get_exchange_rates

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

With no annotations provided, the description carries full burden and adds valuable behavioral context beyond what the schema provides. It discloses that rates are published at '16:00 CET each business day' (timing constraint) and mentions the scope ('~40 currencies'), which helps set expectations about availability and freshness. No contradictions exist.

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 well-structured and appropriately sized. It starts with the core purpose, adds important behavioral context, then provides concrete example questions that illustrate usage without wasting words. Every sentence earns its place by adding value.

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 read-only data retrieval tool with no output schema, the description provides good context about data source, timing, and scope. The example questions effectively demonstrate the tool's capabilities. However, without annotations or output schema, it could benefit from mentioning the return format or data structure.

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 the schema already documents all 5 parameters thoroughly. The description doesn't add any parameter-specific semantics beyond what's in the schema descriptions (e.g., it doesn't explain date format nuances or the '+' syntax further). Baseline 3 is appropriate when schema does the heavy lifting.

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's purpose with specific verb ('Get') and resource ('EUR exchange rates from the European Central Bank'), distinguishing it from siblings like convert_currency (which likely performs conversion) and other economic data tools. It specifies the data source (ECB) and type of rates (reference rates for ~40 currencies).

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 provides clear context for when to use this tool through example questions that demonstrate appropriate use cases (e.g., 'What is the current EUR/USD exchange rate?'). However, it doesn't explicitly state when NOT to use it or mention alternatives like convert_currency for actual currency conversion versus just getting rates.

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