get_departures

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

With no annotations, the description carries the transparency burden. It discloses that the data is real-time and enumerates the fields returned (countdown, platform, delay, status), which is useful. It does not cover side effects, data-source caveats, or failure behavior, but as a read-only getter this is a moderate gap, not a contradiction.

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?

Single sentence, front-loaded with the core purpose, with the result fields packed in without waste. Every part of the sentence earns its place.

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 two-parameter read-only lookup with no output schema, the description supplies enough shape of the response (countdown, platform, delay, status) and the object type (stop/station). It is slightly light on usage context, but the schema covers parameter formats, and nothing essential is missing for invoking the tool.

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 100%, so the schema already documents city and stop_id thoroughly. The description adds only the generic 'stop or station' framing and does not contribute new parameter semantics beyond 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 names a precise verb+resource ('Gets real-time departures') and lists the key result fields (live countdown minutes, platform, delay, status). This makes it clearly a live-departure lookup for a stop/station and distinguishes it from sibling tools like list_routes, get_route_stops, and get_service_alerts.

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 intended context is clear: use this tool when an agent needs live departure information for a specific stop or station. It does not explicitly state when not to use it or name alternatives, but no conflicting guidance is present.

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