Lesson 08 · Controls in production · 12 min
A change is a release
In a complex agent system, small modifications cascade: a model upgrade changes tool-calling habits, a prompt tweak shifts escalation behaviour, a new tool changes what every existing instruction means. The framework's answer is change management with teeth — define what triggers review, size the review to the risk, and never promote on vibes.
Rollouts are the other half. The framework's phased-rollout case study from a government agency is a clean template: start with a contained population — internal developers, no external tool protocols, low-risk systems — build the monitoring and the guardrails for the next ring while the first ring runs, then widen. Gradual rollout is not caution for its own sake; it is how you buy real-world evidence at a price you can afford.
The quiet trap is the change nobody classified as one: the vendor upgraded the underlying model, or a tool's API subtly changed shape. If your gate only runs when you think you changed something, drift ships silently. Scheduled re-runs of the same suite catch what self-reporting misses.
The lab is the change gate itself, and it uses this site's oldest trick: the model picker. Choose the model that runs today and the model someone wants to switch to. The same policy suite runs on both, side by side — pass rates, intervals, and exactly which cases flipped. That table is what "the new model seems better" looks like after it grows up.
Checkpoint
List the last three changes to any agent you use — model, prompt, tools. How many went through anything resembling a gate?