List supported quote currencies

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

Annotations already declare this as a safe read-only operation, so the description's main contribution is specifying that the list is exhaustive ('every currency code') and includes both fiat and crypto categories. This adds behavioral context beyond the annotations without contradicting them.

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 sentence that front-loads the action and includes concrete examples for currency types. Every word contributes necessary information; no filler. It is appropriately sized for the tool's simplicity.

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 zero-parameter list tool with a full output schema and safety annotations, the description covers the essential purpose and scope. It doesn't need to explain return values because the output schema exists. It is fully self-contained for an agent to decide when to call it.

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?

There are zero parameters, and the schema has 100% coverage of that (an empty object). The description doesn't need to explain parameter semantics, and it doesn't provide any misleading information. Baseline for zero params is 4.

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 states a specific action ('List every currency code') and scope ('accepted as a vs_currency by the other tools'), clearly distinguishing it from price or coin-list tools. Examples of fiat and crypto add concrete meaning. It fully addresses what the tool does.

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 phrase 'accepted as a vs_currency by the other tools' provides clear context that this is the reference list for currency validation in sibling tools. While it doesn't explicitly name alternatives or say 'use this before other tools', the intent is unambiguous given no sibling tool covers this function.

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