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

No annotations are provided, so the description carries the full burden. It usefully discloses the cost model ('2 point per returned record') and the returned fields, but says nothing about rate limits, auth requirements, or pagination behavior beyond the schema's start_page.

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 sentences, front-loaded with the action and source; the field enumeration is long but informative rather than redundant. No filler.

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 and no annotations, the description compensates by listing returned fields and the per-record cost. It is nearly complete for an agent to call it correctly, missing only rate-limit/permission context.

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 value by stating the keyword can match company name, brand, or NIF, whereas the schema only documents 'Company name'. This extends the searchable semantics beyond the structured field.

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 (Search) and resource (Spain company registry / Registro Mercantil), and enumerates the returned fields, so an agent knows exactly what it retrieves. It does not explicitly distinguish itself from the sibling run_es_companies, but the search vs. single-company distinction is inferable from the name.

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?

Usage is implied by 'search ... by company name, brand or NIF', but there is no explicit when-to-use guidance, no mention of the run_es_companies alternative, and no stated prerequisites. Adequate but leaves routing to inference.

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