Get Supported Currencies

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

The annotations already declare readOnlyHint=true and openWorldHint=true, so the description does not need to restate safety. It adds the return-format detail ('three-letter currency codes') beyond the annotations, but does not discuss ordering, dynamic membership, or the exact response structure. This is adequate for a simple read-only tool, though not rich.

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, front-loaded sentence with no filler. Every word contributes meaning: action, result type, and content. This is appropriately minimal for such a simple tool.

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 parameters, no output schema, and read-only annotations, the description gives enough information to call the tool and consume its result as a list of currency codes. It could have explicitly tied the tool to validating codes before using conversion endpoints, but that is more usage guidance than a gap in the call contract. Overall, the definition is complete enough for the tool's simplicity.

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 input schema has zero properties, so parameter documentation is vacuously complete and there is nothing for the description to clarify. The baseline for a 0-parameter tool is 4. No parameter-related meaning is missing.

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 ('Returns') and resource ('list of three-letter currency codes for the supported currencies'). The description clearly distinguishes this tool from the sibling exchange-rate and conversion tools, which serve different purposes. An agent can tell it apart without needing to inspect schemas.

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 does not explicitly say when to use this tool versus alternatives, nor does it name exclusions or prerequisites. However, the intended usage—enumerating the supported currency codes before using rate/conversion tools—is reasonably implied by the name and the sibling tool list. It falls short of clear, explicit routing guidance.

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