Get exchange rate

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is known. The description adds valuable behavioral context: 'Quotes expire in about five minutes, so do not cache the result.' This goes beyond the annotations and helps the agent avoid stale data.

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 consists of two tight sentences: the first states the core function and default, the second provides the use case and a critical time-sensitivity warning. Every sentence earns its place, with no redundancy or 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?

For a simple read-only tool with only two optional parameters and no output schema, the description fully covers what the tool returns, the default behavior, the intended usage, and a caching caveat. Given the low complexity and strong annotations/schema, nothing essential is missing.

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?

The schema already documents both parameters with descriptions and enums, giving 100% coverage. The description adds meaning by explaining the conversion context (USD positions to KRW), which clarifies how baseCurrency and quoteCurrency relate. This extra context elevates the score above the baseline of 3.

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 verb and resource: 'Returns the Toss Securities FX rate', and further clarifies the default pair USD->KRW. This clearly distinguishes it from sibling tools, as it is the only exchange-rate tool among the listed siblings.

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?

It provides explicit context on when to use this tool: 'Use it to convert USD positions to KRW.' This gives a clear use case. It does not name alternatives, but given the unique purpose among siblings, this is sufficient.

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