Codex is one of the most popular coding harnesses out there. And MCP makes the experience even better. With Zerobounce MCP integration, you can draft, triage, summarise emails, and much more, all without leaving the terminal or the app, whichever you prefer.
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Connect Zerobounce without Auth hassles
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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 Zerobounce MCP in Codex
Run the setup command
Run this command in your terminal to add the Composio MCP server to Codex.
It will initiate the authentication in a browser window, authorize Codex to access your Composio account.
(Optional) Authenticate with OAuth
To authenticate manually, run the login command to open a browser window and authorize Codex to access your Composio account.
Verify the connection
Run codex mcp list to confirm Composio appears as a registered MCP server.
Codex App
Codex App follows the same approach as VS Code.
- Click ⚙️ on the bottom left → MCP Servers → + Add servers → Streamable HTTP:
- Fill the header and Key fields with
{ "x-consumer-api-key" = "ck_*******" }. - The Key is the Composio API key, that you can find on dashboard.composio.dev
- Click on Authenticate and authorize Codex to your Composio account and you're all set.
- Restart and verify if it's there in
.codex/config.toml
What is the Zerobounce MCP server, and what's possible with it?
The Zerobounce MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Zerobounce account. It provides structured and secure access to your email validation and deliverability tools, so your agent can perform actions like validating emails, scoring leads, managing bulk jobs, and analyzing engagement—all automatically.
- Real-time email validation: Instantly check if email addresses are valid, risky, or undeliverable before sending campaigns or updating your lists.
- Bulk validation and processing: Upload files and process hundreds of emails or domains at once, with tools for tracking job status and retrieving results.
- AI-powered lead scoring: Score individual email addresses using Zerobounce AI to assess lead quality and prioritize outreach.
- Domain and pattern analysis: Identify common email address formats for any domain or run bulk domain searches to optimize your contact strategies.
- Allowlist and blocklist management: Easily update your allow and block lists to fine-tune which addresses pass or fail validation, keeping your lists clean and secure.
Supported Tools & Triggers
Conclusion
You've successfully integrated Zerobounce with Codex using Composio's MCP server. Now you can interact with Zerobounce 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 Zerobounce 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 Zerobounce operations
- Explore cross-app workflows by connecting more toolkits
- Build automation scripts that leverage Codex's AI capabilities











