The Deployment & Rollout Plan

Plan the rollout of this agent to production.

System: [DESCRIBE]
Current state: [DESCRIBE]
Users: [DESCRIBE]
Risk: [DESCRIBE]

Produce:
1. Rollout stages, from safest to full
2. What is validated at each stage before proceeding
3. Success criteria per stage — specific and measurable
4. Rollback criteria per stage — the signal that stops the rollout
5. What runs in shadow mode first, comparing against current
   behaviour without acting
6. Feature flag design: what can be turned off independently
7. Monitoring specific to the rollout
8. Communication: what users are told, and when
9. What is the smallest possible first deployment that would teach
   me something real?

Then:
10. What could go wrong during rollout that would not show in
    testing?
11. What is the fastest possible path from "something is wrong" to
    "it is off"?

For a system with side effects, shadow mode is usually worth the
effort. Tell me specifically what shadow mode would look like here.