An agent constitution is the deployment-time counterpart to a model's training-time safety work. It covers scope (which workflows the agent owns), prohibitions (behaviours it must refuse), escalation (when and how it hands off to humans), tone (how it speaks), and change-control (who can amend it and how).
A usable constitution is short (2–5 pages for a first deployment), specific, testable, and versioned in source control. It is enforced by a policy layer at runtime — not just via system prompts, which drift and can be overridden.
Constitutions are reviewed quarterly and amended whenever scope changes, incidents occur, or red-team evaluations reveal gaps.