firestarter_cancel

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

Annotations already signal destructiveHint=true and idempotentHint=false. The description adds meaningful behavioral context by explaining the financial consequences (voiding a hold vs. refunding a capture) and the shipped-order limitation, going beyond what the annotations alone 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?

The description is two tight sentences with no filler. It front-loads the core action and then provides the key exception and alternative, making it easy for an agent to parse quickly.

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 operation is simple with only two parameters and no nested objects, and the description covers the important state-dependent outcomes. No output schema exists, and while a note about the expected response would make it fully complete, an agent can still invoke this tool correctly based on the provided guidance.

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%, so execution_id and reason are already fully documented in the input schema. The description does not add parameter-level detail, which is acceptable given the schema's completeness but does not exceed the baseline.

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 ('Cancel'), the target ('an active execution'), and the precise scope: voiding an uncaptured authorization hold or refunding a captured payment. It also distinguishes itself from firestarter_return, which is appropriate for shipped orders.

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 explicitly names firestarter_return as the alternative when an order has shipped, creating a clear decision boundary. It also describes the two payment states where cancellation applies, giving the agent the context needed to choose this tool versus a sibling.

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