Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover safety with readOnlyHint, idempotentHint, and destructiveHint. The description adds valuable context: it reveals the return shape (authenticated:true with empty pending[], or connect_url for toolkit and per-install URLs) under different conditions, going beyond what annotations provide.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.