Boundary
The host or wrapper owns the lifecycle events. The tool stays unchanged while the surrounding policy evolves.
What this adds
Enforce boundaries at predictable moments.
Hooks let you intercept execution before and after the underlying capability runs. That means you can block sensitive requests, add logs, or attach validation without changing the tool implementation.
This is where "policy around the tool" starts to become visible.
Done when
The same underlying call can be allowed, blocked, and logged based on hook decisions alone.
Real-world analog
Git hooks are the familiar version of this pattern: a stable command pipeline with policy and automation injected at known lifecycle moments.
Why this matters
It becomes much easier to reason about trust when approval and logging live outside the raw tool call.