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

Annotations already declare destructiveHint=true, readOnlyHint=false, and idempotentHint=false, so the safety profile is covered. The description adds genuinely new behavior: queued vs. running job semantics and the caveat that running cancellations depend on underlying tool support. It stops short of saying what state the job ends in or what errors surface for ineligible jobs.

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?

Three short sentences, zero waste, with the primary action and the eligibility constraint front-loaded and the sibling routing last. Every sentence earns its place.

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 destructive-mutation aspect and the workflow alternative are well covered, but there is no output schema and no statement of what a successful cancel returns or how eligibility failures manifest, and the sole required parameter is unaddressed. Adequate but with clear gaps for a destructive operation.

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% and the description never mentions job_id — not its format, not where to obtain it (list_jobs/get_job), and not what an invalid id returns. With one required but fully undocumented parameter, the description should compensate and does not.

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?

States a specific verb and resource ('Cancel an eligible individual job') and scopes it against the workflow-owned variant, naming cancel_workflow_run as the sibling to use instead. An agent can distinguish this from cancel_workflow_run without opening either schema.

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?

Explicitly states when cancellation applies (queued jobs always, running jobs only with underlying tool support) and when to use an alternative ('Cancel workflow-owned jobs through cancel_workflow_run'). This is exactly the routing guidance needed among 35 siblings.

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