Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the bar is lower. The description still adds substantive epistemic context beyond them: the payload includes negative results and scientific limitations, and no model fitting occurs, meaning the agent is reading precomputed artifacts rather than triggering computation.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.