Agent Hook
A script, request, prompt, or subagent triggered by an event in an agent's lifecycle.
Plain English
A hook lets the environment react when the agent starts, calls a tool, changes files, compacts context, or finishes.
Example
A `PreToolUse` hook blocks destructive database commands before the agent can run them.
Why it matters
Hooks turn agent platforms into programmable runtimes with enforceable local policy.