list_exchange_rates_for_currencies

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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, informing the agent of the safe read-only nature. The description adds no extra behavioral context beyond the annotations, such as return format or rate limits, which is acceptable given the strong annotation coverage.

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 concise sentence with no wasted words. It is shorter than ideal but still effectively communicates the core purpose without fluff.

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?

With no output schema and minimal description, the agent is left uninformed about the return value structure, whether the result is a list of rates or a single rate, and how the 'date' parameter affects the output. The annotations cover safety but not functional completeness, so the description is inadequate for a tool with two parameters and no output schema.

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%, as both 'date' and 'currency_id' have descriptions in the input schema. The description adds no additional meaning about the parameters, so it does not compensate beyond the schema baseline.

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 'Fetch exchange rates for currencies' clearly states the action and resource. It distinguishes itself from sibling tools like 'list_currencies' and 'get_currency' by focusing on exchange rates, though it doesn't mention the required currency_id parameter.

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?

No guidance is provided on when to use this tool versus alternatives. The description does not mention that it requires a currency_id and optional date, nor does it exclude use cases or suggest sibling tools. This falls short of implied usage context.

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