Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, description carries burden. It states main behavior (save current file, or to path if unsaved) and implies path is ignored if already saved. However, it does not disclose overwrite behavior, error handling, or other side effects. It's minimal but not contradictory.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.