job_cancel

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

No annotations are present, so the description carries the full behavioral burden. It discloses that partial WAV files are discarded, which is a key side effect. However, it does not mention whether cancellation is idempotent, what happens to the job status, or if the operation is synchronous.

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 a single, concise sentence with no filler. The core action and side effect are front-loaded, and every word adds value.

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 tool is simple (one param, no output schema), so the description covers the primary action. However, it omits usage context (how to obtain job_id) and any mention of return behavior or error cases. Given the lack of annotations, this is a moderate 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?

Schema coverage is 0%, so the description must compensate. The only parameter, job_id, is self-explanatory, but the description does not explain its origin or format beyond the schema pattern. It lacks context such as 'the ID returned by render_start' or 'a valid job ID from job_status'.

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 action ('Cancel') and resource ('a render owned by this MCP service'), clearly distinguishing it from sibling tools like render_start (create) and job_status (query). The side-effect note about partial WAV files further clarifies its scope.

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?

No guidance is provided on when to use this tool versus alternatives, or when not to use it. It does not mention that job_id should come from render_start or job_status, nor any prerequisites (e.g., job must be running).

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