get_transit_and_directions

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

Annotations already cover read-only, idempotent, and open-world behavior. The description goes beyond these by disclosing that the tool supports automatic English and local language place name resolution (e.g., resolving long hotel names to landmarks), which is not in the schema. It also enumerates the route modes. No contradictions; the added behavioral context is useful for an agent deciding to call this tool.

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 concise sentences. The first sentence states the core purpose with precise output types and scope; the second adds a differentiating capability (place name resolution) with examples. No filler, front-loaded, and easy to parse quickly.

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 that an output schema exists (so return format is specified elsewhere) and annotations cover safety and side effects, the description is largely complete. It covers scope, supported entity types, route modes, and the name resolution feature. Minor details like geographic limitations are handled by the country parameter default. It does not explicitly mention rate limits or failure modes, but these are not critical given the annotations.

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 input schema has 100% description coverage, so each parameter is already explained. The description adds semantic value by providing a concrete example of place name resolution for origin and destination, clarifying that natural language strings are accepted beyond simple addresses. This exceeds the baseline of 3 by giving operational guidance for parameter usage.

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 the verb 'Calculate' and enumerates the exact deliverables: travel routes, turn-by-turn walking steps, public transit (subway/bus), and driving taxi fares. It specifies the resource as 'ANY two travel entities' and lists those entity types (hotels, restaurants, cafes, stations, airports, landmarks). This distinguishes it from the sibling get_hotel_distance_and_transit, which focuses on hotel-specific transit, by emphasizing the universal applicability.

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 provides clear usage context: it is for calculating routes between any two travel entities and highlights place name resolution as a key capability. However, it does not explicitly mention when NOT to use this tool or name alternatives like get_hotel_distance_and_transit. The guidance is implied by the 'ANY' scope but lacks explicit exclusions.

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