What is mcpsense-proxy?

mcpsense-proxy is a small command line tool that solves a specific compatibility problem for developers working with the Model Context Protocol, or MCP, which is a standard used by AI assistants to connect to external tools and data sources. On July 28, 2026, the MCP specification changed in a way that removes an older handshake step and a session tracking header that many existing MCP servers depend on. Any legacy server built around that older, stateful approach would stop working correctly with new clients unless something bridges the gap. This tool sits between a modern, stateless MCP client and an older, stateful MCP server, translating requests from one side to the other. On the front end it speaks the new 2026-07-28 protocol, using the required routing headers and handling the discovery and validation rules that format expects. On the back end it uses the official MCP software development kit to talk to the legacy server, either by starting it as a local process or by connecting to it remotely over HTTP, and it keeps a single warm session open so the very first request does not have to wait through a setup handshake. It requires no server of its own, no account, and no ongoing cost, since it runs locally on the same machine as the client using npx, a command that runs Node.js packages without a separate install step. Setup is a single command line invocation that points to the legacy server's own start command. There is also a demo mode that spins up a bundled example legacy server and walks through three example requests so a user can see the proxy working end to end, plus a recorded terminal session for anyone who wants to preview the tool before installing it. The project includes a development workflow with a test suite and build step for anyone who wants to modify the proxy itself. It is released under the MIT license, so it can be used, copied, and modified freely.