Get exchange rates for a past date. Returns the ECB reference rates that were published on (or nearest before) the given date. Returns: Historical reference rates for the requested date..
| Name | Required | Description | Default |
|---|---|---|---|
| base | No | Base currency as an ISO 4217 code. Defaults to EUR. | |
| date | Yes | Date in YYYY-MM-DD format, e.g. 2024-01-15. | |
| symbols | No | Comma-separated ISO 4217 codes to limit the response to. |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the tool as read-only/non-destructive. The description adds valuable context about returning rates on or nearest before the given date, but omits details on response format or error cases. It does not contradict annotations.
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 short and front-loaded with a clear action, but the final 'Returns:' line is redundant with the preceding sentence and includes a typo, so it doesn't fully earn 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 simple read-only tool, it covers key behavioral details like the 'nearest before' logic and clearly states the return type. However, without an output schema, a bit more detail on the structure of returned rates would be beneficial, though not critical.
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%, so all parameters are already documented. The tool description does not add further meaning to the parameters beyond what the schema provides, warranting the baseline score of 3.
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 tool fetches exchange rates for a past date, specifies ECB reference rates, and highlights the 'nearest before' behavior, distinguishing it from tools like get_latest_rates.
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 context for when to use this tool is clear (for past dates), but it does not explicitly mention alternatives or exclusionary guidance. Still, the purpose is unambiguous enough to imply correct usage.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Each tool serves a distinctly different purpose: listing available currencies, fetching historical rates, and fetching latest rates. No overlap or ambiguity exists between them.
All tools follow the consistent verb_noun pattern 'get_' + resource (currencies, historical_rates, latest_rates). This makes the API predictable and easy to navigate.
With only 3 tools, the server is tightly scoped to its purpose of providing ECB reference rates. Each tool is essential and contributes to a well-rounded API without unnecessary bloat.
The server fully covers the domain of ECB reference rates: you can list supported currencies, retrieve latest rates, and retrieve historical rates. No obvious gaps exist for the stated purpose.