ChatCrystal MCP Server

Local-first AI PKM memory for coding conversations.

What the server does

ChatCrystal is a local-first AI PKM app for developers who solve real problems with Claude Code, Cursor, Codex CLI, Trae, and GitHub Copilot.

• Imports AI coding conversations — from local tool data directories
• Distills conversations into structured notes — with titles, summaries, conclusions, snippets, and tags
• Searches knowledge semantically — with embeddings and relation-aware result expansion
• Builds a tag knowledge graph — where knowledge points are tags and edges show normalized co-occurrence
• Exposes CLI and MCP tools — so agents can recall and write back reusable experience
• Runs locally — with configurable LLM and embedding providers

Installation

chatcrystal on npm is all you need. Most clients run it directly, so configuration is a few lines and a restart.

Credentials and setup notes

Configuration is passed through the environment: CHATCRYSTAL_API_TOKEN, CHATCRYSTAL_DOCKER_LLM_BASE_URL, CHATCRYSTAL_DOCKER_EMBEDDING_BASE_URL. Treat anything key-shaped as a real credential — scope it to the minimum the server needs, and rotate it if it ever lands in a shared config.

• Node.js >= 20 - An LLM provider for summarization - An embedding provider for semantic search LLM and embedding providers are configured separately. Large language models such as Claude, GPT, and Qwen are not embedding models. See the user guide for provider examples.

Worth knowing first

• It runs with your machine's permissions. That is convenient and also the reason to think about what you point it at before you approve a tool call.
• Keep per-call confirmation enabled while you learn its behaviour; it is the cheapest safeguard you have.

Where it fits

Among the knowledge and memory options, the useful question is rarely "what can it do" but "what does it cost you to run" — permissions, credentials, and how much of your context its toolset consumes. It is maintained by ZengLiangYi; worth a glance at recent repository activity before you build anything load-bearing on it.

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