search_journeys

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

With no annotations, the description carries full burden. It discloses that departureTime defaults to 'now' and suggests a user prompt behavior. However, it omits details like read-only nature, result limits, or authentication requirements.

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 concise sentences without extraneous information. The first sentence states the core purpose, and the second provides actionable usage guidance.

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?

While the description covers the main use case and user interaction, it lacks information about the output format or structure, which is not compensated by an output schema. It also could reference that origin and destination come from search_station (though schema mentions 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 coverage is 100%, so the schema already describes all parameters. The description adds only the behavioral hint about asking for departure time, which provides minimal additional semantic value beyond the schema.

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 the verb 'Search for journeys' and the resource 'between two stations', distinguishing it from sibling tools that handle arrivals, departures, disruptions, or station lookup.

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 provides guidance to ask for a departure time if not specified, which helps the agent interact appropriately. However, it does not explicitly contrast with alternatives like get_arrivals/get_departures for single-station queries.

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