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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is fully covered. The description adds useful content context (verification date and source per entry, vehicle classes) but says nothing about pagination, rate limits, or response structure beyond what the output schema likely provides.

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, front-loaded with the resource and its contents, then usage. The long content enumeration is dense but each item adds informational value; no filler sentences.

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?

Output schema exists so return-value explanation is unnecessary, and annotations cover safety. The description sufficiently conveys scope and content for a two-parameter read tool; only the relationship to the route-toll sibling is left implicit.

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%, so both country_code and locale are already well documented in the schema. The description implies country scoping and the vehicle-class dimension but adds no syntax or format detail beyond the schema, so the 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?

States a specific resource (toll reference for one country) and enumerates concrete contents: payment system, per-km rates by vehicle class, vignette prices, concession sections, toll bridges/tunnels. It does not name or distinguish itself from the sibling estimate_route_tolls, which covers a closely related route-based use case.

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 second sentence gives clear context: use it for toll roads, motorway fees, and whether/at what cost a vignette is needed in one country. However, it never names the obvious alternative (estimate_route_tolls) or states when a per-route estimate is preferable, so there are no explicit exclusions.

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