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

With no annotations provided, the description carries the burden and does disclose two important traits: the exact response contents and the payment model ($0.005 USDC per call via x402 on Base), which an agent needs before invoking a paid endpoint. It omits failure behavior (unknown/unsupported currency codes) and latency, keeping it below a 5.

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?

A single dense sentence that front-loads the resource and enumerates returned fields, followed by a separate price sentence. Every clause names a concrete output or the payment requirement; no filler.

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, so the description must characterize returns, and it does so thoroughly (rates, central bank, last change, pp differential, carry side, FX rate with date and source). Only error handling and response shape remain unspecified.

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% and both properties document that base/quote accept ISO 4217 codes or ISO2 country codes. The description adds only the notion of pairing, so the schema does the real work; baseline 3 applies.

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?

States a specific verb+resource: a carry view of one currency pair, enumerating exactly what comes back (policy rates, central bank, last change, differential in pp, carry side, official FX rate with date/source). The 'one currency pair' scope implicitly distinguishes it from carry_ranking, but no sibling is named explicitly.

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 singular 'one currency pair' framing implies this is the per-pair lookup, but the description never states when to use it instead of carry_convert, carry_ranking, or macro_fx. Usage must be inferred from the description rather than read off it.

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