Check tax number

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

The description adds specifics beyond the annotations by identifying the source as the 'public registry' and clarifying that the tool returns company data. Since there is no output schema, this return-value signal is valuable. The description is consistent with the readOnly, openWorld, and idempotent hints.

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 short sentences, no filler. The core lookup behavior and the practical use case are both front-loaded, and every sentence earns its place.

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 one-parameter read-only lookup with rich annotations and full schema coverage, the description covers the behavior, the result, and the intended use case. Nothing essential is missing for an agent to select and invoke this tool 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 already fully documents the single parameter with format examples, so schema coverage is 100%. The description does not add new parameter-level details, but it reinforces that the tax number is the subject of validation. This meets the baseline without exceeding it.

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 action ('Looks up'), the resource ('Hungarian tax number in the public registry'), and the result ('returns the company data behind it'). It is easily distinguished from sibling tools like billingo_list_partners or billingo_get_organization because the lookup is tax-number-driven, not a list or organization-level operation.

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 gives explicit guidance: 'Use this to validate a tax number before creating a partner.' This tells the agent exactly when to invoke the tool. It does not enumerate alternatives or exclusions, but the context is clear enough given the sibling set.

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