The same eligibility rule in four services. Pricing logic nobody will touch. Every copy quietly diverging, and now agents are generating more. Centralize the rules once, and let everything call them.
Versioned. One implementation of the rule, called from every channel that needs it. Changes are reviewed, released, and auditable.
Auditable. The rule your risk team can read, with request history showing every call and version history showing every change.
Single source, enforced everywhere. Versioning on the APIs, so a change rolls out deliberately instead of drifting service by service.
An agent building a new tool doesn't re-implement your eligibility logic from a prompt; it calls the governed API that already encodes it. Your rules become the standing context every build inherits, human or agent.