How to use the Android MCP SMS Server in LibreChat

This guide explains how to connect the Ozeki Android SMS Gateway MCP server to LibreChat, enabling the AI assistant to send SMS messages directly from your Android phone. By following this tutorial, you will learn how to install the Ozeki Android SMS Gateway app, enable its built-in MCP server, configure the allowed domains in LibreChat, register the MCP endpoint, and verify that everything is working by sending a test message.

Solution: How to send SMS from LibreChat

LibreChat is connected to the Ozeki Android SMS MCP Server through the MCP protocol, where LibreChat is the MCP client and the Android phone is the MCP server. The Android phone is connected to the SMS service provider through a wireless mobile network connection. When an SMS is sent, it first travels from LibreChat to the Android phone through the MCP protocol, and the Android phone forwards it to the SMS service provider, which delivers it to the recipient's mobile phone.

What is LibreChat?

LibreChat is an open-source, self-hosted chat application that supports multiple AI providers including OpenAI, Anthropic, and locally hosted models. It can be deployed using Docker and supports MCP servers, which allows it to be extended with external tools such as SMS messaging, database access, and more.

What is an Android SMS MCP Server?

An Android SMS MCP Server is a Model Context Protocol server that runs directly on an Android smartphone and exposes SMS functionality — such as sending text messages and querying SIM subscriptions — as structured tools that any MCP-compatible AI client can call. Once installed and configured, the AI client can send real SMS messages through the phone's SIM card to any phone number, with a single tool call.

Download Ozeki Android SMS Gateway

To use this solution you need to install the Android app on your Android phone.

Download the android app: Android SMS Gateway

https://android-sms-gateway.com/p_51-download-android-sms-gateway.html

Steps to follow

You will need LibreChat installed on your system. If you have not set it up yet, follow our LibreChat installation guide.

Install Ozeki Android SMS Gateway
Enable MCP SMS Server
LibreChat SMS MCP Server Config
Add the SMS MCP Server config to LibreChat
Send a test SMS
Check the SMS in the SMS Gateway logs

Step 1 - Install Ozeki Android SMS Gateway

For a full tutorial on installing the Ozeki Android SMS Gateway, check out our How to install Android SMS Client and Enable Ozeki SMS Client permissions guides.

Before you can use the MCP SMS Server, you need to install the Ozeki SMS Client on your Android device. The app will serve as the local SMS gateway that LibreChat connects to over your Wi-Fi network. Make sure both devices are on the same local network, as this is required for the HTTP connection to work.

Step 2 - Enable MCP SMS Server

For a full tutorial on enabling the MCP server in the Android app, check out our Android MCP SMS Server configuration guide.

Open the Ozeki SMS Client app on your Android device and tap the MCP tab in the bottom navigation bar. Tap the toggle switch to start the MCP server and grant any permission requests that appear, including access to SMS messages. The toggle will switch from "Stopped" to "Running" and the API endpoint URL will appear below. Copy this URL, as you will need it when configuring LibreChat in the next step.

Step 3 - LibreChat SMS MCP Server Config

# Add the following to librechat.yaml to allow the Android gateway domain
# Replace {address} with your Ozeki Android SMS Gateway IP address
mcpSettings:
  allowedDomains:
    - "{address}"

# Restart the LibreChat Docker container after saving the config
docker compose down
docker compose up -d

# MCP server details to enter in the LibreChat UI
Name: Ozeki Android SMS MCP
MCP Server URL: http://{address}:9531/mcp
Transport: Streamable HTTPS
Authentication: None

Example prompt

Send an SMS to +36301234567, the message should be "Hello from LibreChat".

Step 4 - Add the SMS MCP Server config to LibreChat

The following video shows how to configure LibreChat and add the Android SMS MCP server step-by-step. It covers editing the librechat.yaml file, restarting the Docker container, and registering the MCP server through the LibreChat interface.

Locate the librechat.yaml configuration file in your LibreChat installation directory and open it in a text editor. This file controls server-level settings including which external domains are permitted to be used as MCP server endpoints (Figure 1).

Open librechat.yaml config file — Figure 1 - Open the librechat.yaml configuration file

Locate the mcpSettings block in the file, or add it if it does not exist yet. Add the IP address of your Android device to the allowedDomains list as shown below. This is required for LibreChat to permit connections to the Android gateway (Figure 2).

mcpSettings:
  allowedDomains:
    - "{address}"

Locate and add Ozeki SMS MCP to allowed domains — Figure 2 - Add the Android gateway address to the allowed domains

Save the configuration file and close the text editor. The changes will take effect after the Docker container is restarted in the next step (Figure 3).

Save config file and close text editor — Figure 3 - Save the configuration file and close the text editor

Open a terminal window and navigate to your LibreChat installation folder. You can do this by right-clicking inside the folder and selecting Open in Terminal, or by typing the path directly into an existing terminal (Figure 4).

Open LibreChat folder in terminal — Figure 4 - Open the LibreChat folder in a terminal window

Run the following commands to restart the LibreChat Docker container and apply the updated configuration. Wait for the container to fully start before proceeding (Figure 5).

docker compose down
docker compose up -d

Restart the Docker container — Figure 5 - Restart the LibreChat Docker container

Open LibreChat in your browser at http://localhost:3080/ and navigate to the MCP Servers section in the left sidebar. Click the Add button to open the MCP server registration form (Figure 6).

Figure 6 - Navigate to MCP Servers in LibreChat and press Add

Fill in the MCP server details in the registration form. Set the server name, enter the URL using the endpoint shown in the Ozeki SMS Client app, set the Transport to Streamable HTTPS, and set Authentication to None. Check the I trust this application checkbox, then press Create to save the MCP server entry (Figure 7).

Name: Ozeki Android SMS MCP
MCP Server URL: http://{address}:9531/mcp
Transport: Streamable HTTPS
Authentication: None

Configure and create MCP server connection — Figure 7 - Configure the MCP server details and create the connection

The server will appear in the MCP server list. Click the Connect button next to it to establish the connection to the Android gateway (Figure 8).

Figure 8 - Press Connect next to the server in the MCP list

Step 5 - Send a test SMS

The following video shows how to send an SMS message from LibreChat using the Ozeki Android SMS MCP server step-by-step.

Start a new conversation in LibreChat and enable the Ozeki Android SMS MCP tool by clicking the tools icon in the chat toolbar and toggling it on (Figure 7).

Verify Ozeki SMS MCP connection — Figure 9 - Verify the Ozeki SMS MCP server connection

Type a plain language instruction asking the AI to send an SMS to a specific phone number. LibreChat will call the Send SMS tool and process the request (Figure 10).

Send an SMS to +36301234567, the message should be "Hello from LibreChat".

Instruct AI to send an SMS message — Figure 10 - Instruct the AI to send an SMS message

You will see the result of the Send SMS tool call in the chat window. A successful response confirms that the message has been passed to the Android gateway and queued for delivery (Figure 11).

Send SMS tool result — Figure 11 - SMS tool result

Step 6 - Check the SMS in the SMS Gateway logs

The following video shows how to check the gateway logs in the Ozeki SMS Client app step-by-step. This allows you to confirm that the SMS request from LibreChat was received and processed successfully by the Android gateway.

Open the Ozeki SMS Client app on your Android device and navigate to the Settings tab in the bottom navigation bar to access the application settings. Tap the Log option to view the request and response history (Figure 12).

Figure 12 - Open the logs in the gateway settings

Select the MCP tab to show only MCP-related activity. Here you will see the incoming tool call requests from LibreChat and the responses sent back, allowing you to confirm that the SMS was dispatched successfully (Figure 13).

Figure 13 - Select the MCP tab to view the MCP activity logs

Final thoughts

You have successfully configured the Ozeki Android SMS Gateway MCP server with LibreChat. Your Android device is now acting as a local SMS gateway that it can communicate with over your local network, enabling text messages to be sent to any phone number using plain language prompts. All SMS traffic is routed through your Android device's mobile connection, with no cloud messaging API or third-party service required.