Cancel a Clanker's in-flight turn

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

The description adds behavioral details beyond annotations: it explains the return format, the idempotent behavior ('No-op if the session is idle'), and the backend call. Annotations already indicate destructive and idempotent hints, and the description aligns without contradiction.

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 sentences convey all necessary information: the action, return, and edge case. No waste, front-loaded with key details.

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?

Given the simple parameter, full schema coverage, and good annotations, the description is nearly complete. It could possibly mention the source of the run id or prerequisites, but it's adequate for selection and 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 input schema fully describes the single parameter 'id' as 'Run id.' The description does not add any further meaning or usage details beyond what the schema provides, so baseline 3 is appropriate.

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 clearly states the action ('Send ACP session/cancel'), the resource ('Clanker backend'), and the effect ('Returns {id, status}'). The title specifies 'Cancel a Clanker's in-flight turn,' making the tool's purpose distinct from siblings.

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 implicitly tells when to use by stating it cancels an in-flight turn and is a no-op if idle. However, it does not explicitly mention alternatives or when not to use, though the context is clear enough.

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