Claude Code vs Codex CLI — Two Terminal Coding Agents, One Honest Comparison

The terminal got interesting. AI coding started in IDEs with Copilot autocomplete, moved to chat interfaces, and now we've got full agents that run inside your terminal and can edit code, run tests, and loop until they get it right. Claude Code (from Anthropic) and Codex CLI (from OpenAI) are the two most talked-about examples of this. I've used both. Here's what actually matters. What They Are Claude Code is Anthropic's CLI that brings Claude Sonnet/Opus directly into your terminal.