Declarations are not invocations
A model may receive a tool definition without ever calling it. The Skills & Tools view separates declarations from invocations so review teams can prioritize real usage instead of theoretical exposure.
This is the difference between a capability inventory and an activity log. The first tells you what an agent could use. The second tells you what the supported integration actually observed. Both matter, but they answer different security questions.
Capability versus activity
Declared skill → Available capability → Agent invocation → Observed decision → Review evidence