---
title: "Build voice agents with Codex"
description: "Connect OpenAI Codex to Speko's MCP server to create, deploy and test voice agents and phone numbers from the CLI."
canonical: "https://speko.ai/integrations/codex"
last-updated: "2026-11-02"
---

> ## Speko page index
> The complete index of every page on this site is at: https://speko.ai/llms.txt
> Read it before exploring further. It lists the exact Markdown URL for every canonical HTML page.

# Build voice agents with Codex

Connect OpenAI Codex to Speko's MCP server to create, deploy and test voice agents and phone numbers from the CLI.

[Get started free](https://platform.speko.ai/sign-in) $10 in credit on signup

## What you can ask Codex

- Create a voice agent for my dental clinic that books appointments, then deploy it.
- Buy a US phone number and point it at the receptionist agent.
- Pull yesterday's calls, read the transcripts, and tell me where the agent got stuck.
- Write five evals for the booking flow and run them against the current version.
- How much credit do I have left, and what did last week cost?

## Set it up

1. ### 1Add the server to your config
   
   In ~/.codex/config.toml:
   
   ```text
   [mcp_servers.speko]
   url = "https://mcp.speko.ai/mcp"
   ```
2. ### 2Sign in
   
   Codex opens Speko's sign-in on first use.

## What Codex can do

- Create, update, deploy and roll back agents
- Start sessions, place calls, read transcripts and recordings
- Buy, import and route phone numbers, including your own SIP trunk
- Build knowledge bases and run evals
- Read SMS threads and reply from an agent's inbox
- Check usage and credit balance
- Migrate configs from other voice-agent platforms

## Questions

**What can Codex do with Speko?**

Everything the console can, short of managing API keys: create, deploy and roll back agents, buy and route phone numbers, run evals, place calls and read the transcripts.

**How does it sign in?**

OAuth in the browser: the client opens Speko's sign-in, you approve, and it gets a token bound to the MCP endpoint. For automation, send a Speko API key as a Bearer token instead.

**What does it cost?**

The MCP server is free to connect. Calls and agent minutes bill at the published rates on the pricing page, and every account starts with $10 in credit.

Other integrations

- [Speko + Claude](https://speko.ai/integrations/claude)
- [Speko + ChatGPT](https://speko.ai/integrations/chatgpt)
- [Speko + Grok](https://speko.ai/integrations/grok)
- [Speko + Claude Code](https://speko.ai/integrations/claude-code)
- [Speko + Cursor](https://speko.ai/integrations/cursor)
- [Speko + Replit](https://speko.ai/integrations/replit)