Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries full burden. It clearly states the core destructive behavior (replacing content), but it does not disclose prerequisites (e.g., the file must already exist and be active), irreversibility beyond the word 'replace', or any side effects. The statement is minimal but accurate.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.