Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already establish that the tool is read-only and non-destructive. The description adds useful behavioral context by specifying what the lookup returns: canonical constructs, canonical relations with predicates, descendant per-study models, and foundational citations. This goes beyond annotation coverage without contradicting it.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.