ultraworkers/claw-code ? reverse-engineered prompt

I'd like to build a powerful command-line tool, kind of like an "agent harness," for interacting with AI models like Claude directly from my terminal. The whole thing should be written in Rust to make it super fast.

The main command should be claw. I want to be able to run prompts like claw prompt "write a short story about a robot". It should also have a diagnostic command, something like claw doctor, to check that my setup is working. For authentication, it should use an API key from an environment variable, like ANTHROPIC_API_KEY, instead of a web login.

Please structure the project so the main Rust code is in a rust/ subdirectory. Also, generate some good documentation, including a main README.md and a USAGE.md that clearly explains how to build the tool from source and use the different commands.