Install Imperium MCP Security — Prompt-Injection, Jailbreak & Tool Poisoning Firewall in Codex

What you need first

• Codex, installed.
• Nothing else: the server runs on its publisher's machines and Codex connects to it.

Steps

1. Run this in a terminal. It writes the server into ~/.codex/config.toml, which the Codex CLI, its IDE extension and the ChatGPT desktop app share.

codex mcp add mcp-security --url https://mcp-security.agentdiet.dev/mcp

2. Start Codex again and type /mcp: the server is listed.

Check it worked

Ask Codex: List the tools of mcp-security.

If it does not start

401 Unauthorized

The endpoint wants a sign-in or a key. Sign in when Codex asks.