The agent gets worse and nobody tells you
Materially different behaviour month over month
The most repeated complaint is not that agents fail — it's that the same agent behaves differently month to month. Tasks that were routine start taking several attempts. Long refactors terminate early. Context windows quietly degrade and rate limits shift without notice.
What makes this rank first is the second half: vendors rarely communicate the change. Users discover a regression by losing an afternoon to it, which converts a technical problem into a trust problem.
If you're building one: Publish a changelog for model and prompt changes, not just features. Silence during a regression costs more goodwill than the regression.
dev.to — AI agents on Reddit, ten threads on cost and reliability ↗