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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is fully covered. The description adds the data source (ITBI), the 12-month lookback, the fixed universe of 96 districts, and the available sort orders — useful operational context. It says nothing about the shape of the returned ranking or how ties/sparse districts are handled, so it does not go far beyond the 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?

Two sentences, no filler: the first front-loads scope, metric, and source, the second front-loads usage triggers. Nothing redundant against the title or schema.

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 ranking with full schema coverage, no output schema, and no required parameters, the definition supplies enough: data source, timeframe, geography, and ordering options. The only real gap is what the response contains (fields per ranked district, whether prices are medians or means), which an agent would need to frame results.

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% and three parameters are enums, so the enumerations of 'mais caros, mais baratos, maior alta ou queda, por zona e tipo' largely restate what the schema already declares. Baseline 3 applies; the description adds no default behavior, unit, or interaction detail 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 names a specific resource and metric: a ranking of the 96 districts of São Paulo by m² paid over a 12-month ITBI window, with the four possible orderings. It implicitly separates itself from per-neighborhood siblings such as vendas_bairro or resumo_bairro by being cross-district, though it never names those siblings explicitly.

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 closing sentence gives concrete trigger phrases ('bairros mais caros', 'mais barato da zona leste'), which is clear when-to-use guidance. It does not state when NOT to use it or point to a sibling for single-neighborhood or per-property questions.

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