cancel_jobStop a queued or running job to avoid charges; finished jobs remain unaffected.
Stop a queued or running job. A cancelled job is not charged; one that had already finished is left as it is.
| Name | Required | Description | Default |
|---|---|---|---|
| job_id | Yes | The job to stop. |
Changes observed during successful MCP inspections.
v0.2.4Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already carry destructive and idempotent hints; the description adds the financial consequence (not charged) and the exact behavior for already-finished jobs (left as is), which are not present in structured data. No contradiction with annotations.
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, zero filler; the primary action and scope are front-loaded, and the second sentence adds the two behavioral caveats that matter. Every clause 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 destructive tool, the description covers the behavior, the no-charge outcome, and the finished-job edge case, while annotations cover idempotency and destructiveness. It doesn't mention how to obtain a job_id (e.g., from check_job), but that is a minor omission given the schema already names the parameter.
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 coverage is 100% – job_id is already described as 'The job to stop.' The description echoes that semantics but does not add format, source, or validation guidance, so it stays at the baseline for high schema coverage.
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?
States a specific action ('Stop') on a specific resource ('a queued or running job'), and distinguishes itself from siblings like check_job by describing the state targeted and the post-cancellation behavior (not charged, finished jobs unchanged).
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?
Clearly says when the tool applies (queued or running) and when it has no effect (already finished), giving the agent an explicit condition. It does not name the sibling check_job as a status-check alternative, so it falls just short of full alternative routing.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.