OpenAI's 2025 Codex relaunch is a different product from its 2021 namesake. Where the original was a code-completion model, the new Codex is an agent — it can run cloud tasks for hours, draft full PRs from a single prompt, and operate locally via CLI for terminal-resident workflows. The cloud variant sandboxes environments and parallelizes tasks well, making it strong for long-horizon refactors and feature delivery. Bundled access via ChatGPT Plus ($20/mo) is the easiest entry point and a credible alternative to a dedicated coding-tool subscription if you already pay for ChatGPT. For heavy use, Pro ($200/mo) and Team/Enterprise plans unlock higher limits and concurrent task budgets. Compared to Claude Code, Codex's cloud-agent path is the differentiator — long-running autonomous tasks "just run" without your laptop staying open.
Codex is OpenAI's relaunched coding agent (2025), distinct from the original 2021-2023 Codex model. It runs as a cloud-based agent (via chatgpt.com/codex), a local CLI, and an IDE extension, handling tasks from quick edits to long-horizon multi-step engineering work. Bundled with ChatGPT Plus/Pro/Team/Enterprise plans, plus available via API.