fontes_de_dados

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It correctly indicates a read-only listing behavior and mentions the key-requirement aspect, but it does not describe the response format, whether external calls are made, or any other behavioral details. This is adequate but minimal.

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, front-loaded sentence with no filler. Every word adds meaning: the action, the resource, and the distinguishing detail about keys.

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 zero-parameter metadata-listing tool, the description covers the essential purpose and the key-requirement detail. It lacks a more precise statement of output shape, but the tool's low complexity and empty schema make this a minor gap.

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 tool has zero parameters, so there is nothing to document beyond the schema. The description adds useful context about what the returned list contains (data sources and key requirements), earning a score above the no-parameter baseline of 4.

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 uses a specific verb ('Lista') and a clear resource ('as fontes de dados usadas'), and it specifies the key detail that it reports whether each source requires a key. This clearly distinguishes it from the sibling data-retrieval tools, which fetch economic series rather than metadata about data sources.

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 implies the tool is for discovering which data sources are available and their credential requirements, but it does not explicitly state when to use this tool versus the sibling data-getting tools. There is no 'use this before calling get_*' guidance or exclusions.

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