Calcul d'itinéraire

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

With no annotations provided, the description carries the burden of behavioral disclosure. It reveals that results are real-time, multimodal, include connections, and that endpoints accept postal addresses directly without requiring nearest-stop lookup. It does not cover response format or rate limits, but those are not critical for this routing use case.

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?

Three sentences, each earning its place: the core scope, the key address-input behavior, and the sibling routing preference. It is front-loaded and contains no redundant filler.

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?

The description covers scope, input flexibility, arrival-time handling, and the main alternative, which is enough for common calls. Since there is no output schema and no annotations, it could have briefly described the returned itinerary shape, but the core invocation context is complete.

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 baseline is 3. The description adds value beyond the schema by giving a concrete address example and by connecting user intent ('je dois être à X à 9 h') to the when/arrive_by combination, which is a helpful semantic bridge not explicitly in 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 states a clear function: real-time itinerary computation in Île-de-France, with all modes and connections included. It differentiates itself from siblings by emphasizing multimodal routing and explicitly names next_trains_to_paris as the alternative for a specific commute case.

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?

It gives an explicit routing rule: prefer next_trains_to_paris for habitual home → Paris trips. It also translates a natural-language arrival requirement ('je dois être à X à 9 h') into the correct parameter usage, which helps an agent select and invoke the tool correctly.

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