skillmem
[CI] [Glama score] [Listed on mcp.so]
Self-improving skills for Claude Code and Codex — your agents learn, recall, reinforce, and forget.
[skillmem demo: a Russian query finds an English skill, unused skills decay]
Strength has to be earned — saying a skill helped is not evidence, a passing test is:
[skillmem: self-report does not raise strength, a passing test does, and rare rules can be pinned]
Generated from a real run: scripts/demo.sh --record | python3 scripts/cast_to_svg.py > docs/demo-evidence.svg.
skillmem gives Claude Code and the Codex CLI a local, persistent skill & memory layer. After every non-trivial task the agent can record how it was done as a skill; before the next task it recalls the relevant ones; skills that keep proving useful get stronger, and skills nobody uses fade away — the way human memory works.
- $0 per write and per read — no LLM calls, no cloud, no API keys. Plain SQLite on your disk.
- Bilingual hybrid search, fully local — FTS5 BM25 + Snowball stemming (EN/RU) matches inflected forms within a language; the multilingual ONNX embedder is what lets a Russian query find an English skill, so install the
semantic extra if you work across both. All on CPU, offline.
- Ebbinghaus strength model, earned not claimed — strength rises only on evidence from outside the agent's own judgement, falls after a failure, and fades on a schedule when unused; dead skills are swept to a backed-up archive (never deleted). Rules that are rare by nature can be pinned out of decay.
- Provenance, and trust the owner grants — every memory records where it came from (
owner / agent / imported / derived), and only the owner approves one as a rule (skillmem trust <slug>). Anything unapproved — an imported pack, a summary of a transcript that quoted a web page, a rule an agent was talked into saving — is injected inside a marked block that says it is data, not instructions. An agent cannot change a memory the owner wrote or approved: it writes a proposal under a new slug.
- Tamper-evident history — every edit is appended to a SHA256 hash-chain;
skillmem verify detects any after-the-fact tampering.
- Deep Claude Code integration — hooks on five events + 9 MCP tools installed with one command.
- One memory, several agents — Claude Code and Codex share a single database, and every
record carries the agent that wrote it, taken from the MCP handshake, so authorship stays
readable when they learn side by side.
- Cross-platform — macOS (launchd), Windows (schtasks), Linux (systemd user timers, cron fallback).
- No vendor lock —
export-all dumps everything to plain markdown with YAML frontmatter; re-importing the dump yields the same records. One destination per database: the exporter prunes its own stale files via a manifest, and refuses a directory another database exports to rather than overwrite its backup.
Why
Agents repeat their mistakes because each session starts from zero. Existing "memory" tools store facts; skillmem stores procedures — trigger, steps, outcome, lessons — and ranks them by how often they actually helped. The write path costs nothing, so the agent can afford to learn from every task.
What 0.10.0 changed
Memory that an agent writes is not the same thing as a rule you set, and until 0.10.0 this
project treated them the same. An external text — a README, a web page — reaches a transcript,
a model distils it into a note, and the note comes back in the next session under a heading
that reads like your own rules. A document could also talk an agent into saving a rule through
mem_learn, and that rule looked exactly like one you wrote.
Now provenance is a field, trust is an act, and the summariser that reads your transcripts runs
with no tools at all (--tools "" plus --strict-mcp-config; a CLI that does not understand
those flags gets no recap rather than an uncaged one). The full list — including the migration
and what it does and does not approve on upgrade — is in the CHANGELOG.
The seven releases before it, in one line each, because they were all about the same hook:
0.9.3 stopped the Stop hook recursing into itself (one machine spawned 4083 summary sessions in
a day); 0.9.4 put a rate limit on it and stopped a failing model buying a call per turn; 0.9.5
fixed four silent defects, including recall being dead for notebook edits; 0.9.6 stopped a slow
summary overwriting a fresher one; 0.9.7 added skillmem recap and skillmem hooks-status;
0.9.8 stopped a skipped turn reading a 59 MB transcript first; 0.9.9 made publishing a summary
compare-and-swap. Anyone on 0.9.0–0.9.2 should upgrade — those versions contain the
recursion.
How it differs
The memory products in this space — Mem0, Zep, Letta, LangMem, Cognee — are built mostly for
conversational and user memory, entity graphs, or agent-managed context, and most of them offer
a hosted tier. skillmem is narrower on purpose and different on four axes:
Retrieval quality is measured, not asserted: hit@5 0.871 / MRR 0.622 on the full LongMemEval
oracle set, hybrid retrieval, k=5, CPU only, reproducible from this repo — see
Benchmarks for the per-type table and the reporting rules we hold ourselves to.
Does a new session actually remember the last one? Measured on a real database, agent-level
(see Benchmarks):
Quickstart
macOS / Linux:
Windows (PowerShell):
Or from a checkout:
Flags combine in one run — the agents then share one database.
All six agents
Every entry is idempotent and backed up before it is touched; a config that
does not parse is left alone rather than overwritten. Each agent is stamped
with SKILLMEM_AGENT, so in a shared database "who learned this" stays
answerable. skillmem uninstall removes all of them (--no-editors to keep
the editor entries).
init --claude-code registers the MCP server in ~/.claude.json and the hooks in ~/.claude/settings.json (idempotent, with backups). Use --hooks minimal for no hooks at all (only the deny rules for the owner-only commands, below), or --hooks none for MCP only. Hand-written memory files are imported with skillmem migrate --source <dir>; there is no per-turn import hook.
Codex CLI
Appends an [mcp_servers.skillmem] table to ~/.codex/config.toml and marks the entry with
SKILLMEM_AGENT=codex. The tag is belt-and-braces: with no tag set, the server takes the
author's name from the agent's own MCP handshake, so attribution is right in a shared
database whichever way skillmem was installed.
The file is appended to, never rewritten: your own settings and comments stay where you put
them, the result is parsed before it is written, and invalid TOML is refused rather than
overwritten. skillmem uninstall removes the table again and leaves the rest of the file intact.
Codex reads AGENTS.md for project rules; if you keep yours in CLAUDE.md, point Codex at it
with project_doc_fallback_filenames = ["CLAUDE.md"] in the same config file — then both agents
follow one set of rules and one memory.
As a plugin
The repo is also a plugin, in two flavours, both pointing at the same skillmem-mcp binary:
- Agent Plugins (
plugin.json + mcp.json at the repo root) — what the Codex CLI installs from a
marketplace. mcp.json needs both its $schema and "type": "stdio", and the command must be a bare
executable name rather than an absolute path — Codex's parser ignores the file otherwise, with no error.
codex mcp list listing the server is the check that it parsed.
- Claude Code (
.claude-plugin/ + hooks/hooks.json) — MCP server and every hook in one install.
Either way the package itself must be on PATH (pip install skillmem); the plugin wires the server, not the runtime. An MCP Registry manifest (server.json) is in the repo as well:
The plugin requires the skillmem Python package on PATH and replaces skillmem init --claude-code's wiring — use one or the other, not both (see docs/PUBLISHING.md).
A plugin cannot add permission rules, so the plugin path has no deny rules for the owner-only commands (trust, rm, skills-archive, skills-restore, skills rm, import-vault, uninstall --purge-db) — only their TTY check, which a pseudo-terminal gets past. skillmem init --claude-code installs both. Neither is a wall against an agent that has a shell: the rules match the command as written, and a quote inside the verb (skillmem tr''ust x under script) matches none of them. If agents run unattended with Bash on this machine, do not rely on them. The rules are a substring match: on a machine where you develop in a directory named skillmem, they also refuse your own commands there that mention one of those commands, --db, $, a backtick or eval.
Claude Desktop (chat app)
The MCP server also works in the Claude Desktop chat app — add to
claude_desktop_config.json (Settings → Developer → Edit Config):
You get all 9 mem_* tools on demand (search, learn, recall, reinforce…).
The automatic hooks (auto-recall on every prompt, session recap) are a
Claude Code mechanism and do not run in the chat app.
How it works
- learn — after a task that took real debugging, the agent calls
mem_learn with a slug, trigger, steps, outcome, and lessons.
- recall — before the next task,
mem_recall (or the automatic hooks) surfaces the most relevant skills, fusing lexical and semantic signals via Reciprocal Rank Fusion.
- reinforce — when a recalled skill is confirmed by something outside the agent's own judgement (a test that passed, a diff that was accepted, the user saying so),
mem_reinforce raises its strength, so proven skills rank higher next time. The agent calling its own skill useful is recorded but not rewarded; a task that failed after applying a skill lowers it. Rules that matter precisely because they are rarely needed can be exempted from decay with mem_pin.
- decay — a scheduled
skillmem decay run applies Ebbinghaus-style forgetting; skills untouched for months drift to stale, then to an archived state (excluded from recall, restorable with one command, snapshotted to JSONL first).
MCP tools
Skill packs
Third-party skill packs — ponytail, unlazy, addyosmani/agent-skills, anything
that ships SKILL.md files — can live in the same database as your own skills:
Loose in a directory, a pack's skills are loaded on every session whether they
are relevant or not. Imported, they live by the ordinary rules: recalled when
they match, strengthened only when something outside the agent confirms they
helped, faded out when they never do. After a fortnight skills ls says which
pack earned its place.
Nothing from a pack is executed — only SKILL.md files are read. The
repository, commit and licence travel with each skill into a provenance block,
and every import is tagged untrusted-origin: a skill file is a set of
instructions written by a stranger, and you should be able to tell those from
rules you wrote yourself.
Hooks
All hooks are best-effort: a broken database or missing model never blocks Claude Code. Which is
also why skillmem hooks-status exists — a hook that quietly stopped working looks exactly like
one with nothing to do, so it prints runs, skips, failures and the last line of each.
Anything a hook injects that you have not approved travels inside a marked block:
The frame makes the boundary legible; it is not a guarantee that a model ignores an instruction
sitting inside data. That guarantee comes from the reader having no tools — which is why the
summariser has none.
Approve in chat. When a session saves a new rule, the Stop hook pending-rules shows it to you
in full at the end of the reply (read from the database, not from the agent's text). Reply with just
одобряю (or approve) and that exact text becomes your rule; any other reply leaves it unapproved.
Rules too long to show there are left for skillmem trust.
Who can approve. skillmem trust <slug> (and --untrust) refuses to run without a terminal,
so an agent calling it from Bash gets an error, not an approval. To clear the backlog in one go,
run skillmem review: it shows every unapproved user/feedback memory in full (--types for
other kinds) and asks y / n / q for each. The session briefing counts them and asks the agent to
point you here. The other owner-only commands refuse without a terminal
the same way: review, rm, skills-archive (and --restore), skills-restore, skills rm, import-vault
and uninstall --purge-db. The MCP and HTTP servers never count as you, even when they run in
your terminal. A TTY check is accident protection, not a wall — script -q /dev/null skillmem trust x forges one — so
init --claude-code also adds deny rules for those commands to permissions.deny in
~/.claude/settings.json; they stop Claude Code from running the command as a document spells
it. They are glob matches on the command line before the shell rewrites it, so they are not a
wall either: script -qec "skillmem tr''ust x" /dev/null matches none of them. Other agents
need the equivalent rules in their own permission config.
CLI highlights
Uninstall
Config edits are made atomically with timestamped backups; corrupt JSON or TOML is never overwritten.
Guarantees
docs/INVARIANTS.md is the specification skillmem is tested against: sixteen
invariants (approval is bound to the text, only the owner at a terminal grants trust, a sealed
record changes only by the owner, backups round-trip, every read-then-write decision is made
under the write lock, …), the function that enforces each, and their status at the current
release. tests/properties/ checks them. What is still open is listed under "Known issues" in
the CHANGELOG.
Docker
The image exists mostly so catalogues can build and score the server without
guessing at it; the memory lives in the /data volume, so a container restart
keeps it.
Benchmarks
Retrieval quality on LongMemEval (Wu et al., ICLR 2025), full oracle set, hybrid retrieval (FTS5 BM25 + Snowball stemming + paraphrase-multilingual-MiniLM-L12-v2 embeddings, RRF fusion), k=5, CPU only:
Median 0.76 s per query on a laptop CPU, no LLM calls, no network. The pipeline is deterministic: repeated runs produce identical numbers. Reproduce with python bench/longmemeval.py --sample 0 -k 5 (see bench/README.md for the oracle file and reporting rules — we don't publish bare percentages without stating the retrieval mode and embedding model, and we encourage other tools to do the same).
Does the agent remember?
LongMemEval measures retrieval. This measures answers: claude -p with clean settings (no
CLAUDE.md, Claude Code's own auto-memory off), the same model and prompt in both arms, only
skillmem's hooks and MCP server toggled.
The 0.13 change behind the last row — session recaps ranked at half weight so they stop
outranking short curated rules — left LongMemEval at hit@5 0.889 (the table above is the
0.12 run). Caveats we'd rather state than have pointed out: the samples are small, the database
and questions are the author's own, and the cross-session facts are stated explicitly, which is
easier than a decision smeared across an hour of discussion. Without memory the agent answered
"I don't know" every time rather than guessing.
License
Apache-2.0 — see LICENSE.
Built by Liza Studio.
