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

No annotations, so the description must carry the full burden. It usefully discloses that no booking occurs and that there is a micro-payment ($0.01 USDC) tied to a verified link — real behavioral context. However it omits what 'verified' means, who verifies, or what the returned link is.

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, front-loaded with the core action. Efficient but the pricing clause is cryptic out of context and the whole thing reads like a pricing note rather than a tool contract.

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?

A 3-param, 0%-coverage tool with no annotations and no output schema requires far more explanation. Neither the parameters, the return value, nor the 'verified' mechanism is explained.

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 coverage is 0% with 3 undocumented parameters (ccaa, municipio, station_id). The description gives no hint about these fields, their format, or whether station_id is required instead of location. Complete failure to compensate for the schema gap.

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 says 'Enlace de cita del operador' (operator's appointment link) which suggests returning a booking deep-link, but 'cita_itv' plus the fields ccaa/municipio/station_id suggest an appointment booking tool. The negation 'nunca reserva una cita' clarifies it does NOT book, leaving a muddled picture of what it actually returns.

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 precondition 'sólo cuando verificado' implies use only after verification, and the pricing sentence implies a gating condition (verified link = $0.01). But it never names a sibling alternative or a clearer when-to-use vs. buscar_estaciones / tarifa_itv.

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