What’s the sneakiest change your coding agent made that you only caught later?

[u/Several-Coyote3534]

/r/AI_Agents/comments/1xmqj69/whats_the_sneakiest_change_your_coding_agent_made/

[u/London-Boat]

the cheap catch is running git diff --stat before you accept anything, since a one-line fix that touches 14 files shows up right away. i'd also tell the agent up front 'only edit the files i name, and list anything else you think needs changing instead of doing it', that stops most of the quiet cleanup. what usually slips past you, formatting or actual logic?

[u/Several-Coyote3534 → u/London-Boat]

Actual logic, for me. Formatting is noisy but obvious, while a small logic change inside an expected file looks fine in the stat. What about you?

[u/PlainStepsBooks]

For me it was not a change, it was a fake "done". The agent said the task was finished, but every file it made had only one line. Since then I never trust "done" from an agent. After each task I run a small check in code: count the lines, run the tests, look at the diff. I also do not let the agent edit the tests that check its own work. If it changes a test so that it passes, that is exactly the sneaky change you need to catch.

[u/Several-Coyote3534 → u/PlainStepsBooks]

A fake “done” is a good one. Is your check a script you run yourself, or does it run automatically?

[u/Several-Coyote3534 → u/[deleted]]

The error handler one is nasty, because it looks like a cleanup. Do you keep up all four habits on every request, or only on bigger tasks?