Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Goes well beyond the annotations (destructiveHint=true, readOnlyHint=false) by disclosing the three things an agent actually needs: running-task cancellation is a request rather than a guaranteed stop, committed effects and charges are not rolled back, and ownership is enforced. This is exactly the extra context annotations cannot express.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three tight sentences, front-loaded with the core action and its two modes, then the caveats. Nothing is repeated and every clause carries decision-relevant information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values need not be described. Combined with annotations, the description covers the mutation semantics, irreversibility, ownership limits, and no-op case for finished Tasks — nothing an agent needs before invoking is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Only one parameter, and the schema gives no prose for task_id (0% coverage) — just uuid format and pattern. The description never explicitly defines task_id, though its meaning is self-evident from the tool name and the ownership sentence constrains which IDs are valid. Adequate but no added parameter-level detail.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Cancel ... Task') and immediately splits it into the two real behaviors: immediate cancellation of queued work versus a cancellation request for a running Task. No sibling (task_get, task_list, task_list_events) overlaps, so an agent can route to it unambiguously.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives clear use conditions and exclusions: finished Tasks are unaffected, and agents may only cancel Tasks they started. It does not name an alternative tool for other cases, but there is no competing cancel sibling, so the guidance is effectively complete.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.