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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds useful scoping information such as the 2-6 place limit and the 'Cidade/Bairro' formatting rule, but it does not disclose output shape, limitations, or default behavior beyond what the schema already provides.

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 short, information-dense sentences with no filler. The main action and scope come first, and the input format clarification follows immediately. Every sentence 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 simple read-only comparison tool, the description covers what is compared, how many places can be compared, and how to format each place. The schema covers constraints and defaults. It is slightly incomplete because it does not describe the output shape or provide explicit routing to sibling tools, but an agent can still invoke it 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 parameters, enums, and defaults. The description adds concrete format examples ('Joinville' vs 'Jaraguá do Sul/Amizade') and clarifies the comparison criterion, but it does not meaningfully extend parameter semantics beyond the structured 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 uses a concrete verb ('Compara'), specifies the resource (2 a 6 lugares), and defines the comparison metric (preço do m²). It also clarifies the accepted place formats with examples. It does not explicitly distinguish itself from siblings like preco_m2 or ranking_bairros, so it stops short of a perfect score.

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: when the agent needs a side-by-side comparison of multiple cities or neighborhoods by price per square meter. However, there is no explicit 'when not to use' guidance, and no alternative tool is named for single-place price queries or ranking queries.

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