Estimate fiat received

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

Annotations already declare readOnlyHint and idempotentHint. The description adds that the rate is live and non-locking, and that the final rate depends on a buyer fill – valuable context beyond the annotations. It does not describe return format but provides meaningful behavioral nuance.

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-loaded with purpose, and each sentence adds information. No fluff.

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?

For a simple estimator, the description covers purpose, rate source, and binding limitation. However, without an output schema, it does not describe the exact return structure (e.g., estimated amount, rate), leaving a small gap.

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 good descriptions for amount, currency, and platform. The tool description does not add parameter-specific details beyond mentioning Base USDC and fiat, but that is not necessary given the schema already covers it.

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 'Estimate fiat received for Base USDC at the live Chainlink oracle rate' – a specific verb and resource. It distinguishes from sibling tools like peer_cash_prepare and peer_cash_order by indicating this is an estimate, not a binding operation.

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 clarifies this is 'not a locked quote' and that the 'binding rate resolves when a buyer fills', implying this tool is for pre-transaction estimation. However, it does not explicitly name alternatives or state when not to use it, so it has clear context but no exclusions.

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