mcp-reticle

The Wireshark for the Model Context Protocol

See what your Agent sees.

Reticle intercepts, visualizes, and profiles JSON-RPC traffic between your LLM and MCP servers in real-time — with zero latency overhead.

Installation

npm install -g mcp-reticle

Usage

Wrap your MCP server command with mcp-reticle run:

mcp-reticle run --name my-server -- npx -y @modelcontextprotocol/server-filesystem /path/to/dir

Claude Desktop Configuration

Edit ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "filesystem": {
      "command": "mcp-reticle",
      "args": ["run", "--name", "filesystem", "--", "npx", "-y", "@modelcontextprotocol/server-filesystem", "/Users/me/work"]
    }
  }
}

Features

• Deep Packet Inspection — See raw JSON-RPC messages in real-time
• Request/Response Correlation — Automatically links responses to requests
• Latency Profiling — Color-coded latency indicators
• Token Profiling — Real-time token estimation per message
• Multi-Session Support — Debug multiple MCP servers simultaneously
• Zero-Latency Proxy — Microsecond overhead

Documentation

Full documentation at github.com/labterminal/mcp-reticle

License

MIT