Retrieve valid travel directions and their IDs for a specified Metro route using its route ID.
Get valid travel directions for a specific route (e.g., Eastbound/Westbound, Northbound/Southbound) and their direction IDs.
| Name | Required | Description | Default |
|---|---|---|---|
| route_id | Yes | Route ID (e.g. '902' for Green Line, '901' for Blue Line, '94', '4'). |
Changes observed during successful MCP inspections.
v1.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. 'Get' implies a read operation, but the description does not disclose rate limits, error behavior for invalid route IDs, whether data is cached, or any other behavioral traits.
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 a single, front-loaded sentence that conveys the operation, scope, and output with no wasted words.
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 simple one-parameter lookup, the description is largely complete: it states the input, the resource, and what is returned (directions and direction IDs). No output schema exists, so this return information is valuable, though it could mention how the returned direction IDs are intended to be used.
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 100%, and the schema already documents route_id with examples. The description adds no parameter-level detail beyond the schema, which is acceptable given full coverage.
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 specific verb and resource: 'Get valid travel directions for a specific route' and clarifies the output as direction IDs. This clearly distinguishes it from sibling tools like get_route_stops, get_departures, and list_routes.
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 implies when to use the tool: when you need valid directions for a specific route. However, it does not explicitly state when not to use it or name alternatives, leaving the usage context implicit rather than explicit.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.