Hooks

Deterministic callbacks run at lifecycle boundaries before, during, or after agent work.

Active scenario: guard. A pre-tool hook checks the attempted action before the agent can mutate state.

Metrics: determinism: high; latency cost: medium; coverage risk: medium.

Nodes: Refund request, user: The user asks for a refund review that may end in a write action. Agent, worker: The agent proposes a tool call after reading policy and account state. PreToolUse, control: A deterministic check inspects tool name, arguments, path, and risk. Policy, review: Rules block missing order IDs, unsafe commands, or writes outside scope. Write tool, tool: Allowed actions continue; denied actions return a concrete reason. Decision, state: The model sees the hook result and can choose a safer next step.