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 key behaviors: limit is per stop, minutes_after restricts the time window, and stop_ids accept comma-separated values. It does not mention timezone or sorting, but for a read-only 'Get' operation this is adequate context.

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 concise: a one-sentence overview followed by a focused args list. Each parameter gets a single line with clear wording, and there is no filler. The example values embedded in stop_ids are helpful without bloating the text.

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 the tool's moderate complexity (3 params, 1 required), the description covers all necessary aspects: purpose, parameter semantics, defaults, and how to obtain required IDs. An output schema exists, so return structure is handled separately. The description is complete for invoking this tool 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?

Schema coverage is 0%, so the description must fully explain parameters. It does so excellently: stop_ids includes format with examples and a pointer to search_stops; limit and minutes_after explain semantics ('per stop', 'within this many minutes') and defaults. This adds substantial meaning beyond the raw 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 opens with 'Get upcoming departures from a Prague public transit stop,' which is a specific verb ('Get') and resource ('departures from a Prague public transit stop'). It clearly distinguishes from sibling tools that return bicycle counters, air quality, etc., and is unambiguous about its scope.

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 explicit usage guidance by stating 'Use search_stops to find stop IDs by name.' This directs the agent to a sibling tool for the prerequisite step and implies this tool is for the departure lookup itself. Parameter descriptions further clarify how to use each argument (e.g., 'per stop' for limit).

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