Get FX Rates

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

Annotations already declare readOnlyHint=true, so the description adds limited behavioral context. It notes the tool is 'free' and mentions daily/weekly/monthly granularity, which is useful but not essential beyond 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?

Extremely concise: one sentence plus 'Free tool.' Front-loaded with that helpful note. Every word earns its place with no redundancy.

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?

Given no output schema, the description could explain return format, but for a simple read-only tool it is adequate. It covers key inputs and is sufficient for an agent to understand basic behavior.

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 the description adds minimal value beyond the schema. It highlights 'region_ids' and 'time.granularity' from the filters object, but these are already described in the schema properties.

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 uses specific verb 'queries' and resource 'currency pack', clearly identifying the tool's function. It distinguishes from siblings by focusing on FX rates and mentioning key filters like region_ids and time granularity.

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 indicates when to use (for FX data) and mentions key parameters, but does not explicitly exclude use cases or compare with siblings. The sibling tools (e.g., get_catalog, get_earthquake_events) help differentiate context.

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