Claude Code vs Codex CLI: which AI terminal is right for you

If you have spent any time on developer Twitter recently you have heard about both. Claude Code is Anthropic's CLI agent, built around Claude (currently Opus 4.6 and Sonnet 4.6 as of this writing). Codex CLI is OpenAI's answer, built around their own model lineup. Both are open-source-adjacent, both run locally, both are designed to feel like a terminal-native developer who happens to have a brilliant assistant at their elbow.

I have been using both daily for several months now. Here is what I have learned.

The short version

If you want opinionated agentic workflows that "just work" out of the box, pick Claude Code. If you want a more flexible foundation you have to configure but can bend further, pick Codex CLI. Both are excellent. There is no wrong answer.

If you cannot make a decision, install both. They live happily side by side, and MOLTamp works as a shell for either.

Defaults

Claude Code ships with a strong opinion about how an AI agent should behave at the terminal. It has a slash command system out of the box, hooks into your codebase via .claude/ directories, supports custom subagents, has solid sandboxing defaults, and generally acts like a tool that knows what it wants to be. The first hour of using it is mostly "type prompt, watch it work" — very little configuration.

Codex CLI is more of a foundation. It assumes you will bring your own opinions about how the agent should behave, and it gives you more knobs to turn. The result is a longer onboarding curve but a higher ceiling for customization. If you have a specific workflow in mind that does not match Claude Code's built-in patterns, Codex is easier to bend.

Tool use

This is probably the biggest practical difference. Claude Code's tool-use story is mature — file editing, shell execution, git operations, web fetches, MCP server integration, all well-integrated. The agent rarely surprises you with what it can or cannot do.

Codex CLI's tool use is rapidly improving but currently more "you have to wire it up" than "it works." If you are willing to put in the configuration time you can build very specialized agent workflows. If you want defaults that just work, Claude Code wins this category.

Permissions and safety

Both have permission systems that ask you before destructive actions. Claude Code's defaults are more conservative — it tends to ask before running shell commands, before writing to certain paths, before doing anything that could nuke your day. You can loosen this. Codex defaults are slightly more permissive in my experience, which is faster but means you should pay closer attention to what the agent is about to do.

For trusted projects in trusted directories, both can be configured to skip permission prompts. For random projects you cloned five minutes ago, leave the prompts on regardless of which tool you are using.

Model quality

Both are using the best models their parent companies have shipped. As of this writing Claude Opus 4.6 (and its 1M context cousin) is exceptional for long-context coding work, deep refactors, and reasoning across large codebases. The OpenAI side of Codex is competitive on shorter tasks and improving fast.

If your daily work involves wading through large codebases, the long-context Claude models are hard to beat. If your daily work is more "small focused tasks against a clean repo," either tool will work and the speed difference matters more than the quality difference.

Customizing the terminal itself

This is where most developers drop both tools and revert to whatever they were doing before. The terminal experience for both Claude Code and Codex CLI, out of the box, is exactly as exciting as bash. Same fonts, same colors, same lack of any visual personality whatsoever.

Both work inside MOLTamp, which is the skinnable shell I am writing this in. Skin it however you want, drop in widgets, get a music player and an audio visualizer in the corners, run either Claude Code or Codex CLI inside it. The terminal experience improves dramatically and neither tool needs to change.

The honest recommendation

Use Claude Code if you want defaults that work and a strong opinionated agent system. Use Codex CLI if you want a foundation you can heavily customize. Use MOLTamp regardless of which one you pick, because both deserve a better terminal than the one they ship with.

And if you really cannot decide, install both, alias them to two-letter shortcuts, and pick whichever one you reach for more often after a week. The answer will surprise you about half the time.