Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the full burden of behavioral disclosure. It states that the tool marks tasks as completed or not completed, which is a mutation, but it does not specify permissions, side effects, behavior on non-existent tasks, or what happens if the 'done' parameter is omitted. For a mutation tool, this is insufficient transparency.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.