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

Annotations already declare destructiveHint=true and idempotentHint=true, covering safety and idempotency. The description adds the billing implication ('Nothing is charged for an incomplete run'), which is valuable behavioral information beyond annotations. No contradiction detected.

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 no filler. The primary action and condition are front-loaded, and the billing note adds value without redundancy. Every word earns its place.

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, the description covers purpose, usage condition, and a key consequence (billing). With annotations covering destructive and idempotent behavior and an output schema present, nothing essential 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?

Schema description coverage is 100%, and the parameter run_id is well documented in the schema. The tool description does not add additional parameter semantics, but since the schema fully covers it, the baseline of 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 uses a specific verb 'Stop' and resource 'run', and explicitly restricts to queued or in-progress runs. This clearly distinguishes it from sibling tools like start_run, get_run, and list_runs, leaving no ambiguity about its function.

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 states when the tool applies (queued or in-progress runs), which provides clear usage context. It does not explicitly mention alternatives or exclusions, but the scope is obvious given the sibling set. Slight deduction for not naming alternatives, though the condition is clear.

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