get_stops_for_route

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

No annotations are provided, so the description must cover behavioral traits. It mentions the output field 'stpid' but does not disclose potential edge cases (e.g., empty result, error conditions) or any other behavioral aspects like auth or rate limits. The description is adequate but lacks depth.

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 long with no wasted words. The first sentence states the primary purpose; the second provides critical chaining instructions. It is front-loaded and efficient.

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 that an output schema exists (context signal 'has output schema: true'), the description does not need to explain return values. It already provides chaining context (prerequisite and follow-up), making the tool self-contained and well-integrated into the workflow.

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?

The schema covers 100% of parameters, but the description adds valuable clarifications: for 'rt', it specifies the source field from get_routes(); for 'direction', it explicitly states to use the 'id' field (not 'name') from get_directions(). This goes beyond the schema descriptions and reduces ambiguity.

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 uses the verb 'Fetch' and clearly specifies the resource: 'all stops for a route heading in a specified direction'. It distinguishes from sibling tools like get_directions and get_routes by focusing on stops for a specific route and direction.

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: it tells the agent to call get_directions first if a valid direction id is not available, and to use the 'stpid' field output as input to get_predictions_for_stop. This clearly states when to use this tool and its relation to siblings.

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