Station departures / arrivals board

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety and external-data profile is covered. The description adds useful content by listing what the board surfaces (live delay, platform, main stops) and the direction filter, but says nothing about freshness of 'live' data, rate limits, or result ordering.

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?

Two sentences, front-loaded with the core purpose and followed by the optional scoping filter; no filler. The field enumeration is dense but earns its place by telling the agent what comes back.

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 9-parameter read-only board with strong schema coverage, the description adequately covers what the tool returns and the main optional filter. Remaining gaps (live-data freshness, pagination beyond the default limit) are largely handled by the schema defaults.

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 description coverage is 89%, so the schema already documents nearly every parameter including date formats, mode enums, limits and the time window. The description only echoes the direction filter ('services going towards a given place'), adding little beyond what the schema states.

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 verb+resource: a departure/arrival board for a named station or stop, and enumerates the fields returned (time, delay, line, platform, destination). It implicitly distinguishes itself from siblings like find_stops and nearby_stops, though it never names them explicitly.

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?

Usage is implied — use it when you know the station and want its board — and the direction filter is flagged as optional. There is no explicit when-not guidance or pointer to alternatives such as plan_journey for full itineraries, so the agent must infer the boundary.

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