get_exchange_rate

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

No annotations are provided, so the description carries the burden. It clearly indicates a read-only operation ('returns'). It does not mention authentication, rate limits, or error handling for unsupported codes, but for a simple query tool this is adequate.

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 a single sentence plus a list of supported codes. No wasted words. Information is front-loaded and easy to parse.

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?

The description explains what the tool does and lists valid inputs. However, it does not specify the return format (e.g., numeric rate, JSON object) or behavior for invalid codes. Given the lack of output schema, slightly more detail would improve completeness.

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 coverage is 100% with a description for the currency parameter. The description adds value by listing all supported currency codes (USD, GBP, JPY, etc.), which goes beyond the schema's example. This helps the agent avoid invalid inputs.

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 returns the current EUR exchange rate for a given currency code. The verb 'returns' and resource 'current EUR exchange rate' are specific. The sibling tools (calculate_mortgage, get_branch_info) are unrelated, so no confusion.

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 implicitly indicates when to use (when needing EUR exchange rates for supported codes) but does not explicitly exclude alternatives. Since siblings are unrelated, explicit guidance is less critical. The list of supported codes provides constraints.

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