mcpsnoop is a transparent proxy and terminal interface for inspecting the real Model Context Protocol (MCP) traffic between AI clients and MCP servers.
It sits directly in the data path, capturing JSON-RPC frames so you can debug tool calls, capability negotiation, slow or hung requests, and unexpected arguments.
This is free and open source software.
Key Features
- Displays live JSON-RPC requests, responses, notifications, and server stderr.
- Captures the actual traffic exchanged between an AI client and MCP server.
- Replays captured tool calls against a fresh server instance.
- Inspects capabilities negotiated between the client and server.
- Provides pretty-printed JSON frame inspection with search.
- Flags slow, failed, pending, and hung calls.
- Filters traffic by tool, method, request ID, direction, frame type, status, or text.
- Exports sessions in JSON, HTML, and plain text formats.
- Supports stdio and streamable HTTP MCP servers.
- Offers optional key-based redaction of secrets from captured trace copies.
Website: github.com/kerlenton/mcpsnoop
Support:
Developer: Semyon Usachev
License: MIT License
mcpsnoop is written in Go. Learn Go with our recommended free books and free tutorials.
 Explore our carefully curated directory of recommended free and open source software, covering every major software category.The directory forms part of our extensive collection of articles for Linux enthusiasts. It includes hundreds of detailed reviews, together with free and open source alternatives to proprietary software from companies such as Google, Microsoft, Apple, Adobe, IBM, Cisco, Oracle, and Autodesk. LinuxLinks also covers interesting projects worth exploring, Linux-compatible hardware, free programming books and tutorials, and much more. Know a useful free and open source Linux application that we haven’t covered? Tell us about it using our submission form. |
Please read our Comment Policy before commenting.