Transport companies

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

Annotations already declare readOnly/idempotent/openWorld/non-destructive, so the safety profile is covered. The description adds non-obvious data quirks beyond the annotations: rail operators repeat across several ids with each row listing all of them, and bus ids 276/278/280 are the VIP/Economy/Formal taxi classes. Pagination behavior is left to the schema's limit field.

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?

Front-loads the resource list, then the two usage cases, then the data caveats. Three tight sentences with no filler; every clause carries information an agent needs.

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?

An output schema exists, so return-format explanation is unnecessary. Between the mode enum, the code/id semantics, the rail-duplication caveat, and the taxi-class mapping, an agent has everything needed to call and interpret this tool.

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 3 baseline is met by the schema alone. The description adds meaning the schema does not: concrete id/code examples ('W5', bus id 4) and the bus-id-to-taxi-class mapping, which clarifies what the `mode: bus` results actually contain.

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 verb+resource ('List airlines ... rail operators or bus companies') and enumerates the identifier each entity carries (IATA code for airlines, id for rail/bus). The agent immediately knows this is a reference/lookup table rather than a search tool, distinguishing it from mb_search_flights and mb_search_buses.

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?

Explicitly names two use cases: 'to name a code seen in results (airline 'W5', bus company 4)' and 'to find an airline code for the `airlines` filter of mb_search_flights'. This routes the agent from a raw code back to this tool and from this tool forward to a sibling, with concrete examples.

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