Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond the readOnly/idempotent/destructive annotations, the description discloses ordering (newest first), returned fields (status, goal, cost, timing), ownership scoping (caller's own runs), and a tier restriction ('sp500+ (sample rejected)'). It also explains that runs can come from multiple triggers, which meaningfully shapes caller expectations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.