# user-engine policy service Dynamic human subjects arrive as verified KeyCape claims, so the registry defines the protected system while the policy evaluates tenant, roles, and self context from each request. Platform operators may cross tenants; tenant administrators and self-service users may not. Validate with: ```bash flex-auth test-policy -file examples/user-engine/policy_package.md flex-auth load-registry -file examples/user-engine/registry_snapshot.json ```