MBTA MCP Server

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mbta_search_stops

Find MBTA stops by name or location. Use a query for stop names, or provide latitude/longitude with radius for nearby stops.

Instructions

Search for stops by name or near a location.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "query": "<query>"
    },
    "name": "mbta_search_stops"
  }
}

Input Schema

Name	Required	Description
`query`	Yes	Search query for stop names
`latitude`	No	Latitude for location-based search
`longitude`	No	Longitude for location-based search
`radius`	No	Search radius in meters (default: 1000)
`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?

With no annotations, the description carries full behavioral disclosure responsibility, but it only states a generic action. It omits details like whether query is needed for location searches, return format, or any side effects (none expected), leaving behavior largely undefined.

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?

The description is extremely concise (7 words, one sentence) and front-loaded. While it wastes no words, it is arguably too terse to provide sufficient context, but conciseness itself is good.

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

Completeness2/5

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

Given 5 parameters and no output schema, the description is too minimal. It fails to explain combined name/location search behavior, output format, or how it relates to siblings like 'mbta_get_nearby_stops' and 'mbta_get_stops', leaving significant gaps for an agent.

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 coverage is 100% with clear descriptions for all 5 parameters. The description adds the phrase 'near a location' to hint at the role of latitude/longitude, but this is already implicit from the schema. The tool description does not significantly enhance param understanding beyond the schema.

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?

The description clearly states the tool searches for stops by name or location. While it captures the core function, it does not explicitly distinguish from sibling tools like 'mbta_get_nearby_stops' (location-only) or 'mbta_get_stops' (by ID), leaving some ambiguity.

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 is given on when to use this tool versus alternatives. For example, it doesn't compare to 'mbta_get_nearby_stops' for location-only searches or 'mbta_list_all_stops' for unfiltered lists, making selection harder for an agent.

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