brain-mcp — the recorder for your AI conversations
Your AI history is being deleted right now. Claude Code deletes session files older
than cleanupPeriodDays (default 30) at startup. Run this and see your own cliff edge:
find ~/.claude/projects -name '*.jsonl' -exec stat -f '%Sm %N' -t '%Y-%m-%d' {} + | sort | head -3
find ~/.claude/projects -name '*.jsonl' -printf '%TY-%Tm-%Td %p\n' | sort | head -3
The oldest date you see is where your history ends. brain-mcp records it before it goes —
byte-exact, content-hashed, locally — and makes it queryable with citations you can verify
with sed and shasum.
Install
pipx install brain-mcp --pre
brain-mcp install cc
brain-mcp serve
Or as a Claude Code plugin (hooks + server in one step):
/plugin marketplace add mordechaipotash/brain-marketplace
/plugin install brain
What it does
- Captures at source. Claude Code via Stop/SessionEnd hooks (line-deltas + a final
snapshot); Codex and Pi via a 60-second poll-scan. One spool, one floor.
- Keeps the bytes. The floor is
~/.brain/lake/<lane>/<session>.jsonl — append-only,
byte-identical to the original, with an append-only sha256 manifest. Nothing is parsed
and discarded; the DuckDB index is a cache, fully re-derivable from the lake.
- Cites or abstains. Every search hit carries
{file, line span, sha256} — checkable
by anyone with sed -n 'A,Bp' file | shasum -a 256, no database required. Zero hits
return an explicit abstention naming the lanes and dates actually searched.
- Reports health honestly.
fresh = the floor holds everything the agent's files show;
stale = the agent has content the recorder missed; unknown = unmeasured, not
healthy — never folded into "looks fine".
- Backs up verifiably.
brain-mcp backup <dest> syncs lake+manifest and re-hashes
sampled files at the destination. The verify can fail; that is the point.
- Zero network calls at runtime. No telemetry, no cloud, no accounts. Verify it:
there is no httpx/requests import in this package.
| tool | what |
|---|
brain_search | BM25 over everything recorded; cited hits or an explicit abstention |
brain_get | the raw lines behind a citation, with sha verification |
brain_recent | time-ordered recent activity, every row cited |
brain_sessions | session cards per day/agent |
brain_health | per-lane origin-vs-floor freshness; unknown ≠ healthy |
brain_capture_status | is the machinery itself moving (spool, heartbeats, floor) |
brain_backup | verified backup; writes only outside the floor |
🤖 For AI Assistants
You're reading this because your human runs THE RECORDER and gave you access to their
AI history. This is the honesty contract.
The one rule: everything you state from these tools is either CITED or ABSTAINED —
there is no third state. A cited claim carries a checkable pointer (file + line span +
sha256); verify it with brain_get(expect_sha256=...) before building on it. An
abstention means "not found above threshold in the lanes and dates the tool measured" —
it does NOT mean "it never happened". Never fill an abstention with your own guess.
- Present recall as their words, dated: "On 2026-08-19 you wrote: '…' (sess-7f2a.jsonl:412)" —
never as your own knowledge. One claim, one citation.
verified: false from brain_get means the floor changed since indexing. Say so plainly.- A health response containing any
unknown lane is never "everything looks fine".
The honest sentence is: "2 lanes fresh, 1 stale, 1 unmeasured."
- "What do I think about X" →
brain_search(query, role="user"). "How did my thinking
evolve" → add order="time_asc" and read the citations in time order. The server has
no opinion about your human's mind; it has their words, with receipts.
~/.brain/
spool/<lane>/ hooks + scanner write here (atomic, dot-tmp invisible)
lake/<lane>/<session>.jsonl THE FLOOR: append-only, byte-identical to the origin;
a rewrite opens <session>.g2.jsonl — old kept, never deleted
manifest/manifest.jsonl one versioned line per chunk: byte range, line range, sha256
offsets/<lane>/<session> hook fast-path line counters
health/*.last_run side-effect heartbeats (mtimes are the proof, never a report)
brain.duckdb the index — a cache, re-derivable from lake/ + manifest/
Where your agents keep their transcripts: Claude Code ~/.claude/projects/**/*.jsonl
(rolling window!), Codex ~/.codex/sessions/YYYY/MM/DD/rollout-*.jsonl, Pi
~/.pi/agent/sessions/**/*.jsonl.
Other verbs
brain-mcp record
brain-mcp health [--exit-nonzero-on-stale]
brain-mcp doctor
brain-mcp redact <file> --lines A B --reason "..."
brain-mcp migrate-v1 <all_conversations.parquet>
brain-mcp uninstall
v1 → v2
v2 is a rebuild around one principle: capture the bytes first; derive everything else.
v1 parsed conversations into a parquet and discarded the originals — v2's floor makes that
structurally impossible. v1's 25 tools became 7: the synthesis tools ("cognitive patterns",
"switching cost") are gone because a claim that can't carry a line-span citation isn't one
this server makes. Migration: brain-mcp migrate-v1 — v1 rows are kept, marked as derived,
and floor-backed rows win wherever the source still exists.
Windows: out of scope for v2.0. Scheduling is LaunchAgent (macOS) / systemd user timer (Linux).
MIT.