Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond the read-only annotations, it discloses important result semantics: only an exact merged commit is published, proposed/reviewed work is never public, rejection feedback may be truncated, and rechecking will not retrieve omitted findings. These are material behavioral constraints an agent would otherwise miss.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.