Codex CLI: Worktree Sessions Now On by Default
CodexCodex CLI 0.156.0 made worktree sessions the default way the agent isolates git checkouts, two weeks after the capability first shipped as an opt-in --worktree flag. The agent command center can now create a worktree session directly and lets developers filter tasks by status, making it easier to track several sessions running against the same repository at once. Together, the changes turn what was a niche flag for advanced users into Codex's default behavior for running multiple sessions safely.
Key Takeaways
- Worktree session isolation moved from an opt-in
--worktreeflag to default behavior just two weeks after its Sep 9 experimental debut. - New and forked Codex sessions now get their own isolated git checkout automatically, without a developer needing to remember a flag or command.
- The change directly targets developers who run multiple parallel Codex sessions against the same repository, a pattern that grows more common with longer autonomous tasks.
- The agent command center gained the ability to create worktree sessions directly and filter tasks by status.
- Graduating from opt-in to default typically signals OpenAI now considers a feature stable enough for general use.
- Worktree-by-default shipped in the same CLI 0.156.0 release as fullscreen UI and default voice conversations, making it one part of a broader maturity push.
Worktree Isolation Becomes the Default
Codex CLI 0.154.0, released September 9, 2026, introduced experimental worktree support: an opt-in --worktree flag or /worktree command that let developers run a session in its own isolated git checkout, avoiding the common problem of two Codex sessions stepping on each other's uncommitted changes in the same repository. Two weeks later, CLI 0.156.0 (September 22, 2026) turned that experimental capability into the default.
From Flag to Default Behavior
With worktree support now enabled by default, new and forked sessions automatically get their own isolated checkout without a developer needing to remember to pass --worktree or invoke a slash command first. This matters most for anyone running several Codex sessions in parallel against the same codebase, a pattern that has become increasingly common as developers lean on Codex for longer, more autonomous tasks.
Managing Multiple Sessions
The same release expanded Codex's agent command center, the interactive dashboard for tracking active and past sessions, with the ability to create a worktree session directly from the dashboard and filter the task list by status. As worktree-isolated sessions multiply, being able to filter down to just the running tasks, or just the ones waiting on a response, keeps the command center usable rather than becoming a long undifferentiated list.
A Maturity Milestone
Moving from an opt-in flag to default behavior is typically a signal that OpenAI considers a feature stable enough for general use rather than a rough experiment. Combined with the same release's fullscreen UI and default voice conversations, worktree-by-default rounds out one of the more consequential Codex CLI releases since the feature first launched.