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

Annotations already declare destructiveHint=true and idempotentHint=true, and the description adds genuinely new behavioral detail: only remaining work is cancelled, already-completed checks retain their normal credit treatment, and submit scope is required. That partiality of the cancellation is a non-obvious trait worth disclosing.

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 short sentences, with the core action front-loaded and the scope requirement plus credit treatment following. Every clause carries information and nothing is padded.

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, no-output-schema tool, the definition covers the action, the auth requirement, and the partial-cancellation semantics. Minor gaps remain around error behavior for already-finished jobs, but nothing essential to correct invocation 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?

Schema description coverage is 100% with a single documented job_id parameter, so the schema already carries the parameter semantics. The description adds nothing about job_id beyond what the schema states, so baseline 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?

States a specific verb and resource ('Cancel the remaining work in a job'), which is clearly distinct from sibling read tools like fairvalid_get_job or fairvalid_get_results. It does not explicitly name a sibling, but the cancellation action is unambiguous on its own.

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 supplies a prerequisite ('Requires submit scope') but gives no explicit when-to-use or when-not-to-use guidance, and does not mention alternatives or what happens if the job is already finished — usage context is only implied.

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