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

Annotations already declare readOnly/non-destructive/closed-world, and the description adds real context beyond them: free-vs-paid result scope, Spanish stemming/accent handling, 'Sin clave' (no API key required), and a content constraint (public doctrine only, no personal data). It stops short of error/pagination behavior, so not a 5.

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?

Front-loads the core action, then uses short colon-delimited clauses for tier behavior, constraints, and auth. Dense and mostly waste-free, though the tier split and constraint clauses could be marginally tightened.

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 2-parameter tool with no output schema and covering annotations, it supplies the missing pieces: what each tier returns, that no API key is needed, and what data is excluded. Return shape is described in terms of tier rather than structure, which is adequate but leaves some ambiguity on the paid response.

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 100%, so the baseline is 3, but the description adds meaning beyond the schema: the query is matched with stemming and accent normalization, and the IAE code filter is gated to the paid plan. These details explain how parameters actually behave, which the schema descriptions do not.

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 (Busca) and resource (consultas vinculantes de la DGT) plus the search modality (texto libre en español). Naming the DGT source implicitly distinguishes it from the sibling buscar_doctrina_teac, so an agent can route correctly without opening either 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?

Explains the tiered behavior (free = summary of the most relevant consultation; paid = full list plus IAE filter), which is useful usage context. However, it never states when to prefer this over alternatives such as buscar_doctrina_teac or texto_normativa, so selection guidance is only implied.

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