Cosmos MCP vs ChatCrystal

In-depth architectural comparison of the Cosmos MCP and ChatCrystal MCP servers. Compare execution transports, security boundaries, tool capabilities, quality scores, and ready-to-paste client installation snippets for Claude, Cursor, Windsurf, and VS Code.

Which MCP Server Should You Choose?

Choose Cosmos MCP when:

• You need dedicated capabilities in the Knowledge & Memory domain.
• You prefer local stdio subprocess transport architecture.
• Your security boundary fits: API Key required (Free / Open Source).
• You have access to required keys: COSMOS_TOKEN.
• Primary tools included: Shared account-keyed personal knowledge graph, Eleven MCP read and write tools, Portable .polarity graph export.

Explore Cosmos MCP Details

Choose ChatCrystal when:

• You need dedicated capabilities in the Knowledge & Memory domain.
• You prefer local stdio subprocess transport architecture.
• Your security boundary fits: No auth required (Free / Open Source).
• Primary tools included: Imports Claude Code, Cursor, Codex CLI, Trae, and GitHub Copilot chats, Distills conversations into tagged structured notes, Provides embedding-based semantic search.

Feature & Specification Comparison

Specification	Cosmos MCP teampolarity Knowledge & Memory	ChatCrystal ZengLiangYi Knowledge & Memory
Summary	Personal knowledge graph shared across MCP clients. Account-keyed and portable as a .polarity file, with sources for iMessage, browser history, calendar, Claude Desktop transcripts, shell history, Notion, and Obsidian. npx -y @polarity-lab/cosmos-mcp	Local-first AI PKM memory server for coding conversations. Imports Claude Code, Cursor, Codex CLI, Trae, and GitHub Copilot chats into notes, semantic search, tag graphs, Markdown exports, and reusable MCP memory. npx -y chatcrystal mcp
Category & Scope

Tools & Capabilities Breakdown

Ready-to-Paste Client Configurations

Paste either (or both) of these JSON server blocks into your client config file (e.g. claude_desktop_config.json or ~/.cursor/mcp.json).

{
  "mcpServers": {
    "teampolarity-cosmos-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@polarity-lab/cosmos-mcp"
      ],
      "env": {
        "COSMOS_TOKEN": "YOUR_COSMOS_TOKEN_HERE"
      }
    }
  }
}

{
  "mcpServers": {
    "zengliangyi-chatcrystal": {
      "command": "npx",
      "args": [
        "-y",
        "chatcrystal"
      ]
    }
  }
}

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