That's not a harness. That's an agent cli. A harness is something completely different. Wish people could use proper terminology.

A test harness is a collection of software and test data configured to test a program unit by running it under varying conditions and monitoring its behavior and outputs. It automates the execution of test suites, providing the necessary stubs, drivers, and runtime environments so developers can isolate and verify specific code components.

I use opencode (lockedcode is still vaporware), claude, kimi and codex.

And most models. Just no Google models so far, I don't trust them.