mnemos

Give your AI agent a memory it can cite.

Local memory for AI agents. Source citations included.

Claude Code is powerful, but it forgets your project context:

• it forgets why you rejected an architecture,
• it misses your ADRs,
• it invents answers instead of reading your docs,
• it can't reliably cite where a claim came from.

mnemos fixes that by giving it a local, cited memory of:

• your ADRs and design docs
• your notes and runbooks
• your source code
• your OKF knowledge base

No vector database. No Ollama. No Python or Node service. Just one cgo-free Go binary that indexes your files — any plain-Markdown folder works as-is — and serves them over MCP, so Claude can search, read, and cite your own knowledge instead of guessing, with every answer landing on the exact file#section and line range.

Try it in 60 seconds

# 1. install — one cgo-free binary into $GOBIN (requires Go 1.25+)
git clone https://github.com/arhuman/mnemos.git && cd mnemos
make install

# 2. index a project
cd ~/work/myproject
mnemos init                                 # creates ./.mnemos.toml + ./.mnemos/
mnemos ingest docs --collection myproject   # index a directory
mnemos search "why did we choose this architecture"

Prefer make build (→ ./bin/mnemos) to keep it off your $PATH. The default build is pure Go / cgo-free (CGO_ENABLED=0).

search prints citations you can open:

1. security/scim.md#Provisioning
   lines 42-88
   score 12.7

Then wire it into Claude Code (note the absolute --config path):

claude mcp add mnemos -- mnemos serve --config /abs/path/to/myproject/.mnemos.toml

Now Claude answers from your project instead of guessing, and shows its source:

You: How do I recover lost commits?

Claude: Per recovery/reflog.md, the reflog records where HEAD and each branch tip has pointed — even after a hard reset — so you can check out the lost commit's hash. (recovery/reflog.md — "Reflog: recover lost commits")

That's the whole loop — index → ask → cited answer. Everything below is depth: why it's built this way, how it works, and the full capabilities.

⚠️ One gotcha: a document's identity is its path relative to where you ran ingest

A document's URI is its path relative to the scan root you ingested (docs above), not your working directory. Ingesting two directories that each contain (say) index.md resolves both to the same URI: the second ingest silently overwrites the first. To index several trees cleanly, ingest from one common root (mnemos ingest .). Details in docs/paths-and-indexing.md.

Why mnemos

• Truly local-first: runs entirely on your machine. No network, no telemetry, no data leaves your project.
• Zero dependencies: one self-contained, cgo-free Go binary. No Python, Docker, Qdrant, or Ollama.
• Any MCP client: built for Claude Code, works with anything that speaks MCP.
• Cited answers: every result links back to the exact file#section and line range, so claims are verifiable.
• Fast search by default: SQLite FTS5 / bm25 out of the box; optional local semantic + hybrid search behind a build tag.
• Read-write memory: the agent can capture durable notes (remember); you can manage the tree (forget, move, list).
• Safe by default: read-only unless you opt in; writes are path-confined and content is secret-scanned.

How it works

your files  →  mnemos index (SQLite/FTS5)  →  Claude Code memory  →  cited answers

Once wired in, Claude can answer from your project instead of hand-waving, and point back to the source:

• "Why did we choose this architecture?"
• "Where is the ADR about the rule engine?"
• "Summarize what we know about SCIM provisioning."
• "What changed in this project's memory recently?"

Under the hood, the binary embeds an MCP server, an indexing pipeline, a SQLite store, full-text search, an incremental file watcher, and an admin CLI. See docs/architecture.md.

Does it actually retrieve?

A cited hit, out of the box (default lexical build, on a shipped example bundle):

$ mnemos ingest examples/git-recipes/bundle --collection git
$ mnemos search "recover lost commits" --limit 1
1. recovery/reflog.md#Gotcha
   lines 24-28
   score 7.8

Every result is a real file#section and line range you can open — that is the whole point.

Retrieval quality, measured. mnemos eval auto-derives held-out query→source pairs from an OKF bundle (it strips each example block from its own document, then checks whether retrieval still finds the right document) and reports doc-level metrics. On the shipped examples/git-recipes bundle (6 recipes, keyword-style queries):

Retriever	Hit@1	Recall@12	MRR@12
Lexical, default (FTS5 / bm25)	0.83	0.83	0.83
Semantic + hybrid (--semantic)	1.00	1.00	1.00

All three are fractions in [0,1] (×100 for a percentage); higher is better. The @K is the retrieval depth — top‑1 for Hit, top‑12 for the rest:

• Hit@1 — share of queries whose #1 result is the correct document (0.83 = 5/6).
• Recall@12 — share where the correct document appears anywhere in the top 12.
• MRR@12 — mean reciprocal rank: average of 1/(rank of the first correct doc) over the top 12 (1.0 = always ranked first).

The default lexical build already nails keyword retrieval. The optional embed build (see Semantic search) earns its keep on harder, natural-language-over-structured-data queries: on the examples/onpage-seo bundle, whose held-out answers are JSON-LD / sitemap-XML blocks that share no keywords with their prose, lexical scores 0.00 while --semantic recovers Hit@1 0.57 / Recall@12 0.86. Reproduce (N is 6 and 7 respectively — smoke signals, not benchmarks):

mnemos eval examples/git-recipes/bundle              # lexical → 0.83
make build-embed && mnemos models install all-MiniLM-L6-v2
mnemos eval examples/git-recipes/bundle --semantic   # hybrid  → 1.00
mnemos eval examples/onpage-seo/bundle --semantic    # the hard case → 0.57

Connect Claude Code

The 60-second path above used claude mcp add with an absolute --config path:

claude mcp add mnemos -- mnemos serve --config /abs/path/to/project/.mnemos.toml

To share it with the repo, commit it via .mcp.json instead:

{ "mcpServers": { "mnemos": { "command": "mnemos", "args": ["serve", "--config", "/abs/path/to/project/.mnemos.toml"] } } }

Verify with claude mcp list (should show mnemos ✓ connected) and /mcp inside a session. Claude then calls the tools automatically; see Capabilities.

Why the --config path must be absolute

Claude Code does not guarantee the working directory it spawns the server in, so anchoring to the config file is what makes retrieval reliable. mnemos serve resolves a relative [storage].path against the config file's directory, so an absolute --config is all you need: the database, capture directory, and tree root all anchor next to that file regardless of where Claude Code launches the server. A bare mnemos serve only finds your data when the server's working directory happens to be the project root, which Claude Code does not promise; when the database can't be found, serve fails with a clear error instead of silently returning empty results.

One command wires it in: Claude Code reports mnemos ✓ connected.

Semantic search: the question says "disappeared" — a word that appears nowhere in the notes — yet Claude finds and cites recovery/reflog.md.

This clip uses the optional semantic build (make install-embed + mnemos models install all-MiniLM-L6-v2 + use_vectors = true; see Semantic search). The default make install binary is lexical-only, so it won't answer a keyword-free question like this — search by keyword instead (e.g. mnemos search "recover lost commits", which hits the same doc).

Make Claude use memory automatically (optional skill)

MCP tools are passive: they're available, but Claude still has to decide to call mnemos.search before answering or mnemos.remember when you say something worth keeping, and models often don't. The bundled mnemos-okf skill closes that gap by encoding when to reach for memory: recall before answering from assumption, capture durable facts, and drive the OKF tools.

It's optional and Claude Code-specific: the server works with any MCP client without it. Install it user-wide (all projects):

make install-skill        # copies skills/mnemos-okf -> ~/.claude/skills/

Or place it manually, e.g. project-level for this repo only:

mkdir -p .claude/skills && cp -r skills/mnemos-okf .claude/skills/mnemos-okf

Capture is deliberately conservative (durable facts only, secret-scanned) and stays gated behind allow_write/allow_delete: the skill never grants access the config hasn't opted into. See skills/mnemos-okf/SKILL.md.

Capabilities

Claude reaches your memory through MCP tools (and you through the matching CLI commands). Note the spelling: mnemos.search is the MCP tool Claude calls; mnemos search is the CLI command you run.

Query (read-only, no gate)

• mnemos.search: ranked, filtered retrieval with citations.
• mnemos.read: read a precise chunk (by chunk_id) or a whole document (by uri).
• mnemos.context: top-k results as LLM-ready context blocks (uri:start-end → content).
• mnemos.list: walk the OKF tree on disk and annotate each file with index metadata (title, type, tags, collection) plus an indexed flag, so both stored and not-yet-indexed files are visible. Filter by path, collection, type, or indexed state.

Write (requires allow_write = true)

• mnemos.remember: write a note into memory. Pass an optional path (e.g. "adr/0003-rule-engine.md") to place it at an explicit location in the OKF tree instead of auto-naming under [capture].dir. Content is secret-scanned before it is written and indexed.
• mnemos.okfy: convert an existing .txt/.md file in the tree into an OKF document (frontmatter + body) at out (defaults to the source path with a .md extension) and index it, leaving the source intact. The source body is secret-scanned first.

Manage (requires allow_delete = true)

• mnemos.forget: remove a file from the OKF tree and de-index it; idempotent.
• mnemos.move: move a file or directory within the tree and re-index it under the new path. A directory moves its whole subtree, preserving each document's collection. Inbound markdown links to the old paths are not rewritten in V0 (logged as a warning).

Keep memory fresh

Run a watcher to reindex on change (incremental; removes deleted files):

mnemos watch . --collection myproject

Enable write-back in .mnemos.toml so Claude can capture and manage notes:

[mcp]
allow_write = true     # gates mnemos.remember and mnemos.okfy
allow_delete = true    # gates mnemos.forget and mnemos.move

If a watcher is running over the tree, forget/move operations are also seen by the watcher (redundant but idempotent); the tools update the index directly and work without a watcher. Set [capture] defer_to_watcher = true when a watcher covers capture_dir to avoid double indexation of remembered notes.

Semantic search (optional)

The default binary is lexical only (FTS5 / bm25) and stays small and cgo-free. Local semantic + hybrid retrieval is fully implemented but compiled behind the embed build tag, so the ONNX/tokenizer dependencies never enter the default binary. To enable it:

make build-embed                       # or: make install-embed  (still cgo-free, CGO_ENABLED=0)
mnemos models install all-MiniLM-L6-v2 # downloads the embedding model into ~/.mnemos/models
mnemos reindex --embeddings            # compute vectors for already-indexed chunks
mnemos search "why did we choose this architecture" --semantic

--semantic fuses bm25 with vector similarity, so natural-language queries that the lexical index misses still resolve. Without the embed build (or an installed model) the flag is rejected with a clear message; plain mnemos search always works.

How it works under the hood (model, pure-Go ONNX inference, RRF fusion): docs/architecture.md.

OKF support

mnemos natively understands OKF (Open Knowledge Format) bundles, and any Markdown vault with YAML frontmatter and cross-links, with no special mode:

• frontmatter tags/type become fuzzy ranking signals in FTS,
• markdown links are captured as edges (stored, not yet traversed),
• index.md files are treated as structure only (kept out of FTS and the link graph).

OKF bundles double as the corpus for mnemos eval, which auto-derives held-out query→source pairs and reports Hit@1 / Recall@12 / MRR@12 against a committed baseline. See docs/architecture.md.

Reference

• docs/commands.md — every CLI command and its flags.
• docs/configuration.md — the layered .mnemos.toml, with all defaults.
• docs/paths-and-indexing.md — how state is located, what gets indexed, where writes land, and the idempotency/URI rules.
• docs/architecture.md — design principles and the retrieval-evaluation methodology.

Security

• No network, no telemetry; the MCP server is stdio-only.
• Read-only by default. Write-back is opt-in (allow_write = true). Destructive operations (forget, move) require a separate opt-in (allow_delete = true).
• All caller-supplied paths are validated by a confinement guard before any disk operation: .. traversal, absolute paths outside the tree root, symlink escapes, access to .mnemos/, and [security].exclude globs are all rejected.
• Captured content is secret-scanned before it is written or indexed.
• Path/secret exclusion patterns keep .env, keys, and secret dirs out of the index.

See SECURITY.md for the full policy.

Development

make build      # cgo-free binary -> bin/
make test       # go test -race ./...
make audit      # golangci-lint (incl. govet + staticcheck) + govulncheck + race tests
make tools      # install pinned dev tools (golangci-lint, govulncheck)
make help       # list all targets

Architecture, design principles, and the retrieval-evaluation methodology live in docs/architecture.md; design decisions are recorded as ADRs. Contributions welcome; see CONTRIBUTING.md.

License

mnemos is licensed under the MIT License: this covers mnemos's own code and content. The repository also vendors third-party material that is not covered by the MIT License and remains under its own terms; see THIRD-PARTY-NOTICES.md (notably the example OKF bundle in examples/onpage-seo/bundle/).