get_market_clock

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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false. The description adds domain-specific behavior beyond that: it explains the meaning of `current_session`, `sessions`, `next_session`, and that `is_open` only indicates regular market hours. It also discloses the 2026-09-14 aftermarket session addition and the absence of premarket. This is valuable context not present in annotations.

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 a single paragraph that is dense but efficient. The first sentence states the primary purpose and returns. Subsequent sentences add necessary nuance about session semantics and specific dates. No wasted words; every sentence carries important information.

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 zero parameters and the presence of an output schema, the description is complete. It explains what fields are returned (current_session, sessions, next_session, is_open) and clarifies the Korean aftermarket/premarket status, which is essential for correct interpretation. No missing information an agent would need to call this tool correctly.

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 tool has zero parameters, so the baseline is 4. The description does not need to add parameter meaning since there are none. It correctly focuses on explaining what the tool returns rather than parameters.

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 it fetches Korean and US market status, holidays, and recent/next trading days. It names the specific resource (market clock) and the verb '조회' (query). It distinguishes itself from siblings by being the only tool for market session/time information, with no overlap with any other tool.

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 explicitly states when to use: '종목 분석 전 데이터 기준시각을 확인할 때 사용합니다' (use when checking data reference time before stock analysis). It also gives specific contextual details about Korean market sessions and the meaning of fields. It does not mention when not to use, but given its uniqueness among siblings, alternatives are not necessary.

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