Get a SEPTA Regional Rail train's current location, delay status, and stop-by-stop estimated times by train number.
Where a specific train is right now and how late it's running, plus its stop-by-stop estimated times. train_number is SEPTA's train number, e.g. "5305".
| Name | Required | Description | Default |
|---|---|---|---|
| train_number | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, and openWorld, so the safety profile is covered. The description usefully adds that this covers live position, current lateness, and per-stop estimates, but says nothing about data freshness, what happens for an unknown or non-running train number, or response shape.
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?
Two sentences, front-loaded with the returned data, followed by the one bit of parameter guidance needed. No filler or repetition of the tool name.
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?
With no output schema, the description must convey the return content, and it does: current position, delay, and stop-by-stop estimates. The main remaining gap is failure behavior for an invalid or inactive train number, which mildly matters for a single required-parameter lookup.
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 carry the parameter alone, and it does: train_number is identified as SEPTA's train number with a concrete example ('5305'). Only the format constraints (length, leading zeros, validity) remain unspecified.
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?
States a concrete resource (a specific train) and what is returned: real-time position, delay, and stop-by-stop ETAs. That implicitly separates it from static siblings like train_schedule and next_trains, but no sibling is named, so differentiation is left to inference.
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?
Usage is only implied by the described content — an agent can infer this is for live status rather than a timetable. There is no explicit 'use this when...' or exclusion pointing to train_schedule or next_trains for adjacent needs.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.