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GrayMatter

Persistent memory for AI agents

One binary. Drop it in. 90% fewer context tokens, a self-building knowledge graph, and facts that survive across sessions — no Docker, no databases, no config files, no cloud accounts.
Quick startGitHub

General-purpose MCP server. Zero vendor lock-in. Works with Claude Code, Cursor, Codex, OpenCode, Antigravity — and any MCP-compatible client. Also a plain Go library if you don’t use MCP. Free. Offline. No account required.

Context tokens per query vs full-history injection

Why

Section titled “Why”

Every AI agent is stateless by default. Each run re-injects the full conversation history — and that history grows linearly. Two prompts in and you’ve already burned half of your daily quota.

That’s not just a memory problem. That’s a money and performance problem. GrayMatter closes it with a local, embeddable memory layer: recall by meaning, inject the top-8 relevant facts, forget the rest.

90% token reduction

Top-8 relevant facts instead of full-history injection. Measured, not claimed — every figure is machine-checked in CI.

Knowledge graph

Typed entities and co-mention edges, auto-populated from ordinary use. Export to Obsidian with one command.

Self-curation

memory_reflect lets the agent add, update, forget, and link its own memories.

Context block

context-sync projects top facts into CLAUDE.md / AGENTS.md inside an explicit token budget.

Deterministic decay

30-day half-life. Facts fade when nothing touches them. Tombstones, never deletes.

Single binary

~10 MB static. No Docker, no Redis, no config files, no cloud accounts.

Install and wire in under a minute

Section titled “Install and wire in under a minute”
Terminal window
brew install angelnicolasc/tap/graymatter   # macOS / Linux
graymatter init                             # wires MCP config + memory block
graymatter doctor                           # verify everything

Restart your editor. Five memory tools are live. Full instructions, including Scoop, Nix, pre-built binaries, and go install, in the quick start.

What GrayMatter is NOT

Section titled “What GrayMatter is NOT”

Not tied to any vendor. Not a framework. Not a hosted service. Not a knowledge-base UI. It is exactly one thing: the missing stateful layer for Go agents, packaged as an MCP server and a library you import in three lines.