1. Single responsibility works best People tend to model agents on people: a product owner agent, an engineer agent, a QA agent. That fails for the same reason UserService failed. A role is not a scope. It is a bundle of unrelated jobs that share a title. Single-task agents hold up better. A backlog grooming agent. A release notes agent. A migration risk review agent. One job you can describe in a sentence, with a small tool surface and a clear output.