About 40× smaller answers. Search returns a ranked list of names and the lines
that matched, not every entity in full, so the agent can afford to check its
memory before every task.
A web UI for people. See the whole graph grouped by type, follow relations,
and add, edit or delete anything. Agent writes show up live.
Token-lean memory for AI agents: a knowledge graph searched cheaply. Drop-in for server-memory.
MEMORY_FILE_PATH
Zuletzt geprüft
2026-11-14
Sterne
—
Tools
—
Uptime
—
Drop-in replacement. Same memory.jsonl file and the same nine tools as the
reference server. Switch in, and switch back whenever you like.
Works with every agent. Copy-paste setup for Claude Code, MiMo Code, Codex,
Cursor, Copilot, Gemini CLI, Zed, JetBrains and more, plus the instructions that
teach the agent to use it.
Stays small by itself. Short facts, a cap per entity, and an archive for the
overflow, so the graph never grows into a wall of text.
Private and safe. Plain local files, daily backups, a write lock for parallel
sessions, and no network access. One server file, zero dependencies.
The numbers
Measured on a real graph of 237 entities, 355 relations and 1,160 facts
(tokens ≈ characters ÷ 4):
Call
Reference server
memory-lean
read_graph
~77,800 tokens
~2,000 tokens
40× smaller
search_nodes, average of 5 common words
~31,000 tokens
~770 tokens
40× smaller
A narrow search that matches one or two entities saves less, because there is
little to trim. To measure your own graph, run node tools/bench.mjs from a clone;
it is read-only and prints sizes, never content.
Quick start
Claude Code: install the plugin. It adds the server, the instructions as a
skill, a short reminder at the start of each session, and /memory-ui.
The graph is created on the first write at ~/.claude/memory-graph/memory.jsonl,
whichever agent writes it, so all your agents share one memory. Set
MEMORY_FILE_PATH to keep it somewhere else.
Web UI
npx -y memory-lean --ui
This opens your memory in the browser. Everything an agent can do, you can do here:
Explore. Each type gets its own bubble. Click an entity to highlight
everything it connects to, drag nodes to arrange them, and scroll to zoom.
Search matches names, types and facts.
Edit. Add, edit and delete facts, rename an entity or change its type, add
and remove relations, create and delete entities, and restore archived facts.
Every change passes the same checks as the agents' tools.
Watch. Changes your agents make appear within two seconds.
Spot problems. The overview lists pending work, the most connected
entities, and anything over budget, which is also marked on the graph.
The page runs on your machine only (127.0.0.1) and needs the one-time key in
the link it prints, so other websites cannot read or change your memory. Nothing
is uploaded anywhere.
How it works
Search, then open
The reference server answers a search with every matching entity in full, as
pretty-printed JSON. memory-lean answers with a ranked list of names and the lines
that matched:
> search_nodes { "query": "deploy" }
57 match "deploy", top 10 shown (narrow the query or raise limit). open_nodes for full entities.
- shop-backend [service] 12 obs, 6 rel
› 2026-03-02: deployed 2.4.0 to production
› deploy with scripts/release.sh, never by hand
- PENDING shop-backend 2.4.0 [pending] 2 obs, 3 rel
› …mobile apps still call the old endpoint until the deploy of 2.4.0 reaches them
search_nodes returns at most 10 names with snippets, read_graph returns an index of names, and only open_nodes returns full entities.
Short facts
An observation longer than 300 characters is rejected, with a message telling the agent to split it or put the detail in the repo.
A cap per entity
An entity keeps 15 observations. Past that, the oldest dated ones move to archive/<entity>.md. Nothing is deleted: they can be listed and restored, and undated facts (the identity facts) always stay.
Search that narrows
Every word must match somewhere in the entity, so adding a word narrows the result. The reference server looks for the query as one exact phrase.
How it keeps your data safe
Safeguard
What it means
Safe to share
Writers take a lock file, so several agent sessions can use one graph without overwriting each other. Every write replaces the file atomically.
Daily backups
A copy goes to backups/ once a day; the last 7 are kept.
Damaged lines are kept
A line that cannot be read is moved to memory.jsonl.unreadable on the next write and reported, never silently dropped.
Plain files
The graph is JSON lines, archives are Markdown, backups are copies. You can read, grep and edit all of it by hand.
Tools
Tool
What it returns
search_nodes
Ranked list of entity names with counts and up to two matching snippets each. Every word must match the name, type, an observation, or the type of a relation touching the entity.
open_nodes
The full entities you name, as compact text, with every relation touching them and their archive count. Unknown names come back with "did you mean" suggestions.
read_graph
An index: entity names grouped by type, with observation counts. Never the observations.
create_entities
Creates entities; existing names are skipped.
create_relations
Creates relations between existing entities; duplicates are skipped.
add_observations
Adds facts to an entity, enforcing the length limit and the per-entity cap.
delete_observations
Removes observations by exact text.
delete_relations
Removes specific relations.
delete_entities
Removes entities and every relation touching them.
rename_entity
Renames an entity, keeping its observations, relations and archive. Not in the reference server.
archived_observations
Lists what was archived for an entity, optionally filtered, and restores chosen facts. Not in the reference server.
The three read tools are marked read-only, so clients that support it can run them
without asking.
Command line
Command
What it does
memory-lean
Runs the MCP server over stdio. This is what agents start.
memory-lean --ui [port]
Opens the web UI. --no-open only prints the link; --demo uses a throwaway copy of a made-up graph.
memory-lean --protocol
Prints the agent instructions, ready to append to AGENTS.md, CLAUDE.md or GEMINI.md.
memory-lean --skill <dir>
Writes the same instructions as an Agent Skill into <dir>/memory-graph.
memory-lean --lint
Reports what in the graph is over budget. Read-only.
memory-lean --compact
Backs up the graph, then moves overflow observations to the archive.
memory-lean --version
Prints the version.
With npx, put npx -y in front: npx -y memory-lean --ui.
Teach your agent to use it
A memory server only helps if the agent reads it before working and writes to it
when something changes. docs/AGENT-PROTOCOL.md is a
ready-made set of instructions: what to look up at the start of a task, what to
record, how to name things, and what never to store. The Claude Code plugin
includes it. For every other agent, one command installs it:
npx -y memory-lean --protocol >> AGENTS.md # into a rules file: always on
npx -y memory-lean --skill .agents/skills # as an Agent Skill: loaded when relevant
Adjust the entity types and names in it to your own work.
Coming from the reference memory server
Point MEMORY_FILE_PATH at your existing memory.jsonl and swap the command. The
file format is identical, so you can switch back at any time. Existing
observations longer than 300 characters are kept as they are; only new writes are
checked. To see what is over budget, and optionally fix it:
npx -y memory-lean --lint # report only
npx -y memory-lean --compact # back up, then move overflow to archive/
Settings
All optional, set as environment variables on the server:
Variable
Default
Meaning
MEMORY_FILE_PATH
~/.claude/memory-graph/memory.jsonl
Where the graph lives
MEMORY_OBS_MAX_CHARS
300
Longest observation accepted
MEMORY_OBS_MAX
15
Observations per entity before the oldest dated ones are archived
MEMORY_SEARCH_LIMIT
10
Default number of search results
MEMORY_BACKUPS_KEPT
7
Daily backups kept
FAQ
No. The server reads and writes local files and makes no network requests. The
web UI listens on 127.0.0.1 only. Keep the graph out of git, and never
store passwords, keys or tokens in it: record where a secret lives, not its value.
Yes. Every write takes a lock, re-reads the file and replaces it atomically, so
parallel sessions (and the web UI) do not overwrite each other.
It needs no model, no index and no dependencies, and an agent's queries are
mostly names it already knows. Good entity names matter more than clever queries.
When an entity passes 15 facts, the oldest dated ones move to
archive/<entity>.md next to the graph. archived_observations,
or the Archive section in the web UI, lists and restores them.
Roadmap
Claude Code plugin with the server, a skill and /memory-ui
Setup guides for 12 agents
rename_entity and archive restore
A web UI to explore and edit the graph
Listed in the official MCP registry
Listed in the Claude Code plugin directory
Search across the archived facts of every entity
Undo in the web UI
Contributing
Ideas, bug reports and pull requests are welcome. The server is one file with no
dependencies, the web UI is one HTML file, and npm test runs in a few seconds,
so a first change is quick to make. CONTRIBUTING.md has the
layout, the ground rules and a list of good first contributions.
If memory-lean saves you tokens, a ⭐ helps other people find it.
Support
memory-lean is free and MIT licensed. If it is useful to you, you can support the
work:
Noch keine Tool-Liste. Remote-Server erhalten eine nach dem ersten Health-Check.
FAQ
Fragen
Wie installiere ich Memory Lean?
Kopieren Sie auf dieser Seite die stdio-Konfiguration für Cursor, Claude Desktop, Claude Code oder VS Code. Sie nutzt die Installation des Herausgebers, keinen PlugMCP-Proxy.
Benötigt Memory Lean einen API-Schlüssel?
Der Herausgeber nennt diese Umgebungsvariablen: MEMORY_FILE_PATH.
Welchen Transport verwendet Memory Lean?
Memory Lean läuft lokal über stdio.
Wann wurde Memory Lean zuletzt geprüft?
Zuletzt geprüft: 2026-11-14. Token-lean memory for AI agents: a knowledge graph searched cheaply. Drop-in for server-memory.