Brazilian Area Code (DDD) Lookup

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

Annotations already provide readOnlyHint, idempotentHint, etc. The description adds no additional behavioral context beyond stating the source ('BrasilAPI MIT'). Since annotations cover the safety profile, a score of 3 is appropriate.

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 a single, front-loaded sentence with no wasted words. It efficiently conveys the tool's purpose and input/output mapping.

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 lookup tool with one parameter and an output schema (not shown), the description is sufficiently complete to guide invocation. It covers the essential mapping from DDD to state/cities.

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% with a description for the 'ddd' parameter. The description adds no significant new param semantics, as it only restates '2 digits' and the output direction, which is already implied by the schema example.

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 clearly states the tool's function: 'Look up Brazilian area code (DDD, 2 digits) → state and cities.' It directly specifies the input (2-digit DDD) and output (state and cities), distinguishing it from sibling tools like gov.brasilapi.cep or gov.brasilapi.cnpj.

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 implies when to use (for DDD lookups) and the context is clear from the tool name and title. However, it does not explicitly mention when not to use or provide alternatives, though sibling tools cover other Brazilian data types.

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