População do Brasil em tempo real

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

Annotations already declare readOnlyHint/idempotentHint/destructiveHint false; the description adds live GET API behavior and return format (Markdown plus typed structuredContent), and reinforces idempotency. 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?

Description is compact and organized with bullets for outputs and exclusions. Every section adds value; no redundant or promotional language.

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?

With one optional enum parameter, rich annotations, output schema, and the description covering source, scope, alternatives, and return behavior, nothing essential is missing.

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% and the single localidade parameter is fully documented with an enum and default. Description doesn't add new parameter-level semantics beyond contextualizing national-only scope, so baseline 3 is appropriate.

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?

Description opens with a specific verb+resource: 'Returns real-time Brazilian population projection' and enumerates exact outputs (population estimate, birth/death rates, daily increment). It explicitly differentiates from siblings by stating it ONLY returns Brazil's national projection and naming alternatives.

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?

Provides explicit 'Use a different tool when' guidance with five named sibling tools and their specific use cases. This satisfies both when-to-use and when-not-to-use.

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