Correct. If you try to create a coding agent using the raw Codex or Claude code API and you build your own “write tool”, and don’t give the model their “native

Correct. If you try to create a coding agent using the raw Codex or Claude code API and you build your own “write tool”, and don’t give the model their “native patch tool”, 70%+ of the time it’s write/ patch fails because it tries to do the operation using the write/ patch tool it was trained on.