Ferry fares

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety and external-data behavior are covered. The description adds useful fare-specific context by specifying NT$ currency and fare granularity by route, ticket, cabin, and passenger type, but it does not discuss missing-route behavior, availability, or response shape beyond pricing dimensions.

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, front-loads the core purpose, and uses the example efficiently to illustrate valid port values. There is no wasted text.

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 schema fully covers the three inputs, and annotations cover read-only/open-world behavior. Because there is no output schema, the description responsibly states the fare unit and breakdown dimensions, though it could be slightly more explicit about what a typical response contains when no fares exist.

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 from, to, and city are already well documented. The description contributes only an example using from="基隆" and to="南竿" and does not add semantics beyond the schema, so the baseline score of 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 resource and result: ferry fares in NT$ between two ports, with fare breakdowns by route, ticket, cabin, and passenger type. It is clear enough to distinguish a fare lookup from ferry timetable, live board, alerts, or positions tools, though it does not explicitly name those siblings.

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?

Usage is implied by the name and description: use this to look up ferry fares once departure and arrival ports are known. There is no explicit when-to-use guidance, no exclusions, and no named alternative such as ferry_timetable for schedules.

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