OpenAI’s new open-sourced coding agent
So, very silently, OpenAI, after releasing GPT-4.1 just a couple of days back, last night released OpenAI Codex CLI, a free coding agent for your terminal.
What is OpenAI Codex CLI?
Codex CLI is like having ChatGPT right inside your terminal — but way more hands-on. It doesn’t just talk about code, it runs it, edits files, helps you iterate, and keeps everything under version control. Whether you’re debugging, building features, or just too tired to Google that one command again, Codex CLI’s got your back.
https://medium.com/media/b00c8fc237c9f64872ad3d710888c462/href
Data Science in Your Pocket – No Rocket Science
It’s made for developers who live in the terminal and want AI that actually understands their project, not just throws out generic advice. You get:
Instant setup (just drop in your OpenAI API key)
Built-in safety (no network, sandboxed directory)
Visual smarts (yes, you can feed it screenshots or diagrams). Supports Multimodal stuff !!
Full transparency (open-source and community-driven)
Core Features
Chat-Driven Development
- Terminal-based tool that combines Chatgpt-level reasoning with the ability to execute code, manipulate files, and iterate under version control.
- Works directly in your repo, understanding and executing commands in context.
Zero Setup
- Just requires an OpenAI API key (OPENAI_API_KEY environment variable).
npm install -g @openai/codex
Interactive & Non-Interactive Modes
- Interactive REPL: Run codex to start a conversational session.
- Direct Execution: Pass prompts as arguments:
codex "explain this codebase to me"
Autonomous Execution Modes
- Controlled via –approval-mode flag:
Suggest (default): Only reads files; requires approval for writes/commands.
Auto Edit: Reads and patches files; requires approval for shell commands.
Full Auto: Fully autonomous (sandboxed, network-disabled).
Sandboxed Execution
- Security-first: Runs in a network-disabled, directory-sandboxed environment.
- Platform-specific hardening:
macOS: Uses Apple Seatbelt (sandbox-exec).
Linux: Runs in Docker with iptables blocking egress.
Multimodal Support
- Can process screenshots/diagrams to implement features (future capability).
Project-Aware Memory
- Merges Markdown instructions from:
~/.codex/instructions.md (global)
codex.md (repo/subdirectory)
System Requirements
Examples
OpenAI Codex CLI vs Cursor.ai
Integration:
- Codex CLI: Terminal-based, lightweight, and standalone.
- Cursor.ai: Integrated with Visual Studio Code, seamless for IDE users.
- Verdict: Cursor.ai is the winner for those who prefer an integrated IDE experience.
Functionality:
- Codex CLI: Multi-modal input (text, screenshots, diagrams), sandboxed execution, and security-focused.
- Cursor.ai: Comprehensive editing and agent capabilities, suitable for complex codebase modifications.
- Verdict: Cursor.ai wins for complex codebase modifications and integrations.
Ease of Use:
- Codex CLI: Simple to set up with zero configuration.
- Cursor.ai: Requires installation of the Visual Studio Code extension.
- Verdict: Codex CLI is easier to set up and use for those who prefer minimal setup.
Security:
- Codex CLI: Offers different approval modes (suggest, auto-edit, full-auto) and runs in a sandboxed environment.
- Cursor.ai: Security features are not explicitly highlighted.
- Verdict: Codex CLI is the winner for security-conscious projects.
Community and Contribution:
- Codex CLI: Fully open-source, allowing community contributions.
- Cursor.ai: Not open-source, limiting community involvement.
- Verdict: Codex CLI is better for those interested in contributing to open-source projects.
Versatility:
- Codex CLI: Compatible with the latest OpenAI models, offering advanced reasoning and code generation.
- Cursor.ai: Supports a wide range of programming languages and integrates with other AI tools.
- Verdict: Both are versatile, but Codex CLI has an edge with its multi-modal input and advanced reasoning capabilities.
LLM support:
- Codex CLI: Compatible with the latest OpenAI models only for now.
- Cursor.ai: Supports a wide range of LLMs.
- Verdict: Cursor.ai is any day better
Final Verdict
- For Integrated IDE Experience: Cursor.ai
- For Complex Codebase Modifications: Cursor.ai
- For Minimal Setup and Ease of Use: Codex CLI
- For Security: Codex CLI
- For Open-Source Contribution: Codex CLI
- For Versatility and Advanced Reasoning: Codex CLI
- LLM Support: Cursor.ai
Concluding,
OpenAI Codex CLI transforms terminal workflows by embedding AI-driven code execution, debugging, and version control directly into the command line. Offering zero-setup simplicity, sandboxed security, and granular approval modes, it prioritizes speed, safety, and developer control. While Cursor.ai thrives in IDEs, Codex CLI stands out as the lightweight, open-source ally for terminal-centric coders. A pivotal shift toward contextual, hands-on AI power.
Explore Codex CLI here
GitHub – openai/codex: Lightweight coding agent that runs in your terminal
OpenAI Codex CLI: Coding Agent for terminal was originally published in Data Science in Your Pocket on Medium, where people are continuing the conversation by highlighting and responding to this story.
