Celest-Chat , a lazy panel to check each others

A browser editor that sits beside a live AI coding session: the transcript on the left, a real multi-file editor on the right, with diffs projected into open tabs as the agent edits them.

It runs as root — so the first feature built for it was an attack on it. The save route had no auth: a cross-origin POST could overwrite any file on the machine. Fixed with a six-line gate above the router, then re-attacked to prove it held.

Python stdlib only. No framework, no bundler, no database.