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

Annotations already declare readOnlyHint=false and destructiveHint=false, and the description adds the crucial nuance: nothing is sent and nothing is charged, the draft is only actionable after payment on review_url. It also discloses content rules (no legal claims added, never include DNI/NIE/NIF) and the output fields. It does not mention rate limits or what happens to an existing draft with the same content, so it falls just short of the top mark.

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 front-loaded with the trigger condition and approval workflow before the output behavior and exclusions. It is dense but nearly every clause carries operational meaning; the only slight excess is the repetition of the no-payment/no-send message alongside the post-call instruction.

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 non-readonly, nested-object, six-parameter tool with no output schema, the description covers inputs, side-effect limits, the return payload (page count, prices, review_url), and the required follow-up conversation. Nothing an agent needs in order to call it correctly or explain the result 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 the baseline is 3. The description goes beyond it by explaining that the body must be passed exactly as approved with no address blocks, date or signature (those are added automatically), and by warning against ID numbers, which is a real semantic constraint not encoded in the schema.

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 and resource ('renders the exact A4 letter ... as a PDF, stores it as a draft') and names what it returns (page count, per-option price, review_url). It also explicitly names the siblings it is not for ('use quote_burofax' for prices, 'get_burofax_status' for tracking).

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?

It gives explicit preconditions (user has approved the final text and supplied both postal addresses in Spain), the required pre-call step (show the full text and get approval), and the post-call step (show review_url, tell the user nothing goes out until they pay). It also routes to the right sibling for prices and tracking.

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