validate_telefone

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

No annotations are provided, so the description carries full burden. It discloses that the tool returns formatted values and types, implying read-only behavior. It could be more explicit about error handling or idempotency, but the given information is largely sufficient for a validation tool.

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 concise, using two sentences that front-load the purpose and then detail the behavior. Every word adds value without redundancy.

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?

Given the tool has a single input parameter and an output schema (not shown), the description covers input expectations, output fields, and accepted formats fully. It is complete for a validation tool.

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 input schema provides only a 'value' string parameter with 0% description coverage. The description compensates by explaining that the value should be a Brazilian phone number, accepted formats, and the output fields, adding significant meaning 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 clearly states the tool validates and formats Brazilian phone numbers, specifying mobile (11 digits) and landline (10 digits) cases, and details accepted formats (with/without +55, any mask). This distinguishes it clearly from sibling tools like validate_cpf or validate_cnpj, which handle different identifiers.

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?

Though the sibling tools are for different validation tasks, implying use for phone numbers, the description does not explicitly state when to use this tool or provide exclusions or alternatives. It lacks guidance on when not to use it or prerequisites.

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