Dutch vehicle lookup — $0.020 per call (x402, USDC on Base). Registration, fuel/EV, APK (roadworthiness) and open recalls (terugroepacties) for a Dutch licence plate (kenteken).
| Name | Required | Description | Default |
|---|---|---|---|
| kenteken | Yes | Dutch licence plate, case/format-insensitive (e.g. 0001TJ). |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries full responsibility. It discloses the per-call fee and enumerates the data categories returned, which gives a clear behavioral picture. It does not discuss rate limits or optional filters, but the scope is well-defined for a simple lookup.
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 that immediately states the tool's purpose and then lists its features and pricing. No waste.
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 single-parameter schema and absence of an output schema, the description provides sufficient context by naming the four result categories and the cost. It doesn't specify the return format, but for this simple lookup that may not be necessary.
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 documents the parameter fully (Dutch licence plate, case-insensitive, with an example), so the description adds little beyond confirming 'kenteken' is the plate. Baseline 3 is appropriate given high schema coverage.
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?
Clearly identifies itself as a Dutch vehicle lookup tool, enumerating specific data categories (registration, fuel/EV, APK, recalls) that distinguish it from sibling tools focused on other Dutch data domains.
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 context of sibling tools makes it clear this is the only vehicle-related tool, so the use case is unambiguous. However, it does not explicitly state when not to use it or mention any alternative; it relies on the tool name and sibling context.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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Each tool targets a distinct data source or function: address lookup, building info, demographics, elevation, school holidays, vehicle lookup, validation, currency conversion, plus meta-tools for catalog and sample responses. There is no meaningful overlap between any pair of tools.
The Dutch-specific tools all follow a consistent 'nl_<subject>' pattern (nl_address, nl_building, etc.), and all names use snake_case. However, three tools (catalog, global_fx, sample) break the prefix pattern, creating a minor inconsistency but remaining clear and readable.
With 11 tools, the server is well-scoped for a Dutch open data API. Each tool covers a distinct data domain, and the count is within the ideal range without feeling excessive or sparse.
The tool surface covers a broad range of Dutch open data lookups, including addresses, buildings, demographics, elevation, holidays, and vehicles, along with validation and a sample mechanism. Minor gaps exist (e.g., no weather or property value data), but the core domain is well represented.