Gemini fairs poorly at tool use, even in its own CLI and even in Antigravity. It gets into a mess just editing source files, it's tragic because it's actually not a bad model otherwise.
It frequently fails to apply its diffs at first but it always succeeds eventually for me. I'm happy with it. I understand it is slower than other models but it also costs barely anything per month.
However you feel about OpenAI, at least their harness is actually open source and they don’t send lawyers after oss projects like opencode