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

With no annotations provided, the description carries the full burden. It conveys that the tool is a read-only listing operation (via 'Lista') and discloses exactly what it returns (sigla UF and full name). While it doesn't discuss rate limits or side effects, for a simple constant-data tool, this is sufficient context.

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 three short sentences, front-loaded with the core action in the first sentence, followed by usage guidance and output details. Every sentence contributes value, with no redundancy or irrelevant information.

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 tool with no parameters and no output schema, the description is fully complete: it states the exact scope (27 states), the output fields (UF and name), and usage criteria. No additional context is needed.

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?

The tool has zero parameters, so the baseline is 4 per the rubric. The description doesn't need to elaborate on parameters, and it doesn't.

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 explicitly states the tool lists all 27 Brazilian states with their UF abbreviations, using a specific verb ('Lista') and resource ('estados brasileiros'). This fully distinguishes it from the sibling tools, which are all holiday- or municipality-related.

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 clearly says when to use the tool ('Use quando precisar consultar as siglas dos estados ou quando o usuário perguntar quais são os estados do Brasil'), which is explicit guidance. However, it does not mention when not to use it or alternatives, though the sibling tools make this obvious.

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