Buses arriving at a stop

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

Annotations already establish readOnlyHint=true and openWorldHint=true, so the main behavioral burden is lighter. The description adds useful beyond-annotation context: results are ordered soonest first, include minutes to arrival, destination/heading, and subsequent buses, and cover all routes at one stop.

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 definition is front-loaded with the core behavior and then immediately gives the input pattern and examples. Both sentences earn their place, and there is no redundant or vague 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?

For a read-only, open-world live-arrival tool with no output schema, the description does a good job explaining the main return contents and ordering. It is not fully complete about edge cases such as empty results or ambiguity handling, but the schema covers all parameters thoroughly.

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 all four parameters already have clear schema-level documentation. The description reinforces the stationUID source and gives examples, but it does not add much beyond the schema and does not mention the limit parameter.

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 gives a specific verb-and-resource picture: it returns every bus due at one stop across all routes, ordered soonest first, with arrival minutes and destinations. It clearly separates itself from bus_stops_nearby by explaining that stationUID comes from that sibling, but it does not explicitly distinguish itself from other bus-related siblings such as bus_eta or bus_timetable.

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 tells the agent to supply either a stationUID from bus_stops_nearby or a stop name and provides concrete examples, which implies the likely workflow. However, it does not state when to use this tool instead of bus_eta, bus_timetable, bus_positions, or other bus siblings, nor does it give exclusions.

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