cancel_job

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

With no annotations provided, the description carries the full burden. It does disclose a key behavioral trait—that cancellation kills the headless session—but does not elaborate on reversibility, side effects on job output, or whether the cancellation is asynchronous. This is partial disclosure but not comprehensive.

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 sentence with no unnecessary words. The core action ('Cancel a running job') is front-loaded, and the parenthetical adds essential behavioral detail. It is highly concise and well-structured.

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 one-parameter cancellation tool, the description covers the essential action and primary side effect. However, it lacks details about error handling (e.g., what happens if the job is already finished), whether cancellation is synchronous, or any prerequisites. The presence of an output schema reduces the need to describe return values, but overall the description is adequate yet not rich.

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. The only parameter, job_id, is never explained; its meaning is only implied by the tool's purpose. The description does not clarify how to obtain a valid job_id or that it must reference a running job.

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 a specific verb ('Cancel') and a clear resource ('a running job'), and adds the clarifying detail that it 'kills the headless Claude session.' This clearly distinguishes it from related tools like job_status, wait_job, and list_jobs without needing to inspect their schemas.

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 states only what the tool does, not when to use it relative to alternatives. It does not mention conditions for use (e.g., only when a job is running) or contrast with siblings like job_status or wait_job. No guidance on when to avoid this tool is provided.

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