Get next departures from a stop

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

With no annotations, the description must convey behavioral context. It discloses that the tool returns realtime delays and cancellations and lists the output fields, which is useful. However, it does not explicitly state read-only nature, error handling, or potential rate limits. The description provides moderate transparency but leaves important behavioral aspects implicit.

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 sentences, with the primary action stated first and the output structure succinctly enumerated. Every clause adds value, wasting no words. It is front-loaded with the core purpose and then provides complementary 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?

For a tool with two parameters and full schema coverage, the description adequately explains what the response contains (line, destination, scheduled/expected times, delay, platform, cancellation). It omits potential error scenarios or time zone assumptions, but given the simplicity of the operation, the description covers the essential context an agent needs to invoke it correctly.

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?

Both parameters are fully described in the schema (stop_place_id and count), so schema coverage is 100%. The description does not add significant meaning beyond what the schema already documents—it only repeats the stop concept and adds output context, not parameter details. This matches the baseline of 3 for high schema coverage.

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 specific action ('get the next departures') on a specific resource ('a stop place (Entur)') and highlights distinguishing features (realtime delays and cancellations). This clearly differentiates it from sibling tools like plan_trip or get_realtime_status, which serve different purposes.

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 does not provide guidance on when to use this tool versus alternatives. It does not mention exclusions, prerequisites (other than a hint in the schema), or conditions that would favor get_departures over plan_trip or get_realtime_status. Agents would need to infer usage from the tool name and sibling context.

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