get_mainline_day_of_week_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 for behavioral disclosure. It does mention the update frequency (갱신: 매월 1일, M-2), which is a useful behavioral trait. However, it does not explicitly state that the operation is read-only, does not describe any side effects, authentication needs, or response behavior. For a statistics retrieval tool, the lack of a read-only hint is a gap, though the 'get' prefix and the content type imply a safe query. The update info adds value beyond the schema, but more context would elevate it.

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 two short sentences: the first states the core purpose and update cadence, the second maps the two parameters. It is front-loaded with the main purpose, with zero filler. Every part 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?

Given the presence of an output schema (so return values are documented separately), the description covers the essential elements: what the tool does, when the data is refreshed, and what the two parameters mean. It does not explicitly state that parameters are optional (though the schema shows defaults), nor does it give guidance on required vs. optional usage, but the schema handles that. The description is sufficient for an agent to call it correctly, though a brief usage example or clarification of required inputs would improve it.

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%, so the description must explain parameters, and it does: 'run_ym=운행연월(YYYYMM)' provides the meaning and format, while 'rte_nm=노선명' gives the field meaning. This adds clear semantic value beyond the bare schema entries, enabling the agent to construct correct queries. Both parameters are covered concisely.

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 explicitly states the tool provides '간선열차 요일별 이용인원 통계' (mainline train day-of-week usage statistics), which is a specific verb+resource. It clearly distinguishes itself from sibling tools like get_mainline_station_per (station-based stats) and get_mainline_route_per (route-based stats) by focusing on the day-of-week breakdown. The update cadence is also mentioned, adding specificity.

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 does not explicitly name alternatives or state 'use when', but the tool name and description make its purpose unmistakable, and the sibling context (multiple get_mainline_* statistics tools) implies it is the right choice for day-of-week usage data. The relative clarity of the purpose is sufficient for an agent to infer usage, though it could be more explicit about not using it for station/route-level stats.

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