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

Annotations already cover read-only, idempotent, and non-destructive hints, so the safety bar is lowered. The description adds substantial behavioral context: the exact return envelope { codigoSenador, tipo, count, itens }, item shapes varying by tipo, and the empty-result behavior (count 0 and empty itens). This gives the agent a reliable mental model of edge cases.

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 longer than average, but every sentence earns its place: definition, enum semantics, return shape, empty behavior, required parameter sourcing, sibling differentiation, and an example. The purpose is front-loaded, and the structure is logical. Slightly verbose due to exhaustive enum enumeration, but justified.

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 two required parameters, an output schema, and a complex multi-type behavior, the description covers everything an agent needs: how to obtain the input, what each tipo returns, the response envelope, the empty case, and the alternative tool for other data. There is no missing piece for correct invocation.

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 coverage is 100%, so the baseline is 3. The description goes further by explaining the semantic meaning of each tipo enum value with concrete item fields, and provides a complete example mapping codigoSenador and tipo to a real use case. This adds value beyond the schema's bare 'Qual histórico consultar'.

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 states a specific verb and resource: 'Histórico funcional de um senador conforme o parâmetro tipo'. It enumerates all six possible values with their item shapes, and explicitly differentiates itself from senado_obter_senador for biographical/mandate data. An agent can immediately understand what this tool does and what it is not for.

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 explicit when-to-use guidance: use this for functional history (licenças, comissões, cargos, etc.), and use senado_obter_senador for biographical data and mandates. It also tells the agent how to get the required codigoSenador via senado_listar_senadores. This routes the agent correctly among the many siblings.

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