Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description's one added behavioral fact is that the SHA-256 is intended for a later checked edit, which hints at optimistic-concurrency semantics. It says nothing about truncation, pagination, or what happens at file boundaries.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.