cancel_run

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

Annotations already declare idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds genuinely non-obvious semantics: cancellation is cooperative and only takes effect at the next provider call or mutation, meaning the agent should not expect or poll for immediate effect. It still omits what the response looks like or how to confirm the run actually stopped.

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 tightly written sentences with the purpose front-loaded and the behavioral caveat immediately after. Nothing is redundant and nothing extraneous remains.

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 one-parameter, non-destructive cancellation call the definition covers purpose and the key timing behavior. However, with no output schema present, the description says nothing about the return value or how the agent learns whether cancellation was accepted, leaving a modest but real gap.

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?

There is a single parameter (run_id) with 0% schema description coverage, so the description technically has room to compensate. It only indirectly conveys that run_id must reference an active run; no format or sourcing guidance is given, but the parameter is a trivially understood identifier.

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 and resource ('Request cancellation of an active run'), which is unambiguous and clearly distinct from sibling tools like observe_window or list_windows. It does not explicitly name or contrast itself with siblings, but the action is self-evident.

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?

'Active run' implies the prerequisite that the run must still be in progress, but there is no explicit when-to-use/when-not guidance, no mention of alternatives, and no statement of what to do if the run has already completed.

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