How to integrate Open sea MCP with Codex

Codex is one of the most popular coding harnesses out there. And MCP makes the experience even better. With Open sea 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 Open sea MCP in Codex

Codex CLI

Run the command in your terminal.

This will auto-redirect you to the Rube authentication 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.

To verify, click on the Open config.toml

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:

2. 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"

3. Save, restart the extension, and start working.

The Open sea MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your OpenSea account. It provides structured and secure access to your NFT marketplace activity, so your agent can perform actions like listing NFTs for sale, creating and fulfilling offers, checking account details, and managing your marketplace orders on your behalf.

• NFT listing automation: Quickly list any ERC721 or ERC1155 NFT for sale on OpenSea, specifying price and collection details—all handled by your agent.
• Offer creation and management: Instruct your agent to create criteria-based or single-item offers to purchase specific NFTs or those matching certain traits within a collection.
• Order and listing fulfillment: Let your agent retrieve all necessary information and signatures to fulfill existing listings or offers, making transactions seamless and secure.
• Marketplace activity insights: Have the agent pull your profile details, fetch all active listings or offers for a given collection, and provide you with up-to-date marketplace snapshots.
• Order cancellation and management: Direct your agent to cancel open orders, listings, or offers off-chain, helping you stay in control of your marketplace participation with ease.

Conclusion

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