Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover readOnly, idempotent, openWorld, and non-destructive, so the safety bar is low. The description adds real behavioral context: this is a composite operation that performs a crawl and can optionally spawn a local Lighthouse CLI process, which is a heavyweight side effect worth knowing. It stops short of noting runtime, rate limits, or crawl cost.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.