Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover the safety profile (readOnly, idempotent, non-destructive), but the description adds genuinely novel behavior: local Tesseract execution, a free-sample-plus-paid-URL response shape, 'no charge here', and the $0.01 Base USDC x402 cost to unlock the full result. This two-tier payment mechanic is exactly what annotations cannot convey. It stops short of noting rate limits or failure modes, hence not a 5.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.