Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. 'Toggle clip content on a frame' does disclose that this is a state-changing operation on a frame's clip property. However, it does not mention side effects, return value, or that 'clip' is a boolean to be set explicitly rather than toggled from its current state.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.