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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint. The description adds concrete details beyond those annotations: 'a live GET against the public IBGE SIDRA/Pesquisas API' and 'Returns a Markdown list.' It could also mention error or rate-limit behavior, but for a read-only list tool the disclosure is solid and non-contradictory.

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 Purpose, Features, Main surveys, Examples, and Routing sections, and the core statement is front-loaded. The main-survey list is slightly extra but informative for an agent unfamiliar with IBGE domains, and overall the text is not bloated.

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 tool is simple: zero required parameters, 100% schema coverage, an output schema, and clear annotations. The description covers what it does, how to invoke it, what it does not do, and its read-only behavior. An agent has everything needed to call it correctly without further 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?

Schema coverage is 100%, so the baseline is 3, but the description adds value by mapping parameters to concrete examples: busca="população" and detalhes="pnad". It also characterizes busca as searching by name/code and detalhes as showing details and tables, going beyond the bare schema descriptions.

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 opens with a specific verb and resource: 'Lists available IBGE surveys and their tables.' The Features list enumerates search, details, and categorization capabilities, and the closing 'This lists surveys, not data' explicitly distinguishes it from data-query siblings. An agent can clearly tell this tool apart from ibge_sidra, ibge_sidra_tabelas, and the wrapper tools.

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 explicitly routes to alternatives: 'To find table codes use ibge_sidra_tabelas; to query data use ibge_sidra (or a wrapper...).' The examples further clarify when to call with no parameters, with busca, and with detalhes. This leaves little ambiguity about when to select this tool versus its siblings.

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