MBTA MCP Server

Overview Schema Source Related Servers Discussions Admin

mbta_get_live_facilities

Retrieve real-time facility status and outages. Use facility ID for specific updates or pagination for multiple results.

Instructions

Get real-time facility status and outages.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "mbta_get_live_facilities"
  }
}

Input Schema

Name	Required	Description	Default
`facility_id`	No	Specific facility ID to get status for
`page_limit`	No	Number of results to return (default: 10)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0May 26, 2026

TDQS

C2.9/5.0

Behavior2/5

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

No annotations provided, so description bears full responsibility. It lacks details on return format, data freshness, or any side effects. Minimal disclosure beyond the action.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Single concise sentence, front-loaded with main purpose. However, it omits important details that could be included without making it verbose.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple tool with 2 optional params and no output schema, description is somewhat complete, but missing explanation of return value (e.g., list of facility statuses) and how facility IDs are obtained.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema covers both parameters with descriptions (100% coverage), so baseline is 3. Description adds no extra parameter insight, but does not detract.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

Description clearly states verb 'Get' and resource 'real-time facility status and outages', distinguishing from static facility tools like mbta_get_facilities. However, it could be more specific about what types of facilities are covered.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance on when to use this tool versus siblings like mbta_get_facilities or mbta_list_all_facilities. Agent must infer use case from name alone.

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