Codex Knowledge Base
Agent Identity Key Rotation and Security Operations for Codex CLI
The v0.123 release of Codex CLI introduced AuthMode::AgentIdentity, giving each agent its own Ed25519 key pair and replacing forwarded bearer tokens with.
Legacy Code Archaeology with Codex CLI: Understanding, Documenting, and Safely Modernising Unfamiliar Codebases
Every senior developer has faced it: a critical system written by people who left years ago, sparse documentation, no tests.
Prompt Injection Defence for Codex CLI: Attack Vectors, Real CVEs, and Practical Hardening
Prompt injection remains OWASP's number-one vulnerability for LLM applications in 2026, appearing in an estimated 73% of production AI deployments.
Mutation Testing with Codex CLI: Why Your AI-Generated Tests Are Lying and How to Fix Them
AI coding agents are excellent at generating tests that hit every line of your code. They are also excellent at generating tests that assert almost nothing.
Context Fragment Injection: Modular DeveloperInstructions via Plugins
Until today, Codex CLI assembled its system prompt as a single monolithic DeveloperInstructions blob — one giant string stuffed into the developer-role.
Codex CLI for Ruby on Rails Teams: AGENTS.md, Bundler Sandboxing, and RSpec Workflows
Ruby on Rails remains one of the most productive full-stack frameworks in production, powering applications from Shopify to GitHub.
Codex CLI Remote Connections: Running Agents on Remote Hosts with SSH, WebSocket, and Secure Tunnels
Your code lives on a beefy cloud devbox. Your credentials sit in a vault accessible only from a private subnet. Your CI runners spin up ephemeral containers.
Prompt Caching in Codex CLI: How the Agent Loop Stays Linear and How to Maximise Cache Hits
Every Codex CLI session resends the full conversation history on each turn. Without mitigation, this is quadratic in cost and latency. The engineering.
Codex CLI Plugin System: Building, Sharing, and Managing Reusable Agent Workflows
Codex CLI v0.122 elevated plugins from an app-only curiosity to a first-class workflow primitive across the entire Codex surface.
Codex CLI and Docker MCP Toolkit: Secure Containerised Tool Servers at Scale
The Model Context Protocol gives Codex CLI access to external tools — databases, filesystems, APIs, browsers.