Institutional memory for AI agents.
A compiled Rust MCP server that gives any AI agent platform persistent, structured memory across sessions. Full-text search, entity graphs, temporal scoring, supersession chains — framework-independent and local-first.
brew install thekeystoneproject/tap/stonememOr download the binary from keystoneproject.dev.
# Start the server
stonemem serve
# Activate your license key
stonemem activate SM-XXXX-XXXX-XXXX-XXXXPoint any MCP-compatible agent platform at 127.0.0.1:3391. That's it.
# ~/.stonemem/config.toml
host = "127.0.0.1"
port = 3391
data_dir = "~/.stonemem"Environment overrides: STONEMEM_HOST, STONEMEM_PORT, STONEMEM_DATA_DIR.
- Full-text search with BM25 ranking
- Entity extraction and relationship graph
- Temporal scoring — recent knowledge ranked higher
- Supersession chains — new facts replace outdated ones
- Namespace isolation per agent + shared namespaces
- Auto-deduplication across sessions
Any platform that speaks MCP connects directly:
- Claude Code / Claude Desktop
- Hermes
- CrewAI
- LangGraph
- OpenHands
- Haystack
- Google ADK
- Microsoft Agent Framework
| Free | Pro ($9/mo) | Enterprise ($49/mo) | |
|---|---|---|---|
| Memory entries | 10,000 | Unlimited | Unlimited |
| Namespaces | 1 | Unlimited | Unlimited |
| Full-text search | Yes | Yes | Yes |
| Deduplication | Yes | Yes | Yes |
| Entity graph | — | Yes | Yes |
| Temporal scoring | — | Yes | Yes |
| Shared namespaces | — | — | Yes |
Get a key at keystoneproject.dev.
Your data stays on your machine, in open SQLite databases you own. No cloud dependency. No vendor lock-in.
Full documentation at keystoneproject.dev/docs.
stonemem is part of the Stone suite — three compiled Rust MCP servers for AI agent infrastructure:
- stonemem — Institutional memory (this repo)
- stonemux — Multi-agent coordination
- stonegate — Universal tool gateway
Proprietary — Copyright (c) 2026 The Keystone Project, Inc. All rights reserved.