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

Annotations only declare readOnlyHint=true; the description adds material context beyond that, notably the $0.02 USDC per-call x402 pricing model, which is essential for an agent deciding whether to call. It also enumerates the returned field groups, though it says nothing about behavior for an invalid or unknown establishment ID.

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?

A single dense sentence: what the tool returns, the source, the lookup key, then the cost. Nothing is repeated and nothing is wasted.

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 one-parameter lookup with readOnly annotations and no output schema, the description covers purpose, returned content, and cost. The remaining gap is the unwritten prerequisite of resolving the ID through the search sibling and the handling of unknown IDs.

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?

There is a single parameter with 100% schema description coverage ('DENUE establishment ID'), so the schema already does the work. The description repeats 'by establishment ID' without adding format, validation, or sourcing guidance, so it meets but does not exceed the baseline.

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 resource and scope: a single full business record from INEGI's DENUE, keyed by establishment ID, with the field groups it returns. The emphasis on 'one' and 'by establishment ID' implicitly contrasts it with the sibling search and nearby tools, though no sibling is named.

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 only implied: the mention of 'by establishment ID' hints that an ID is required and that lookup follows a search, but the description never says when to use this instead of empresas_buscar or empresas_cerca, nor how the ID is obtained.

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