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

Annotations already declare read-only, idempotent, and non-destructive behavior. The description adds substantial extra context: 'Hospedado pela plataforma, sem credenciais da plataforma, pague por consulta com crédito pré-pago' (hosted by platform, no platform credentials, pay per query) and 'não é dado sigiloso' (not confidential data), along with LGPD responsibilities. This goes beyond annotations and clarifies commercial and privacy implications.

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 but contains redundancy, e.g., 'consulta em fonte oficial' and later 'Consulta informação de fontes e órgãos oficiais brasileiros' repeat the same idea. It is front-loaded with the core purpose and then adds payment and compliance details, but could be streamlined without losing meaning.

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 simple two-parameter tool with read-only annotations, the description provides enough context for basic usage, including payment model and data sensitivity. However, it fails to describe parameter semantics (which ID to provide, whether both can be used) and lacks any output expectations, making it incomplete for an agent to invoke reliably without additional inference.

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 defines 'cpf' and 'cnpj' as string parameters with zero schema description coverage. The description does not explain these parameters at all, leaving the agent uncertain about how to populate them or whether one is required. With 0% coverage and no compensatory description, this is a critical gap.

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 function: 'MPT PE: Certidão Negativa de Feitos, consulta em fonte oficial' – it queries official negative certificates from Brazilian sources. This specific verb and resource effectively differentiate it from sibling tools like authenticate or connect, which are generic platform utilities.

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 context about the query being from official sources and paid via prepaid credit, but it does not explicitly state when to use this tool over alternatives or when not to. There is no mention of use cases like checking a specific CPF/CNPJ or exclusions, so guidance is implied rather than explicit.

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