get_license_plate_countryHow a country's license plate looks and reads (standard, size, format) and every region code on its plates, grouped by region — e.g. which region is 77 or 199 on Russian plates.
| Name | Required | Description | Default |
|---|---|---|---|
| locale | No | Language of country and region names. Default en. | |
| country | Yes | ISO 3166-1 alpha-2 country code, e.g. RU. |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is fully covered. The description adds the grouping-by-region output shape, but nothing about data coverage, lookup failures for unknown countries, or localization behavior beyond what the schema enum already shows.
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?
A single front-loaded sentence that leads with the primary payload (how the plate looks/reads) before the secondary region-code detail. Slightly dense with parentheticals, but every clause carries content.
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?
No output schema exists, so the description must convey the return shape and it does — plate format characteristics plus region codes grouped by region. For a two-parameter read-only lookup this is nearly sufficient; only error/coverage behavior for unsupported countries is unstated.
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%, with country (ISO 3166-1 alpha-2) and locale fully documented in the schema, so the baseline is 3. The description reinforces that region codes are country-specific but adds no format or default guidance 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?
States a specific resource (license plate format/region codes for a country) with concrete returnable content: standard, size, format, and region codes grouped by region. The Russian-plate example (77, 199) pins down exactly what 'region code' means, and it is clearly distinct from get_license_plate_image and list_license_plate_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?
Usage is only implied — an agent can infer this is a reference lookup for a known country, but there is no explicit 'use this when...' and no routing guidance against siblings like list_license_plate_countries or get_license_plate_image. Nothing is misleading, but nothing steers selection either.
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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