comfyui_cancel_job

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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the mutation risk is disclosed. The description adds the scope (running or queued jobs) but does not explain what happens to partial outputs or whether canceling an already-finished job is a no-op. Since annotations provide the core safety profile, the description offers only marginal additional behavioral context, earning a 3.

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, focused sentence with no unnecessary words. It front-loads the action ('Cancel') and immediately specifies the resource and target parameter, making it highly efficient and easy to parse.

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 simple single-parameter tool, the description is largely complete: it states the action, the resource, and the targeting mechanism. With annotations covering destructive behavior and idempotency, and an output schema present, the remaining gaps are minor—missing guidance on alternatives and error handling when the job doesn't exist. Given the tool's simplicity, this is very close to fully sufficient.

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%, so the description must compensate. It clarifies that prompt_id is the identifier of the job to cancel, which adds meaning beyond the schema's bare type declaration. However, it does not explain how to obtain a prompt_id or what formats are valid, leaving some ambiguity for a parameter central to the operation.

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 the specific verb 'Cancel' with the resource 'job' and the targeting mechanism 'by its prompt_id'. This clearly distinguishes the tool from siblings like comfyui_interrupt (which stops the running job) and comfyui_clear_queue (which clears the entire queue), making its unique role obvious.

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 implies usage when you have a prompt_id and want to cancel that specific job, but it does not explicitly state when to prefer this tool over alternatives like comfyui_interrupt or comfyui_clear_queue. No exclusions or alternative recommendations are provided, leaving the guidance at an implied level.

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