Taiwan Railway fares

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is clear. The description adds valuable behavioral context by specifying that fares are returned per train type and passenger type, along with distance—information not present in annotations. No rate limits or error behavior are described, but that is less critical here.

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, front-loaded sentence with an example, containing no redundant or filler content. 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 tool's simplicity, rich parameter schema, and the absence of an output schema, the description is complete enough: it clarifies the return content (fares per train type/passenger type, distance) and provides a usage example. Nothing essential for correct invocation is missing.

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 both parameters thoroughly. The description provides an example (from '臺北' to '高雄') that illustrates station name usage, but it adds little beyond what the schema already conveys. 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 states a specific verb (fares) and resource (TRA single-journey between two stations), and distinguishes itself from timetable/train siblings by focusing on fares. It also details the output breakdown by train type, passenger type, and distance.

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 context implies usage (when you need TRA fares between two stations), but there is no explicit guidance on when to choose this over alternatives like thsr_fare or tra_timetable. No exclusions or prerequisites are mentioned.

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