And it can fail in great ways. Last example: I asked claude for a non-trivial backup and recovery script using restic. I gave it the whole restic repo and it still made up parameters that don't exist in the code (but exist in a pull request that's been sitting not merged for 10+ months).

Interesting. I don't think I've seen hallucinations at that level when it's referencing source code.

Though my workflow always starts in plan mode where Claude is clearly more thorough (which is the reason it takes 10x as long as going straight to impl). I rarely skip it.