미국 장 운영 정보 조회

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

Annotations already signal read-only, idempotent, and non-destructive behavior. The description adds value by explaining null semantics (null means pre/after market not operating, regular market closed) and detailing the structure of the return object, which is not provided by an output schema.

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 well-structured with a summary line, a clear Args section, and a bulleted Returns list. It is front-loaded with the core purpose and each sentence earns its place without unnecessary verbosity.

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?

Despite having no output schema, the description enumerates all return fields and their null semantics, making the tool's behavior fully transparent. With only one optional parameter and read-only annotations, the description is complete for this tool's complexity.

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 provides 100% coverage for the 'date' parameter, including its format, optionality, and default behavior. The description repeats this information without adding new meaning, so the baseline of 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?

The description uses a specific verb ('조회합니다' - retrieves) and clearly states the resource: US stock market operating hours. It distinguishes from the sibling toss_get_kr_market_calendar by specifying 'US' and enumerates the specific return fields (pre-market, regular market, after-market, business days).

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 provides clear context: it retrieves US market hours for a specific date, defaulting to today if omitted. However, it does not explicitly mention when to choose this tool over alternatives, such as the KR market calendar sibling, so it stops short of a full 5.

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