Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It confirms this is a mutation of an existing event but says nothing about permissions, whether the patch is partial or full replacement, whether omitted fields are preserved, or reversibility. Only the minimal 'existing' precondition is conveyed.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.