Memory MCP Server
The reference memory server — a local knowledge graph where your agent files entities, relations, and observations between sessions. Simple, inspectable, and exactly as smart as what gets put in it.
What it actually does
Part of the official reference collection, this gives an agent persistent memory as a plain knowledge graph: entities, typed relations between them, and timestamped observations, stored in a local file you can open and read. The agent decides what to remember and recall through explicit tool calls — create an entity, link two of them, search the graph. There are no embeddings and no vector database, which is both the limitation and the appeal: retrieval is exact-match and traversal, and the whole memory is auditable with a text editor. It's the right first memory system precisely because you can see everything it knows.
Install
Read the source before you run this. Yes, actually.
From the desk
The Sunnyvale take
A JSON file with opinions, and we mean that kindly. The transparency is the feature: when your agent 'remembers' something wrong, you can find the exact line and delete it. Most memory products can't say that.
Why it matters
Cross-session memory is the difference between a tool and a colleague. This is the canonical, minimal implementation — the baseline every fancier memory system should have to beat.
In practice
Let an agent that helps with your team's standup keep a graph of who owns what; next week it already knows, and you can read exactly why.
The skeptic's note
'Memory' oversells what an unpruned graph becomes after three months. Without curation it's a junk drawer with relations — schedule the cleanup or inherit the clutter.
Use cases
- Remembering people, projects, and preferences across sessions
- A running fact base the agent maintains about your codebase
- Auditable memory in workflows where you must know what the agent knows
Risks & caveats
Writes a single local graph file. Whatever the agent chooses to remember — including things you'd rather it didn't — persists in plaintext, so know where that file lives and what lands in it.
Related tools
Full indexSame shelf, different trade-offs.
Filesystem MCP Server
The reference server that gives an agent read/write access to your disk, fenced to directories you name. Simple, official, and the single sharpest tool in the drawer.
Sequential Thinking MCP Server
A reference server that gives the model a numbered, revisable scratchpad for working through hard problems — thought, revise, branch, conclude. No network, no files, just protocol.