forex-rates

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

Discloses source (open.er-api.com, free, no key), update schedule (~00:00 UTC), and supports all ISO 4217 bases. No annotations exist, so description carries full burden—adequately covers behavioral traits.

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 front-load core purpose. Second sentence lists many use cases, making it slightly verbose but still clear and organized.

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?

Covers source, update frequency, and use cases. Without output schema, description could mention return format (e.g., JSON structure), but overall sufficient for 3-param tool.

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%, so baseline is 3. Description adds context about defaults and examples (e.g., 'convert' example) but doesn't significantly extend schema-provided semantics.

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?

Description clearly states it provides real-time fiat exchange rates, defaults to USD, and offers filtered subsets. It distinguishes from siblings like forex-historical by emphasizing real-time and daily updates.

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?

Includes explicit use cases (USD→KRW conversion, cross-border payments, DeFi workflows) and mentions source and update cadence. Lacks explicit when-not-to-use, but context is sufficient given sibling tools.

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