How to integrate Addresszen 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 Addresszen MCP integration, you can draft, triage, summarise emails, and much more, all without leaving the terminal or the app, whichever you prefer.

Also integrate Addresszen with

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 Addresszen MCP in Codex

Run the setup command

Run this command in your terminal to add the Composio MCP server to Codex.

Terminal

It will initiate the authentication in a browser window, authorize Codex to access your Composio account.

Composio authentication page

(Optional) Authenticate with OAuth

To authenticate manually, run the login command to open a browser window and authorize Codex to access your Composio account.

bash
codex mcp login composio

Verify the connection

Run codex mcp list to confirm Composio appears as a registered MCP server.

bash
codex mcp list

Codex App

Codex App follows the same approach as VS Code.

  1. Click ⚙️ on the bottom left → MCP Servers → + Add servers → Streamable HTTP:
  2. Fill the header and Key fields with { "x-consumer-api-key" = "ck_*******" }.
  3. The Key is the Composio API key, that you can find on dashboard.composio.dev
  4. Click on Authenticate and authorize Codex to your Composio account and you're all set.
Codex App MCP setup
  1. Restart and verify if it's there in .codex/config.toml
bash
[mcp_servers.composio]
url = "https://connect.composio.dev/mcp"
http_headers = { "x-consumer-api-key" = "ck_*******" }

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

The Addresszen MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Addresszen account. It provides structured and secure access to real-time address autocomplete and verification services, so your agent can suggest accurate addresses, validate API keys, and resolve complete address details on your behalf.

  • Instant address autocomplete and suggestions: Enable your agent to quickly provide users with accurate address suggestions as they type, reducing input errors and saving time.
  • Address resolution and formatting: Let your agent resolve address suggestion IDs into full, deliverable US-format addresses for shipping, billing, or form completion.
  • API key validation and monitoring: Easily verify whether your Addresszen API key is active and usable before making further requests, ensuring seamless integrations.
  • Seamless address validation in workflows: Automate the process of checking and completing addresses, so your agent can support onboarding, checkout, or CRM data entry without manual review.

Supported Tools & Triggers

Tools
Key AvailabilityTool to get public information on an api key, including whether it is currently usable.
Resolve Address USATool to resolve an address autocompletion by its address id and return the full address in us format.

Conclusion

You've successfully integrated Addresszen with Codex using Composio's MCP server. Now you can interact with Addresszen 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 Addresszen operations
  • Managed authentication through Composio
  • 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 Addresszen operations
  • Explore cross-app workflows by connecting more toolkits
  • Build automation scripts that leverage Codex's AI capabilities

How to build Addresszen MCP Agent with another framework

FAQ

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

With a standalone Addresszen MCP server, the agents and LLMs can only access a fixed set of Addresszen tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Addresszen 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 Addresszen tools.

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

Yes, absolutely. You can configure which Addresszen 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 Addresszen data and credentials are handled as safely as possible.

Used by agents from

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glean
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Context
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HubSpot
Agent.ai
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Context
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HubSpot
Agent.ai
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Never worry about agent reliability

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