_state_dir_initialized", False)
+    _log("test message")
+    # _log should have created the state dir under the existing palace root
+    assert (fake_root / "hook_state").exists()
+    assert (fake_root / "hook_state" / "hook.log").is_file()
+
+
+def test_regular_file_at_palace_root_treated_as_absent(tmp_path, monkeypatch):
+    """A regular file at ~/.mempalace must be treated the same as absent.
+
+    ``Path.exists()`` returns True for a regular file, which would let the
+    kill-switch be bypassed and crash later when ``STATE_DIR.mkdir()`` runs
+    on ``NotADirectoryError``. ``_palace_root_exists()`` must use
+    ``is_dir()`` so a stray file (or broken symlink) short-circuits cleanly.
+    """
+    fake_root = tmp_path / "file-not-dir"
+    fake_root.write_text("oops, this is a file not a directory")
+    monkeypatch.setattr(hooks_cli_mod, "PALACE_ROOT", fake_root)
+    monkeypatch.setattr(hooks_cli_mod, "STATE_DIR", fake_root / "hook_state")
+    monkeypatch.setattr(hooks_cli_mod, "_state_dir_initialized", False)
+
+    # _palace_root_exists() is the source of truth — it must return False.
+    assert hooks_cli_mod._palace_root_exists() is False
+
+    # Hooks must short-circuit (return {} on stdout) and not touch disk.
+    buf = io.StringIO()
+    with contextlib.redirect_stdout(buf):
+        hook_session_start({"session_id": "file-at-root"}, "claude-code")
+    assert json.loads(buf.getvalue() or "{}") == {}
+
+    # _log must also short-circuit — it must NOT try to mkdir a path under a
+    # regular file (which would raise NotADirectoryError).
+    _log("test message")  # would raise if not short-circuited
+
+    # The stray file is left untouched; we never try to convert it.
+    assert fake_root.is_file()
+    assert fake_root.read_text() == "oops, this is a file not a directory"

tests/test_knowledge_graph.py

@@ -5,6 +5,8 @@ Covers: entity CRUD, triple CRUD, temporal queries, invalidation,
 timeline, stats, and edge cases (duplicate triples, ID collisions).
 """
 
+import pytest
+
 
 class TestEntityOperations:
     def test_add_entity(self, kg):
@@ -45,6 +47,38 @@ class TestTripleOperations:
         tid2 = kg.add_triple("Alice", "works_at", "Acme")
         assert tid1 != tid2  # new triple since old one was closed
 
+    def test_add_triple_rejects_inverted_interval(self, kg):
+        # valid_to before valid_from would never satisfy
+        # `valid_from <= as_of AND valid_to >= as_of` — silently invisible
+        # to every query. Reject at write time instead.
+        with pytest.raises(ValueError, match="before valid_from"):
+            kg.add_triple(
+                "Alice",
+                "worked_at",
+                "Acme",
+                valid_from="2026-03-01",
+                valid_to="2026-02-01",
+            )
+
+    def test_add_triple_accepts_equal_dates(self, kg):
+        # Same-day intervals are valid (point-in-time facts).
+        tid = kg.add_triple(
+            "Alice",
+            "joined",
+            "Acme",
+            valid_from="2026-03-15",
+            valid_to="2026-03-15",
+        )
+        assert tid.startswith("t_alice_joined_acme_")
+
+    def test_add_triple_allows_only_one_bound(self, kg):
+        # The guard only fires when BOTH bounds are set.
+        tid1 = kg.add_triple("Alice", "knows", "Bob", valid_from="2026-01-01")
+        assert tid1.startswith("t_alice_knows_bob_")
+        kg.invalidate("Alice", "knows", "Bob", ended="2026-02-01")
+        tid2 = kg.add_triple("Alice", "knew", "Bob", valid_to="2026-03-01")
+        assert tid2.startswith("t_alice_knew_bob_")
+
 
 class TestQueries:
     def test_query_outgoing(self, seeded_kg):

tests/test_layers.py

@@ -655,3 +655,72 @@ def test_memory_stack_status_with_palace(tmp_path):
 
     assert result["total_drawers"] == 42
     assert result["L0_identity"]["exists"] is True
+
+
+# ── Layer1 / Layer2 None-metadata guards ───────────────────────────────
+#
+# Chroma 1.5.x can return ``None`` inside the ``metadatas`` / ``documents``
+# lists for partially-flushed rows. The Layer1.generate() and
+# Layer2.retrieve() loops previously called ``meta.get(...)`` without
+# coercing, raising ``AttributeError: 'NoneType' object has no attribute
+# 'get'`` and blowing up the whole wake-up render. These tests guard that
+# the loops tolerate the None entries and render the rest of the result.
+
+
+def test_layer1_handles_none_metadata():
+    """Layer1.generate tolerates None entries in the metadatas list."""
+    docs = ["important memory", "another memory"]
+    metas = [{"room": "decisions", "source_file": "a.txt"}, None]
+    mock_col = _mock_chromadb_for_layer(docs, metas)
+
+    with (
+        patch("mempalace.layers.MempalaceConfig") as mock_cfg,
+        patch("mempalace.layers._get_collection", return_value=mock_col),
+    ):
+        mock_cfg.return_value.palace_path = "/fake"
+        layer = Layer1(palace_path="/fake")
+        # Should not raise AttributeError on the None entry.
+        result = layer.generate()
+
+    assert "ESSENTIAL STORY" in result
+    assert "important memory" in result
+
+
+def test_layer1_handles_none_document():
+    """Layer1.generate tolerates None entries in the documents list."""
+    docs = ["first doc", None]
+    metas = [
+        {"room": "r", "source_file": "a.txt"},
+        {"room": "r", "source_file": "b.txt"},
+    ]
+    mock_col = _mock_chromadb_for_layer(docs, metas)
+
+    with (
+        patch("mempalace.layers.MempalaceConfig") as mock_cfg,
+        patch("mempalace.layers._get_collection", return_value=mock_col),
+    ):
+        mock_cfg.return_value.palace_path = "/fake"
+        layer = Layer1(palace_path="/fake")
+        result = layer.generate()
+
+    assert result  # Render succeeded despite the None document.
+
+
+def test_layer2_handles_none_metadata():
+    """Layer2.retrieve tolerates None entries in the metadatas list."""
+    mock_col = MagicMock()
+    mock_col.get.return_value = {
+        "documents": ["first doc", "second doc"],
+        "metadatas": [{"room": "r", "source_file": "a.txt"}, None],
+    }
+
+    with (
+        patch("mempalace.layers.MempalaceConfig") as mock_cfg,
+        patch("mempalace.layers._get_collection", return_value=mock_col),
+    ):
+        mock_cfg.return_value.palace_path = "/fake"
+        layer = Layer2(palace_path="/fake")
+        # Should not raise AttributeError on the None entry.
+        result = layer.retrieve()
+
+    assert "L2 — ON-DEMAND" in result

tests/test_mcp_server.py

@@ -8,7 +8,9 @@ via monkeypatch to avoid touching real data.
 
 from datetime import datetime
 import json
+import os
 import sys
+from unittest.mock import MagicMock
 
 import pytest
 
@@ -18,7 +20,7 @@ def _patch_mcp_server(monkeypatch, config, kg):
     from mempalace import mcp_server
 
     monkeypatch.setattr(mcp_server, "_config", config)
-    monkeypatch.setattr(mcp_server, "_kg", kg)
+    monkeypatch.setattr(mcp_server, "_get_kg", lambda: kg)
 
 
 def _get_collection(palace_path, create=False):
@@ -146,6 +148,20 @@ class TestHandleRequest:
         )
         assert resp["error"]["code"] == -32601
 
+    def test_tools_call_missing_params(self):
+        from mempalace.mcp_server import handle_request
+
+        for bad_params in [None, {}, {"arguments": {}}]:
+            resp = handle_request(
+                {
+                    "method": "tools/call",
+                    "id": 15,
+                    "params": bad_params,
+                }
+            )
+            assert resp["error"]["code"] == -32602
+            assert "Invalid params" in resp["error"]["message"]
+
     def test_unknown_method(self):
         from mempalace.mcp_server import handle_request
 
@@ -188,6 +204,17 @@ class TestHandleRequest:
         resp = handle_request({"method": None, "id": 99, "params": {}})
         assert resp["error"]["code"] == -32601
 
+    @pytest.mark.parametrize("payload", [None, [], "plain", 42, True])
+    def test_handle_request_invalid_payload_returns_jsonrpc_error(self, payload):
+        from mempalace.mcp_server import handle_request
+
+        resp = handle_request(payload)
+        assert resp == {
+            "jsonrpc": "2.0",
+            "id": None,
+            "error": {"code": -32600, "message": "Invalid Request"},
+        }
+
     def test_tools_call_dispatches(self, monkeypatch, config, palace_path, seeded_kg):
         _patch_mcp_server(monkeypatch, config, seeded_kg)
         from mempalace.mcp_server import handle_request
@@ -457,6 +484,26 @@ class TestWriteTools:
         assert result2["success"] is True
         assert result2["reason"] == "already_exists"
 
+    def test_add_drawer_fails_when_readback_misses(self, monkeypatch, config, kg):
+        _patch_mcp_server(monkeypatch, config, kg)
+        from mempalace import mcp_server
+
+        class _FakeGetResult:
+            ids = []
+
+        class _FakeCol:
+            def get(self, **kwargs):
+                return _FakeGetResult()
+
+            def upsert(self, **kwargs):
+                return None
+
+        monkeypatch.setattr(mcp_server, "_get_collection", lambda create=False: _FakeCol())
+
+        result = mcp_server.tool_add_drawer("w", "r", "content")
+        assert result["success"] is False
+        assert "not readable" in result["error"]
+
     def test_add_drawer_shared_header_no_collision(self, monkeypatch, config, palace_path, kg):
         """Documents sharing a >100-char header must get distinct IDs (full-content hash)."""
         _patch_mcp_server(monkeypatch, config, kg)
@@ -495,6 +542,41 @@ class TestWriteTools:
         result = tool_delete_drawer("nonexistent_drawer")
         assert result["success"] is False
 
+    def test_check_duplicate_handles_none_metadata(self, monkeypatch, config, kg):
+        """tool_check_duplicate must tolerate None entries in the result lists
+        that ChromaDB 1.5.x returns for partially-flushed rows.
+
+        Previously ``meta = results["metadatas"][0][i]`` was unguarded and
+        raised ``AttributeError: 'NoneType' object has no attribute 'get'``
+        the moment the first matching drawer came back with None metadata —
+        surfacing to the MCP client as the uninformative
+        ``"Duplicate check failed"`` because the broad ``except Exception``
+        wrapper swallows the real cause.
+        """
+        _patch_mcp_server(monkeypatch, config, kg)
+        from mempalace import mcp_server
+
+        mock_col = MagicMock()
+        mock_col.query.return_value = {
+            "ids": [["d1", "d2"]],
+            "distances": [[0.05, 0.05]],
+            "metadatas": [[{"wing": "w", "room": "r"}, None]],
+            "documents": [["first doc", None]],
+        }
+        monkeypatch.setattr(mcp_server, "_get_collection", lambda: mock_col)
+
+        result = mcp_server.tool_check_duplicate("any content", threshold=0.5)
+
+        # Both entries land in matches (above threshold), None ones rendered
+        # with sentinel values rather than crashing the whole response.
+        assert result.get("is_duplicate") is True
+        assert len(result["matches"]) == 2
+        # The None-metadata entry falls back to sentinels.
+        none_entry = result["matches"][1]
+        assert none_entry["wing"] == "?"
+        assert none_entry["room"] == "?"
+        assert none_entry["content"] == ""
+
     def test_check_duplicate(self, monkeypatch, config, palace_path, seeded_collection, kg):
         _patch_mcp_server(monkeypatch, config, kg)
         from mempalace.mcp_server import tool_check_duplicate
@@ -788,6 +870,59 @@ class TestKGTools:
         result = tool_kg_stats()
         assert result["entities"] >= 4
 
+    # --- Date validation at the MCP boundary (issue #1164) ---
+
+    def test_kg_add_rejects_invalid_valid_from(self, monkeypatch, config, palace_path, kg):
+        _patch_mcp_server(monkeypatch, config, kg)
+        from mempalace.mcp_server import tool_kg_add
+
+        result = tool_kg_add(
+            subject="Alice",
+            predicate="likes",
+            object="coffee",
+            valid_from="Jan 2025",
+        )
+        assert result["success"] is False
+        assert "valid_from" in result["error"]
+        assert "ISO-8601" in result["error"]
+
+    def test_kg_query_rejects_invalid_as_of(self, monkeypatch, config, palace_path, seeded_kg):
+        _patch_mcp_server(monkeypatch, config, seeded_kg)
+        from mempalace.mcp_server import tool_kg_query
+
+        result = tool_kg_query(entity="Max", as_of="March 2026")
+        assert "error" in result
+        assert "as_of" in result["error"]
+
+    def test_kg_invalidate_rejects_invalid_ended(self, monkeypatch, config, palace_path, seeded_kg):
+        _patch_mcp_server(monkeypatch, config, seeded_kg)
+        from mempalace.mcp_server import tool_kg_invalidate
+
+        result = tool_kg_invalidate(
+            subject="Max",
+            predicate="does",
+            object="chess",
+            ended="yesterday",
+        )
+        assert result["success"] is False
+        assert "ended" in result["error"]
+
+    def test_kg_query_rejects_partial_iso_dates(self, monkeypatch, config, palace_path, seeded_kg):
+        _patch_mcp_server(monkeypatch, config, seeded_kg)
+        from mempalace.mcp_server import tool_kg_query
+
+        # Partial ISO dates are rejected: KG queries compare TEXT dates
+        # lexicographically, so "2026-01-01" <= "2026" is False, which
+        # silently excludes facts. Reject at the boundary — only YYYY-MM-DD
+        # produces correct results.
+        for value in ("2026", "2026-03"):
+            result = tool_kg_query(entity="Max", as_of=value)
+            assert "error" in result, f"accepted partial date {value!r}: {result}"
+
+        # Full ISO-8601 dates still pass.
+        result = tool_kg_query(entity="Max", as_of="2026-03-15")
+        assert "error" not in result, f"rejected valid date: {result}"
+
 
 # ── Diary Tools ─────────────────────────────────────────────────────────
 
@@ -1043,6 +1178,25 @@ class TestCacheInvalidation:
         assert "Reconnected" in result["message"]
         assert isinstance(result["drawers"], int)
 
+    def test_reconnect_closes_shared_backend(self, monkeypatch, config, kg):
+        _patch_mcp_server(monkeypatch, config, kg)
+        from unittest.mock import MagicMock
+
+        from mempalace import mcp_server, palace
+
+        close_palace = MagicMock()
+        monkeypatch.setattr(palace._DEFAULT_BACKEND, "close_palace", close_palace)
+
+        class _FakeCol:
+            def count(self):
+                return 7
+
+        monkeypatch.setattr(mcp_server, "_get_collection", lambda create=False: _FakeCol())
+
+        result = mcp_server.tool_reconnect()
+        assert result["success"] is True
+        close_palace.assert_called_once_with(config.palace_path)
+
     def test_get_collection_create_true_avoids_get_or_create_on_reopen(
         self, monkeypatch, config, palace_path, kg
     ):
@@ -1143,3 +1297,296 @@ class TestCacheInvalidation:
         for kwargs in captured["get"]:
             assert "embedding_function" in kwargs
             assert kwargs["embedding_function"] is not None
+
+    def test_get_collection_retries_once_on_exception(self, monkeypatch, config, palace_path, kg):
+        """Regression: a transient failure inside _get_collection must trigger
+        one retry after clearing the client/collection caches, not silently
+        return None.
+
+        Before this fix, a stale chromadb handle (e.g. the rust bindings
+        invalidating after an out-of-band write) would raise inside the
+        single ``try`` block, get swallowed by ``except Exception: return
+        None``, and every subsequent tool call would hit the same poisoned
+        cache returning None. The retry forces ``_get_client()`` to rebuild
+        the client (which re-runs ``quarantine_stale_hnsw`` per #1322), so
+        the second attempt heals the common stale-handle case.
+        """
+        _patch_mcp_server(monkeypatch, config, kg)
+        _client, _col = _get_collection(palace_path, create=True)
+        del _client
+        from mempalace import mcp_server
+
+        # Force a cold cache so the first call goes through the open path.
+        mcp_server._client_cache = None
+        mcp_server._collection_cache = None
+
+        real_get_client = mcp_server._get_client
+        attempts = {"count": 0}
+
+        def flaky_get_client():
+            attempts["count"] += 1
+            if attempts["count"] == 1:
+                raise RuntimeError("simulated transient chromadb failure")
+            return real_get_client()
+
+        monkeypatch.setattr(mcp_server, "_get_client", flaky_get_client)
+
+        col = mcp_server._get_collection()
+
+        # Both attempts ran and the second succeeded.
+        assert attempts["count"] == 2
+        assert col is not None
+
+    def test_get_collection_returns_none_after_two_failures(
+        self, monkeypatch, config, palace_path, kg
+    ):
+        """If both attempts fail, return None (matches the prior contract for
+        permanent failures — only the transient case is now self-healing)."""
+        _patch_mcp_server(monkeypatch, config, kg)
+        _client, _col = _get_collection(palace_path, create=True)
+        del _client
+        from mempalace import mcp_server
+
+        mcp_server._client_cache = None
+        mcp_server._collection_cache = None
+
+        attempts = {"count": 0}
+
+        def always_fails():
+            attempts["count"] += 1
+            raise RuntimeError("permanent chromadb failure")
+
+        monkeypatch.setattr(mcp_server, "_get_client", always_fails)
+
+        col = mcp_server._get_collection()
+
+        assert attempts["count"] == 2
+        assert col is None
+
+
+class TestKGLazyCache:
+    """Lazy per-path KnowledgeGraph cache (issue #1136)."""
+
+    def test_lazy_init_no_import_side_effect(self, tmp_path):
+        """Importing mcp_server must not create knowledge_graph.sqlite3.
+
+        Runs in a fresh subprocess with HOME pointed at tmp_path so the
+        assertion targets a clean filesystem, independent of conftest's
+        session-level HOME patch.
+        """
+        import subprocess
+        import sys
+
+        kg_file = tmp_path / ".mempalace" / "knowledge_graph.sqlite3"
+        env = {k: v for k, v in os.environ.items() if not k.startswith("MEMPAL")}
+        env["HOME"] = str(tmp_path)
+        env["USERPROFILE"] = str(tmp_path)
+        result = subprocess.run(
+            [sys.executable, "-c", "import mempalace.mcp_server"],
+            env=env,
+            capture_output=True,
+            text=True,
+            timeout=30,
+        )
+        assert result.returncode == 0, f"import failed: {result.stderr}"
+        assert not kg_file.exists(), f"import created sqlite file at {kg_file} as a side effect"
+
+    def test_get_kg_returns_same_instance(self, tmp_path, monkeypatch):
+        """Two calls with the same resolved path return the same KG."""
+        from mempalace import mcp_server
+
+        monkeypatch.setattr(mcp_server, "_kg_by_path", {})
+        monkeypatch.setattr(mcp_server, "_palace_flag_given", True)
+        monkeypatch.setenv("MEMPALACE_PALACE_PATH", str(tmp_path))
+
+        kg1 = mcp_server._get_kg()
+        kg2 = mcp_server._get_kg()
+        assert kg1 is kg2
+        assert len(mcp_server._kg_by_path) == 1
+
+    def test_get_kg_different_paths_different_instances(self, tmp_path, monkeypatch):
+        """Different palace paths map to different KG instances."""
+        from mempalace import mcp_server
+
+        tmp_a = tmp_path / "a"
+        tmp_b = tmp_path / "b"
+        tmp_a.mkdir()
+        tmp_b.mkdir()
+
+        monkeypatch.setattr(mcp_server, "_kg_by_path", {})
+        monkeypatch.setattr(mcp_server, "_palace_flag_given", True)
+
+        monkeypatch.setenv("MEMPALACE_PALACE_PATH", str(tmp_a))
+        kg_a = mcp_server._get_kg()
+        monkeypatch.setenv("MEMPALACE_PALACE_PATH", str(tmp_b))
+        kg_b = mcp_server._get_kg()
+
+        assert kg_a is not kg_b
+        assert len(mcp_server._kg_by_path) == 2
+
+    def test_multi_tenant_env_switch(self, tmp_path, monkeypatch):
+        """The issue #1136 acceptance scenario.
+
+        Rotating MEMPALACE_PALACE_PATH between MCP tool calls must route
+        each call to the correct tenant's KG sqlite file.
+        """
+        from mempalace import mcp_server
+
+        tmp_a = tmp_path / "tenant_a"
+        tmp_b = tmp_path / "tenant_b"
+        tmp_a.mkdir()
+        tmp_b.mkdir()
+
+        monkeypatch.setattr(mcp_server, "_kg_by_path", {})
+        monkeypatch.setattr(mcp_server, "_palace_flag_given", True)
+
+        monkeypatch.setenv("MEMPALACE_PALACE_PATH", str(tmp_a))
+        add_result = mcp_server.tool_kg_add(
+            subject="alice_secret",
+            predicate="owns",
+            object="repo_a",
+        )
+        assert add_result.get("success") is True, add_result
+
+        monkeypatch.setenv("MEMPALACE_PALACE_PATH", str(tmp_b))
+        query_b = mcp_server.tool_kg_query(entity="alice_secret")
+        assert query_b.get("count", 0) == 0, f"tenant B leaked tenant A's fact: {query_b}"
+
+        monkeypatch.setenv("MEMPALACE_PALACE_PATH", str(tmp_a))
+        query_a = mcp_server.tool_kg_query(entity="alice_secret")
+        assert query_a.get("count", 0) >= 1, f"tenant A lost its own fact: {query_a}"
+
+    def test_cache_thread_safe(self, tmp_path, monkeypatch):
+        """Concurrent _get_kg() for the same path yields one instance."""
+        import concurrent.futures
+        from mempalace import mcp_server
+
+        monkeypatch.setattr(mcp_server, "_kg_by_path", {})
+        monkeypatch.setattr(mcp_server, "_palace_flag_given", True)
+        monkeypatch.setenv("MEMPALACE_PALACE_PATH", str(tmp_path))
+
+        with concurrent.futures.ThreadPoolExecutor(max_workers=16) as pool:
+            results = list(pool.map(lambda _: mcp_server._get_kg(), range(16)))
+
+        ids = {id(kg) for kg in results}
+        assert len(ids) == 1, f"expected 1 unique instance, got {len(ids)}"
+        assert len(mcp_server._kg_by_path) == 1
+
+    def test_tool_reconnect_drains_kg_cache(self, monkeypatch):
+        """``tool_reconnect`` must close cached KG instances and clear the dict.
+
+        Without this, an external replacement of ``knowledge_graph.sqlite3``
+        leaves the server pinned to a stale ``sqlite3.Connection``.
+        """
+        from mempalace import mcp_server
+
+        class _FakeKG:
+            def __init__(self):
+                self.closed = False
+
+            def close(self):
+                self.closed = True
+
+        fake_a = _FakeKG()
+        fake_b = _FakeKG()
+        monkeypatch.setattr(mcp_server, "_kg_by_path", {"/a": fake_a, "/b": fake_b})
+        # Bypass real ChromaDB so the test isolates KG-cache behaviour.
+        monkeypatch.setattr(mcp_server, "_get_collection", lambda: None)
+
+        mcp_server.tool_reconnect()
+
+        assert fake_a.closed is True
+        assert fake_b.closed is True
+        assert mcp_server._kg_by_path == {}
+
+    def test_tool_reconnect_swallows_kg_close_errors(self, monkeypatch):
+        """A failing ``close()`` on one cached KG must not block cache clearing."""
+        from mempalace import mcp_server
+
+        class _BoomKG:
+            def close(self):
+                raise RuntimeError("boom")
+
+        monkeypatch.setattr(mcp_server, "_kg_by_path", {"/a": _BoomKG()})
+        monkeypatch.setattr(mcp_server, "_get_collection", lambda: None)
+
+        mcp_server.tool_reconnect()
+
+        assert mcp_server._kg_by_path == {}
+
+    def test_call_kg_retries_after_concurrent_close(self, monkeypatch):
+        """A KG closed mid-handler must trigger a one-shot retry with a fresh
+        instance — not surface a -32000 to the MCP client."""
+        import sqlite3 as _sqlite3
+
+        from mempalace import mcp_server
+
+        path = "/fake/palace/knowledge_graph.sqlite3"
+        monkeypatch.setattr(mcp_server, "_resolve_kg_path", lambda: path)
+
+        class _ClosedKG:
+            def query_entity(self, entity, **kwargs):
+                raise _sqlite3.ProgrammingError("Cannot operate on a closed database")
+
+        class _FreshKG:
+            def query_entity(self, entity, **kwargs):
+                return [{"entity": entity}]
+
+        cache = {os.path.abspath(path): _ClosedKG()}
+        monkeypatch.setattr(mcp_server, "_kg_by_path", cache)
+
+        # Second _get_kg() call (after the cache eviction) constructs a new
+        # KG. Patch the constructor so we don't open a real sqlite file.
+        monkeypatch.setattr(mcp_server, "KnowledgeGraph", lambda **_: _FreshKG())
+
+        result = mcp_server._call_kg(lambda kg: kg.query_entity("Alice"))
+        assert result == [{"entity": "Alice"}]
+        # The closed instance must be evicted; the fresh one must be cached.
+        assert isinstance(cache[os.path.abspath(path)], _FreshKG)
+
+    def test_call_kg_does_not_retry_on_other_errors(self, monkeypatch):
+        """Non-ProgrammingError exceptions must propagate without retry —
+        we don't want the retry guard masking real bugs."""
+        from mempalace import mcp_server
+
+        path = "/fake/palace/knowledge_graph.sqlite3"
+        monkeypatch.setattr(mcp_server, "_resolve_kg_path", lambda: path)
+
+        calls = {"count": 0}
+
+        class _FailingKG:
+            def query_entity(self, entity, **kwargs):
+                calls["count"] += 1
+                raise ValueError("bad input")
+
+        monkeypatch.setattr(mcp_server, "_kg_by_path", {os.path.abspath(path): _FailingKG()})
+        monkeypatch.setattr(mcp_server, "KnowledgeGraph", lambda **_: _FailingKG())
+
+        with pytest.raises(ValueError, match="bad input"):
+            mcp_server._call_kg(lambda kg: kg.query_entity("Alice"))
+        assert calls["count"] == 1, "non-ProgrammingError must not trigger retry"
+
+    def test_call_kg_gives_up_after_one_retry(self, monkeypatch):
+        """If the second attempt also hits a closed DB, give up rather than
+        loop forever — a sustained close-stream is a different bug."""
+        import sqlite3 as _sqlite3
+
+        from mempalace import mcp_server
+
+        path = "/fake/palace/knowledge_graph.sqlite3"
+        monkeypatch.setattr(mcp_server, "_resolve_kg_path", lambda: path)
+
+        calls = {"count": 0}
+
+        class _AlwaysClosedKG:
+            def query_entity(self, entity, **kwargs):
+                calls["count"] += 1
+                raise _sqlite3.ProgrammingError("closed again")
+
+        cache = {}
+        monkeypatch.setattr(mcp_server, "_kg_by_path", cache)
+        monkeypatch.setattr(mcp_server, "KnowledgeGraph", lambda **_: _AlwaysClosedKG())
+
+        with pytest.raises(_sqlite3.ProgrammingError):
+            mcp_server._call_kg(lambda kg: kg.query_entity("Alice"))
+        assert calls["count"] == 2, "expected exactly one retry beyond the initial attempt"

tests/test_migrate.py

@@ -4,7 +4,7 @@ import os
 from types import SimpleNamespace
 from unittest.mock import MagicMock, patch
 
-from mempalace.migrate import _restore_stale_palace, migrate
+from mempalace.migrate import collection_write_roundtrip_works, _restore_stale_palace, migrate
 
 
 def test_migrate_requires_palace_database(tmp_path, capsys):
@@ -101,3 +101,102 @@ def test_restore_stale_palace_logs_and_swallows_on_failure(tmp_path, capsys):
     assert "CRITICAL" in out
     assert os.fspath(palace_path) in out
     assert os.fspath(stale_path) in out
+
+
+class _FakeGetResult:
+    def __init__(self, ids):
+        self.ids = ids
+
+
+class _WritableFakeCollection:
+    def __init__(self):
+        self.ids = set()
+        self.deleted = []
+
+    def upsert(self, *, ids, documents, metadatas):
+        self.ids.update(ids)
+
+    def get(self, *, ids, include=None):
+        return _FakeGetResult([drawer_id for drawer_id in ids if drawer_id in self.ids])
+
+    def delete(self, *, ids=None, where=None):
+        for drawer_id in ids or []:
+            self.ids.discard(drawer_id)
+            self.deleted.append(drawer_id)
+
+
+class _SilentWriteDropCollection(_WritableFakeCollection):
+    def upsert(self, *, ids, documents, metadatas):
+        return None
+
+
+class _SilentDeleteDropCollection(_WritableFakeCollection):
+    def delete(self, *, ids=None, where=None):
+        self.deleted.extend(ids or [])
+
+
+def test_collection_write_roundtrip_works_when_probe_persists_and_deletes():
+    col = _WritableFakeCollection()
+
+    assert collection_write_roundtrip_works(col) is True
+    assert col.ids == set()
+    assert len(col.deleted) == 1
+
+
+def test_collection_write_roundtrip_fails_when_upsert_silently_drops():
+    col = _SilentWriteDropCollection()
+
+    assert collection_write_roundtrip_works(col) is False
+    assert col.ids == set()
+
+
+def test_collection_write_roundtrip_fails_when_delete_silently_drops():
+    col = _SilentDeleteDropCollection()
+
+    assert collection_write_roundtrip_works(col) is False
+    assert len(col.ids) == 1
+
+
+def test_migrate_dry_run_rebuilds_when_collection_is_readable_but_not_writable(tmp_path, capsys):
+    palace_dir = tmp_path / "palace"
+    palace_dir.mkdir()
+    (palace_dir / "chroma.sqlite3").write_text("db")
+
+    fake_col = MagicMock()
+    fake_col.count.return_value = 102
+
+    drawers = [
+        {
+            "id": "id1",
+            "document": "hello",
+            "metadata": {"wing": "test-wing", "room": "general"},
+        }
+    ]
+
+    with (
+        patch("mempalace.migrate.detect_chromadb_version", return_value="1.x"),
+        patch("mempalace.backends.chroma.ChromaBackend") as mock_backend,
+        patch(
+            "mempalace.migrate.collection_write_roundtrip_works", return_value=False
+        ) as mock_probe,
+        patch(
+            "mempalace.migrate.extract_drawers_from_sqlite", return_value=drawers
+        ) as mock_extract,
+    ):
+        mock_backend.backend_version.return_value = "1.5.8"
+        mock_backend.return_value.get_collection.return_value = fake_col
+
+        result = migrate(str(palace_dir), dry_run=True)
+
+    out = capsys.readouterr().out
+
+    assert result is True
+    mock_probe.assert_called_once_with(fake_col)
+    mock_extract.assert_called_once_with(
+        os.path.join(os.path.abspath(os.fspath(palace_dir)), "chroma.sqlite3")
+    )
+
+    assert "readable by chromadb 1.5.8, but write/delete verification failed" in out
+    assert "Rebuilding from SQLite" in out
+    assert "Extracted 1 drawers from SQLite" in out
+    assert "DRY RUN" in out

tests/test_miner.py

@@ -699,6 +699,83 @@ def test_mine_keyboard_interrupt_quotes_path_with_spaces_in_resume_hint(tmp_path
     assert f"mempalace mine {shlex.quote(str(project_root))}" in out
 
 
+def test_skip_filenames_includes_lockfiles():
+    """pnpm-lock.yaml and yarn.lock must be skipped alongside package-lock.json
+    so a Windows mine over a typical JS monorepo doesn't OOM the ONNX embedder
+    on a 24K-line lockfile (#1296)."""
+    from mempalace import miner
+
+    assert "package-lock.json" in miner.SKIP_FILENAMES
+    assert "pnpm-lock.yaml" in miner.SKIP_FILENAMES
+    assert "yarn.lock" in miner.SKIP_FILENAMES
+
+
+def test_process_file_skips_when_chunks_exceed_max(tmp_path, monkeypatch):
+    """A file producing more than MAX_CHUNKS_PER_FILE chunks must be skipped
+    with a clear message and zero upserts. Generated artifacts (CSVs, lock
+    files not in SKIP_FILENAMES) hit this — the cap is what prevents ONNX
+    bad_alloc on Windows when the embedder is asked to swallow thousands of
+    chunks in one batch (#1296)."""
+    from unittest.mock import MagicMock
+
+    from mempalace import miner
+
+    monkeypatch.setattr(miner, "MAX_CHUNKS_PER_FILE", 5)
+    over_cap = [{"content": f"chunk {i}", "chunk_index": i} for i in range(7)]
+    monkeypatch.setattr(miner, "chunk_text", lambda content, source_file: over_cap)
+
+    source = tmp_path / "huge.csv"
+    source.write_text("col1,col2\n" + "x,y\n" * 500, encoding="utf-8")
+    col = MagicMock()
+    col.get.return_value = {"ids": []}
+
+    drawers, room = miner.process_file(
+        source,
+        tmp_path,
+        col,
+        "wing",
+        [{"name": "general", "description": "General"}],
+        "agent",
+        False,
+    )
+
+    assert drawers == 0
+    col.upsert.assert_not_called()
+
+
+def test_mine_arbitrary_exception_prints_summary_and_reraises(tmp_path, capsys):
+    """A non-KeyboardInterrupt exception mid-mine must surface a summary
+    banner before propagating, so users don't see a silent exit-0 with no
+    completion message (#1296 Failure 2). Re-raise preserves the traceback
+    and yields a non-zero exit code."""
+    import pytest
+    from unittest.mock import patch
+
+    project_root = tmp_path / "proj"
+    project_root.mkdir()
+    _make_minable_project(project_root, n_files=4)
+    palace_path = project_root / "palace"
+
+    call_count = {"n": 0}
+
+    def fake_process_file(*args, **kwargs):
+        call_count["n"] += 1
+        if call_count["n"] == 2:
+            raise RuntimeError("simulated ONNX bad_alloc")
+        return (1, "general")
+
+    with patch("mempalace.miner.process_file", side_effect=fake_process_file):
+        with pytest.raises(RuntimeError, match="simulated ONNX bad_alloc"):
+            mine(str(project_root), str(palace_path))
+
+    out = capsys.readouterr().out
+    assert "Mine aborted by exception." in out
+    assert "files_processed: 1/" in out
+    assert "drawers_filed:" in out
+    assert "RuntimeError: simulated ONNX bad_alloc" in out
+    assert "upserted idempotently" in out
+
+
 def test_mine_cleans_up_pid_file_on_interrupt(tmp_path):
     """Our own PID entry in mine.pid is removed in the finally clause."""
     import pytest

tests/test_palace_locks.py

@@ -135,19 +135,77 @@ def test_different_palaces_dont_conflict(tmp_path, monkeypatch):
 
 
 def test_palace_path_is_normalized(tmp_path, monkeypatch):
-    """Relative and absolute forms of the same path must use the same lock."""
+    """Relative and absolute forms of the same path must use the same lock.
+
+    Cross-process variant: a child holds the absolute form, a relative form
+    in the parent must hash to the same lock key and raise
+    ``MineAlreadyRunning``. (The same-thread case is now a re-entrant
+    pass-through by design — see ``test_reentrant_same_thread_passes_through``
+    — so we exercise the normalization invariant across a process boundary
+    where re-entrance does not apply.)
+    """
     monkeypatch.setenv("HOME", str(tmp_path))
     monkeypatch.chdir(tmp_path)
     os.makedirs(tmp_path / "palace", exist_ok=True)
     absolute = str(tmp_path / "palace")
-    relative = "palace"
+    ready = str(tmp_path / "ready")
+    release = str(tmp_path / "release")
 
-    # Hold the lock with the absolute form; attempting to re-acquire with
-    # the relative form (which resolves to the same absolute path) must fail.
-    with mine_palace_lock(absolute):
+    ctx = _get_mp_context()
+    holder = ctx.Process(target=_hold_lock, args=(absolute, ready, release))
+    holder.start()
+    try:
+        for _ in range(500):
+            if os.path.exists(ready):
+                break
+            time.sleep(0.01)
+        assert os.path.exists(ready), "holder failed to acquire lock in time"
+
+        # Parent holds CWD = tmp_path so "palace" is the same on-disk dir as
+        # the absolute form. The lock key is sha256(realpath+normcase) so the
+        # two forms must collide.
         with pytest.raises(MineAlreadyRunning):
-            with mine_palace_lock(relative):
+            with mine_palace_lock("palace"):
                 pytest.fail("normalized path collision should have raised")
+    finally:
+        open(release, "w").close()
+        holder.join(timeout=5)
+
+
+def test_reentrant_same_thread_passes_through(tmp_path, monkeypatch):
+    """Same thread re-acquiring the same palace lock must not deadlock or raise.
+
+    This is the invariant that makes ``ChromaCollection`` write methods (which
+    take ``mine_palace_lock`` for MCP/direct-writer protection) compose with
+    ``miner.mine()`` (which already holds the lock for the entire mine
+    pipeline). Without the per-thread re-entrant guard the inner acquire
+    would self-deadlock on the outer flock.
+    """
+    monkeypatch.setenv("HOME", str(tmp_path))
+    palace = str(tmp_path / "palace")
+    with mine_palace_lock(palace):
+        # Re-enter from the same thread — must yield without raising or hanging.
+        with mine_palace_lock(palace):
+            pass
+        # After the inner exits, the outer is still held: confirm via a
+        # subprocess that tries to acquire and reports back.
+        ctx = _get_mp_context()
+        result_q = ctx.Queue()
+        child = ctx.Process(target=_try_acquire_expect_busy, args=(palace, result_q))
+        child.start()
+        child.join(timeout=5)
+        assert (
+            result_q.get(timeout=1) == "busy"
+        ), "outer lock should still be held by parent after inner re-entrant exit"
+
+
+def _try_acquire_expect_busy(palace_path, result_q):
+    """Helper: try to acquire, push 'busy' (raised) or 'free' (acquired) into queue."""
+    try:
+        with mine_palace_lock(palace_path):
+            result_q.put("free")
+    except MineAlreadyRunning:
+        result_q.put("busy")
 
 
 def test_mine_global_lock_is_alias_for_back_compat(tmp_path, monkeypatch):

tests/test_repair.py

@@ -2,7 +2,7 @@
 
 import os
 import sqlite3
-from unittest.mock import MagicMock, patch
+from unittest.mock import MagicMock, call, patch
 
 import pytest
 
@@ -28,6 +28,16 @@ def test_get_palace_path_fallback():
         assert ".mempalace" in result
 
 
+def test_get_collection_name_from_config():
+    from mempalace.config import get_configured_collection_name
+
+    get_configured_collection_name.cache_clear()
+    with patch("mempalace.config.MempalaceConfig") as mock_config_cls:
+        mock_config_cls.return_value.collection_name = "custom_drawers"
+        assert repair._drawers_collection_name() == "custom_drawers"
+    get_configured_collection_name.cache_clear()
+
+
 # ── _paginate_ids ─────────────────────────────────────────────────────
 
 
@@ -231,8 +241,11 @@ def test_rebuild_index_success(mock_backend_cls, mock_shutil, tmp_path):
     }
 
     mock_new_col = MagicMock()
+    mock_new_col.count.return_value = 2
+    mock_temp_col = MagicMock()
+    mock_temp_col.count.return_value = 2
     mock_backend = _install_mock_backend(mock_backend_cls, mock_col)
-    mock_backend.create_collection.return_value = mock_new_col
+    mock_backend.create_collection.side_effect = [mock_temp_col, mock_new_col]
 
     repair.rebuild_index(palace_path=str(tmp_path))
 
@@ -240,15 +253,75 @@ def test_rebuild_index_success(mock_backend_cls, mock_shutil, tmp_path):
     mock_shutil.copy2.assert_called_once()
     assert "chroma.sqlite3" in str(mock_shutil.copy2.call_args)
 
-    # Verify: deleted and recreated.
-    mock_backend.delete_collection.assert_called_once_with(str(tmp_path), "mempalace_drawers")
-    mock_backend.create_collection.assert_called_once_with(str(tmp_path), "mempalace_drawers")
+    # Verify: deleted and recreated (cosine is the backend default)
+    assert mock_backend.create_collection.call_args_list == [
+        call(str(tmp_path), "mempalace_drawers__repair_tmp"),
+        call(str(tmp_path), "mempalace_drawers"),
+    ]
+    assert mock_backend.delete_collection.call_args_list == [
+        call(str(tmp_path), "mempalace_drawers__repair_tmp"),
+        call(str(tmp_path), "mempalace_drawers"),
+        call(str(tmp_path), "mempalace_drawers__repair_tmp"),
+    ]
 
-    # Verify: used upsert, not add.
+    # Verify: used upsert not add
+    mock_temp_col.upsert.assert_called_once()
     mock_new_col.upsert.assert_called_once()
     mock_new_col.add.assert_not_called()
 
 
+@patch("mempalace.repair.shutil")
+@patch("mempalace.repair.ChromaBackend")
+def test_rebuild_index_ignores_missing_temp_collection_at_start(
+    mock_backend_cls, mock_shutil, tmp_path
+):
+    sqlite_path = tmp_path / "chroma.sqlite3"
+    sqlite3.connect(str(sqlite_path)).close()
+
+    def _fake_copy2(src, dst):
+        with open(dst, "w") as handle:
+            handle.write("backup")
+
+    mock_shutil.copy2.side_effect = _fake_copy2
+
+    mock_col = MagicMock()
+    mock_col.count.return_value = 2
+    mock_col.get.return_value = {
+        "ids": ["id1", "id2"],
+        "documents": ["doc1", "doc2"],
+        "metadatas": [{"wing": "a"}, {"wing": "b"}],
+    }
+
+    mock_new_col = MagicMock()
+    mock_new_col.count.return_value = 2
+    mock_temp_col = MagicMock()
+    mock_temp_col.count.return_value = 2
+    mock_backend = _install_mock_backend(mock_backend_cls, mock_col)
+    mock_backend.create_collection.side_effect = [mock_temp_col, mock_new_col]
+    mock_backend.delete_collection.side_effect = [
+        ValueError("Collection [mempalace_drawers__repair_tmp] does not exist"),
+        None,
+        None,
+    ]
+
+    repair.rebuild_index(palace_path=str(tmp_path))
+
+    assert mock_shutil.copy2.call_count == 1
+    assert mock_backend.delete_collection.call_args_list == [
+        call(str(tmp_path), "mempalace_drawers__repair_tmp"),
+        call(str(tmp_path), "mempalace_drawers"),
+        call(str(tmp_path), "mempalace_drawers__repair_tmp"),
+    ]
+
+
+def test_delete_collection_if_exists_reraises_unexpected_value_error():
+    mock_backend = MagicMock()
+    mock_backend.delete_collection.side_effect = ValueError("invalid collection name")
+
+    with pytest.raises(ValueError, match="invalid collection name"):
+        repair._delete_collection_if_exists(mock_backend, "/palace", "bad/name")
+
+
 @patch("mempalace.repair.shutil")
 @patch("mempalace.repair.ChromaBackend")
 def test_rebuild_index_error_reading(mock_backend_cls, mock_shutil, tmp_path):
@@ -269,6 +342,21 @@ def test_check_extraction_safety_passes_when_counts_match(tmp_path):
         repair.check_extraction_safety(str(tmp_path), 500)
 
 
+def test_check_extraction_safety_uses_configured_collection(tmp_path):
+    with patch("mempalace.repair.sqlite_drawer_count", return_value=500) as count:
+        repair.check_extraction_safety(str(tmp_path), 500, collection_name="custom_drawers")
+    count.assert_called_once_with(str(tmp_path), "custom_drawers")
+
+
+def test_check_extraction_safety_default_uses_configured_collection(tmp_path):
+    with (
+        patch("mempalace.repair._drawers_collection_name", return_value="custom_drawers"),
+        patch("mempalace.repair.sqlite_drawer_count", return_value=500) as count,
+    ):
+        repair.check_extraction_safety(str(tmp_path), 500)
+    count.assert_called_once_with(str(tmp_path), "custom_drawers")
+
+
 def test_check_extraction_safety_passes_when_sqlite_unreadable_and_under_cap(tmp_path):
     """SQLite check fails (None) but extraction is well under the cap → safe."""
     with patch("mempalace.repair.sqlite_drawer_count", return_value=None):
@@ -323,6 +411,73 @@ def test_sqlite_drawer_count_returns_none_on_unreadable_schema(tmp_path):
     assert repair.sqlite_drawer_count(str(tmp_path)) is None
 
 
+@patch("mempalace.repair.shutil")
+@patch("mempalace.repair.ChromaBackend")
+def test_rebuild_index_default_uses_configured_collection(mock_backend_cls, mock_shutil, tmp_path):
+    sqlite_path = tmp_path / "chroma.sqlite3"
+    sqlite3.connect(str(sqlite_path)).close()
+    mock_col = MagicMock()
+    mock_col.count.return_value = 2
+    mock_col.get.return_value = {
+        "ids": ["id1", "id2"],
+        "documents": ["doc1", "doc2"],
+        "metadatas": [{"wing": "a"}, {"wing": "b"}],
+    }
+    mock_temp_col = MagicMock()
+    mock_temp_col.count.return_value = 2
+    mock_new_col = MagicMock()
+    mock_new_col.count.return_value = 2
+    mock_backend = _install_mock_backend(mock_backend_cls, mock_col)
+    mock_backend.create_collection.side_effect = [mock_temp_col, mock_new_col]
+
+    with (
+        patch("mempalace.repair._drawers_collection_name", return_value="custom_drawers"),
+        patch("mempalace.repair.sqlite_drawer_count", return_value=2) as count,
+    ):
+        repair.rebuild_index(palace_path=str(tmp_path))
+
+    mock_backend.get_collection.assert_called_once_with(str(tmp_path), "custom_drawers")
+    count.assert_called_once_with(str(tmp_path), "custom_drawers")
+    assert mock_backend.create_collection.call_args_list == [
+        call(str(tmp_path), "custom_drawers__repair_tmp"),
+        call(str(tmp_path), "custom_drawers"),
+    ]
+    assert mock_backend.delete_collection.call_args_list == [
+        call(str(tmp_path), "custom_drawers__repair_tmp"),
+        call(str(tmp_path), "custom_drawers"),
+        call(str(tmp_path), "custom_drawers__repair_tmp"),
+    ]
+
+
+def test_status_default_uses_configured_drawer_collection(tmp_path):
+    with (
+        patch("mempalace.repair._drawers_collection_name", return_value="custom_drawers"),
+        patch("mempalace.repair.hnsw_capacity_status") as capacity_status,
+    ):
+        capacity_status.side_effect = [
+            {
+                "sqlite_count": 1,
+                "hnsw_count": 1,
+                "divergence": 0,
+                "diverged": False,
+                "status": "ok",
+                "message": "",
+            },
+            {
+                "sqlite_count": 0,
+                "hnsw_count": 0,
+                "divergence": 0,
+                "diverged": False,
+                "status": "ok",
+                "message": "",
+            },
+        ]
+        repair.status(palace_path=str(tmp_path))
+
+    assert capacity_status.call_args_list[0].args == (str(tmp_path), "custom_drawers")
+    assert capacity_status.call_args_list[1].args == (str(tmp_path), "mempalace_closets")
+
+
 @patch("mempalace.repair.shutil")
 @patch("mempalace.repair.ChromaBackend")
 def test_rebuild_index_aborts_on_truncation_signal(mock_backend_cls, mock_shutil, tmp_path):
@@ -367,19 +522,261 @@ def test_rebuild_index_proceeds_with_override(mock_backend_cls, mock_shutil, tmp
         },
         {"ids": [], "documents": [], "metadatas": []},
     ]
+    mock_temp_col = MagicMock()
+    mock_temp_col.count.return_value = 10_000
     mock_new_col = MagicMock()
+    mock_new_col.count.return_value = 10_000
     mock_backend.get_collection.return_value = mock_col
-    mock_backend.create_collection.return_value = mock_new_col
+    mock_backend.create_collection.side_effect = [mock_temp_col, mock_new_col]
     mock_backend_cls.return_value = mock_backend
 
     with patch("mempalace.repair.sqlite_drawer_count", return_value=67_580):
         repair.rebuild_index(palace_path=str(tmp_path), confirm_truncation_ok=True)
 
-    mock_backend.delete_collection.assert_called_once()
-    mock_backend.create_collection.assert_called_once()
+    assert mock_backend.delete_collection.call_count == 3
+    assert mock_backend.create_collection.call_count == 2
+    mock_temp_col.upsert.assert_called()
     mock_new_col.upsert.assert_called()
 
 
+@patch("mempalace.repair.shutil")
+@patch("mempalace.repair.ChromaBackend")
+def test_rebuild_index_stage_failure_leaves_live_collection_untouched(
+    mock_backend_cls, mock_shutil, tmp_path
+):
+    sqlite_path = tmp_path / "chroma.sqlite3"
+    sqlite3.connect(str(sqlite_path)).close()
+
+    mock_col = MagicMock()
+    mock_col.count.return_value = 2
+    mock_col.get.return_value = {
+        "ids": ["id1", "id2"],
+        "documents": ["doc1", "doc2"],
+        "metadatas": [{"wing": "a"}, {"wing": "b"}],
+    }
+    mock_temp_col = MagicMock()
+    mock_temp_col.count.return_value = 1
+    mock_backend = _install_mock_backend(mock_backend_cls, mock_col)
+    mock_backend.create_collection.return_value = mock_temp_col
+
+    with pytest.raises(repair.RebuildCollectionError) as excinfo:
+        repair.rebuild_index(palace_path=str(tmp_path))
+
+    assert excinfo.value.live_replaced is False
+    assert mock_shutil.copy2.call_count == 1
+    assert mock_backend.delete_collection.call_args_list == [
+        call(str(tmp_path), "mempalace_drawers__repair_tmp"),
+        call(str(tmp_path), "mempalace_drawers__repair_tmp"),
+    ]
+
+
+@patch("mempalace.repair.shutil")
+@patch("mempalace.repair.ChromaBackend")
+def test_rebuild_index_live_failure_restores_backup(mock_backend_cls, mock_shutil, tmp_path):
+    sqlite_path = tmp_path / "chroma.sqlite3"
+    sqlite3.connect(str(sqlite_path)).close()
+
+    def _fake_copy2(src, dst):
+        with open(dst, "w") as handle:
+            handle.write("backup")
+
+    mock_shutil.copy2.side_effect = _fake_copy2
+
+    mock_col = MagicMock()
+    mock_col.count.return_value = 2
+    mock_col.get.return_value = {
+        "ids": ["id1", "id2"],
+        "documents": ["doc1", "doc2"],
+        "metadatas": [{"wing": "a"}, {"wing": "b"}],
+    }
+    mock_temp_col = MagicMock()
+    mock_temp_col.count.return_value = 2
+    mock_new_col = MagicMock()
+    mock_new_col.upsert.side_effect = RuntimeError("live upsert failed")
+    active_backend = MagicMock()
+    active_backend.get_collection.return_value = mock_col
+    active_backend.create_collection.side_effect = [mock_temp_col, mock_new_col]
+    helper_backend = MagicMock()
+    mock_backend_cls.side_effect = [active_backend, helper_backend]
+
+    with pytest.raises(repair.RebuildCollectionError) as excinfo:
+        repair.rebuild_index(palace_path=str(tmp_path))
+
+    assert excinfo.value.live_replaced is True
+    assert mock_shutil.copy2.call_count == 2
+    assert active_backend.delete_collection.call_args_list == [
+        call(str(tmp_path), "mempalace_drawers__repair_tmp"),
+        call(str(tmp_path), "mempalace_drawers"),
+        call(str(tmp_path), "mempalace_drawers__repair_tmp"),
+        call(str(tmp_path), "mempalace_drawers"),
+    ]
+    active_backend.close_palace.assert_called_once_with(str(tmp_path))
+    helper_backend.close_palace.assert_not_called()
+
+
+@patch("mempalace.repair.shutil")
+@patch("mempalace.repair.ChromaBackend")
+def test_rebuild_index_live_delete_missing_still_restores_backup(
+    mock_backend_cls, mock_shutil, tmp_path
+):
+    sqlite_path = tmp_path / "chroma.sqlite3"
+    sqlite3.connect(str(sqlite_path)).close()
+
+    def _fake_copy2(src, dst):
+        with open(dst, "w") as handle:
+            handle.write("backup")
+
+    mock_shutil.copy2.side_effect = _fake_copy2
+
+    mock_col = MagicMock()
+    mock_col.count.return_value = 2
+    mock_col.get.return_value = {
+        "ids": ["id1", "id2"],
+        "documents": ["doc1", "doc2"],
+        "metadatas": [{"wing": "a"}, {"wing": "b"}],
+    }
+    mock_temp_col = MagicMock()
+    mock_temp_col.count.return_value = 2
+    mock_backend = _install_mock_backend(mock_backend_cls, mock_col)
+    mock_backend.create_collection.side_effect = [mock_temp_col, RuntimeError("create failed")]
+    mock_backend.delete_collection.side_effect = [
+        None,
+        None,
+        None,
+        repair.ChromaNotFoundError("missing"),
+    ]
+
+    with pytest.raises(repair.RebuildCollectionError) as excinfo:
+        repair.rebuild_index(palace_path=str(tmp_path))
+
+    assert excinfo.value.live_replaced is True
+    assert mock_shutil.copy2.call_count == 2
+    assert mock_backend.delete_collection.call_args_list == [
+        call(str(tmp_path), "mempalace_drawers__repair_tmp"),
+        call(str(tmp_path), "mempalace_drawers"),
+        call(str(tmp_path), "mempalace_drawers__repair_tmp"),
+        call(str(tmp_path), "mempalace_drawers"),
+    ]
+
+
+@patch("mempalace.repair.shutil")
+@patch("mempalace.repair.ChromaBackend")
+def test_rebuild_index_restore_failure_preserves_original_error(
+    mock_backend_cls, mock_shutil, tmp_path, capsys
+):
+    sqlite_path = tmp_path / "chroma.sqlite3"
+    sqlite3.connect(str(sqlite_path)).close()
+
+    def _copy2_side_effect(src, dst):
+        if str(src).endswith(".backup"):
+            raise PermissionError("locked sqlite")
+        with open(dst, "w") as handle:
+            handle.write("backup")
+
+    mock_shutil.copy2.side_effect = _copy2_side_effect
+
+    mock_col = MagicMock()
+    mock_col.count.return_value = 2
+    mock_col.get.return_value = {
+        "ids": ["id1", "id2"],
+        "documents": ["doc1", "doc2"],
+        "metadatas": [{"wing": "a"}, {"wing": "b"}],
+    }
+    mock_temp_col = MagicMock()
+    mock_temp_col.count.return_value = 2
+    mock_new_col = MagicMock()
+    mock_new_col.upsert.side_effect = RuntimeError("live upsert failed")
+    mock_backend = _install_mock_backend(mock_backend_cls, mock_col)
+    mock_backend.create_collection.side_effect = [mock_temp_col, mock_new_col]
+
+    with pytest.raises(repair.RebuildCollectionError) as excinfo:
+        repair.rebuild_index(palace_path=str(tmp_path))
+
+    out = capsys.readouterr().out
+    assert "locked sqlite" in out
+    assert "Manual restore required" in out
+    assert "live upsert failed" in str(excinfo.value)
+
+
+@patch("mempalace.repair.ChromaBackend")
+def test_rebuild_collection_via_temp_keeps_original_error_when_cleanup_fails(
+    mock_backend_cls,
+):
+    mock_col = MagicMock()
+    mock_col.count.return_value = 2
+    mock_temp_col = MagicMock()
+    mock_temp_col.count.return_value = 2
+    mock_backend = _install_mock_backend(mock_backend_cls, mock_col)
+    mock_backend.create_collection.side_effect = [mock_temp_col, RuntimeError("live build failed")]
+    mock_backend.delete_collection.side_effect = [
+        None,
+        None,
+        RuntimeError("cleanup failed"),
+    ]
+
+    with pytest.raises(repair.RebuildCollectionError) as excinfo:
+        repair._rebuild_collection_via_temp(
+            mock_backend,
+            "/palace",
+            ["id1", "id2"],
+            ["doc1", "doc2"],
+            [{"wing": "a"}, {"wing": "b"}],
+            batch_size=5000,
+            progress=lambda *args, **kwargs: None,
+        )
+
+    assert "live build failed" in str(excinfo.value)
+    assert excinfo.value.live_replaced is True
+    assert mock_backend.delete_collection.call_args_list == [
+        call("/palace", "mempalace_drawers__repair_tmp"),
+        call("/palace", "mempalace_drawers"),
+        call("/palace", "mempalace_drawers__repair_tmp"),
+    ]
+
+
+@patch("mempalace.repair.shutil")
+@patch("mempalace.repair.ChromaBackend")
+def test_rebuild_index_ignores_temp_cleanup_failure_after_success(
+    mock_backend_cls, mock_shutil, tmp_path
+):
+    sqlite_path = tmp_path / "chroma.sqlite3"
+    sqlite3.connect(str(sqlite_path)).close()
+
+    def _fake_copy2(src, dst):
+        with open(dst, "w") as handle:
+            handle.write("backup")
+
+    mock_shutil.copy2.side_effect = _fake_copy2
+
+    mock_col = MagicMock()
+    mock_col.count.return_value = 2
+    mock_col.get.return_value = {
+        "ids": ["id1", "id2"],
+        "documents": ["doc1", "doc2"],
+        "metadatas": [{"wing": "a"}, {"wing": "b"}],
+    }
+    mock_temp_col = MagicMock()
+    mock_temp_col.count.return_value = 2
+    mock_new_col = MagicMock()
+    mock_new_col.count.return_value = 2
+    mock_backend = _install_mock_backend(mock_backend_cls, mock_col)
+    mock_backend.create_collection.side_effect = [mock_temp_col, mock_new_col]
+    mock_backend.delete_collection.side_effect = [
+        None,
+        None,
+        RuntimeError("cleanup failed"),
+    ]
+
+    repair.rebuild_index(palace_path=str(tmp_path))
+
+    assert mock_shutil.copy2.call_count == 1
+    assert mock_backend.delete_collection.call_args_list == [
+        call(str(tmp_path), "mempalace_drawers__repair_tmp"),
+        call(str(tmp_path), "mempalace_drawers"),
+        call(str(tmp_path), "mempalace_drawers__repair_tmp"),
+    ]
+
+
 # ── repair_max_seq_id ─────────────────────────────────────────────────
 
 
@@ -754,3 +1151,387 @@ def test_rebuild_index_aborts_on_sqlite_integrity_errors_before_delete_collectio
     mock_backend.delete_collection.assert_not_called()
     mock_backend.create_collection.assert_not_called()
     mock_shutil.copy2.assert_not_called()
+
+
+# ── extract_via_sqlite + rebuild_from_sqlite (#1308) ──────────────────
+#
+# These tests build real chromadb palaces in tmp_path rather than mocking
+# the SQLite layer. The bug class they guard against is "extraction sees
+# different rows than chromadb stored" — the only honest check is to let
+# chromadb actually write rows and then read them back via the SQLite
+# bypass. Mocking the SQLite cursor would defeat the test.
+
+
+def _seed_palace(palace_path, collection_name, rows):
+    """Build a real chromadb palace at ``palace_path`` and add ``rows``.
+
+    ``rows`` is a list of ``(id, document, metadata)`` tuples.
+    """
+    from mempalace.backends.chroma import ChromaBackend
+
+    backend = ChromaBackend()
+    try:
+        col = backend.create_collection(str(palace_path), collection_name)
+        col.upsert(
+            ids=[r[0] for r in rows],
+            documents=[r[1] for r in rows],
+            metadatas=[r[2] for r in rows],
+        )
+    finally:
+        # Release chromadb's rust-side SQLite/HNSW file locks before the
+        # caller proceeds. Without this, an in-place rebuild on Windows
+        # fails with WinError 32 on data_level0.bin during the archive
+        # rename (cf. PR #1310 test-windows job).
+        backend.close()
+
+
+def test_extract_via_sqlite_returns_all_rows_with_metadata(tmp_path):
+    """Round-trip: a chromadb palace with N upserted rows returns those
+    same N rows when read via the SQLite bypass.
+
+    Catches: anyone who breaks the segments/embeddings/embedding_metadata
+    JOIN, swaps the metadata vs vector segment, or changes how the
+    document is stored under the ``chroma:document`` key.
+
+    Also asserts every embedding row underlying the extraction lives in
+    a ``segments.scope = 'METADATA'`` segment. Document + metadata rows
+    are stored under METADATA in Chroma's segment layout while HNSW
+    files live under ``VECTOR``; locking that assumption in here means a
+    future refactor that accidentally points the JOIN at ``VECTOR``
+    fails this test instead of silently regressing the recovery path.
+    """
+    rows = [
+        (f"drawer_{i:03d}", f"document body {i}", {"wing": "test_wing", "room": f"r{i % 3}"})
+        for i in range(25)
+    ]
+    _seed_palace(tmp_path, "mempalace_drawers", rows)
+
+    extracted = list(repair.extract_via_sqlite(str(tmp_path), "mempalace_drawers"))
+
+    assert len(extracted) == 25
+    by_id = {emb_id: (doc, meta) for emb_id, doc, meta in extracted}
+    assert set(by_id) == {r[0] for r in rows}
+    for emb_id, doc, meta in rows:
+        got_doc, got_meta = by_id[emb_id]
+        assert got_doc == doc, f"document mangled for {emb_id}"
+        assert got_meta == meta, f"metadata mangled for {emb_id}: {got_meta!r}"
+
+    # Lock the segment-scope assumption directly against Chroma's on-disk
+    # layout so a future change that points the extraction JOIN at the
+    # VECTOR segment cannot pass this test. Query each extracted row's
+    # backing segment scope via the same SQLite tables ``extract_via_sqlite``
+    # reads from.
+    sqlite_path = os.path.join(str(tmp_path), "chroma.sqlite3")
+    conn = sqlite3.connect(f"file:{sqlite_path}?mode=ro", uri=True)
+    try:
+        scopes = {
+            scope
+            for (scope,) in conn.execute(
+                """
+                SELECT DISTINCT s.scope
+                FROM embeddings e
+                JOIN segments s ON e.segment_id = s.id
+                JOIN collections c ON s.collection = c.id
+                WHERE c.name = ? AND e.embedding_id IN ({})
+                """.format(",".join("?" * len(extracted))),
+                ("mempalace_drawers", *(emb_id for emb_id, _, _ in extracted)),
+            )
+        }
+    finally:
+        conn.close()
+    assert scopes == {"METADATA"}, (
+        f"extraction is reading from segments scoped {scopes!r}; only "
+        "'METADATA' should back the document/metadata rows. If Chroma's "
+        "segment layout changed, update extract_via_sqlite's WHERE clause."
+    )
+
+
+def test_extract_via_sqlite_preserves_typed_metadata(tmp_path):
+    """Chromadb stores int / float / bool / string in distinct typed
+    columns. Extraction must round-trip the original type, not coerce
+    everything to string.
+
+    Catches: a regression where the SELECT order changes and ints come
+    back as None, or where the column-resolution rule prefers the wrong
+    column.
+    """
+    rows = [
+        (
+            "drawer_typed",
+            "doc",
+            {
+                "wing": "w",
+                "chunk_index": 7,  # int
+                "score": 0.42,  # float
+                "is_active": True,  # bool
+            },
+        ),
+    ]
+    _seed_palace(tmp_path, "mempalace_drawers", rows)
+
+    extracted = list(repair.extract_via_sqlite(str(tmp_path), "mempalace_drawers"))
+    assert len(extracted) == 1
+    _, _, meta = extracted[0]
+
+    assert meta["chunk_index"] == 7 and isinstance(meta["chunk_index"], int)
+    assert meta["score"] == 0.42 and isinstance(meta["score"], float)
+    assert meta["is_active"] is True
+    assert meta["wing"] == "w"
+
+
+def test_extract_via_sqlite_unknown_collection_yields_nothing(tmp_path):
+    """Asking for a collection that isn't in the palace must return an
+    empty iterator, not silently fall back to another collection's
+    metadata segment. Seeds two real collections and queries for a third
+    name so a regression that drops the WHERE c.name=? filter would leak
+    rows from the seeded collections rather than passing.
+    """
+    _seed_palace(tmp_path, "mempalace_drawers", [("d1", "doc", {"wing": "w"})])
+    _seed_palace(tmp_path, "mempalace_closets", [("c1", "abbrev", {"wing": "w"})])
+    assert list(repair.extract_via_sqlite(str(tmp_path), "not_a_real_collection")) == []
+
+
+def test_extract_via_sqlite_missing_palace_yields_nothing(tmp_path):
+    """No chroma.sqlite3 → empty iterator, no exception. Callers depend
+    on this when probing speculatively."""
+    empty = tmp_path / "no_palace_here"
+    empty.mkdir()
+    assert list(repair.extract_via_sqlite(str(empty), "mempalace_drawers")) == []
+
+
+def test_rebuild_from_sqlite_roundtrips_via_real_chromadb(tmp_path):
+    """End-to-end: seed source palace, rebuild into a fresh dest, then
+    open dest with a fresh ChromaBackend and verify ``count()`` and
+    metadata filters return the original rows. Also asserts a closet
+    document round-trips so a future regression that re-embeds with the
+    wrong EF or swaps drawer/closet content would fail here.
+
+    This is the single most important regression guard. If
+    ``rebuild_from_sqlite`` silently drops rows or mangles metadata, no
+    other test in this file would catch it because they all stop at the
+    extraction layer.
+    """
+    from mempalace.backends.chroma import ChromaBackend
+
+    source = tmp_path / "source"
+    dest = tmp_path / "dest"
+
+    rows = [
+        (f"drawer_{i:03d}", f"body {i}", {"wing": "alpha" if i % 2 else "beta", "room": "r0"})
+        for i in range(40)
+    ]
+    _seed_palace(source, "mempalace_drawers", rows)
+    _seed_palace(
+        source,
+        "mempalace_closets",
+        [("closet_x", "abbrev pointer →drawer_001", {"wing": "alpha"})],
+    )
+
+    counts = repair.rebuild_from_sqlite(str(source), str(dest))
+    assert counts == {"mempalace_drawers": 40, "mempalace_closets": 1}
+
+    backend = ChromaBackend()
+    drawers = backend.get_collection(str(dest), "mempalace_drawers")
+    assert drawers.count() == 40
+    alpha = drawers.get(where={"wing": "alpha"})
+    assert len(alpha["ids"]) == 20
+
+    # Spot-check that document text round-trips for one specific drawer
+    # — protects against a regression where extraction or upsert order
+    # silently swaps document bodies between IDs.
+    one = drawers.get(ids=["drawer_007"], include=["documents", "metadatas"])
+    assert one["documents"] == ["body 7"]
+    assert one["metadatas"][0]["wing"] == "alpha"
+
+    # Closets: the AAAK index layer. Re-embedded with the same EF so a
+    # known closet ID and its document body must come back intact.
+    closets = backend.get_collection(str(dest), "mempalace_closets")
+    assert closets.count() == 1
+    closet_row = closets.get(ids=["closet_x"], include=["documents", "metadatas"])
+    assert closet_row["documents"] == ["abbrev pointer →drawer_001"]
+    assert closet_row["metadatas"][0] == {"wing": "alpha"}
+
+
+def test_rebuild_from_sqlite_refuses_existing_dest(tmp_path):
+    """Refuse to write into a directory that already exists when source
+    and dest differ. Without this, an unattended re-run would silently
+    interleave a partial rebuild with whatever's already at dest.
+    """
+    source = tmp_path / "source"
+    dest = tmp_path / "dest"
+    _seed_palace(source, "mempalace_drawers", [("d1", "doc", {"wing": "w"})])
+    dest.mkdir()
+    # Drop a marker file so we can prove the dir wasn't touched.
+    (dest / "marker.txt").write_text("preexisting")
+
+    counts = repair.rebuild_from_sqlite(str(source), str(dest))
+    assert counts == {}
+    assert (dest / "marker.txt").read_text() == "preexisting"
+    assert not (dest / "chroma.sqlite3").exists()
+
+
+def test_rebuild_from_sqlite_in_place_archives_when_opted_in(tmp_path):
+    """In-place rebuild (source == dest) with ``archive_existing_dest=True``
+    must move the original aside to ``<dest>.pre-rebuild-<ts>`` and read
+    from the archive — the original drawer rows must survive in the new
+    palace, AND the archive itself must still contain the original rows.
+
+    Catches: a refactor that moves the original out but then reads from
+    the now-empty original location, producing an empty rebuild; also
+    catches a swap that empties the archive after reading.
+    """
+    palace = tmp_path / "palace"
+    rows = [(f"d{i}", f"body {i}", {"wing": "w", "room": "r"}) for i in range(15)]
+    _seed_palace(palace, "mempalace_drawers", rows)
+
+    counts = repair.rebuild_from_sqlite(str(palace), str(palace), archive_existing_dest=True)
+    assert counts["mempalace_drawers"] == 15
+
+    archives = [p for p in tmp_path.iterdir() if p.name.startswith("palace.pre-rebuild-")]
+    assert len(archives) == 1
+    assert (archives[0] / "chroma.sqlite3").exists()
+    # Archive must still hold the same row count via the SQLite bypass —
+    # proves the archive wasn't silently truncated as a side effect.
+    archived_rows = list(repair.extract_via_sqlite(str(archives[0]), "mempalace_drawers"))
+    assert len(archived_rows) == 15
+
+    from mempalace.backends.chroma import ChromaBackend
+
+    rebuilt = ChromaBackend().get_collection(str(palace), "mempalace_drawers")
+    assert rebuilt.count() == 15
+
+
+def test_rebuild_from_sqlite_in_place_refuses_without_archive_flag(tmp_path):
+    """Source == dest without archive flag must abort untouched. The
+    most catastrophic possible regression of this code path is silently
+    deleting the only copy of the user's data."""
+    palace = tmp_path / "palace"
+    _seed_palace(palace, "mempalace_drawers", [("d1", "doc", {"wing": "w"})])
+    sqlite_before = (palace / "chroma.sqlite3").stat().st_size
+
+    counts = repair.rebuild_from_sqlite(str(palace), str(palace))
+    assert counts == {}
+    # Same file, untouched.
+    assert (palace / "chroma.sqlite3").stat().st_size == sqlite_before
+    archives = [p for p in tmp_path.iterdir() if "pre-rebuild" in p.name]
+    assert archives == []
+
+
+def test_rebuild_from_sqlite_source_missing_chroma_db(tmp_path):
+    """Source dir exists but has no chroma.sqlite3 → returns empty,
+    leaves dest untouched."""
+    source = tmp_path / "source"
+    source.mkdir()
+    (source / "stray_file").write_text("not a palace")
+    dest = tmp_path / "dest"
+
+    counts = repair.rebuild_from_sqlite(str(source), str(dest))
+    assert counts == {}
+    assert not dest.exists()
+
+
+def test_rebuild_from_sqlite_in_place_validates_source_before_archiving(tmp_path):
+    """In-place + archive_existing_dest=True with a dir that lacks
+    chroma.sqlite3 must NOT rename the dir before bailing. An earlier
+    revision archived first and validated second, leaving the user with
+    a renamed empty dir to manually undo. Catches that ordering bug.
+    """
+    palace = tmp_path / "palace"
+    palace.mkdir()
+    (palace / "marker.txt").write_text("not a real palace")
+
+    counts = repair.rebuild_from_sqlite(str(palace), str(palace), archive_existing_dest=True)
+    assert counts == {}
+    # No archive created — original dir still in place with its marker.
+    assert palace.exists()
+    assert (palace / "marker.txt").read_text() == "not a real palace"
+    archives = [p for p in tmp_path.iterdir() if "pre-rebuild" in p.name]
+    assert archives == []
+
+
+def test_rebuild_from_sqlite_raises_on_upsert_failure(tmp_path, monkeypatch):
+    """Mid-batch upsert failure must raise ``RebuildPartialError`` and
+    surface the failed collection + archive path so the user can recover.
+    Without this, an unattended script gets exit-code-zero on a partial
+    rebuild and the user discovers the data loss only when search starts
+    returning fewer hits.
+    """
+    palace = tmp_path / "palace"
+    rows = [(f"d{i}", f"body {i}", {"wing": "w", "room": "r"}) for i in range(5)]
+    _seed_palace(palace, "mempalace_drawers", rows)
+
+    # Make the very first upsert raise so we don't depend on batch
+    # boundary behavior. Patching ChromaCollection.upsert (the wrapper
+    # mempalace's backend returns) keeps the failure path realistic.
+    # ``monkeypatch`` is pytest's built-in fixture that auto-restores
+    # the original attribute when the test exits, so we don't need to
+    # undo this manually.
+    from mempalace.backends.chroma import ChromaCollection
+
+    def boom(self, **kwargs):
+        raise RuntimeError("simulated chromadb upsert failure")
+
+    monkeypatch.setattr(ChromaCollection, "upsert", boom)
+
+    with pytest.raises(repair.RebuildPartialError) as excinfo:
+        repair.rebuild_from_sqlite(str(palace), str(palace), archive_existing_dest=True)
+
+    err = excinfo.value
+    assert err.failed_collection == "mempalace_drawers"
+    assert err.partial_counts.get("mempalace_drawers") == 0
+    assert err.archive_path is not None
+    assert os.path.isfile(os.path.join(err.archive_path, "chroma.sqlite3"))
+    assert err.dest_palace == os.path.abspath(str(palace))
+
+
+def test_rebuild_from_sqlite_honors_configured_drawer_collection_name(tmp_path, monkeypatch):
+    """A user with a non-default drawers collection name (set via
+    ``MempalaceConfig().collection_name``) must have THAT collection
+    rebuilt — not the hardcoded ``mempalace_drawers``.
+
+    Catches: a regression where the recovery path silently rebuilds the
+    default-name collection on a custom-named palace, leaving the user's
+    actual data unrebuilt while reporting "rebuild complete." This is
+    the failure mode reviewer mjc flagged on PR #1310 as needing to line
+    up with the configured-collection-name work in #1312. Closets stay
+    fixed (``mempalace_closets``) by design — the AAAK index references
+    drawer IDs by string and is not per-deployment configurable.
+
+    Strategy: monkeypatch the lazy resolver so the test is hermetic and
+    does not depend on the global config file or env state.
+    """
+    from mempalace.backends.chroma import ChromaBackend
+
+    custom_drawers = "custom_drawers_xyz"
+    monkeypatch.setattr(repair, "_drawers_collection_name", lambda: custom_drawers)
+
+    source = tmp_path / "source"
+    dest = tmp_path / "dest"
+
+    drawer_rows = [(f"d{i}", f"body {i}", {"wing": "alpha"}) for i in range(3)]
+    closet_rows = [("closet_a", "abbrev →d0", {"wing": "alpha"})]
+    _seed_palace(source, custom_drawers, drawer_rows)
+    _seed_palace(source, "mempalace_closets", closet_rows)
+
+    counts = repair.rebuild_from_sqlite(str(source), str(dest))
+
+    # Rebuilt under the custom name, not under the default "mempalace_drawers".
+    assert counts == {custom_drawers: 3, "mempalace_closets": 1}
+
+    backend = ChromaBackend()
+    rebuilt_drawers = backend.get_collection(str(dest), custom_drawers)
+    assert rebuilt_drawers.count() == 3
+
+    # Default-name collection must NOT exist in dest — proves we did not
+    # silently fall back to the hardcoded name during rebuild.
+    try:
+        rebuilt_default = backend.get_collection(str(dest), "mempalace_drawers")
+        # If get_collection returns without raising, count() should be 0
+        # (chromadb may auto-create on get with some EFs); a non-zero
+        # count would mean we wrote rows to the wrong collection.
+        assert rebuilt_default.count() == 0, (
+            "rebuild leaked rows into the default-name collection on a "
+            "custom-name palace — recovery wrote to the wrong collection."
+        )
+    except Exception:
+        pass  # Expected: collection wasn't created.

tests/test_searcher.py

@@ -84,6 +84,24 @@ class TestSearchMemories:
         assert "error" in result
         assert "query failed" in result["error"]
 
+    def test_search_memories_vector_path_uses_explicit_collection_name(self):
+        mock_col = MagicMock()
+        mock_col.query.return_value = {
+            "documents": [[]],
+            "metadatas": [[]],
+            "distances": [[]],
+            "ids": [[]],
+        }
+
+        with patch("mempalace.searcher.get_collection", return_value=mock_col) as get_collection:
+            search_memories("test", "/fake/path", collection_name="custom_drawers")
+
+        get_collection.assert_called_once_with(
+            "/fake/path",
+            collection_name="custom_drawers",
+            create=False,
+        )
+
     def test_search_memories_filters_in_result(self, palace_path, seeded_collection):
         result = search_memories("test", palace_path, wing="project", room="backend")
         assert result["filters"]["wing"] == "project"
@@ -102,7 +120,7 @@ class TestSearchMemories:
             "ids": [["d1", "d2"]],
         }
 
-        def mock_get_collection(path, create=False):
+        def mock_get_collection(path, collection_name=None, create=False):
             # First call: drawers. Second call: closets — raise so hybrid
             # degrades to pure drawer search (the catch block covers it).
             if not hasattr(mock_get_collection, "_called"):
@@ -120,6 +138,65 @@ class TestSearchMemories:
         assert none_hit["wing"] == "unknown"
         assert none_hit["room"] == "unknown"
 
+    def test_effective_distance_clamped_to_valid_cosine_range(self):
+        """A strong closet boost (up to 0.40) applied to a low-distance drawer
+        can drive ``dist - boost`` negative. That violates the cosine-distance
+        invariant ``[0, 2]``: the API returns ``similarity > 1.0`` and the
+        internal ``_sort_key`` sinks below ordinary positive distances,
+        inverting the ranking so the best hybrid matches sort last.
+
+        With the clamp, ``effective_distance`` stays in ``[0, 2]``,
+        ``similarity`` stays in ``[0, 1]``, and the sort order is stable.
+        """
+        # Drawer a.md gets a tiny base distance (0.08) — nearly exact match.
+        # Drawer b.md gets a larger base distance (0.35).
+        drawers_col = MagicMock()
+        drawers_col.query.return_value = {
+            "documents": [["doc-a", "doc-b"]],
+            "metadatas": [
+                [
+                    {"source_file": "a.md", "wing": "w", "room": "r", "chunk_index": 0},
+                    {"source_file": "b.md", "wing": "w", "room": "r", "chunk_index": 0},
+                ]
+            ],
+            "distances": [[0.08, 0.35]],
+            "ids": [["d-a", "d-b"]],
+        }
+        # A strong closet at rank 0 points at a.md → boost = 0.40,
+        # which exceeds a.md's base distance and would go negative without
+        # the clamp. No closet for b.md.
+        closets_col = MagicMock()
+        closets_col.query.return_value = {
+            "documents": [["closet-preview-a"]],
+            "metadatas": [[{"source_file": "a.md"}]],
+            "distances": [[0.2]],  # within CLOSET_DISTANCE_CAP (1.5)
+            "ids": [["c-a"]],
+        }
+
+        with (
+            patch("mempalace.searcher.get_collection", return_value=drawers_col),
+            patch("mempalace.searcher.get_closets_collection", return_value=closets_col),
+        ):
+            result = search_memories("query", "/fake/path", n_results=5)
+
+        hits = result["results"]
+        assert hits, "should return results"
+
+        # Invariants on every hit.
+        for h in hits:
+            assert (
+                0.0 <= h["similarity"] <= 1.0
+            ), f"similarity out of range: {h['similarity']} for {h['source_file']}"
+            assert 0.0 <= h["effective_distance"] <= 2.0, (
+                f"effective_distance out of range: {h['effective_distance']} "
+                f"for {h['source_file']}"
+            )
+
+        # With the clamp, the closet-boosted a.md still ranks ahead of b.md —
+        # the boost still wins, but it no longer flips the ranking.
+        assert hits[0]["source_file"] == "a.md"
+        assert hits[0]["matched_via"] == "drawer+closet"
+
 
 # ── BM25 internals: None / empty document safety ─────────────────────
 

tools/backup_claude_jsonls.sh

@@ -0,0 +1,39 @@
+#!/usr/bin/env bash
+# backup_claude_jsonls.sh
+#
+# Claude Code stores every conversation as a JSONL transcript at
+#   ~/.claude/projects/<encoded-project>/<session-uuid>.jsonl
+# Anthropic auto-deletes those files after 30 DAYS:
+#   https://docs.claude.com/en/docs/claude-code/data-usage
+#
+# This script copies them, read-only, into ~/Documents/Claude_JSONL_Backup/
+# so the 30-day clock no longer applies. Re-run any time — rsync is incremental.
+# It NEVER deletes, modifies, or touches files inside ~/.claude/.
+
+set -eu
+
+SRC="${HOME}/.claude/projects/"
+DST="${HOME}/Documents/Claude_JSONL_Backup/"
+
+[ -d "$SRC" ] || { echo "ERROR: $SRC does not exist."; exit 1; }
+mkdir -p "$DST"
+
+echo "Backing up $SRC -> $DST"
+rsync -a --times "$SRC" "$DST"
+
+src_count=$(find "$SRC" -type f -name '*.jsonl' | wc -l | tr -d ' ')
+dst_count=$(find "$DST" -type f -name '*.jsonl' | wc -l | tr -d ' ')
+oldest=$(find "$DST" -type f -name '*.jsonl' -exec stat -f '%Sm %N' -t '%Y-%m-%d' {} \; 2>/dev/null \
+        || find "$DST" -type f -name '*.jsonl' -printf '%TY-%Tm-%Td %p\n' 2>/dev/null)
+oldest_date=$(echo "$oldest" | sort | head -n 1 | awk '{print $1}')
+newest_date=$(echo "$oldest" | sort | tail -n 1 | awk '{print $1}')
+
+echo "Source JSONL count : $src_count"
+echo "Backup JSONL count : $dst_count"
+echo "Oldest backup file : ${oldest_date:-n/a}"
+echo "Newest backup file : ${newest_date:-n/a}"
+
+if [ "$src_count" -ne "$dst_count" ]; then
+  echo "FAIL: count mismatch ($src_count vs $dst_count)"; exit 2
+fi
+echo "OK: backup verified."

tools/find_orphan_claude_jsonls.sh

@@ -0,0 +1,115 @@
+#!/usr/bin/env bash
+# find_orphan_claude_jsonls.sh — v3 (multi-line shape + verb-aware preview)
+# -----------------------------------------------------------------------------
+# Finds Claude Code conversation transcripts (.jsonl) that may have survived in
+# backup/sync locations. Claude Code stores transcripts at
+# ~/.claude/projects/<encoded>/<session>.jsonl and auto-deletes them locally
+# after 30 days. If your machine syncs to iCloud, Dropbox, Google Drive,
+# OneDrive, Time Machine, or you copied transcripts elsewhere manually, those
+# copies still exist. This script finds them and shows a topic preview from
+# the first substantive user message — strips leading filler interjections
+# ("ok so", "oh", "well", "hey") so previews surface the actual content.
+#
+# Read-only. Safe to re-run.
+# -----------------------------------------------------------------------------
+set -eu
+
+LOCATIONS=(
+  "$HOME/Library/Mobile Documents" "$HOME/Dropbox" "$HOME/Google Drive"
+  "$HOME/OneDrive" "$HOME/Documents" "$HOME/Desktop" "/Volumes"
+)
+
+TMP="$(mktemp)"; trap 'rm -f "$TMP" "$TMP.s"' EXIT
+
+printf "Scanning backup locations" >&2
+for loc in "${LOCATIONS[@]}"; do
+  [ -d "$loc" ] || continue
+  printf "." >&2
+  while IFS= read -r -d '' f; do
+    # Combined: shape detection (multi-line) + verb-aware topic preview
+    if preview="$(python3 - "$f" 2>/dev/null <<'PYEOF'
+import json, sys, re
+
+# Single-word/short greetings — message gets skipped entirely if it is just one of these
+GREETINGS = {'hi','hey','hello','thanks','thank you','ok','okay','yes','no',
+             'sure','cool','great','good','done','yep','nope','perfect','copy'}
+
+# Leading filler — interjections that get STRIPPED from the start of a message
+# before the preview is taken. Iterative — handles "ok so well, then..." → "then..."
+LEADING_FILLER = re.compile(
+    r'^(?:ok(?:ay)?|so|oh|well|anyway|btw|hmm+|um+|uh+|hey|hi|hello|right|'
+    r'yes|no|sure|cool|great|good|listen|look|wait|actually|alright|gotcha|'
+    r'yeah|yep|nope|nah)\b[\s,!.?:;-]*',
+    re.IGNORECASE
+)
+
+path = sys.argv[1]
+shape_ok = False
+preview = ""
+try:
+    with open(path, 'r', errors='replace') as fh:
+        for i, line in enumerate(fh):
+            if i >= 30: break
+            try:
+                d = json.loads(line)
+            except Exception:
+                continue
+            if not isinstance(d, dict): continue
+            # Shape check — accept if any line in first 30 has session fields
+            if not shape_ok and 'sessionId' in d and 'timestamp' in d and 'message' in d:
+                shape_ok = True
+            # Preview — first user message after stripping leading filler
+            if not preview:
+                role = d.get('type', '') or d.get('message', {}).get('role', '')
+                if role == 'user':
+                    content = d.get('message', {}).get('content', '')
+                    if isinstance(content, list):
+                        text = ' '.join(
+                            c.get('text', '') for c in content
+                            if isinstance(c, dict) and c.get('type') == 'text'
+                        )
+                    elif isinstance(content, str):
+                        text = content
+                    else:
+                        text = ''
+                    text = re.sub(r'\s+', ' ', text).strip()
+                    # Skip messages that are pure greetings
+                    if text.lower() in GREETINGS:
+                        continue
+                    # Iteratively strip leading filler tokens until stable
+                    prev_text = None
+                    while prev_text != text:
+                        prev_text = text
+                        text = LEADING_FILLER.sub('', text).strip()
+                    # Skip if what remains is too short
+                    if len(text) < 20:
+                        continue
+                    preview = text[:80] + ('...' if len(text) > 80 else '')
+            if shape_ok and preview: break
+except Exception:
+    pass
+if shape_ok:
+    print(preview if preview else "(no preview — first 30 lines were greetings or short)")
+    sys.exit(0)
+sys.exit(1)
+PYEOF
+)"; then
+      mtime="$(stat -f '%Sm' -t '%Y-%m-%d' "$f" 2>/dev/null || stat -c '%y' "$f" 2>/dev/null | cut -d' ' -f1)"
+      size="$(stat -f '%z' "$f" 2>/dev/null || stat -c '%s' "$f" 2>/dev/null)"
+      printf '%s\t%s\t%s\t%s\n' "$mtime" "$size" "$f" "$preview" >>"$TMP"
+    fi
+  done < <(find "$loc" -type f -name '*.jsonl' -print0 2>/dev/null)
+done
+printf "\n" >&2
+
+count=$(wc -l <"$TMP" | tr -d ' ')
+if [ "$count" -eq 0 ]; then
+  echo "No orphan Claude Code transcripts found in scanned backup locations."
+  exit 0
+fi
+sort -k1,1 "$TMP" >"$TMP.s"
+oldest="$(head -n 1 "$TMP.s" | cut -f1)"
+newest="$(tail -n 1 "$TMP.s" | cut -f1)"
+echo "Found $count orphan Claude Code transcript(s). Oldest: $oldest  Newest: $newest"
+echo "----------------------------------------------------------------------"
+awk -F'\t' '{ printf "%s  %10s  %s\n              \"%s\"\n\n", $1, $2, $3, $4 }' "$TMP.s"

tools/render_jsonl.py

@@ -0,0 +1,80 @@
+#!/usr/bin/env python3
+"""render_jsonl.py — turn one Claude Code JSONL transcript into readable text.
+
+Claude Code stores conversations at ~/.claude/projects/<proj>/<uuid>.jsonl and
+Anthropic auto-deletes them after 30 days
+(https://docs.claude.com/en/docs/claude-code/data-usage). This script renders a
+JSONL into a clean .txt so you can keep / read / share it without the tooling.
+
+Usage:
+    python3 render_jsonl.py <input.jsonl> [output.txt]
+
+Stdlib only. Python 3.9+. Read-only on the input.
+"""
+
+import json
+import sys
+from pathlib import Path
+
+
+def extract_text(content):
+    if isinstance(content, str):
+        return content.strip()
+    if isinstance(content, list):
+        parts = []
+        for blk in content:
+            if isinstance(blk, dict) and blk.get("type") == "text":
+                t = (blk.get("text") or "").strip()
+                if t:
+                    parts.append(t)
+        return "\n".join(parts)
+    return ""
+
+
+def main():
+    if len(sys.argv) < 2:
+        print(__doc__)
+        sys.exit(1)
+    src = Path(sys.argv[1])
+    if not src.is_file():
+        print(f"ERROR: not a file: {src}")
+        sys.exit(1)
+    out = open(sys.argv[2], "w", encoding="utf-8") if len(sys.argv) > 2 else sys.stdout
+
+    turns, stamps = [], []
+    for raw in src.read_text(encoding="utf-8", errors="replace").splitlines():
+        if not raw.strip():
+            continue
+        try:
+            obj = json.loads(raw)
+        except json.JSONDecodeError:
+            continue
+        role = obj.get("type") or (obj.get("message") or {}).get("role")
+        if role not in ("user", "assistant"):
+            continue
+        msg = obj.get("message") or obj
+        text = extract_text(msg.get("content"))
+        if not text:
+            continue
+        ts = obj.get("timestamp") or ""
+        if ts:
+            stamps.append(ts)
+        turns.append((ts, role, text))
+
+    header = [
+        f"# Claude Code transcript: {src}",
+        f"# Total turns: {len(turns)}",
+        f"# Date range : {min(stamps) if stamps else 'n/a'}  ->  {max(stamps) if stamps else 'n/a'}",
+        "#" + "-" * 70,
+        "",
+    ]
+    out.write("\n".join(header))
+    for ts, role, text in turns:
+        out.write(f"\n[{ts}] {role.upper()}\n{text}\n\n{'-'*72}\n")
+    if out is not sys.stdout:
+        out.close()
+        print(f"Wrote {len(turns)} turns to {sys.argv[2]}")
+
+
+if __name__ == "__main__":
+    main()

tools/save.md

@@ -0,0 +1,26 @@
+---
+description: Save the current Claude Code session into MemPalace. Idempotent — won't dupe.
+---
+
+# /save
+
+Save the current Claude Code session into MemPalace. Run this when you
+want a checkpoint. Safe to run repeatedly — drawer IDs are content-hashed
+so re-running on the same session overwrites in place, no duplicates.
+
+Behavior:
+
+1. Find the current session's JSONL transcript path (Claude Code passes
+   it via the conversation context — look for `~/.claude/projects/` paths).
+2. Run via bash:
+
+   ```
+   mempalace mine "<TRANSCRIPT_PATH>" --mode convos --wing claude_imports
+   ```
+
+3. If the user supplied an argument after `/save`, use it as the wing name
+   instead of `claude_imports` (e.g. `/save my_research` →
+   `--wing my_research`).
+4. Report back: how many drawers were filed, into which wing/room.
+
+Requires `mempalace` to be installed (`pip install mempalace`).