Taiwan Railway timetable

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds a genuine behavioral trait: the upstream data horizon of about two months ahead, and the fact that today's results start from now. It does not mention the default result cap or what happens when no trains match.

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?

Three short sentences, front-loaded with the resource and return fields, then the coverage caveat, then a concrete example. Slightly telegraphic ("from now on for today") but no sentence is wasted.

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?

With no output schema, the description usefully enumerates the returned fields and states the data horizon, which is enough for an agent to call it correctly. Remaining gaps are minor: result-count default is only in the schema, and directionality/empty-result behavior is unstated.

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%, so the schema already documents station name/ID formats, date pattern, HH:mm for after, and limit bounds. The description's example (from "臺北", to "花蓮", date "2026-10-23") reinforces format but adds no semantics the schema lacks, and it says nothing about `limit` or the `after` cutoff beyond the default.

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?

States a specific resource and scope: TRA trains between two stations on a given day, plus exactly what each row contains (train type, departure, arrival, travel time). Naming TRA (臺鐵) implicitly separates it from thsr_timetable/thsr_train and the bus/ferry timetable siblings, but it never explicitly contrasts with tra_live_board or tra_train, so sibling disambiguation is left to inference.

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?

"TDX covers about two months ahead" is a real usage constraint and "from now on for today" signals the default behavior for same-day queries. However, no alternative is named — an agent must guess whether live departures belong to tra_live_board or whether a single train's details belong to tra_train.

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