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

Annotations already indicate readOnlyHint and idempotentHint, but the description adds valuable behavioral context: no platform credentials are needed, payment per query is required, data is public (not confidential), and the client is the data controller under LGPD. These details go beyond annotations and clarify operational constraints without contradicting them.

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 concise paragraph that front-loads the core purpose in the first sentence. It then adds payment and data nature details. While the LGPD disclaimer and repeated emphasis on data being public add some redundancy, the overall structure is efficient and each sentence contributes useful context.

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 absence of an output schema and 0% parameter descriptions, the description should provide complete guidance on query construction. It covers payment and data nature but omits critical instructions: whether cpf or cnpj is mandatory, how to specify the certificate type, and what the response will contain. This leaves a significant gap for an agent to use the tool correctly.

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, leaving the description responsible for clarifying parameters. However, it only vaguely references 'certidões CNDA' and does not explain the meaning or usage of 'tipo_certidao', 'cpf', or 'cnpj' beyond their names. It fails to compensate for the schema's lack of descriptions, offering no guidance on which identifiers are required or their formats.

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: 'SEFAZ PI Visualizar certidões CNDA: CND, consulta em fonte oficial.' It names the specific action (visualizar/consultar) and resource (certidões CNDA). This distinguishes it from sibling tools (authenticate, connect, marketplace, etc.) which operate on platform-level concerns, making its purpose unambiguous.

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 clear context on usage: the tool is hosted by the platform, requires no platform credentials, and charges per consultation with prepaid credit. It implies usage for querying official Brazilian tax certificates. However, it does not explicitly state when to use this tool over alternatives or mention any exclusions; because siblings are unrelated, this absence is minor but prevents a perfect score.

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