get_subway_arrivals

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

No annotations are provided, so the description carries the full burden. It states the scope (two lines at Suwon Station), which is adequate for a simple retrieval tool. However, it does not disclose additional behavioral details like data freshness, update frequency, or any constraints, though the presence of an output schema may partially compensate.

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, clear sentence that conveys the purpose efficiently. It is front-loaded with the essential information. However, it could be slightly more structured by separating the station and line scopes.

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?

The description claims it provides information for 'Suwon Station' (수원역), but the input schema allows the station parameter to be changed to any station name. This creates a mismatch between description and schema, making the description incomplete regarding the tool's actual flexibility. Additionally, no guidance on line-specific usage is given.

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 100%, with the parameter 'station' already described in the schema (name and default value). The description adds no extra semantic information about the parameter, so baseline 3 is appropriate.

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 that the tool provides real-time subway arrival information for Line 1 and Suin-Bundang Line at Suwon Station. The verb 'provides' and the specific resource (arrival info for two lines) are clearly identified. However, it does not explicitly distinguish from the sibling tool 'get_line_arrivals', which may focus on a single line.

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?

There is no guidance on when to use this tool versus alternatives, such as the sibling tool 'get_line_arrivals'. No when-to-use or when-not-to-use information is provided, and no prerequisites or context are mentioned.

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