validate_tva_fr

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

Annotations already indicate readOnlyHint and idempotentHint. The description adds transparency by detailing the validation formula for numeric keys and the return structure, going beyond what annotations provide without 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?

Two sentences that are perfectly concise: the first defines the function and format, the second covers validation logic and return shape. No redundant 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?

Given the output schema is described in the description, annotations cover safety, and no nested objects, the description is complete for an agent to understand invocation and outcome.

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 description coverage is 100%. The description adds value by providing an example and explaining the format requirement, reinforcing what the schema states.

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 it validates a French TVA intracom number, specifies the required format 'FR' + 2 alphanumeric key + 9-digit SIREN, and lists return fields. It distinctly sets itself apart from sibling tools that validate VAT numbers for other countries.

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 usage for French VAT validation without explicit when-to-use or when-not-to-use guidance. However, given sibling tools are other country VAT validators, the context is clear enough for an agent to select this tool for French numbers.

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