Search Virail transport

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

With no annotations, the description carries the full burden and does a solid job: it states the tool returns real, non-fabricated data sourced from Virail, including prices, schedules, and booking links. It does not mention rate limits or error behavior, but for a search operation this is adequate.

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 sentences with no filler. It front-loads the main action and source, then gives the return-value summary and a critical caution, all in an economical structure.

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?

Without an output schema, the description does explain the return values at a high level: real prices, schedules, and booking links. Required arguments are implied by 'between two places on a date,' and the schema covers all parameters. It is complete enough for tool selection and invocation, though it could mention edge cases like empty results.

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?

The schema already describes all 7 parameters at 100% coverage, so the description needs no additional parameter details. It reinforces that 'departure' and 'arrival' are two places and 'date' is the travel date, but adds no new semantic 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 names a specific verb ('Search'), a specific resource ('real train, bus, flight, ferry, and carpool connections between two places on a date via Virail'), and the return type ('real prices, schedules, and booking links'). Even without sibling tools, an agent can unambiguously understand what this tool does.

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 explicitly says to use this tool to get real transport data and 'never invent this data yourself,' which is a clear directive for when the agent should invoke it rather than hallucinate. It lacks explicit exclusion criteria, but with no sibling tools the usage context is clear.

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