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

The description adds meaningful behavioral context beyond the annotations: no credentials needed, prepaid per-query billing, data is public/non-confidential, and the customer is the data controller under LGPD. It also aligns with the readOnlyHint, idempotentHint, and destructiveHint annotations, with no contradiction.

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 reasonably concise, front-loads the core purpose, and includes important operational details (credentials, cost, LGPD) in a compact form. It could be slightly tighter by separating legal disclaimers from the main functionality, but it remains efficient and readable.

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?

For a simple query tool with good annotations, the description covers operational context well (cost, credentials, data nature, legal responsibility), but it omits critical query details: no parameter format guidance, no example values, and no description of the return value since no output schema exists. An agent would likely need additional information to invoke it correctly with real-world inputs.

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 0%, so the description must compensate for the two parameters (codigo_estado, nome_municipio), but it does not explain expected formats (e.g., whether codigo_estado is a UF abbreviation or numeric IBGE code) or how the parameters relate to the returned area. The parameter names are self-explanatory at a basic level, but no value is added beyond the schema.

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 'IBGE: Área territorial brasileira, consulta em fonte oficial', which clearly identifies the tool as querying Brazilian territorial area information from the official IBGE source. It distinguishes itself from the sibling tools (auth, marketplace, report_bug, etc.), though it does not explicitly state that the output is the area value for the given municipality/state.

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 practical usage context: the tool requires no platform credentials, is billed per query with prepaid credit, and queries only public official data. It does not explicitly state when not to use the tool or name alternatives, but the context is clear enough for selecting it over non-query sibling tools.

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