I must be doing something wrong, because I can't get OpenCode to actually do anything useful, and not for lack of trying. Claude code gets me great results instantly, opencode (if I can't make it talk to a model, which isn't easy for Gemini) gets me… something, but it's nowhere near as useful as claude code. I don't know why there is so much difference, because theoretically there shouldn't be. Is it the prompt that Anthropic has been polishing in Claude code for so long?

Claude models in opencode use the Claude code system prompt, are you comparing Claude code to opencode with non anthropic models?

I only played with Claude Code briefly but my experience with OpenCode was amazing. My experience it works the best with Claude especially Sonnet models (I use it with Claude Sonnet 4.5 with my Copilot subscription).