CPFHub.io

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 adds important context about authentication requirements ('Requer autenticação via API key'), which is valuable behavioral information. However, it doesn't describe what happens when authentication fails, rate limits, or other behavioral traits like response format or error conditions.

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 appropriately concise with two sentences that each serve a clear purpose: the first states what the tool does, the second states authentication requirements. It's front-loaded with the core functionality. There's minimal waste, though it could potentially be structured slightly better.

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 the tool has no annotations, no output schema, and a simple single parameter, the description provides adequate basic information about what the tool does and authentication requirements. However, for a tool that presumably returns structured quota information, the description doesn't explain what specific information is returned or the format, leaving some gaps in completeness.

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 description coverage is 100%, so the schema already documents the single parameter 'api_key' with its description. The description doesn't add any additional meaning about parameters beyond what's in the schema. The baseline of 3 is appropriate when the schema does the heavy lifting.

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 tool's purpose: 'Retorna informações sobre o saldo de créditos e plano do usuário' (Returns information about credit balance and user plan). It specifies the verb (returns) and resource (credit balance and user plan information), but doesn't differentiate from the sibling tool 'lookup_cpf' which presumably serves a different purpose.

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 provides some usage context by stating 'Requer autenticação via API key' (Requires authentication via API key), which implies when authentication is needed. However, it doesn't explicitly state when to use this tool versus the sibling 'lookup_cpf' or provide any exclusion criteria or alternative tools.

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

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It adds value by specifying authentication requirements ('Requer autenticação via API key') and the return data format ('Retorna nome, data de nascimento e gênero'). However, it lacks details on rate limits, error handling, data freshness, or any destructive effects (though this is a lookup tool, so likely read-only). The description doesn't contradict annotations, as none exist.

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 appropriately sized and front-loaded: it starts with the core purpose, then lists return values, and ends with authentication requirements. Every sentence earns its place—no wasted words or redundancy. It's concise yet informative, fitting the tool's complexity.

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 the tool's moderate complexity (2 parameters, no output schema, no annotations), the description is somewhat complete but has gaps. It covers purpose, return data, and authentication, but lacks details on error cases, rate limits, or how it relates to the sibling tool. Without annotations or output schema, more behavioral context would improve completeness, but it's minimally adequate.

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 description coverage is 100%, with both parameters ('cpf' and 'api_key') well-documented in the schema. The description doesn't add any parameter-specific information beyond what the schema provides (e.g., no extra details on CPF format or API key usage). With high schema coverage, the baseline score is 3, as the description doesn't compensate but also doesn't detract.

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 tool's purpose: 'Consulta informações de um CPF brasileiro' (consult information about a Brazilian CPF). It specifies the verb (consulta/consult) and resource (CPF), and lists the returned data (nome, data de nascimento e gênero). However, it doesn't explicitly differentiate from the sibling tool 'get_quota_info', which appears unrelated but could be a complementary tool for checking usage limits.

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 usage context by stating 'Requer autenticação via API key' (requires authentication via API key), which suggests this tool should be used when authentication is available. However, it doesn't provide explicit guidance on when to use this tool versus alternatives (e.g., no mention of 'get_quota_info' or other potential tools), nor does it specify any exclusions or prerequisites beyond authentication.

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