Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden of behavioral disclosure. It only says 'Undo last mutation,' which reveals the action but not its effects, reversibility, what qualifies as a mutation, whether the mutation is global or project-scoped, or whether undoing may itself be destructive.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.