search_trains

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

No annotations are provided, so the description carries full burden. It describes input parameters and output (formatted string with times/durations), but lacks details on side effects, authentication (api_key optional but not explained), rate limits, or error handling.

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 well-structured with 'Args' and 'Returns' sections, each parameter is clearly described, and the entire text is concise without unnecessary details.

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 6 parameters (2 required) and no annotations, the description covers all parameters and explains the return value (formatted string). However, it could include more detail on pagination behavior or error responses, and the output schema exists but is not summarized in the description.

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 0%, yet the description adds substantial meaning: lists example city names for origin/destination, explains flexible date formats, specifies default and max values for page/per_page, and clarifies api_key as optional.

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 it searches for train journeys between two cities on a specific date, using the verb 'Search' and resource 'train journeys'. It distinguishes from siblings 'find_station' and 'get_train_prices' by focusing on journey search.

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 explains when to use the tool (search for train journeys) and provides date format guidance. However, it does not explicitly state when not to use it or mention alternatives like 'get_train_prices' for pricing.

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