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PopNx MCPMCP servers for people who use AI · explained in plain words

ChatCrystal

by ZengLiangYiversion 0.6.2i★ –iRuns on your computer
Registry nameio.github.ZengLiangYi/chatcrystal

Install

Overview

Description from the maker (original English)

Local-first AI PKM memory for coding conversations.

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

  • Connection: Runs on your computer
  • Transport: stdio
  • Category: Search & AI memory
  • You need to fill in: CHATCRYSTAL_API_TOKEN

Install

Pick the AI app you use, then copy the settings.

Before you install

  • Basic checks: 1 of 1 passed
  • Runs on your computer with your user’s permissions (files, network, apps).
  • You fill in yourself: CHATCRYSTAL_BASE_URL, CHATCRYSTAL_API_TOKEN

Values marked secret are keys to your account. Never share them or paste them into a chat.

You need

  • npmNode.js installed (for the npx command)

Which app do you use?

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "chatcrystal": {
      "command": "npx",
      "args": [
        "-y",
        "chatcrystal",
        "mcp"
      ],
      "env": {
        "CHATCRYSTAL_BASE_URL": "your-value",
        "CHATCRYSTAL_API_TOKEN": "your-value"
      }
    }
  }
}

Run this in your terminal

claude mcp add chatcrystal --env CHATCRYSTAL_BASE_URL=your-value --env CHATCRYSTAL_API_TOKEN=your-value -- npx -y chatcrystal mcp

Fill in the empty values before running it.

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "chatcrystal": {
      "command": "npx",
      "args": [
        "-y",
        "chatcrystal",
        "mcp"
      ],
      "env": {
        "CHATCRYSTAL_BASE_URL": "your-value",
        "CHATCRYSTAL_API_TOKEN": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "chatcrystal": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "chatcrystal",
        "mcp"
      ],
      "env": {
        "CHATCRYSTAL_BASE_URL": "your-value",
        "CHATCRYSTAL_API_TOKEN": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

Values you fill in

  • CHATCRYSTAL_BASE_URL env
    Optional ChatCrystal Core URL. Leave empty to use the local default at http://localhost:3721.
  • CHATCRYSTAL_API_TOKEN secret env
    Optional token for a protected ChatCrystal Cloud or remote instance.

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 7, 2026

  • ✓ Pass

    Maker matches the repo

    The registry name was verified with the GitHub account ZengLiangYi, which owns the repo

  • … Not checked yet

    Still maintained

    We have not read this repo from GitHub yet

  • … Not checked yet

    Has a licence

    We have not read this repo from GitHub yet

  • – Not applicable

    Endpoint responds

    This one runs on your computer; there is no internet endpoint

  • – Not applicable

    Sign-in with OAuth

    Runs on your computer and uses local settings instead

  • … Not checked yet

    No hidden instructions in tool descriptions

    Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Search & AI memoryi

  • More stars than 0% of the other 5653 servers in this category
  • Published to the registry more recently than 72% of the other 5653 servers in this category
  • Basic checks equal to or better than 100% of the other 5653 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is ChatCrystal safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

You need to fill in: CHATCRYSTAL_API_TOKEN

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (0.6.2) reached the registry 15 days ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.

What can I use instead?

In the same category: Context7, Codebase Memory, Exa

Alternatives

Servers in the same category from other makers, sorted by stars.

Reading a card:★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

Context7

by upstash

Feeds AI the latest docs for libraries and frameworks before it answers, so code it writes does not use outdated, removed functions.

Computer or cloud★ 64,224MITUpdated yesterday
Install

Codebase Memory

by DeusData

Codebase knowledge graph for AI agents — 162 languages, sub-ms queries, 99% fewer tokens.

Runs on your computer★ 48,148MITUpdated 21 days ago
Install

Exa

by exa-labs

Connect AI agents to Exa for web search, content fetching, and multi-step research.

Runs in the cloud★ 5,213MITUpdated 2 months ago
Install

README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

ChatCrystal

Crystallize knowledge from your AI conversations


ChatCrystal collects conversations from AI coding tools (Claude Code, Cursor, Codex CLI, Trae, GitHub Copilot), uses LLM to distill them into searchable structured notes, and builds your personal knowledge base.

Install

npm install -g chatcrystal

Requires Node.js >= 20 and an LLM service (Ollama, OpenAI, OrcaRouter, Anthropic, Google AI, or any OpenAI-compatible API).

Quick Start

crystal import                     # Scan and import AI conversations

crystal summarize --all # Batch summarize into notes crystal search "React state" # Semantic search your knowledge

The server auto-launches in background on first command. No manual setup needed.

Cloud Connection

For a Docker cloud instance, save the shared token once:

crystal connect https://chatcrystal.example.com --token "your-long-token"

crystal import --yes

crystal import still scans and parses histories on the local device, then uploads normalized conversations to the cloud instance. The cloud server does not scan your local filesystem. crystal mcp reuses the same saved connection and token.

HTTPS is recommended for cloud connections, but HTTP works when that is the deployment you choose.

To manage a Docker cloud token:

# Rotate when you still know the current token.

crystal --base-url https://chatcrystal.example.com token rotate "new-long-token-at-least-16-chars" --current "old-token"

Reset stored auth from the Docker host when the token is lost.

docker compose exec chatcrystal crystal token reset --yes docker compose exec chatcrystal cat /data/setup-code

If CHATCRYSTAL_API_TOKEN is set in the deployment environment, change that environment variable and recreate the container instead of using token reset.

CLI Commands

# Knowledge retrieval

crystal search [--limit 10] # Semantic search crystal notes list [--tag X] # Browse notes crystal notes get # View note detail crystal notes relations # View note relations crystal tags # List tags with counts

Data management

crystal import [--source claude-code] # Import conversations crystal summarize # Summarize one conversation crystal summarize --all # Batch summarize crystal summarize --retry-errors # Retry failed summaries crystal status # Server status and DB stats

Configuration

crystal config get # View config crystal config set llm.provider openai # Update config crystal config test # Test LLM connection

Server management

crystal serve # Start server (foreground) crystal serve -d # Start server (daemon) crystal serve stop # Stop daemon crystal serve status # Check if running

Global options: --base-url (server address), --token (cloud API token), --json (force JSON output), --version

Output: TTY-aware — colored tables in terminal, JSON when piped.

MCP Server

Integrate with AI coding tools so they can retrieve knowledge from your conversation history during coding.

crystal mcp                             # Start MCP stdio server
Claude Code

Add to settings.json:

{

"mcpServers": { "chatcrystal": { "command": "crystal", "args": ["mcp"] } } }

MCP Tools
ToolDescription
search_knowledgeSemantic search across notes when you need relevance-ranked matches
get_noteGet full note content (summary, conclusions, code snippets)
list_notesBrowse paginated note summaries by tag or title/summary keyword
get_relationsGet related notes with relationship types
recall_for_taskRead-only task recall that loads project memories first, then optional global lessons
validate_task_memoryDry-run validation before writing a task memory; returns acceptance, reasons, warnings, and note fields
write_task_memoryPersist reusable task memories after meaningful work

Configuration

Runtime configuration is stored in config.json under the active data directory. CLI, MCP, repo/dev checkouts, npm global installs, and Electron default to ~/.chatcrystal/data. Use crystal config set for persistent config. .env remains available only as an optional local override layer.

# LLM (ollama/openai/orcarouter/anthropic/google/azure/custom)

crystal config set llm.provider openai crystal config set llm.model gpt-4o crystal config set llm.apiKey sk-...

Embedding (ollama/openai/google/azure/custom)

crystal config set embedding.provider ollama crystal config set embedding.model nomic-embed-text

OrcaRouter uses ChatCrystal's built-in https://api.orcarouter.ai/v1 Base URL. Set llm.provider to orcarouter, provide an API Key, and select a discovered model in the Web UI; no llm.baseURL is required. Get an OrcaRouter API Key.

Data Sources

Automatically detects and imports from:

SourcePath
Claude Code~/.claude/projects/**/*.jsonl
Codex CLI~/.codex/sessions/**/*.jsonl
CursorPlatform-specific state.vscdb
TraePlatform-specific state.vscdb
GitHub CopilotVS Code chatSessions/*.jsonl / *.json

Web UI & Desktop App

ChatCrystal also has a web UI and Electron desktop app. See the GitHub repository for details.

License

Apache License 2.0

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