Municípios do Brasil

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, but the description adds valuable behavioral context: it is 'a live GET against the public IBGE Localidades API' and 'Returns a Markdown table.' It also notes the total count (5,570 municipalities), giving the agent a sense of volume and scope. No contradictions with annotations.

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 well-structured with clear sections: features, examples, alternatives, and behavior. It is front-loaded with the main purpose and avoids fluff. Every sentence and bullet adds useful information, making it appropriately sized for the tool's functionality.

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?

The combination of annotations, full schema descriptions, an output schema, and a comprehensive description covers all needed context: what it does, when to use it, how to use it (examples), what it returns, and how it behaves. The 'Use a different tool when' section addresses the broader IBGE tool family, making the description complete for an agent to select and invoke 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?

Schema description coverage is 100%, so the schema already documents all three parameters. The description enriches usage with concrete examples (uf='SP', busca='Campinas', uf='MG', busca='Belo') and highlights the '7-digit IBGE code' output, but adds no new parameter semantics beyond the schema. Baseline 3 applies.

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?

Description opens with a specific verb+resource: 'Lists Brazilian municipalities from IBGE.' It outlines three distinct features (list by state, list all, search by name) and explicitly distinguishes from sibling tools (ibge_geocodigo, ibge_localidade, ibge_vizinhos) in the 'Use a different tool when' section. This leaves no ambiguity about what the tool does.

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?

Explicit 'when vs. alternatives' guidance is provided: 'Use a different tool when: Resolve/decode a code at any level... → ibge_geocodigo; Full details/hierarchy... → ibge_localidade; Neighboring municipalities → ibge_vizinhos.' The features and examples also clarify specific use cases (e.g., uf='SP', busca='Campinas'), covering both when to use and when not to use this tool.

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