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

Annotations already declare readOnlyHint, destructiveHint=false, and openWorldHint=false. The description adds meaningful context beyond that: no API key is required, and AI-enriched fields (ai_summary, fiscal_signals) need a paid plan. This goes beyond the safety profile and is useful for an agent deciding on auth or feature availability.

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 returned fields and then adds two short, high-value sentences about access and pricing. Slightly dense in the first sentence but no wasted words; appropriately sized for a simple lookup.

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 simple read-only lookup with no output schema, the description usefully enumerates return fields and clarifies access/pricing. Missing details on code format and error behavior are minor gaps, but the definition is nearly complete for its complexity.

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 0%, so the description must compensate. It only says 'un código CNAE 2025', which identifies the code family but does not describe the expected format, punctuation, or provide examples. The schema pattern hints at digits and dots, but the description adds little semantic meaning beyond the type name.

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 the resource clearly: a record for a CNAE 2025 code, listing the fields returned and distinguishing it from the 2009 sibling via 'CNAE 2025'. The verb is implied ('Ficha de') rather than explicit, but an agent can tell what it retrieves and how it differs from detalle_cnae_2009.

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?

No explicit guidance on when to use this versus buscar_codigo, detalle_cnae_2009, or other siblings. It mentions access conditions ('Sin clave') and paid AI features, but these are behavioral notes, not usage instructions.

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