validate_vat

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

With no annotations, the description carries full burden but only discloses cost ('$0.001 USDC via x402'). It does not mention whether the tool makes network calls, returns a boolean, handles errors, or requires special authentication beyond cost.

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?

While extremely short, the description is under-specified. 'Validate vat' is redundant, 'Other Utilities tool' is unhelpful filler, and only the cost sentence contributes any real information. The structure fails to front-load functional details.

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?

The tool has a complex generic schema, no output schema, and no annotations. The description provides zero information about expected input structure, output format, error conditions, or network dependencies, making it impossible for an agent to 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?

The schema only declares a generic 'params' object with no inner properties. The description adds no meaning about what keys or values this object should take (e.g., vat_number, country_code), leaving the agent without any clue how to construct a valid request.

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 'validate vat — Other Utilities tool' merely restates the tool name and adds a generic category, providing no specific verb+resource. It fails to clarify what is validated (e.g., a VAT number format, country-specific registration) and does not distinguish it from siblings like vat_calc or validate_email.

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 offers no guidance on when to use this tool, what scenarios it suits, or how it differs from alternatives. No context about prerequisites, expected inputs, or comparison to related validation tools is present.

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