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

With no annotations, the description carries the behavioral burden and does a good job: it discloses the ranking basis, sorting order, FX-change condition, central-bank-rate-change flag, and the $0.01 USDC x402 payment model on Base. It could still say more about freshness or error behavior, but it provides substantial context beyond the schema.

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 dense but front-loaded, starting with the core ranking purpose before listing outputs and price. Every clause contributes useful information, though the single long sentence could be split for readability.

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?

There is no output schema or annotations, so the description has to explain the return content, and it does: rate differential, FX change, and rate-change flag. It is complete enough for a two-parameter ranking tool, with only minor gaps around exact response shape or pagination 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 description coverage is 100%, so both parameters are already well documented. The description reinforces the funding-currency concept and the sorted-descending ranking behavior, but it does not add parameter-specific semantics beyond what the schema already provides.

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 a specific resource and operation: a carry ranking of about 38 currencies versus a funding currency. It distinguishes itself from a pair-level tool by emphasizing a cross-currency ranking, though it does not explicitly name sibling alternatives such as carry_pair or macro_policy_rates.

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?

Usage is implied by the tool name and the description of the ranking output, but there is no explicit guidance on when to choose this over carry_pair, carry_convert, or macro_policy_rates. The description explains what the tool returns more than when an agent should invoke it.

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