trip_search

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

With no annotations, the description must carry the burden, and it does well by stating what the tool returns ('departure/arrival times, duration, changes, and legs') and mentioning defaults for time/time_mode. It does not discuss error cases or rate limits, but for a search tool, this is adequate and transparent about core behavior.

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 relatively long but well-structured: an executive summary, a usage note, a return description, and a numbered Args list. Every sentence adds value, though a tiny bit of redundancy exists (e.g., 'Provide station IDs or names' repeated in Args). It earns a 4, not a 5, due to slight verbosity.

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 the tool's complexity (8 params, no schema descriptions, no annotations), this description is comprehensive. It covers all parameters, defaults, supported time modes, and returned data. It also hints at the relationship between IDs and names. However, it does not explain what happens if both an ID and name are provided (which takes precedence) or mention sibling tools for alternative use cases, so it is not a perfect 5.

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%, so the description fully compensates by explaining every parameter with examples ('Wien Hbf', '2026-04-15T08:00:00'), clarifying that station IDs or names can be used, and specifying defaults and modes. This goes far beyond the raw schema and gives the AI agent everything needed to correctly fill parameters.

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 opens with a specific verb and resource: 'Search train connections between two OeBB stations.' This clearly distinguishes it from siblings like station_board (which likely shows departures for a single station) or search_station (which finds stations). The scope is unmistakable.

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 gives clear context by mentioning 'Supports future trip planning via time/time_mode parameters,' implying when to use this for planning versus real-time lookups. However, it does not explicitly name sibling tools or state when not to use it, so it falls short of a 5.

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