How do I use Crosmos MCP Server?

1. Click on "Install Server". 2. Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state. 3. In the chat, type @ followed by the MCP server name and your instructions, e.g., "@Crosmos MCP Server search memories about machine learning project" That's it! The server will respond to your query, and you can continue using it as needed. Here is a step-by-step guide with screenshots.

Crosmos MCP Server

Beta — Crosmos is in early access. APIs and features may change. Feedback welcome at github.com/crosmos-org/crosmos-mcp.

MCP server for the Crosmos memory layer.

Tools

Tool	Description
`crosmos_search_memories`	Semantic + keyword + graph retrieval
`crosmos_add_memory`	Store content with auto entity/relation extraction
`crosmos_list_spaces`	List available memory spaces
`crosmos_health_check`	Verify API connectivity and status

Quick Start

npx @crosmos/crosmos-mcp setup

This runs the interactive setup:

Authenticate — Enter your API key (get one at console.crosmos.dev)
Install to clients — Auto-detects installed MCP clients (Claude Desktop, Claude Code, opencode, Cursor, VS Code, Windsurf, Cline, Roo-Cline, Zed) and writes the server config
Install skill — Auto-detects your AI editor(s) and installs the Crosmos skill

No global install needed — npx handles everything. Clients are configured to run npx -y @crosmos/crosmos-mcp so they always pick up the latest version.

Manual Setup

1. Authenticate

npx @crosmos/crosmos-mcp auth login

Or set the environment variable:

export CROSMOS_API_KEY=csk_your_api_key_here

2. Configure your client

Config location:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
Linux: ~/.config/Claude/claude_desktop_config.json
Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "crosmos-memory": {
      "command": "npx",
      "args": ["-y", "@crosmos/crosmos-mcp"]
    }
  }
}

claude mcp add crosmos-memory -- npx -y @crosmos/crosmos-mcp

~/.config/opencode/opencode.json:

{
  "mcp": {
    "crosmos-memory": {
      "type": "local",
      "command": ["npx", "-y", "@crosmos/crosmos-mcp"]
    }
  }
}

~/.cursor/mcp.json:

{
  "mcpServers": {
    "crosmos-memory": {
      "command": "npx",
      "args": ["-y", "@crosmos/crosmos-mcp"]
    }
  }
}

macOS: ~/Library/Application Support/Code/User/mcp.json
Linux: ~/.config/Code/User/mcp.json
Windows: %APPDATA%\Code\User\mcp.json

{
  "servers": {
    "crosmos-memory": {
      "command": "npx",
      "args": ["-y", "@crosmos/crosmos-mcp"]
    }
  }
}

~/.codeium/windsurf/mcp_config.json:

{
  "mcpServers": {
    "crosmos-memory": {
      "command": "npx",
      "args": ["-y", "@crosmos/crosmos-mcp"]
    }
  }
}

The server uses stdio transport. Point your client to npx -y @crosmos/crosmos-mcp and set:

Variable	Value
`CROSMOS_API_KEY`	Your API key (`csk_...`)
`CROSMOS_API_BASE_URL`	`https://api.crosmos.dev` (default)

3. (Optional) Install the skill

npx @crosmos/crosmos-mcp skill install opencode    # or: cursor, claude-code, windsurf, vscode

CLI Reference

npx @crosmos/crosmos-mcp                     # Start MCP server (stdio)
npx @crosmos/crosmos-mcp setup               # Interactive setup (auth + client install + skill)
npx @crosmos/crosmos-mcp auth login          # Authenticate with API key
npx @crosmos/crosmos-mcp auth login --base-url URL # Custom API base URL
npx @crosmos/crosmos-mcp auth logout         # Remove stored credentials
npx @crosmos/crosmos-mcp auth status         # Show auth state
npx @crosmos/crosmos-mcp skill install <client>  # Install Crosmos skill

Environment Variables

Variable	Description	Default
`CROSMOS_API_KEY`	API key (overrides credentials file)	—
`CROSMOS_API_BASE_URL`	API base URL	`https://api.crosmos.dev`
`CROSMOS_API_TIMEOUT`	Request timeout (ms)	`30000`
`DEFAULT_SPACE_ID`	Default memory space UUID	—
`DEFAULT_SPACE_NAME`	Default memory space name (resolved via `/spaces?name=`); ignored if `DEFAULT_SPACE_ID` is set	—

Credential resolution order: CROSMOS_API_KEY env var → ~/.crosmos/credentials.json → error.

Development

npm run dev          # stdio mode with watch
npm run dev:http     # HTTP mode with watch
npm run build        # compile TypeScript
npm run lint         # biome check
npm run format       # biome format

License

MIT

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Crosmos MCP Server

Crosmos MCP Server

Tools

Quick Start

Manual Setup

1. Authenticate

2. Configure your client

3. (Optional) Install the skill

CLI Reference

Environment Variables

Development

License

Resources

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