By "planning", I actually meant "thought of one time". So, I did it. The endpoint verifies that the destination specified by the POST is in my project folder.

By "planning", I actually meant "thought of one time". So, I did it. The endpoint verifies that the destination specified by the POST is in my project folder. If it points at an existing file, it creates a version. It does not overwrite. I added a CLI, watchFile, that blocks Claude until the file shows up. And made a skill that tells Claude to respond nicely to "Make an interactive document that...". Claude Code has basically made software functionality, "Your wishes come true".