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

Annotations already declare destructiveHint=true and idempotentHint=true. The description adds meaningful context beyond annotations: it explains the idempotent behavior with already_absent for never-existing or already-cancelled ids, the job_already_terminal refusal for completed/failed jobs, and that it returns the updated job record. This provides actionable behavioral details.

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 two sentences with no redundancy. The main action is stated first, followed by critical edge-case behavior. It is efficiently structured and every sentence contributes essential information.

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?

With a single parameter, no output schema, and clear annotations, the description covers all necessary information: the action, the applicable job states, idempotency details, error conditions, and the return value (updated job record with terminal status). Nothing essential is missing.

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?

The input schema has 100% coverage for job_id with a description ('UUID of the async job'). The tool description does not add any additional parameter semantics beyond that. Since schema coverage is complete, the baseline of 3 applies.

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 verb ('Cancel') and a specific resource ('queued or running async simulation job by id'). It clearly differentiates from list_jobs by specifying the scope. An agent can unambiguously understand what this tool does.

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 explicitly says 'Use this for queued or running jobs; list_jobs shows their states,' providing clear when-to-use guidance. It also implies when not to use it by mentioning that completed or failed jobs are refused. However, it does not explicitly mention alternative cancellation tools like cancel_agent_run, though those target a different resource type.

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