Can my AI check when the next L train is arriving at my station?

Yes! Use the `get_train_arrivals` tool with the station mapId (a 5-digit parent station ID, e.g., 40360 for Clark/Lake, 40900 for Jackson). Your AI will return all upcoming trains with destination names, line colors (Red, Blue, Brown, Green, Orange, Purple, Pink, Yellow), predicted arrival times in minutes, operating status (on-time, delayed, approaching, boarding, departing), and whether the train is scheduled or real-time tracked. If you do not know the mapId, it can be found in the CTA GTFS s

How do I check when the next CTA bus is arriving at a specific stop?

First use `get_bus_stops` with a route ID to find the stop ID (stpid) for your location. Then use `get_bus_predictions` with that stop ID to get real-time estimated arrival times, route information, destination descriptions, and vehicle IDs. For route-filtered predictions, you can also pass the route ID to narrow results to a specific bus line. Stop IDs are numeric identifiers assigned by CTA to each physical bus stop across Chicago.

Are there any service disruptions affecting the Red Line or my bus route right now?

Use `get_service_alerts` to check all active service disruptions across the CTA system. This returns alerts with affected routes and stations, disruption descriptions, severity levels, cause types (maintenance, incident, weather, special events, construction), and detour information. You can also use `get_route_status` for a quick system-wide health check showing which L lines and bus routes are running on-time, delayed, or have planned work. Always check this before planning any CTA journey.

CTA MCP Server for LangChain 11 tools — connect in under 2 minutes

Name: CTA
Availability: InStock
Author: Vinkius

python.langchain.com/docs/integrations/tools/mcp

Built by Vinkius GDPR 11 Tools Framework

LangChain is the leading Python framework for composable LLM applications. Connect CTA through Vinkius and LangChain agents can call every tool natively. combine them with retrievers, memory, and output parsers for sophisticated AI pipelines.

Get MCP Server for AI Agents

ASK AI ABOUT THIS MCP SERVER

Open in ChatGPT Open in Claude Open in Perplexity

Vinkius supports streamable HTTP and SSE.

python

import asyncio
from langchain_mcp_adapters.client import MultiServerMCPClient
from langchain_openai import ChatOpenAI
from langgraph.prebuilt import create_react_agent

async def main():
    # Your Vinkius token. get it at cloud.vinkius.com
    async with MultiServerMCPClient({
        "cta": {
            "transport": "streamable_http",
            "url": "https://edge.vinkius.com/[YOUR_TOKEN_HERE]/mcp",
        }
    }) as client:
        tools = client.get_tools()
        agent = create_react_agent(
            ChatOpenAI(model="gpt-4o"),
            tools,
        )
        response = await agent.ainvoke({
            "messages": [{
                "role": "user",
                "content": "Using CTA, show me what tools are available.",
            }]
        })
        print(response["messages"][-1].content)

asyncio.run(main())

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* Every MCP server runs on Vinkius-managed infrastructure inside AWS - a purpose-built runtime with per-request V8 isolates, Ed25519 signed audit chains, and sub-40ms cold starts optimized for native MCP execution. See our infrastructure

About CTA MCP Server

Connect your CTA API Chicago public transit data platform to any AI agent and take full control of real-time L train and CTA Bus tracking, arrival predictions, service disruption monitoring, and route status awareness through natural conversation.

LangChain's ecosystem of 500+ components combines seamlessly with CTA through native MCP adapters. Connect 11 tools via Vinkius and use ReAct agents, Plan-and-Execute strategies, or custom agent architectures. with LangSmith tracing giving full visibility into every tool call, latency, and token cost.

What you can do

L Train Arrivals — Get real-time arrival predictions for any CTA L station with train destinations and line colors
L Train Positions — Track live positions of all active trains system-wide or filtered by line (Red, Blue, Brown, Green, Orange, Purple, Pink, Yellow)
Bus Predictions — Get estimated arrival times for any CTA bus stop with route and destination info
Bus Vehicle Tracking — Track real-time GPS positions of all active CTA buses system-wide or by route
Bus Routes — List all CTA bus routes across Chicago neighborhoods
Bus Stops — Get all stops for any bus route with coordinates and direction information
Service Alerts — Monitor active disruptions across L trains and buses with severity and alternatives
Route Status — Quick system-wide health check showing which lines are running on-time or delayed
Stop Details — Get detailed location info for any CTA bus stop
Route Directions — Understand direction patterns (northbound, southbound) for any bus route
System Connectivity — Verify API connectivity and synchronize timestamps

The CTA MCP Server exposes 11 tools through the Vinkius. Connect it to LangChain in under two minutes — no API keys to rotate, no infrastructure to provision, no vendor lock-in. Your configuration, your data, your control.

How to Connect CTA to LangChain via MCP

Follow these steps to integrate the CTA MCP Server with LangChain.

Install dependencies

Run pip install langchain langchain-mcp-adapters langgraph langchain-openai

Replace the token

Replace [YOUR_TOKEN_HERE] with your Vinkius token

Run the agent

Save the code and run python agent.py

Explore tools

The agent discovers 11 tools from CTA via MCP

Why Use LangChain with the CTA MCP Server

LangChain provides unique advantages when paired with CTA through the Model Context Protocol.

The largest ecosystem of integrations, chains, and agents. combine CTA MCP tools with 500+ LangChain components

Agent architecture supports ReAct, Plan-and-Execute, and custom strategies with full MCP tool access at every step

LangSmith tracing gives you complete visibility into tool calls, latencies, and token usage for production debugging

Memory and conversation persistence let agents maintain context across CTA queries for multi-turn workflows

CTA + LangChain Use Cases

Practical scenarios where LangChain combined with the CTA MCP Server delivers measurable value.

RAG with live data: combine CTA tool results with vector store retrievals for answers grounded in both real-time and historical data

Autonomous research agents: LangChain agents query CTA, synthesize findings, and generate comprehensive research reports

Multi-tool orchestration: chain CTA tools with web scrapers, databases, and calculators in a single agent run

Production monitoring: use LangSmith to trace every CTA tool call, measure latency, and optimize your agent's performance

CTA MCP Tools for LangChain (11)

These 11 tools become available when you connect CTA to LangChain via MCP:

get_bus_predictions

Returns predicted arrival times in minutes and seconds, route IDs, destination descriptions, vehicle IDs, block IDs, trip designators, and whether buses are scheduled or real-time tracked. Based on real-time vehicle tracking and schedule adherence. Essential for real-time bus arrival awareness, passenger waiting time estimation, trip timing, and connection coordination. AI agents should use this when users ask "when is the next 22 Clark bus at stop 1234", "show predictions for this stop", or need real-time arrival data for a specific CTA bus stop. Stop IDs can be found using get_bus_stops. Get next bus arrival predictions for a specific CTA bus stop

get_bus_routes

Returns route IDs, short names (e.g., "22", "36"), long names (e.g., "22-Clark", "36-Broadway"), route colors, and route directions. Covers local, limited-stop, and express services across all Chicago neighborhoods. Essential for route discovery, service area analysis, transit network understanding, and identifying route IDs for use in stop and prediction queries. AI agents should use this when users ask "list all CTA bus routes", "what routes serve downtown Chicago", or need to identify route IDs for subsequent CTA Bus Tracker queries. List all CTA bus routes in Chicago

get_bus_stops

Returns stop IDs (stpid), stop names, geographic coordinates (latitude, longitude), stop sequence order, and direction information (northbound, southbound, eastbound, westbound). Essential for stop discovery, journey planning, accessibility mapping, and identifying stop IDs for use in arrival prediction queries. AI agents should use this when users ask "list all stops on route 22 Clark", "find bus stops along Michigan Avenue", or need to identify stop IDs for use in get_bus_predictions queries. List all bus stops for a specific CTA bus route

get_bus_vehicles

Returns vehicle IDs (vid), route IDs, latitude/longitude coordinates, heading direction, speed, trip designators, block IDs, destination descriptions, and pattern names. Can query all buses system-wide or filter by specific route ID for targeted route-level tracking. Essential for real-time bus fleet monitoring, passenger arrival estimation, route-level service awareness, and transit operations management. AI agents should reference this when users ask "where are all the buses on route 22", "track bus positions system-wide", or need real-time vehicle position data for fleet visualization. Get real-time positions of active CTA bus vehicles system-wide or filtered by route

get_route_directions

Returns direction IDs (0 or 1), direction names (e.g., "Northbound", "Southbound", "Eastbound", "Westbound"), and associated route metadata. Essential for understanding route patterns, direction identification for stop queries, and trip planning with correct directional awareness. AI agents should use this when users ask "what directions does route 22 serve", "is there a northbound option for route 36", or need directional metadata to understand bus route geometry and plan trips in the correct direction. Get direction information for a specific CTA bus route

get_route_status

Returns route IDs, route names, status indicators (GOOD DELAYS, SLOWLY, SEVERE DELAYS, PLANNED WORK, SERVICE DISRUPTION, SUSPENDED), and status descriptions. Essential for quick system-wide health checks, commute planning, and understanding overall CTA reliability at a glance. AI agents should reference this when users ask "how is CTA running today", "what lines are delayed", or need a quick overview of system-wide service status before detailed trip planning. Get current status of all CTA train lines and bus routes

get_service_alerts

Returns alert descriptions, affected routes and stations, severity levels, cause types (maintenance, incident, weather, special events, construction), start and end timestamps, detour information, and alternative service recommendations. Can query all alerts system-wide or filter by specific route. Essential for service disruption awareness, alternative route planning, passenger communication, and understanding system reliability. AI agents should use this when users ask "are there any delays on the Red Line", "is CTA running normally today", or need to check service reliability before planning CTA journeys. Get current service alerts and disruptions across the CTA system

get_stop_details

Returns stop ID, stop name, geographic coordinates (latitude, longitude), and any associated route information. Essential for stop identification, accessibility planning, transit network analysis, and passenger information. AI agents should use this when users ask "tell me about stop 1234", "where is this bus stop located", or need detailed stop metadata to contextualize transit queries and trip planning. Get detailed information about a specific CTA bus stop

get_system_time

Returns the official server timestamp in standard format. Useful for synchronizing local clocks with the CTA system, verifying API connectivity, testing authentication, and timestamp alignment for real-time data correlation. AI agents should use this as a connectivity check before making more complex queries, or when users need to verify API responsiveness and authentication validity. Get the current CTA Bus Tracker system timestamp

get_train_arrivals

Returns predicted arrival times in minutes, train run numbers, destination stations, line colors (Red, Blue, Brown, Green, Orange, Purple, Pink, Yellow), operating status (on-time, delayed, scheduled, unscheduled, approaching, boarding, departing), and whether the train is approaching or at the station. Essential for real-time L tracking, passenger waiting time estimation, trip timing, and connection coordination. AI agents should use this when users ask "when is the next Red Line train at Clark/Lake", "show upcoming trains at this station", or need real-time arrival predictions for a specific CTA L station. MapIds are 5-digit station identifiers (e.g., 40360 for Clark/Lake, 40900 for Jackson). Station IDs can be found in the CTA GTFS static data feed. Get real-time train arrival predictions for a specific L station

get_train_positions

Returns train run numbers, line colors, next station IDs, service types (train, 5-car, 8-car), heading directions (North, South, East, West, Northeast, Northwest, Southeast, Southwest), scheduled vs. real-time status, and delay indicators. Can query all trains system-wide or filter by specific line (Red, Blue, Brown, Green, Orange, Purple, Pink, Yellow). Essential for real-time train tracking, network-wide service awareness, fleet monitoring, and understanding train distribution across the L system. AI agents should reference this when users ask "where are all the Red Line trains", "show train positions on the Blue Line", or need to visualize train locations for operational monitoring or passenger information. Get real-time positions of all active CTA trains system-wide or filtered by line

Example Prompts for CTA in LangChain

Ready-to-use prompts you can give your LangChain agent to start working with CTA immediately.

"When is the next Red Line train arriving at Clark/Lake?"

"Show me all CTA bus stops on route 22 Clark."

"How is CTA running today? Any delays on the L or bus routes?"

Troubleshooting CTA MCP Server with LangChain

Common issues when connecting CTA to LangChain through the Vinkius, and how to resolve them.

MultiServerMCPClient not found

Install: pip install langchain-mcp-adapters

CTA + LangChain FAQ

Common questions about integrating CTA MCP Server with LangChain.

How does LangChain connect to MCP servers?

Use langchain-mcp-adapters to create an MCP client. LangChain discovers all tools and wraps them as native LangChain tools compatible with any agent type.

Which LangChain agent types work with MCP?

All agent types including ReAct, OpenAI Functions, and custom agents work with MCP tools. The tools appear as standard LangChain tools after the adapter wraps them.