Disclosure: I built this, and it is fully open source. I am posting it as a build-in-public update, not a paid product ad.



What I built: Tandem is a local MCP bridge that lets [Claude.ai](http://Claude.ai) or ChatGPT open, resume, and manage a real Claude Code session on your computer.



Why I built it: I kept doing product/spec thinking in browser chat, then switching to Claude Code in the terminal for the real work. The annoying part was the handoff: copy the plan into the terminal, wait for output, copy results back into the brainstorm, repeat.



What changed: Claude Code can now respond back into the browser chat, and the browser chat can answer back down through the CLI. That means the workflow can run as a loop instead of a manual copy-paste chain.



Build detail: it uses real interactive Claude Code sessions in tmux. This is not a hosted SaaS agent and not just headless claude -p orchestration. The point was to keep the actual coding session local while letting the brainstorming tool manage it.



What I learned building it: the hard part is not just launching a terminal command. The hard part is making the loop reliable enough to resume sessions, read incremental output, avoid leaking secrets in screenshots, and keep the security model honest.



Caveat: it runs real commands locally, so the token is basically a password and the cwd allowlist matters.



Demo attached. Feedback I want: is the build-in-public story clear, or does this still need a simpler explanation?



Repo:

[https://github.com/Maxmedawar/tandem](https://github.com/Maxmedawar/tandem)

Building Tandem in public: an open-source bridge from browser chat to local Claude Code