MCP in Claude Desktop

Claude Desktop is Anthropic's desktop app for macOS and Windows. With the Synapse MCP server configured, Claude gets native access to all 79 Synapse tools — it can store memories, recall them, manage tasks, chat with you, and more.

Prerequisites

• Claude Desktop app (macOS or Windows)
• Node.js 18+ installed (node --version)
• Your Synapse Mind Key

Step 1: Open the Config File

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

If the file doesn't exist, create it.

Step 2: Add Synapse MCP Server

{
  "mcpServers": {
    "synapse": {
      "command": "npx",
      "args": ["-y", "synapse-mcp-api@latest"],
      "env": {
        "SYNAPSE_MIND_KEY": "mk_YOUR_MIND_KEY_HERE",
        "SYNAPSE_URL": "https://synapse.schaefer.zone"
      }
    }
  }
}

Step 3: Restart Claude Desktop

1. Fully quit Claude Desktop (Cmd+Q on macOS, not just close window)
2. Reopen Claude Desktop
3. Start a new chat
4. Look for the 🔌 plug icon in the bottom-left — it should say "79 tools"

Step 4: Test It

In a new chat, type:

memory_recall aufrufen

Claude should call the memory_recall tool and respond with a summary of your stored memories (or "No memories yet" if your mind is empty).

Available Tools (Selection)

Full list: What is MCP?

Troubleshooting

No tools appear in Claude Desktop

1. Verify Node.js version: node --version (must be ≥ 18)
2. Check the config file is valid JSON (no trailing commas)
3. Restart Claude Desktop fully (Cmd+Q, not just close)
4. Check Claude Desktop logs: ~/Library/Logs/Claude/mcp.log (macOS)

"Mind Key invalid" error

• Verify SYNAPSE_MIND_KEY starts with mk_
• Get a fresh key via POST /minds (requires JWT from /login)
• No quotes around the key in the JSON

npx not found

• Install Node.js 18+: https://nodejs.org/
• Restart terminal after install
• On macOS with Homebrew: brew install node

Tools show but calls fail

• Check SYNAPSE_URL is reachable: curl https://synapse.schaefer.zone/health
• Verify your Mind Key works: curl -H "Authorization: Bearer mk_..." https://synapse.schaefer.zone/memory/recall
• See MCP Troubleshooting

Tool Profiles (Save Tokens)

If you're using a smaller LLM or want to save context tokens, set a tool profile:

{
  "mcpServers": {
    "synapse": {
      "command": "npx",
      "args": ["-y", "synapse-mcp-api@latest"],
      "env": {
        "SYNAPSE_MIND_KEY": "mk_...",
        "SYNAPSE_URL": "https://synapse.schaefer.zone",
        "MCP_PROFILE": "standard"
      }
    }
  }
}

Profiles: minimal (8 tools), standard (25), full (119, default).

Next Steps

• Claude Code Setup
• Cursor Setup
• MCP Troubleshooting