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

Annotations already mark it read-only, idempotent, and non-destructive, and the description adds valuable behavior beyond that: nothing is sent, it is a paid model call, it is limited to 20 per hour, and it shares the billing gate with applying. This meaningfully informs an agent's cost and side-effect expectations.

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 compact and front-loaded with the triggering use cases, then the output composition, then key constraints. Every sentence earns its place and there is no redundant restating of the title or schema.

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 description is complete: it explains what the tool does, what the generated result contains, that it is preview-only, and the cost/rate-limit behavior. An agent has enough to select and invoke it correctly.

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 covers job_id 100%, including its source, so the description does not need to add much. It reinforces that the parameter selects the one vacancy being tailored, but that is a minor addition rather than essential semantic clarification.

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: 'Rewrite this account's CV for one vacancy' with a clear list of output components. The 'preview only' framing and 'Nothing is sent' distinguish it from sending/apply tools like start_apply_run and get_sent_cv_pdf.

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 names user request phrasings that should trigger this tool: 'tailor my resume for this job' or 'what would you send for this one'. It gives clear context, though it does not explicitly name alternative tools or state when not to use it.

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