Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden and leaves the key questions unanswered: does the active project switch to the new file or remain on the original, is an existing file at the path overwritten, are parent directories created, and does the project get saved first? For a file-writing mutation these are material gaps.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.