Cancel a background Codex job

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

The description goes well beyond the annotations by revealing the exact kill mechanism (SIGTERM, then SIGKILL after a grace period) and the return semantics ('Reports honestly whether this call is what cancelled it'). This is valuable behavioral context that the destructiveHint annotation alone does not provide, and nothing contradicts the 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 convey purpose, mechanism, and outcome without waste. The core action is front-loaded, and each sentence earns its place by adding essential operational detail.

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 with no output schema, this description is complete: it explains what is cancelled, how (signal sequence), when the tool is appropriate, and what result to expect. An agent has enough context to call it correctly and interpret the outcome.

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%: the job_id parameter already has a full description including signal behavior. The tool description repeats this rather than adding new parameter-level meaning, so the baseline of 3 is appropriate.

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 an unambiguous action ('Stop a run that is still going') with a specific resource and even details the shutdown sequence (SIGTERM then SIGKILL). It clearly differentiates from siblings like codex_job_status and codex_job_logs by focusing on cancellation rather than inspection.

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 phrase 'Stop a run that is still going' conveys the primary use case: cancel an active background job. It does not explicitly name alternatives or say when not to use it, but the context is clear enough for an agent to route to this tool instead of job_status or job_logs.

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