Buy Vignette Pass — European motorway vignettes

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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description goes further by disclosing the actual deliverables — official prices plus a service fee in EUR, non-vignette tolls, and a pre-filled order link — which matters because there is no output schema. It does not discuss coverage limits, whether some countries lack vignettes, or result freshness.

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 densely packed sentence that lists outputs in a logical order, with the core product (vignettes needed) front-loaded ahead of supporting details like prices and the order link. It is long but every clause carries information; only the trailing order-link clause could be trimmed.

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?

Five parameters, no output schema, and no nested objects — the description compensates for the missing output schema by enumerating exactly what comes back (products, prices with service fee, tolls, order link). Combined with full schema coverage and clear annotations, an agent has what it needs to call this correctly, though vehicle-class scope and country coverage limits remain 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% and all five parameters carry their own descriptions (defaults for start/end, enum for lang, city-or-country-code for from/to), so the schema does the heavy lifting. The description only reinforces the from/to semantics with 'between two places' and hints at dates via 'covering the dates in each country', adding no syntax or format detail beyond the schema. Baseline 3 applies.

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 names a specific resource and scope: motorway vignettes required for a passenger-car trip between two European places, plus the ancillary outputs (cheapest product per country, prices in EUR, non-vignette tolls, pre-filled order link). It is a noun-phrase output inventory rather than a verb+resource statement, but an agent understands immediately what it yields and can distinguish it from the static list_cities / list_vignette_countries siblings.

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: 'between two places in Europe' and 'passenger-car trip' scope it, and the presence of 'from'/'to' shows it is route-specific rather than a lookup. There is no explicit when-to-use statement, no exclusion (e.g. no mention that this is car-only vs. other vehicle classes), and no routing to the sibling list tools for exploring supported countries or cities.

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

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

Annotations already declare readOnlyHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is covered. The description adds no further behavior beyond that: it does not describe output format, whether results are static or dynamic, pagination, or the data source, leaving the agent with little beyond the annotations.

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 two short sentences and front-loads the core resource concept. It is efficient, though the second sentence about ISO country codes is ambiguous and could confuse rather than clarify.

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 zero-parameter list tool with no output schema, the description should clearly say what is returned. It implies city names but never states the output shape or scope, and the country-code note is unexplained. The presence of annotations covers safety, but return-value context is still incomplete.

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 tool takes zero parameters, so there is no parameter semantics to document. Per the baseline rule for zero params, a 4 is appropriate; the description does not need to explain inputs, though it could have clarified whether the tool itself accepts filtering arguments.

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?

It identifies the resource as city names and local spellings accepted by get_route_vignettes, which distinguishes it from list_vignette_countries. However, it never states the action (list/return) and the trailing 'ISO country codes are accepted too' muddies whether the tool itself returns country codes or simply notes a sibling's input format.

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 a relationship to get_route_vignettes but gives no explicit when-to-use instruction, no prerequisites, and no guidance on choosing this tool over list_vignette_countries. An agent must infer that it should call list_cities before get_route_vignettes to discover valid arguments.

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

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

Annotations already declare readOnlyHint=true, openWorldHint=true and destructiveHint=false, so the safety profile is covered. The description adds useful return-shape context (countries, products, official price, total in EUR), which matters since there is no output schema, but it says nothing about auth, rate limits, or currency conversion caveats.

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 dense sentence that front-loads the scope and then the payload, with no filler. The parenthetical country list is arguably redundant given the country codes are the literal answer, but it reinforces coverage efficiently.

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 zero-parameter, read-only catalogue listing with no output schema, the description adequately conveys what comes back (all countries, their products, official prices, totals in EUR). Minor gaps around ordering or freshness do not block correct invocation.

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 tool takes zero parameters, so there is nothing for the description to disambiguate. Baseline 4 applies; the mention of EUR pricing is contextual rather than parameter documentation.

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 verb and resource: every country with a car vignette plus all products with official price and total in EUR, and even enumerates the country codes. It is clear what the tool returns, though it does not explicitly differentiate itself from the sibling get_route_vignettes.

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 'Every country ... we cover' phrasing implies a broad enumeration use case (get the full catalogue rather than a route-specific lookup), which implicitly contrasts with get_route_vignettes. However, there is no explicit when-to-use or when-not-to-use guidance and no alternative named.

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