compras_pncp_ata_arquivos

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

The annotations already cover read-only and idempotent behavior. The description adds useful behavioral details beyond that: cache for 15 minutes, no key needed, files can be downloaded via a simple GET on the returned `url`, and additivos appear as additional documents. This is good transparency, though not exhaustive about response shape.

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 compact and well-structured: purpose, endpoint, special handling of additivos, download method, and cache. It is front-loaded with the main action and avoids unnecessary detail, making it easy for an agent to parse quickly.

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 that an output schema exists, the description does not need to enumerate return fields. It provides the operational context needed to use the tool correctly: it lists ata files including additivos, explains how to distinguish them, shows how to download, and mentions caching. This is sufficient for the intended use.

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 input schema already has 100% field coverage with meaningful descriptions, including the relationship between `sequencial_ata` and `numeroControlePncpAta`. The tool description itself does not add substantial parameter-level semantics beyond showing the endpoint path and stating that no key is required, so it stays at the baseline for complete schemas.

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 the action ('Lista os ARQUIVOS...'), the resource ('uma Ata de Registro de Preços no PNCP'), and includes the exact endpoint path. It also distinguishes the content by noting it covers both the ata and its additivos, so an agent can tell it apart from other file-listing tools.

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?

The description gives clear context for when the tool is appropriate: when one needs the files of an ARP ata, with no authentication key required. It also provides guidance on how to interpret additivos in the response (differentiate by `titulo` and `dataPublicacaoPncp`). It does not explicitly name alternative tools, so it stops short of a 5.

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