Google finds stale TODO comments distract coding agents from assigned tasks

Google's analysis of agent traces across thousands of engineers found that 13% of coding-agent sessions exposed agents to inline TODO(bug/...) or FIXME(bug/...) references, and 6% of those exposed sessions triggered follow-up actions the user had not requested.

Google says 41% of these unprompted detours chased bugs that were already closed, and 57% expanded into scope creep on open bugs. Google reports that, compared with sessions without such detours, the affected sessions used 70% more steps, 77% more tokens and 105% more wait time.

The figures come from Google's Developers Blog, which describes the study as drawing on hundreds of millions of individual agent steps.