compras

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

With no annotations, the description carries the full burden of disclosure. It mentions ordering (most recent first) and the default limit, but does not state whether the operation is read-only, if there are side effects, or any authentication/rate-limit requirements. The tool appears to be a query operation, but that is not explicitly stated.

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 description is a single sentence that packs the core action, ordering, and all filter options, front-loading the main purpose. It is dense but not verbose, though the long list of estado values could be clearer with delimiters or bullet formatting.

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?

Given 6 parameters, no schema descriptions, and no annotations, the description covers the essential filter names and some allowed values, plus ordering and default. It does not explain the meaning of 'agente' and 'contem' in detail, nor explicitly confirm read-only behavior, but the existing output schema mitigates return-format gaps. Overall adequate but with notable omissions.

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?

The schema has 0% description coverage, so the description must compensate. It provides explicit allowed values for 'estado', examples for 'rede' (CAIP-2) and 'trilho' (x402/invoice/mpp/ap2), and a range/default for 'limite'. However, 'agente' and 'contem' are only named, with no added semantics beyond their titles, leaving gaps.

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 clearly states it retrieves book purchases, most recent first, and enumerates the available filters. It is specific about the resource (book purchases) and the operation (listing), but it does not explicitly contrast with sibling tools like 'compra' (singular) or 'gasto', leaving some ambiguity about when this tool is the right choice.

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 usage guidance is provided. The description lists filters but does not state when to use this tool versus alternatives, nor any exclusions or conditions. An agent would have to infer usage from the filter names alone.

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