Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The annotations declare readOnlyHint=true, covering safety. The description adds that it returns added, removed, and unchanged lines, which is basic output behavior. It does not disclose any potential limitations (e.g., large input handling, format details) or other behavioral nuances, but given annotations cover the safety profile, a score of 3 is appropriate.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.