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

Annotations already declare readOnly, idempotent, non-destructive and openWorld, so the safety profile is covered. The description adds non-obvious operating context: the BDNS registry as source, a 2022 floor on data, and a metered cost requiring the Business plan. It doesn't mention pagination or caps on results, which for a list-returning tool would have been useful.

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 payload is front-loaded — data scope first, then outputs, then use case, then cost. Every clause carries information; the only near-redundancy is the trailing English gloss, which is short and aids disambiguation.

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 compensates by enumerating the shape of the response (year summary, instrument summary, top convocatorias, concessions list). Combined with full schema coverage and read-only annotations, an agent has everything needed to call 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 coverage is 100%, so cif, year and limit are already fully documented in the schema. The description's mention of 'resumen por año' hints at the year filter's role but adds no format or behavior detail beyond the schema. Baseline 3 applies when the schema does the heavy lifting.

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?

Names the specific resource (subvenciones, préstamos, garantías, ventajas fiscales), the source (BDNS), the time scope (desde 2022), the addressee (empresa española) and the exact outputs (resumen por año, por instrumento, convocatorias con más importe, lista de concesiones). This clearly separates it from siblings such as get_public_contracts or check_sanctions without ambiguity.

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?

'Úsala para prospección de ayudas o para saber cuánto dinero público recibe' gives concrete use cases, and the 'Plan Business; gasta 1 consulta' note warns about a cost/eligibility constraint up front. It stops short of naming when NOT to use it or pointing to a sibling alternative for adjacent data.

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