AI actors are the people and organizations who play an active role in an AI system's lifecycle. NIST's lifecycle has design, development, deployment, and operation and monitoring work, with testing, evaluation, verification and validation (TEVV) all the way through, and risk management starts at planning and design. Ideally the people who check a model are not the people who build and use it. Risk combines how likely an event is with how big its consequences would be. NIST's framework has four functions, GOVERN, MAP, MEASURE and MANAGE, used again and again rather than as a checklist. Trustworthy AI balances characteristics that pull against each other, and all AI actors share the job of deciding whether AI is the right tool at all.