mcp-reticle

<p align="center"> <picture> <source media="(prefers-color-scheme: dark)" srcset="https://raw.githubusercontent.com/labterminal/mcp-reticle/main/frontend/src/assets/logo-white.png" /> <source media="(prefers-color-scheme: light)" srcset="https://raw.githubusercontent.com/labterminal/mcp-reticle/main/frontend/src/assets/logo.png" /> <img src="https://raw.githubusercontent.com/labterminal/mcp-reticle/main/frontend/src/assets/logo.png" alt="Reticle Logo" width="120" /> </picture> </p>

<h1 align="center">RETICLE</h1>

<p align="center"> <strong>The Wireshark for the Model Context Protocol (MCP)</strong> </p>

<p align="center"> <a href="LICENSE"> <img src="https://img.shields.io/badge/License-MIT-blue.svg" alt="License: MIT" /> </a> <a href="https://www.npmjs.com/package/mcp-reticle"> <img src="https://img.shields.io/npm/v/mcp-reticle.svg" alt="npm" /> </a> <a href="https://pypi.org/project/mcp-reticle/"> <img src="https://img.shields.io/pypi/v/mcp-reticle.svg" alt="PyPI" /> </a> <a href="https://github.com/labterminal/mcp-reticle/wiki"> <img src="https://img.shields.io/badge/docs-wiki-informational" alt="Docs (Wiki)" /> </a> <img src="https://img.shields.io/badge/Platform-macOS%20%7C%20Linux%20%7C%20Windows-lightgrey.svg" alt="Platform" /> </p>

<p align="center"> <em>See what your agent sees.</em> </p>

<p align="center"> Reticle intercepts, visualizes, and profiles MCP JSON-RPC traffic in real time — designed for microsecond-level overhead. </p>

<p align="center"> <a href="#quick-start">Quick start</a> · <a href="#installation">Install</a> · <a href="#documentation">Docs</a> · <a href="#security--privacy">Security</a> · <a href="#contributing">Contributing</a> </p>

<p align="center"> <img src="https://raw.githubusercontent.com/labterminal/mcp-reticle/main/frontend/src/styles/reticle.png" alt="Reticle Screenshot" width="900" /> </p>

---

What is Reticle?

Reticle is a proxy + UI for debugging MCP integrations:

• inspect raw JSON-RPC messages (requests / notifications / responses)
• correlate request ↔ response instantly
• profile latency and token estimates
• capture server stderr and crashes
• record sessions and export logs

Supported transports: stdio, Streamable HTTP, WebSocket, HTTP/SSE.

---

Quick start

1) Install

# npm
npm install -g mcp-reticle

# pip
pip install mcp-reticle

# Homebrew
brew install labterminal/mcp-reticle/mcp-reticle

2) Wrap your MCP server (stdio)

Replace your MCP server command with mcp-reticle run --name <name> -- <command...>.

Example (Claude Desktop-style config):

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

3) Launch the UI

mcp-reticle ui

Optional: log-only mode (no UI)

mcp-reticle run --log -- npx -y @modelcontextprotocol/server-memory

Optional: proxy an HTTP-based MCP server

mcp-reticle proxy --name api --upstream http://localhost:8080 --listen 3001

---

Installation

If you prefer building from source:

git clone https://github.com/labterminal/mcp-reticle.git
cd mcp-reticle
just build

---

Documentation

All guides and deep dives are in the GitHub Wiki:

• Getting started
• CLI reference
• Client configuration
• Troubleshooting
• Architecture
• Security & privacy
• Development
• Exports

---

CLI overview

Command	Purpose
mcp-reticle run	Wrap stdio MCP servers and inspect traffic
mcp-reticle proxy	Reverse proxy HTTP/SSE/WebSocket transports
mcp-reticle ui	Launch the desktop UI
mcp-reticle daemon	Headless telemetry hub

Full details: CLI reference

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Security & privacy

Reticle can capture tool inputs/outputs and server stderr. Treat recordings and exports as sensitive artifacts.

Recommended reading: Security & privacy

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Contributing

• Repo guidelines: CONTRIBUTING.md
• Dev setup and commands: Development guide

---

License

MIT — see LICENSE.