JustCall MCP Server for LangChain 10 tools — connect in under 2 minutes
LangChain is the leading Python framework for composable LLM applications. Connect JustCall through the Vinkius and LangChain agents can call every tool natively — combine them with retrievers, memory, and output parsers for sophisticated AI pipelines.
ASK AI ABOUT THIS MCP SERVER
Vinkius supports streamable HTTP and SSE.
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({
"justcall": {
"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 JustCall, show me what tools are available.",
}]
})
print(response["messages"][-1].content)
asyncio.run(main())
* 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 JustCall MCP Server
Empower your AI agents with JustCall's cloud phone system. This MCP server allows you to list and retrieve phone calls, track SMS/MMS messages, manage contacts, and access call recordings directly through the JustCall API. Ideal for automating communication workflows and sales engagement.
LangChain's ecosystem of 500+ components combines seamlessly with JustCall through native MCP adapters. Connect 10 tools via the 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.
The JustCall MCP Server exposes 10 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 JustCall to LangChain via MCP
Follow these steps to integrate the JustCall 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 10 tools from JustCall via MCP
Why Use LangChain with the JustCall MCP Server
LangChain provides unique advantages when paired with JustCall through the Model Context Protocol.
The largest ecosystem of integrations, chains, and agents — combine JustCall 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 JustCall queries for multi-turn workflows
JustCall + LangChain Use Cases
Practical scenarios where LangChain combined with the JustCall MCP Server delivers measurable value.
RAG with live data: combine JustCall tool results with vector store retrievals for answers grounded in both real-time and historical data
Autonomous research agents: LangChain agents query JustCall, synthesize findings, and generate comprehensive research reports
Multi-tool orchestration: chain JustCall tools with web scrapers, databases, and calculators in a single agent run
Production monitoring: use LangSmith to trace every JustCall tool call, measure latency, and optimize your agent's performance
JustCall MCP Tools for LangChain (10)
These 10 tools become available when you connect JustCall to LangChain via MCP:
get_call
Includes timestamps, participants, and associated notes. Use this for deep investigation of a specific communication event. Retrieves details for a specific call
get_contact
Returns associated phone numbers, email addresses, and metadata. Use this for detailed customer vetting before or after a call. Retrieves details for a specific contact
list_calls
Returns call direction (inbound/outbound), duration, status, and IDs. Use this to audit communication activity or track call volumes. Lists all phone calls
list_campaigns
g., dialer campaigns). Useful for monitoring sales outreach and telemarketing efforts. Lists all calling campaigns
list_contacts
Returns names, phone numbers, and IDs. Use this to search for customers or provide contact information to the user. Lists all contacts in JustCall
list_messages
Includes message content, sender/receiver, and delivery status. Essential for monitoring text-based customer interactions. Lists all SMS/MMS messages
list_numbers
Useful for identifying which numbers are available for specific campaigns or teams. Lists all phone numbers in your JustCall account
list_recordings
Use this when the user wants to audit call quality or retrieve a specific conversation record. Lists all call recordings
list_users
Useful for identifying which agent handled a specific call or message. Lists all users in your organization
list_webhooks
Useful for auditing system integrations. Lists all configured webhooks
Example Prompts for JustCall in LangChain
Ready-to-use prompts you can give your LangChain agent to start working with JustCall immediately.
"List all recent phone calls in JustCall."
"Show me the latest SMS messages."
"Check the details for contact ID '123'."
Troubleshooting JustCall MCP Server with LangChain
Common issues when connecting JustCall to LangChain through the Vinkius, and how to resolve them.
MultiServerMCPClient not found
pip install langchain-mcp-adaptersJustCall + LangChain FAQ
Common questions about integrating JustCall MCP Server with LangChain.
How does LangChain connect to MCP servers?
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?
Can I trace MCP tool calls in LangSmith?
Connect JustCall with your favorite client
Step-by-step setup guides for every MCP-compatible client and framework:
Anthropic's native desktop app for Claude with built-in MCP support.
AI-first code editor with integrated LLM-powered coding assistance.
GitHub Copilot in VS Code with Agent mode and MCP support.
Purpose-built IDE for agentic AI coding workflows.
Autonomous AI coding agent that runs inside VS Code.
Anthropic's agentic CLI for terminal-first development.
Python SDK for building production-grade OpenAI agent workflows.
Google's framework for building production AI agents.
Type-safe agent development for Python with first-class MCP support.
TypeScript toolkit for building AI-powered web applications.
TypeScript-native agent framework for modern web stacks.
Python framework for orchestrating collaborative AI agent crews.
Leading Python framework for composable LLM applications.
Data-aware AI agent framework for structured and unstructured sources.
Microsoft's framework for multi-agent collaborative conversations.
Connect JustCall to LangChain
Get your token, paste the configuration, and start using 10 tools in under 2 minutes. No API key management needed.