alt Hacker NewsIt's worth noting that Claude Code itself doesn't use the `insert` tool. (It also uses custom edit tool not the suite's predefined str_replace)
Also as a person developing agentic code tools since before Claude Code, I'm skeptical if str_replace provides accuracy improvement over just full rewrite.
Back in the day when SOTA models would do lazy coding like `// ... rest of the code ...`, full rewrite wasn't easy. Search/replace was fast, efficient and without the lazy coding. However, it came with slight accuracy drop.
Today that accuracy drop might be minimal/absent, but I'm not sure if it could lead to improvements like preventing doc corruption.
I've tested this extensively in a workflow (not agentic) context, and you're right, the underlying models are both good at full rewrite of code files, and at doing search/replace.
They've been decent at full rewrite for 2 years. I don't think they were good at search/replace until a year ago, but I'm not so sure.
It's true that the models 2 years ago would sometimes make errors in whole rewrite - e.g removing comments was fairly common. But I've never seen one randomly remove one character or anything like that. These days they're really good.
Main reason agentic harnesses use search/replace is speed and cost, surely! Whole file output is expensive for small changes.