Does Retell handle the telephone lines, or do I need my own Twilio/carrier?

Retell AI is designed to integrate seamlessly into telephony workflows but generally focuses on the conversational agent side. They provide features to list and attach numbers (`list_phone_numbers`), but you often purchase those numbers or link a custom SIP trunk through Retell accounts. You can run `list_phone_numbers` to see your currently available direct lines.

How do I create an outbound call programmatically with my assistant?

Simply ask your assistant to "Call X using my Y agent." Behind the scenes, the AI relies on the `create_phone_call` tool, transmitting a JSON payload supplying the `from_number` (a Retell registered phone number), `to_number` (destination), and an `override_agent_id` parameter to assign your voice agent correctly.

Can the AI initiate voice calls in a web browser instead of over the phone?

Yes. Use the `register_web_call` tool to create a browser-based voice session. This returns a connection URL and access token that your frontend application can use to start a real-time WebRTC conversation with a Retell voice agent, without requiring any phone line.

Retell AI MCP Server for OpenAI Agents SDK 10 tools — connect in under 2 minutes

Name: Retell AI
Availability: InStock
Author: Vinkius

openai.github.io/openai-agents-python/mcp

Built by Vinkius GDPR 10 Tools SDK

The OpenAI Agents SDK enables production-grade agent workflows in Python. Connect Retell AI through Vinkius and your agents gain typed, auto-discovered tools with built-in guardrails. no manual schema definitions required.

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 agents import Agent, Runner
from agents.mcp import MCPServerStreamableHttp

async def main():
    # Your Vinkius token. get it at cloud.vinkius.com
    async with MCPServerStreamableHttp(
        url="https://edge.vinkius.com/[YOUR_TOKEN_HERE]/mcp"
    ) as mcp_server:

        agent = Agent(
            name="Retell AI Assistant",
            instructions=(
                "You help users interact with Retell AI. "
                "You have access to 10 tools."
            ),
            mcp_servers=[mcp_server],
        )

        result = await Runner.run(
            agent, "List all available tools from Retell AI"
        )
        print(result.final_output)

asyncio.run(main())

Fully ManagedVinkius Servers

60%Token savings

High SecurityEnterprise-grade

IAMAccess control

EU AI ActCompliant

DLPData protection

V8 IsolateSandboxed

Ed25519Audit chain

<40msKill switch

Stream every event to Splunk, Datadog, or your own webhook in real-time

* 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 Retell AI MCP Server

Connect your conversational assistant directly to Retell AI, a powerful platform for building voice-driven conversational agents. Empower your AI to orchestrate, analyze, and automate phone calls or web-based voice interactions seamlessly via simple text commands. From provisioning intelligent voice agents to placing outbound calls to customers, this integration brings the full telecommunication stack directly to your chat interface.

The OpenAI Agents SDK auto-discovers all 10 tools from Retell AI through native MCP integration. Build agents with built-in guardrails, tracing, and handoff patterns. chain multiple agents where one queries Retell AI, another analyzes results, and a third generates reports, all orchestrated through Vinkius.

What you can do

Automate Phone Calls — Command your assistant to initiate outbound voice interactions on your behalf (create_phone_call) or register active sessions for web browser integration (register_web_call).
Build and Manage Voice Agents — Dynamically orchestrate AI agent personalities (create_agent, update_agent) and configure their underlying conversational brain (create_llm) with specific system instructions and models.
Analyze Telemetry — Keep track of your infrastructure by querying historical call logs (list_calls), investigating specific conversations for transcripts and sentiment analysis (get_call_details), surveying available text-to-speech voices (list_voices), and reviewing provisioned communication lines (list_phone_numbers and list_agents).

The Retell AI MCP Server exposes 10 tools through the Vinkius. Connect it to OpenAI Agents SDK 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 Retell AI to OpenAI Agents SDK via MCP

Follow these steps to integrate the Retell AI MCP Server with OpenAI Agents SDK.

Install the SDK

Run pip install openai-agents in your Python environment

Replace the token

Replace [YOUR_TOKEN_HERE] with your Vinkius token from cloud.vinkius.com

Run the script

Save the code above and run it: python agent.py

Explore tools

The agent will automatically discover 10 tools from Retell AI

Why Use OpenAI Agents SDK with the Retell AI MCP Server

OpenAI Agents SDK provides unique advantages when paired with Retell AI through the Model Context Protocol.

Native MCP integration via `MCPServerSse`, pass the URL and the SDK auto-discovers all tools with full type safety

Built-in guardrails, tracing, and handoff patterns let you build production-grade agents without reinventing safety infrastructure

Lightweight and composable: chain multiple agents and MCP servers in a single pipeline with minimal boilerplate

First-party OpenAI support ensures optimal compatibility with GPT models for tool calling and structured output

Retell AI + OpenAI Agents SDK Use Cases

Practical scenarios where OpenAI Agents SDK combined with the Retell AI MCP Server delivers measurable value.

Automated workflows: build agents that query Retell AI, process the data, and trigger follow-up actions autonomously

Multi-agent orchestration: create specialist agents. one queries Retell AI, another analyzes results, a third generates reports

Data enrichment pipelines: stream data through Retell AI tools and transform it with OpenAI models in a single async loop

Customer support bots: agents query Retell AI to resolve tickets, look up records, and update statuses without human intervention

Retell AI MCP Tools for OpenAI Agents SDK (10)

These 10 tools become available when you connect Retell AI to OpenAI Agents SDK via MCP:

create_agent

Creates a new AI voice agent

create_llm

Configures a Retell-hosted LLM

create_phone_call

Provide a JSON payload with "from_number" and "to_number". Initiates an outbound phone call

get_call_details

Retrieves details for a specific call

list_agents

Lists all configured AI voice agents

list_calls

Lists all historical and active calls

list_phone_numbers

Lists all phone numbers associated with the account

list_voices

Lists all available text-to-speech voices

register_web_call

Registers a new web-based call

update_agent

Updates an existing AI voice agent

Example Prompts for Retell AI in OpenAI Agents SDK

Ready-to-use prompts you can give your OpenAI Agents SDK agent to start working with Retell AI immediately.

"Can you show me the transcripts for call ID `c_f3a123`?"

"List all available agents I can use."

"We are testing out new numbers. Please use 'from_number' `+18005551234` and dial `+14085551234` assigning my 'agent_555'."

Troubleshooting Retell AI MCP Server with OpenAI Agents SDK

Common issues when connecting Retell AI to OpenAI Agents SDK through the Vinkius, and how to resolve them.

MCPServerStreamableHttp not found

Ensure you have the latest version: pip install --upgrade openai-agents

Agent not calling tools

Make sure your prompt explicitly references the task the tools can help with.

Retell AI + OpenAI Agents SDK FAQ

Common questions about integrating Retell AI MCP Server with OpenAI Agents SDK.

How does the OpenAI Agents SDK connect to MCP?

Use MCPServerSse(url=...) to create a server connection. The SDK auto-discovers all tools and makes them available to your agent with full type information.