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

Far beyond the readOnlyHint/openWorldHint annotations, it discloses a hard quota (20 calls per client per UTC day, shared across the Colombia tools), what happens at exhaustion (an error naming the paid endpoint), and the exact fallback cost and payment mechanics ($0.003 USDC per successful call over x402 on Base, no account or key). It also attributes the data source, license, and a non-official-service disclaimer, which matters for how an agent should present results.

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 purpose and returned fields, then layers scope, provenance, quota, and fallback in a logical order with no filler. It runs long for a single-parameter tool, but each sentence carries distinct operational value (license terms and pricing are not padding for a paid-fallback API).

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?

There is no output schema, so listing the returned fields inline is essential and done here. Combined with the entity-type restriction, the daily quota shared with sibling tools, and the documented paid fallback, an agent has everything needed to call it, interpret the response, and handle quota errors.

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?

Only one parameter and schema coverage is 100%, with the schema itself supplying the NIT format and examples (900170781 or 900170781-7). The description adds nothing about the nit argument — no accepted variants, normalization, or failure behavior — so the baseline 3 applies.

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 ("Short RUES matrícula status for a Colombian NIT") and enumerates what comes back: estado values such as ACTIVA/CANCELADA, last renewal, vigencia, and an active flag. The word "Short" plus the field list clearly separates it from co_company_lookup's presumably fuller record, so an agent can pick between them without opening a 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?

Gives a firm eligibility rule — legal entities / ESAL only, natural-person data is never returned — which tells the agent when not to call it. It names the sibling co_company_lookup only in the quota-sharing sentence rather than as a routing alternative, so the "use X instead when Y" guidance is implicit rather than explicit.

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