Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the burden of disclosing behavior. It mentions the limit cap (default 20, max 100) and that api_key enables higher rate limits, which is useful. However, it does not explain matching semantics (exact vs substring), whether results are sorted, or any authorization requirements beyond the optional api_key.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.