Memspec

Memspec is Git-backed project memory for AI coding agents, with verification and drift detection. Claims about code are anchored to file SHAs; when the code changes, memspec flags the claim for review instead of letting facts rot silently. Duplicate rejection, typed supersede chains, and per-claim provenance turn memory into testable claims, not a notes file.

Markdown files under .memspec/ are the canonical source of truth: human-readable, git-diffable, greppable. Lose the index, lose speed — not data. No backend service. No hosted memory API. No vendor lock-in.

Architecture

Agents remember claims and observe notes; everything lands as markdown under .memspec/. From there a structured layer — lifecycle (active → superseded → retired), code anchors, typed links, and temporal validity — feeds FTS5/hybrid search, the MCP server, and session-start hooks, so the next session wakes up with the right context instead of amnesia.

Features

• File-canonical. Memories are markdown files with YAML frontmatter. Human-readable, git-diffable, greppable. Lose the index, lose speed — not data.
• Three claim types + observations. fact, decision, procedure with per-type TTLs; observation for point-in-time notes with hard expiry.
• Lifecycle, not curation. active | superseded | retired. Corrections create a new memory linked back to the original; supersede chains preserve the reason on every record involved. Past TTL = stale flag at read time, never deletion.
• Code-anchored verification. Tie memories to git blob SHAs. When code drifts, memspec flags drifted anchors for review instead of letting facts about code rot silently.
• Linked notes (v0.5+). Records reference other records by id (refines, supports, depends_on, conflicts_with, supersedes, superseded_by). Search can follow these links one or more hops to surface neighbours alongside direct matches; --include-superseded lets link-following reach archived predecessors (v0.6+).
• Temporal validity (v0.5+). Optional valid_from / valid_to per memory. Search with --as-of <iso> filters by world-state truth window, orthogonal to the check_by review schedule.
• Operator-tier storage (v0.4+). Records sourced by the operator land in a separate filesystem path with stricter overwrite protection (--override-operator required to supersede).
• Layered stores (v0.6+). A project .memspec/ and a global ~/.memspec/ merge at retrieval time — project records take priority, global merges as a lower layer. Every search, context, and MCP path honours the configured stores: layers.
• Dedup-aware writes. remember refuses near-duplicate claims and points at the existing record, so memory accretes corrections via supersede instead of silent duplicates.
• Hybrid search. SQLite FTS5 + BM25 by default; optional dense embeddings rerank via OpenAI-compatible endpoints or Ollama.
• MCP server. Eleven tools, first-class integration with Claude Code, Cursor, Codex.
• Witnessed claims. Every memory carries verified_with (anchor | operator | evidence | assertion) — provenance, not a confidence score.
• Dream pass (v0.7+). Periodic reflection script (memspec-dream) reads the last N days of memspec writes and git log, asks an LLM to surface stale memories, supersede candidates, verify candidates, missing relations, and behavioural rules worth promoting. Output is review material, never auto-applied.
• Zero infrastructure. npm install -g memspec + memspec init. No accounts, no API keys, no hosted services.

Install

npm install -g memspec

Or local:

git clone https://github.com/siimvene/memspec.git
cd memspec && npm install && npm run build && npm link

Quick start

memspec init                                            # interactive setup, creates .memspec/

memspec remember fact "Auth uses JWT" \                 # write a claim, anchor it to code
  --source agent --tags auth --anchor src/auth/jwt.ts

memspec search "auth"                                   # BM25; --expand-edges follows linked notes

memspec reconcile                                       # find anchored claims whose code drifted
memspec verify ms_01HXK... --evidence "still JWT"       # confirm still true; refreshes timestamp

memspec supersede ms_01HXK... \                         # or replace with a corrected version
  --reason "Migrated to OAuth" --body "Now OAuth2 + PKCE"

The anchor → reconcile → verify | supersede loop is the differentiator: claims about code stay accountable to the code.

Why not just AGENTS.md?

Approach	Reviewable in Git	Code-anchored	Lifecycle	Search	Self-hosted
AGENTS.md / CLAUDE.md	yes	no	none	grep	yes
MEMORY.md / scratchpad	yes	no	none	grep	yes
Vector DB (Chroma, Qdrant)	no	no	manual	semantic	yes
Hosted memory API (Mem0, Letta)	no	no	hosted	hosted	no
Memspec	per-claim	yes	typed states	FTS5 + optional hybrid	yes

If project memory fits in a paragraph in a single file, AGENTS.md is fine. Memspec is for when memory grows into a list of claims that need to track code reality, expire, supersede, and link to each other.

Memory model

Three claim types plus observations, agent-operated, lifecycle handled in the tool:

Type	Captures	Default TTL
fact	Verified project state	90d
decision	A choice with rationale	180d
procedure	A reusable workflow	90d
observation	Point-in-time, hard expiry	7d

Each memory is one markdown file with YAML frontmatter. Past check_by → stale flag at read time, never deletion. memspec sweep is the only removal path, operator-approved one item at a time.

States: active | superseded | retired. Corrections create a new memory linked back to the original; supersede chains preserve the reason on every record involved. Everything lives in git history.

Linked notes

Records reference other records by id in their frontmatter — refines, supports, depends_on, conflicts_with, supersedes, superseded_by. Search can follow these links to surface neighbours alongside direct matches:

memspec search "v0.5 plan" --expand-edges --expand-depth 1

Follows the listed ids one hop out and includes the linked notes in results. Each surfaced neighbour carries expanded_via showing how it got there. --include-superseded lets expansion reach archived predecessors via supersede chains. --as-of <iso> filters by valid_from / valid_to for world-state queries.

Code-anchored verification

Calendar TTL is the wrong signal for facts about code. Memspec ties claims to file SHAs:

• memspec anchor <id> <files...> — record the git blob SHAs of the files this memory depends on
• memspec verify <id> — refresh "still true"; drifted anchors flag for review without mutating the memory
• memspec reconcile — scan all anchored memories for drift, including uncommitted edits

Drifted memories never auto-archive. They surface for human judgement via memspec status.

Search

Two engines, picked at memspec init:

• FTS5 (default): SQLite full-text + BM25. Zero setup beyond better-sqlite3.
• Hybrid: FTS5 candidates plus embeddings rerank. OpenAI-compatible endpoints or Ollama.

Index rebuilds on demand from the markdown files. Lose the index, lose speed — not data.

Trust profiles

Memspec doesn't enforce a write policy; the agent's instruction file does (see AGENTS-ADDON.md). Two reference profiles:

Operator solo (default). The agent writes facts, decisions, procedures, and observations freely. Duplicate rejection, anchor drift, and supersede chains catch bad writes. Friction-free; relies on git log to undo mistakes. Suits single-operator setups where memspec is your own agent infrastructure.

Team review. For shared repos with multiple writers:

• Observations: agent writes freely.
• Facts: agent writes only when anchored to code; anchorless facts route to a PR for review.
• Decisions: drafted by agent, merged by human.
• Procedures: agent-written, reviewed at first use.
• Operator-tier claims: never overridden without --override-operator and a reason in the supersede record.
• Secrets: never stored. Anywhere. Ever.

Pick the profile in your AGENTS.md / CLAUDE.md and the agent will follow it. The store records every write, so deviations show up in git log.

MCP server

memspec-mcp                          # stdio in current project
memspec-mcp --cwd /path/to/project   # pin a root

memspec init auto-creates .mcp.json for host tool discovery (Claude Code, Cursor, etc).

Eleven MCP tools: memspec_search, memspec_get, memspec_remember, memspec_supersede, memspec_relate, memspec_observe, memspec_verify, memspec_anchor, memspec_reconcile, memspec_status, memspec_export. The CLI exposes a superset (init, migrate, sweep, context are CLI-only — store creation, schema migration, physical removal, and session-start context are operator acts, not an agent surface).

For manual .mcp.json setup:

{
  "mcpServers": {
    "memspec": { "command": "memspec-mcp", "args": ["--cwd", "/abs/path/to/project"] }
  }
}

Global store

~/.memspec/ is a cross-project memory layer for personal preferences, common patterns, infra knowledge. When both stores exist, the project store takes priority; global merges as a lower layer.

memspec init --cwd ~/.memspec

Store layout

.memspec/
  memory/
    facts/  decisions/  procedures/        # active, agent-tier
    operator/{facts,decisions,procedures}/ # operator-tier (separate path)
  observations/                            # raw, unclassified
  archive/                                 # superseded + retired
  config.yaml                              # search engine, embeddings, decay

Frontmatter fields per record: id, kind, type, state, source, source_kind, verified_with (anchor | operator | evidence | assertion), tags, check_by, anchors, supersedes, superseded_by, conflicts_with, refines, supports, depends_on, optional valid_from / valid_to. Human-readable, git-diffable, greppable.

CLI reference

Command	What
memspec init	Create .memspec/, configure search, install hooks
memspec remember <type> <title> --source <who>	Write a fact/decision/procedure
memspec observe <text>	Capture a point-in-time observation
memspec search <query> [--expand-edges] [--include-superseded] [--as-of <iso>]	Search; optionally follow linked notes
memspec context [--query] [--limit]	Token-budgeted memory dump for session-start hooks
memspec supersede <id> --reason "..." [--body] [--merge-from <ids>]	Replace, retract, or merge records
memspec relate --from <id> --to <id> --type <kind>	Wire a link between records after the fact
memspec verify <id> [--evidence "..."]	Mark a memory still true; checks anchors
memspec anchor <id> <files...>	Link a memory to file SHAs
memspec reconcile	Find anchored memories with drifted code
memspec status	Health readout (counts, witness, stale, drift, conflicts)
memspec sweep	Interactively retire stale items (operator-only removal path)
memspec export --format <jsonl|graphml|dot>	Export records and links to stdout
memspec migrate	v0.2/v0.3 → v0.4+ store migration (idempotent, dry-run by default)

Hooks for Claude Code

memspec init installs two hooks at ~/.claude/hooks/:

• memspec-session-start.js — runs memspec context and injects memory into the session prompt so the agent doesn't have to remember to search
• memspec-consolidate.js — on commit, prompts the agent to write memories about what just shipped

Configurable in .memspec/config.yaml. Pass --no-install-hooks to skip. See hooks/ for the scripts.

Dream pass

A periodic reflection over the store. Reads the last N days of memspec writes + git log, asks an LLM to surface stale memories, supersede / merge candidates, verify candidates, missing typed relations, and behavioural rules worth promoting to your agent instruction file. Proposals only — never auto-applied.

memspec-dream                          # weekly default (7 days, current .memspec/)
memspec-dream 14                       # custom window
MEMSPEC_DREAM_AUTOCOMMIT=1 memspec-dream

Output lands at <store>/dream/YYYY-MM-DD.md for a human to review. Defaults to invoking claude (Claude Code CLI) headlessly; override with MEMSPEC_LLM_BIN and MEMSPEC_LLM_ARGS for other CLIs.

Cron example (Sunday 22:00 local):

0 22 * * 0  cd /path/to/project && MEMSPEC_DREAM_AUTOCOMMIT=1 memspec-dream

Inspired by Aaron Fulkerson's Exo and the dream-skill prior art.

Docs

• SPEC.md — design rationale and frontmatter schema
• SCHEMA.md — generated field reference (regenerated from Zod via npm run schema)
• CHANGELOG.md — release history
• MIGRATION-v0.3.md — v0.2/v0.3 → v0.4+ upgrade path
• AGENTS-ADDON.md — block to paste into AGENTS.md / CLAUDE.md if init couldn't patch your repo

License

MIT