diff --git a/mempalace/convo_miner.py b/mempalace/convo_miner.py
index ba98d0e..3e7b5a4 100644
--- a/mempalace/convo_miner.py
+++ b/mempalace/convo_miner.py
@@ -55,7 +55,11 @@ CONVO_EXTENSIONS = {
 
 MIN_CHUNK_SIZE = 30
 CHUNK_SIZE = 800  # chars per drawer — align with miner.py
-MAX_FILE_SIZE = 10 * 1024 * 1024  # 10 MB — skip files larger than this
+MAX_FILE_SIZE = 500 * 1024 * 1024  # 500 MB — skip files larger than this.
+# Matches miner.py at 500 MB. Long Claude Code sessions, multi-year
+# ChatGPT exports, and lifetime Slack dumps routinely exceed 10 MB; the
+# cap at that level silently dropped them with `continue`. Source size
+# does not affect storage or embedding cost — chunking happens downstream.
 
 
 def _register_file(collection, source_file: str, wing: str, agent: str):
diff --git a/tests/test_convo_miner_size_cap.py b/tests/test_convo_miner_size_cap.py
new file mode 100644
index 0000000..ea0d6d1
--- /dev/null
+++ b/tests/test_convo_miner_size_cap.py
@@ -0,0 +1,31 @@
+"""TDD: convo_miner.py must not silently drop transcripts larger than 10 MB.
+
+Mirrors the miner.py fix shipped in the same PR family (see
+test_miner_jsonl_visibility.py). Long Claude Code sessions, ChatGPT
+exports, and multi-year Slack dumps routinely exceed 10 MB. The cap
+silently `continue`s past them at convo_miner.py:~289, same silent-drop
+pattern as the project miner's.
+
+Written BEFORE the fix.
+"""
+
+from mempalace.convo_miner import MAX_FILE_SIZE
+
+
+class TestConvoMinerSizeCap:
+    def test_max_file_size_accommodates_long_transcripts(self):
+        """The cap must be well above any realistic transcript.
+
+        Long sessions and lifetime exports exceed 10 MB. The cap exists
+        as a sanity rail against pathological binaries, not as a limit
+        on legitimate text — downstream chunking means source size does
+        not matter for storage or embedding cost.
+        """
+        assert MAX_FILE_SIZE >= 100 * 1024 * 1024, (
+            f"convo_miner.MAX_FILE_SIZE is {MAX_FILE_SIZE} bytes "
+            f"({MAX_FILE_SIZE / 1024 / 1024:.0f} MB). Same silent-drop "
+            "bug as miner.py's old 10 MB cap — long transcripts get "
+            "filtered out at convo_miner.py:~289 with `continue`. "
+            "Raise to at least 100 MB (match miner.py at 500 MB for "
+            "consistency across both miners)."
+        )