Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations are absent, so the description carries the full burden, and it credibly communicates the core behavior: a pretty-printed, indented JSON output. It does not cover edge cases like invalid JSON handling, but for a pure formatting tool with an output schema, that is a relatively minor gap.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.