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

Beyond the annotations (destructive, not read-only, idempotent), the description discloses that cancellation is best-effort, requires continued polling, and may not guarantee a refund. This adds meaningful behavioral context that the structured annotations alone do not convey.

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?

Two concise sentences front-load the action and scope, then add crucial behavioral guidance. Every clause earns its place with no redundant restatement of the tool name or title.

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?

For a single-parameter cancellation tool with a rich output schema and annotations covering mutability and destructiveness, the description provides the essential behavioral expectations: best-effort cancellation, continued polling, and refund caveat. Nothing critical is missing for correct invocation.

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?

The schema has 0% description coverage, so the description must compensate. It does so by clarifying that task_id refers to an 'owned source-video task,' adding ownership and domain context. For a single obvious UUID parameter, this is sufficient semantic grounding.

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?

The description uses a specific verb ('cancel') and clearly identifies the resource ('owned source-video task'), distinguishing it from sibling tools like cancel_animation and cancel_animation_export. The phrase 'source-video task' maps directly to the video-generation domain of generate_video/get_video_generation, so an agent can disambiguate it without opening the schema.

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?

The description gives practical context—'Continue polling' and 'cancellation does not guarantee a refund'—but does not explicitly state when to use this tool versus alternatives such as cancel_animation or get_video_generation. Usage is implied rather than named, so it falls short of a clear routing guideline.

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