Latest ECB reference rates

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

No annotations are provided, so the description must carry the behavioral burden. It does: it explains cross rates go through the euro, gives the conversion interpretation, and mentions that returns include the ECB rate date and cache age. This acknowledges a possible cache behavior. It does not disclose permission/limits, but for a read-only reference-data tool this is sufficient.

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?

Two sentences, zero filler, and the core action plus the key interpretation detail are front-loaded. Every sentence is valuable and no redundancy exists.

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 tool with only two optional parameters and no output schema, the description is reasonably complete: it defines what is returned (ECB rate date, cache age) and explains the core rate semantics. The only noticeable gap is not routing the agent between the many sibling rate tools, but that is already captured in the usage dimension.

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 schema already covers both base and quotes at 100% coverage, so the baseline is 3. The description reinforces base semantics and cross-rate behavior but adds little about the quotes parameter beyond what the schema states.

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 is for the latest ECB daily reference rates and even gives a concrete interpretation example (1.0812 for USD = 1 base = 1.0812 USD). It implies 'latest' to distinguish from rate_history/rate_on, but it does not explicitly name sibling alternatives.

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?

'Call this tool for the latest ECB daily reference rates' implies the right context (current/latest data), but the description gives no explicit exclusions or pointers to siblings such as rate_history, fx_rates_for, or rate_on. There is no guidance for when to prefer this over alternatives.

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