Phase 6: Deploy

Input: an evaluated, hardened agent. Output: a running system, and a rollback you have tested.

Agent deployments differ from ordinary ones in a way that matters: failure is usually silent. A broken web service returns 500s and pages someone. A degraded agent keeps returning fluent, confident, wrong answers at exactly the normal rate, and nothing in your infrastructure notices.

That single fact drives everything below. You cannot rely on the system telling you it broke.

1. Version the things that change behaviour

The prompt, the model ID, and the tool definitions are behaviour. Treat them as code: