Sooo, I love Claude 3.7, and use it every day, I prefer it to Gemini models mostly, but I've just given Opus 4 a spin with Claude Code (codebase in Go) for a mostly greenfield feature (new files mostly) and... the thinking process is good, but 70-80% of tool calls are failing for me.

And I mean basic tools like "Write", "Update" failing with invalid syntax.

5 attempts to write a file (all failed) and it continues trying with the following comment

> I keep forgetting to add the content parameter. Let me fix that.

So something is wrong here. Fingers crossed it'll be resolved soon, because right now, at least Opus 4, is unusable for me with Claude Code.

The files it did succeed in creating were high quality.

Alright, I think I found the reason, clearly a bug: https://github.com/anthropics/claude-code/issues/1236#issuec...

Basically it seems to be hitting the max output token count (writing out a whole new file in one go), stops the response, and the invalid tool call parameters error is a red herring.