Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint/destructiveHint, making the trailing 'Read-only' largely redundant. The valuable addition is the return-content description ('the memory plus the note's title and path'), which is real behavioral disclosure given there is no output schema.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.