Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries full burden but lacks behavioral details. It implies a mutation (marking as complete) but doesn't disclose side effects (e.g., if completion triggers notifications, updates timestamps, or affects list visibility), permissions required, or error conditions. This leaves gaps for safe agent operation.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.