frankfurter_currencies

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

No annotations are present, so the description carries the burden. 'List all currencies' implies a complete, read-only reference lookup with no destructive side effects, which is reasonable context. However, it does not disclose the return shape (codes vs. names) or any auth/rate-limit considerations.

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; the resource and its source API are stated immediately. Every word earns its place.

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?

For a zero-parameter, no-output-schema reference tool this is nearly sufficient: it says what is listed and from where. A brief note on the returned identifier format would make it fully complete.

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 tool takes zero parameters, so the baseline is 4 and there is no parameter semantics for the description to explain. Schema coverage is 100% and additionalProperties is false, so nothing is left ambiguous.

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 ('List') and resource ('currencies') and adds the scope that they are supported by the Frankfurter ECB exchange-rate API. This is unambiguous, though it does not explicitly contrast itself with sibling rate tools like frankfurter_latest or frankfurter_convert.

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 gives no guidance on when to use this versus alternatives. Several siblings surface currency lists (forex_currencies, exchangerate_codes, currency_api_list), yet the description provides no condition or exclusion to discriminate them.

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