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

Annotations already flag destructive and idempotent, but the description adds substantive context beyond them: the full price returns as store credit immediately, the job closes with closed_reason cancelled_unproved, an artifact (cancel_jws) is produced, and repeats are safe. It also specifies the exact error code for the wrong state. This is a complete behavioral picture of a mutation.

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?

Efficient: the precondition and outcome are front-loaded, and the trailing sentence covers the failure mode. Slightly dense with nested parentheses, but every clause carries information an agent needs.

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 no output schema, the description supplies the full post-call state (refund to store credit, closed reason, signed statement) and the error case (409). Combined with complete parameter docs and annotations, nothing needed to invoke it correctly 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%, so job_id and passport_token are already documented in the schema. The description only implicitly references the job being cancelled and adds no format or sourcing detail beyond the schema, so 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?

States a specific verb (cancel) and resource (a website test/job), plus the exact precondition status (needs_verification). This lets an agent distinguish it from accept_job, dispute_job, or claim_refund without opening any 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 defines the use condition (status needs_verification) and the alternative outcome for any other status (409 job_not_cancellable), which functions as clear when-not guidance. It does not name sibling tools like dispute_job as the alternative path for other statuses, keeping it just short of a 5.

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