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

No annotations are provided, so the description must carry the full burden. It discloses the use of live rates and the return structure, but it omits behavioral details like error handling, rate limits, or whether the tool is read-only. A 3 is appropriate as it adds some value but lacks depth.

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 extremely concise: two sentences with no wasted words. The purpose is stated first, followed by the return format. It is well-structured and easy to parse.

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 tool's simplicity and lack of output schema, the description covers the core functionality and return structure. However, it lacks details on parameter formats, error conditions, and supported currencies. With no schema descriptions, the tool description is incomplete for an agent to use confidently without additional context.

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 0%, yet the description does not explain the parameters at all. It offers no guidance on how to format currencies (e.g., ISO codes), what units 'amount' uses, or any constraints. The description adds no meaning beyond the parameter names in 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?

The description clearly states the action ('convert'), the resource ('travel budget between currencies'), and the data source ('live Frankfurter rates'). It distinguishes the tool from its siblings (get_country_info, get_weather, health_check) which are unrelated to currency conversion.

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 usage for currency conversion, but it provides no explicit guidance on when to use it versus alternatives, nor does it state limitations (e.g., supported currency codes, rate update frequency). The lack of exclusions or context makes it minimally adequate.

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