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

Annotations already indicate idempotent, destructive, and open-world behavior. The description adds 'bounded', 'may be refused', and 'may lose a race with terminal completion', providing extra context on failure modes and semantics beyond the annotations.

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 with zero waste. The action is front-loaded, and each clause adds relevant behavioral detail.

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?

The description covers idempotency, refusal, and race conditions, which are key behaviors for a cancellation tool. An output schema exists (though not shown here), so not explaining the return format is acceptable. Lacks explicit guidance on interpreting results, but that likely resides in the output schema.

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?

Single parameter invocation_id is self-evident from the tool name and description. Although schema coverage is 0%, the description implies the target invocation, which compensates for the lack of schema descriptions.

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 states a specific verb ('cancel') and resource ('one invocation'), and the scope is clear. It is immediately distinguishable from sibling tools that get, prepare, or search invocations.

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?

No explicit when-to-use or alternatives are given, but the note about idempotency and possible refusal implicitly informs retry behavior. It does not guide on when to use this versus checking status first.

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