> One does often hear that where LLMs shine is with greenfield code generation but they all start to struggle working with pre-existing code.

Don't we all?

I'm better at pre-existing code, if only because empty text files give me writers block.

Whether we do or not it's besides the point. The comparison was between Claude, which produced competent greenfield code, and Gemini which struggled with brownfield. The comparison is stacked in Claude's favour.

Nope.