Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Goes well beyond the annotations by disclosing the 15MB input cap, 24-hour hosted download URL validity, free demo quota of 3 renders/day, API key authentication format, and 25-unit cost per render. No contradiction with readOnlyHint=false, openWorldHint=true, or other annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.