get_mainline_station_per

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. The freshness note '갱신: 매일 D-2~D-1' (updated daily, 2 days delayed) does add genuinely useful latency context. However, nothing is disclosed about the return format, whether opr_ymd and opr_ymd_gte/lte conflict, or how results behave with all parameters empty.

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?

One compact Korean sentence front-loads the purpose, appends the freshness caveat, and enumerates all four parameters with their formats. Zero wasted words; every clause earns its place.

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?

An output schema exists, so return values need not be documented. All parameters are covered in the description. The gap is operational ambiguity: all 4 parameters are optional, and the description never clarifies that a date filter is expected or that opr_ymd excludes opr_ymd_gte/lte — leaving an agent unsure what an unconstrained call returns. Moderate incompleteness for a multi-parameter tool.

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?

With 0% schema description coverage, the description must compensate, and it does: each parameter is mapped to meaning and format (opr_ymd=YYYYMMDD specific date, opr_ymd_gte/lte=period, stn_nm=station name). This adds real value beyond the bare schema. It stops short of clarifying that opr_ymd and the range parameters are alternatives rather than complements, holding it below 5.

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?

Description states '간선열차 역별 승하차 통계' (mainline train station boarding/alighting statistics), identifying the resource (mainline trains) and granularity (station-level) with enough specificity to be distinguished from siblings like get_wide_rail_station_per and get_mainline_route_per. It stops short of naming these alternatives, so a 4 rather than 5.

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?

No guidance on when to use this tool versus alternatives. The agent must infer mainline-vs-wide-rail and station-vs-route distinctions from the name alone. No exclusions, no preconditions, and no mention of when NOT to use it are provided.

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