cancel_transfer

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

Annotations already declare destructiveHint=false and idempotentHint=true; the description earns credit by adding the non-obvious behavioral detail that the partial file and checkpoint survive the cancel. What it still omits is whether the cancelled job can be resumed and whether cancel is reversible, which matters for a non-destructive-but-terminal action.

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?

One sentence, front-loaded with the action and immediately followed by the constraint that distinguishes it. Nothing is padded or repeated from the schema.

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 action tool with full annotations and an output schema, the definition covers the essential behavioral question (what is preserved). The remaining gap is the relationship to pause/resume, which an agent needs in order to pick the right tool.

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 0% and the single job_id parameter carries no description anywhere, so the description should compensate but does not explain what a job_id is or where to obtain it. The phrase 'this session's transfer' weakly implies the job is session-scoped, which is the only added semantic signal.

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?

Names a specific verb ('Stop') and resource ('this session's transfer') and immediately scopes the side effect ('without deleting its partial file or checkpoint'). It does not, however, distinguish itself from the sibling pause_transfer, which is the closest source of confusion for an agent choosing between the two.

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?

Usage is only implied: an agent can infer this is the 'give up on the transfer' action because of the preserved-checkpoint clause, but the description never states when to cancel versus when to pause, nor whether a cancelled transfer can be restarted later. No explicit alternative is named despite pause_transfer and resume_transfer being siblings.

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