Both tools do the same thing at a glance: you describe a change, they edit your repository. The differences that matter show up after the first hour, not in the first ten minutes.
This comparison is based on using both on the same tasks in the same repositories. Where a claim comes from a vendor rather than our own testing, it is marked as such.
Where they differ
| Claude Code | Codex | |
|---|---|---|
| Primary surface | Terminal, with IDE and web clients | IDE and web, with a CLI |
| Long-session behaviour | Compacts context and continues | Tends toward shorter sessions |
| Permission model | Per-tool prompts, configurable modes | Approval-based |
| Extensibility | MCP servers, skills, hooks | Extensions |
Long tasks
The clearest practical difference is what happens when a task outgrows a single context window. Claude Code summarises the session and keeps going, which suits multi-step refactors that touch many files. That behaviour is not free — a summary loses detail, and occasionally the detail it loses is the one that mattered.
For short, well-bounded tasks the difference is invisible, and either tool is fine.
Reviewing what changed
Neither tool removes the need to read the diff. Both will confidently produce plausible code that does not do what you asked, and both are much better at writing code than at noticing that the requirement was ambiguous.
The habit that pays off with either is the same: small tasks, read every diff, and keep the test suite fast enough that the agent can run it after each change.
Which to use
If your work is mostly terminal-based and involves large multi-file changes, Claude Code’s session handling is the stronger fit. If your team already lives in an IDE workflow and tasks are naturally small, that advantage largely disappears.
Neither choice is difficult to reverse, which is worth remembering before spending long on the decision. The switching cost is a few days of habit, not a migration.