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

With no annotations, the description carries the full burden and does substantial work: it enumerates the returned fields (status values Vigente/Liquidada/Concurso, officers, branches) and discloses the '10 point per returned record' cost. It omits auth requirements, rate limits, and failure behavior, but the return-content and cost disclosure is well beyond typical.

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 verb, resource, and source before the field enumeration, and the cost note is placed last. The long comma-separated field list is dense but each item is informative; structure is sound though slightly run-on.

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 must describe returns and does so comprehensively (identifiers, status, address, officers, related entries). Combined with cost and source coverage, an agent has enough to call it correctly; only error/edge-case behavior is absent.

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% and there is a single parameter whose description ('NIF/CIF or registry URL. e.g. A15075062') already documents format and example. The description's 'by NIF/CIF or registry link' merely restates the schema, so baseline 3 is appropriate.

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 ('Get one company from the Spain registry') and names the exact data source (Registro Mercantil, Registradores de España). The word 'one' and the single-identifier input clearly distinguish it from the sibling run_es_companies_search, 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?

The description implies usage via the required NIF/CIF or registry-link input (you must already know the identifier), but never states when to prefer this over run_es_companies_search or how to obtain an identifier. Usage context is inferable but not explicit.

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