How to integrate Engage MCP with Codex

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Introduction

Codex is one of the most popular coding harnesses out there. And MCP makes the experience even better. With Engage MCP integration, you can draft, triage, summarise emails, and much more, all without leaving the terminal or app, whichever you prefer.

Composio removes the Authentication handling completely from you. We handle the entire integration lifecycle, and all you need to do is just copy the URL below, authenticate inside Codex, and start using it.

Why use Composio?

Apart from a managed and hosted MCP server, you will get:

  • CodeAct: A dedicated workbench that allows GPT to write its code to handle complex tool chaining. Reduces to-and-fro with LLMs for frequent tool calling.
  • Large tool responses: Handle them to minimise context rot.
  • Dynamic just-in-time access to 20,000 tools across 870+ other Apps for cross-app workflows. It loads the tools you need, so GPTs aren't overwhelmed by tools you don't need.

How to install Engage MCP in Codex

Codex CLI

Run the command in your terminal.

Terminal

This will auto-redirect you to the Rube authentication page.

Rube authentication redirect page

Once you're authenticated, you will be able to access the tools.

Verify the installation by running:

codex mcp list

If you otherwise prefer to use config.toml, add the following URL to it. You can get the bearer token from rube.app → Use Rube → MCP URL → Generate token

[projects."/home/user/composio"]
trust_level = "untrusted"

[mcp_servers.rube]
bearer_token_env_var = "your bearer token"
enabled = true
url = "https://rube.app/mcp"

Codex in VS Code

If you have installed Codex in VS Code.

Then: ⚙️ → MCP Settings → + Add servers → Streamable HTTP:

Add the Rube MCP URL: https://rube.app/mcp and the bearer token.

VS Code MCP Settings

To verify, click on the Open config.toml

Open config toml in Codex

Make sure it's there:

[mcp_servers.composio_rube]
bearer_token_env_var = "your bearer token"
enabled = true
url = "https://rube.app/mcp"

Codex App

Codex App follows the same approach as VS Code.

  1. Click ⚙️ on the bottom left → MCP Servers → + Add servers → Streamable HTTP:
Codex App MCP Settings
  1. Restart and verify if it's there in .codex/config.toml
[mcp_servers.composio_rube]
bearer_token_env_var = "your bearer token"
enabled = true
url = "https://rube.app/mcp"
  1. Save, restart the extension, and start working.

What is the Engage MCP server, and what's possible with it?

The Engage MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Engage account. It provides structured and secure access so your agent can perform Engage operations on your behalf.

Supported Tools & Triggers

Tools
Add Customer to AccountsTool to add a customer to one or more account entities.
Add User to ListsTool to add a Customer or Account to one or more Lists in Engage.
Archive ListTool to archive a List in Engage.
Archive UserTool to archive a user in Engage.
Convert User TypeTool to convert a user between Customer and Account entity types.
Create ListTool to create a new List in Engage for organizing subscribers.
Create UserTool to create a new user (Customer or Account) in Engage.
Delete Subscriber From ListTool to remove a subscriber from a List entirely (different from unsubscribing).
Delete UserTool to completely delete all user data for a Customer or Account.
Get Account MembersTool to retrieve all members (Customers) of an Account in Engage.
Get ListTool to retrieve a single List by its ID.
Get User By IDTool to retrieve a single user by their user ID.
List ListsTool to retrieve a paginated list of all Lists in Engage.
List UsersTool to retrieve a paginated list of all users in Engage.
Merge UsersTool to merge two user profiles in Engage.
Remove Customer from AccountTool to remove a Customer from an Account in Engage.
Batch RequestTool to batch multiple create user, update user, and add user events operations into a single API call.
Subscribe User to ListTool to create a user and subscribe them to an Engage.
Track User EventTool to add user events to Engage.
Update Account RoleTool to update the role of a Customer in an Account or set a new one if none exists.
Update Subscriber StatusTool to update a subscriber's status on a List.
Update UserTool to update user data and attributes on Engage.

Conclusion

You've successfully integrated Engage with Codex using Composio's Rube MCP server. Now you can interact with Engage directly from your terminal, VS Code, or the Codex App using natural language commands.

Key benefits of this setup:

  • Seamless integration across CLI, VS Code, and standalone app
  • Natural language commands for Engage operations
  • Managed authentication through Composio's Rube
  • Access to 20,000+ tools across 870+ apps for cross-app workflows
  • CodeAct workbench for complex tool chaining

Next steps:

  • Try asking Codex to perform various Engage operations
  • Explore cross-app workflows by connecting more toolkits
  • Build automation scripts that leverage Codex's AI capabilities

How to build Engage MCP Agent with another framework

FAQ

What are the differences in Tool Router MCP and Engage MCP?

With a standalone Engage MCP server, the agents and LLMs can only access a fixed set of Engage tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Engage and many other apps based on the task at hand, all through a single MCP endpoint.

Can I use Tool Router MCP with Codex?

Yes, you can. Codex fully supports MCP integration. You get structured tool calling, message history handling, and model orchestration while Tool Router takes care of discovering and serving the right Engage tools.

Can I manage the permissions and scopes for Engage while using Tool Router?

Yes, absolutely. You can configure which Engage scopes and actions are allowed when connecting your account to Composio. You can also bring your own OAuth credentials or API configuration so you keep full control over what the agent can do.

How safe is my data with Composio Tool Router?

All sensitive data such as tokens, keys, and configuration is fully encrypted at rest and in transit. Composio is SOC 2 Type 2 compliant and follows strict security practices so your Engage data and credentials are handled as safely as possible.

Used by agents from

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Context
Letta
glean
HubSpot
Agent.ai
Altera
DataStax
Entelligence
Rolai
Context
Letta
glean
HubSpot
Agent.ai
Altera
DataStax
Entelligence
Rolai

Never worry about agent reliability

We handle tool reliability, observability, and security so you never have to second-guess an agent action.