OpenAI Codex

Overview

Codex is the reason "which coding agent" has become a question about which subscription you already pay for. It ships as a CLI, an IDE extension, a cloud agent that works on a branch while you do something else, and inside the ChatGPT desktop app, and every one of those surfaces is included in every ChatGPT tier — Free, Go at $8, Plus at $20, Pro from $100, Business at $20 a seat — with ChatGPT Work and Codex drawing on one shared usage budget. That bundling is the pitch and the catch. Usage on credit-based plans is metered in token credits, so the cost of a long refactor is less predictable than a seat price suggests, and reviewers find the entry tiers hit limits fast. A team can instead point Codex at an API key and pay standard API rates in CI. Independent reviewers in 2026 report it being more token-efficient than Claude Code on comparable tasks; treat that as a reviewer finding, not a benchmark. Buy Codex if your team already pays for ChatGPT and wants an agent across terminal, editor, and cloud without a new vendor. Buy Claude Code if you want the agent in the terminal with explicit permission modes and project instructions, or Cursor if the editor is where your developers live.

Pros & Cons