fuel_prices

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

The description adds that results are aggregated (average/minimum per type), which is behavioral information beyond the annotations. However, it does not disclose other traits like data freshness, city scope, or limitations. Annotations already indicate read-only, idempotent, and open-world, so the description provides moderate additional context.

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 short sentence that efficiently conveys the core functionality. No wasted words or unnecessary details.

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 and no output schema, the description provides the basic purpose and output (aggregated averages/minimums per fuel type). However, it lacks specifics on fuel types, units (e.g., currency), and the exact structure of the response, which could be needed for 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 schema has 0% description coverage, and the description does not explain the 'slug' parameter beyond implying it identifies a city. The description adds minimal semantic value for the parameter, leaving the agent to infer its meaning.

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 it provides current fuel prices of a city, aggregated as average and minimum per type. It uses a specific verb (provides) and resource (fuel prices), and the domain distinguishes it from other tools, though it does not explicitly differentiate from 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?

There is no guidance on when to use this tool versus alternatives, nor any exclusions or context. The description simply states what it does without any usage context.

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