How to configure the Ozeki SMS MCP Server in Codex

This guide walks you through integrating the Ozeki SMS MCP Server with OpenAI Codex, a terminal-based AI coding assistant. By following this tutorial, you will learn how to edit the Codex configuration file, register the Ozeki SMS Gateway as an MCP server, and verify the connection using the built-in MCP status command.

What is an MCP server?

An MCP (Model Context Protocol) server exposes tools that an AI model can call during a conversation. In this setup, the Ozeki SMS MCP Server provides SMS tools such as sending messages and listing incoming SMS. Codex connects to the MCP server over HTTP and authenticates using the API key you generated for your MCP user account.

Codex SMS MCP Server Overview
Codex SMS MCP Server Overview

Codex MCP server configuration

# Codex configuration file location:
C:\Users\%USERPROFILE%\.codex\config.toml

# Add the following block under the mcpServers section in config.yaml
# Replace {address} with your Ozeki SMS Gateway host IP
# Replace your-bearer-token with your API key
[mcp_servers.Ozeki]
url = "http://{address}:9529/mcp"
http_headers = { "Authorization" = "Bearer your-bearer-token" }

Steps to follow

We assume Ozeki SMS Gateway is already installed on your system and you have already created an MCP user account with an API key. You will also need OpenAI Codex installed on your system.

  1. Edit the Codex configuration file
  2. Start Codex
  3. Verify the MCP server connection

Video tutorial

The following video shows how to add the Ozeki SMS MCP Server to Codex step-by-step.

Step 1 - Edit the Codex configuration file

Navigate to the Codex configuration directory at C:\Users\%USERPROFILE%\.codex\ using File Explorer. You can open this folder quickly by typing %USERPROFILE%\.codex directly into the File Explorer address bar and pressing Enter (Figure 1).

Navigate to Codex config directory
Figure 1 - Navigate to the Codex configuration directory

Open the config.toml file in a text editor such as Notepad. This file stores all Codex configuration, including any MCP servers that Codex should connect to on startup (Figure 2).

Open config.toml in text editor
Figure 2 - Open config.toml in a text editor

Add the Ozeki SMS MCP Server entry to the file as shown below. Replace {address} with the IP address or hostname of your Ozeki SMS Gateway installation, and replace the Bearer token with the API key you generated for your MCP user account (Figure 3). 

[mcp_servers.Ozeki]
url = "http://{address}:9529/mcp"
http_headers = { "Authorization" = "Bearer your-bearer-token" }

Add Ozeki SMS MCP to config
Figure 3 - Add the Ozeki SMS MCP Server entry to config.toml

Save the configuration file and close the text editor. The changes will take effect the next time Codex is started (Figure 4).

Save config and exit text editor
Figure 4 - Save the configuration file and close the text editor

Step 2 - Start Codex

Open a terminal window by searching for Terminal in the Start menu. It is important to open a fresh terminal session after editing the configuration file so that Codex loads the updated settings (Figure 5).

Open a terminal
Figure 5 - Open a new terminal window

Type codex and press Enter to launch Codex. It will start up and attempt to connect to all MCP servers listed in the configuration file (Figure 6). 

codex

Start Codex
Figure 6 - Start Codex in the terminal

Step 3 - Verify the MCP server connection

Once Codex has started, run the /mcp command to display the connection status of all configured MCP servers. Verify that the Ozeki server is listed and its status shows as connected, confirming that Codex has successfully reached your gateway using the configured URL and API key (Figure 7). 

/mcp

Run MCP command and check status
Figure 7 - Run the /mcp command and verify the Ozeki SMS MCP Server connection

Summary

You have successfully added the Ozeki SMS MCP Server to Codex and confirmed that the connection is active. The Bearer token in the configuration file ensures that every request from Codex is authenticated against your Ozeki SMS Gateway. With the server connected, the AI agent can send and receive SMS messages without additional setup. Codex can now act on SMS-related instructions simply by being asked to do so in plain language.

More information