get_exchange_rate

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

No annotations are provided, so the description carries the full behavioral burden. It discloses the key distinction — historical rate when date_time is supplied versus latest when omitted — which is core to correct invocation. It does not disclose failure behavior for unsupported currencies, whether credentials are required, or the rate basis (mid-market vs bid/ask), making coverage adequate but not rich.

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 compact and well-structured: a single-purpose first sentence followed by a clean Args block. Every element earns its place, and the Korean parenthetical is harmless bilingual redundancy rather than filler. The core purpose is front-loaded ahead of parameter details.

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?

Given the low complexity (three optional parameters, simple string/null types) and the presence of an output schema, the description is not responsible for explaining return values. It thoroughly covers parameters and the core latest-versus-historical behavior. The only minor gaps are explicit base/quote direction semantics and any credential requirements.

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 0% and the schema has no enums, yet the description fully documents all three parameters: the allowed KRW/USD values for both currency arguments and the ISO 8601 semantics of date_time. This completely compensates for the schema's lack of descriptions, leaving no parameter ambiguity for the agent.

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 opening line 'Get the exchange rate between two currencies' uses a specific verb and resource, stating exactly what the tool returns. No sibling tool covers currency exchange rates — the closest siblings are stock price and disclosure tools — so the purpose is unambiguous and self-distinguishing.

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 Args block gives clear usage context: passing a date_time retrieves a historical rate while omitting it returns the latest rate, and both currencies are constrained to KRW or USD. This makes the supported scope obvious. However, it names no alternatives or explicit when-not-to-use conditions, so exclusions are absent.

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