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

Annotations already declare readOnly, idempotent, closed-world, non-destructive, so the safety profile is covered. The description adds real context beyond them: the explicit privacy guarantee (no names or e-mail addresses returned) and the fact that results include reporting destinations for forged documents. It does not describe behavior for invalid or malformed codes, which keeps it from a 5.

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?

The core action and accepted inputs are front-loaded, and the privacy and reporting details follow in a logical order. It is a single dense sentence with many clauses, which is efficient but slightly heavy to parse; no sentence 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 read-only lookup with an output schema present, the description covers input formats, verification facets, privacy boundaries, and the reporting pointer. Nothing an agent needs in order to call it correctly is missing.

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% and the single parameter is already documented, so the baseline is 3. The description earns an extra point by adding the 32-character length constraint and restating the two accepted formats in the context of what is being verified.

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?

The description opens with a specific verb+resource ("Checks a document issued on Reciba") and enumerates exactly what is verified: document type, issue date/time, issuer account and e-mail confirmation, counterparty acceptance, and OpenTimestamps status. This is clearly distinguishable from siblings like prepare_document and list_document_types.

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?

It states the two accepted input forms (the 32-character code under the QR code, or the reciba.com.br/d/ link) and gives a concrete usage scenario ("When a document looks forged or misused"). It stops short of explicitly naming when to prefer a sibling tool, but the verification-only scope is unambiguous.

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