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

Annotations already cover read-only, idempotent, non-destructive behavior. The description adds a useful non-obvious caveat: in 1992–1997, the UF dimension refers to the establishment/file UF rather than residence, and it points to get_available_years.uf_basis and the notes for further detail. It does not explain ranking order or limit behavior, but the output schema reduces the need for that.

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?

Three sentences with no filler: the first states the action, the second states the output value, and the third delivers an important temporal caveat. Everything is front-loaded and earns its place.

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 read-only tool with 100% schema coverage, two enums, an output schema, and annotations, the description needs little else. It provides a clear purpose, the kind of results it generates, and the key historical data caveat, making it complete enough 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 baseline is 3. The description adds meaning beyond the schema by clarifying that the uf/compare_by semantic changes in 1992–1997, which is not evident from the enum description alone.

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: it 'compara internações entre UFs ou regiões do Brasil' and clarifies that it produces rankings and identifies regional variations. This is enough to distinguish it from siblings like compare_icsap_trends, which focus on ICSAP trends rather than general hospitalization comparisons by geography.

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 intended use is implied: use it when comparing hospitalizations across UFs or regions and when rankings are desired. However, it does not explicitly state when not to use it or name sibling alternatives such as get_hospitalizations or compare_icsap_trends, so some routing decisions are left to inference.

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