Auth header: `Authorization: Bearer $ECHO_KEY` — `export ECHO_KEY=<token>` before running these recipes (`echo.py` resolves it automatically: `ECHO_KEY` → `~/.echo-memory/credentials` → deprecated baked-in fallback). The literal key is never stored in docs.
> **Prefer `scripts/echo.py` over the raw recipes below.** It wraps every verb with auth, status checking, retry, idempotent append, and frontmatter patches, and runs on any platform with a Python interpreter. The `curl` recipes here are the underlying mechanics and a **\*nix/bash fallback** (they use heredocs and `--data-binary`); on Windows, prefer `echo.py` or an equivalent. **If you call `curl` directly, check the HTTP status** — add `-o /dev/null -w "%{http_code}"` and branch on it. A `PATCH` to a non-existent heading returns `400 invalid-target` (errorCode 40080) and the write is *silently lost*; a bare `curl` that ignores status will report success anyway. `GET` returns `404` for a missing file. Treat any `>= 400` as a failed operation, surface it, and do not continue as if it succeeded.
`echo.request()` keeps **one persistent keep-alive connection per thread** and reuses it across calls, instead of opening a fresh TCP+TLS connection per request. Against a remote HTTPS endpoint the repeated handshake was the dominant cost, so a full-vault pass used to make hundreds of serial handshakes and exceed the agent/tool timeout (which kills the run mid-flight). A stale pooled connection reconnects transparently; the `(status, body)` contract is unchanged (status `0` still means transport failure, so the offline write-queue still triggers).
For bulk reads, **`echo.read_many(paths)`** fans GETs across a thread pool and returns `{path: text_or_None}` — resilient (one unreadable file becomes `None` rather than aborting the batch). `sweep.py` and `vault_lint.py` prefetch the whole vault once with it and share that single cache across every pass, so no note is fetched more than once. Net effect: a several-minute full-vault sweep becomes sub-second on a few-hundred-note vault.
Tuning knobs (env overrides):
-`ECHO_TIMEOUT` (default `30`) — per-request socket timeout in seconds. With concurrency, one slow file only blocks its own worker, not the run.
-`ECHO_WORKERS` (default `8`) — `read_many` thread-pool size. Raise it for very large vaults; lower it to be gentler on the backend.
For a vault large enough that even the concurrent pass approaches the tool timeout, run the script with the harness's background-execution option rather than blocking the turn.
`PATCH` edits inside a file without rewriting it. Target and operation are set via headers.
### Append under a heading
**Heading targets must be the FULL heading path, `::`-delimited from the top-level heading.** A bare subheading name returns `400 invalid-target` (errorCode 40080). Example: `## Fact / Pattern` nested under `# Operator Preferences` → `Target: Operator Preferences::Fact / Pattern`. Percent-encode non-ASCII characters (e.g. `H%C3%A9llo`); spaces are fine.
```bash
cat > /tmp/obs_patch.md << 'OBSEOF'
Jason prefers concise status updates — lead with the decision.
Only on explicit operator request. Deletion is destructive.
---
## URL-Encoding Notes
- Path separators (`/`) in the vault path are **literal** — do not encode them.
- Spaces in filenames or heading targets in a URL: use `%20`.
- Nested heading levels in a URL path: use `%3A%3A` for `::`.
- Heading text in the `Target:` header: the **full heading path** joined by `::` (e.g. `Operator Preferences::Fact / Pattern`), no `#`; spaces are fine; percent-encode non-ASCII.
| Ongoing area of responsibility (standing domain, no end state) | `areas/<domain>/<slug>.md` (`<domain>`: `business`/`personal`/`learning`/`systems`) | PUT |
| Journal rollup | `journal/{weekly/YYYY-Www,monthly/YYYY-MM,quarterly/YYYY-Qn,annual/YYYY}.md` (weekly = opt-in on first session of a new ISO week; monthly = offered with Vault Health; quarterly/annual = manual) | PUT |
| Vault-health audit (agent self-maintenance) | `_agent/health/YYYY-MM-vault-health.md` (monthly; NOT a journal entry) | PUT |
| Session-end orientation pointer | `_agent/heartbeat/last-session.md` (one line, overwritten each session end) | PUT |
