Guide

What is Codex collaboration mode?

It's how Codex works with you, one person at a time. What the modes do now, and how teams share Codex work.

Published 2026-10-05 · by Richard Kaminsky and Mitchell Lipyansky

Codex collaboration mode is the setting that decides how OpenAI's Codex works with you. As of October 2026 it has two modes: Plan, where Codex researches and proposes a plan without changing anything, and Default, where it makes reasonable assumptions and carries out the request. You switch with Shift+Tab or /plan in the CLI, and with /plan in the IDE extension and the desktop app. Despite the name, it involves one person: it's about how the agent collaborates with its user, not about several people sharing a session. The early-2026 version had three modes, Plan, Pair Programming and Execute, behind a collaboration_modes flag that no longer does anything.

Key takeaways

  • Two modes now: Plan, which changes nothing and ends in a plan, and Default, which does the work.
  • Shift+Tab cycles the modes in the CLI; /plan works in the CLI, the IDE extension and the app.
  • collaboration_modes = true in config.toml is left over from early 2026. The feature is always on.
  • It's single-user. Teams share Codex work through AGENTS.md, shared cloud environments, @codex review on GitHub and @ChatGPT in Slack.

What are Codex's collaboration modes?

  • Plan. Codex reads the code and works out a plan without making changes; its instructions say it must not perform mutating actions, and the plan is written so it can be handed to another engineer or agent to carry out. You approve or amend the plan, then Codex implements it.
  • Default. Codex strongly prefers making reasonable assumptions and carrying out the request.

A collaboration mode is a preset: the mode plus a model, a reasoning effort and instructions. Plan can have its own reasoning effort through plan_mode_reasoning_effort in config.toml (OpenAI), and since Codex 0.156.0 a resumed session comes back in Plan mode if it was in Plan mode.

How do you switch modes?

  • CLI: Shift+Tab cycles the modes while Codex is idle, and the status line shows the current one. /plan switches to Plan and can send a prompt at the same time (OpenAI).
  • IDE extension and desktop app: /plan toggles plan mode.
  • App-server clients: turn/start takes a collaborationMode, and collaborationMode/list lists the presets. Both are marked experimental (OpenAI).

What happened to Pair Programming and Execute?

Collaboration modes arrived in Codex CLI 0.88.0 on January 21, 2026, as an experimental feature with three modes, Plan, Pair Programming and Execute, and a /collab command. Plan mode was switched on by default in 0.94.0 on February 2, the visible modes were cut to Default and Plan in 0.95.0 two days later, and the collaboration_modes feature flag was removed in 0.105.0 on February 25. /collab was removed in May because it did the same thing as /plan, and the hidden Pair Programming and Execute modes were deleted in 0.147.0 in August; their names now map to Default (openai/codex releases). If your config.toml still says collaboration_modes = true, it does no harm and does nothing.

Is collaboration mode for teams?

No. The retired Pair Programming mode's instructions told Codex that "the user is right with you in the terminal," and a collaboration mode carries only a mode, a model, a reasoning effort and instructions, with no list of participants. One person runs the session and answers its approvals, which go to them or to Codex's AI reviewer (Coding agent approvals for teams). Codex's separate multi-agent tools let one Codex start and message subagents, which is several agents for one person, too.

How do teams share Codex work?

  • AGENTS.md, checked into the repository, gives every teammate's Codex the same instructions.
  • Cloud environments can be shared with a ChatGPT workspace, but sharing the setup doesn't give anyone access to someone else's task (OpenAI).
  • GitHub: mention @codex review in a pull request for a review.
  • Slack: @Codex is now @ChatGPT. A teammate's follow-up from another account may start a separate task, and a reply in the thread doesn't give the channel access to the task (OpenAI).

Plans and prices are in Codex for teams.

How can several people steer one Codex session?

Not in Codex itself. Poly (usepoly.co) runs the real Codex in a browser room, with GPT models included. When the room is in plan mode, Codex's own plan arrives as a card on every member's screen, and anyone in the room can approve it, amend it or send it back; in the modes that ask, edits and commands then wait for any member's approval. Free to start. The other options, for Codex and Claude Code, are in Claude Code collaboration.

Common questions

How do I turn on plan mode in Codex?

Press Shift+Tab in the CLI to cycle to Plan, or type /plan, which also works in the IDE extension and the desktop app.

Does collaboration_modes = true still do anything?

No. The feature flag was removed in Codex 0.105.0 in February 2026, and collaboration modes are always on. The key is kept only so old config files still load.

Is Codex collaboration mode multiplayer?

No. It shapes how Codex works with its one user. For several people in one Codex session, it has to run somewhere they all share, such as a Poly room.

What is the difference between Plan and Default mode?

Plan researches and proposes without changing files or running mutating commands. Default makes reasonable assumptions and carries out the request.

About the authors

Written by Richard Kaminsky and Mitchell Lipyansky, the co-founders of Poly. Poly is a multiplayer AI coding workspace: a shared room where your team works with one AI agent, together. It runs at usepoly.co: any member can approve the agent's changes, and every turn ends with a receipt naming who ran it and what it cost. Corrections: support@usepoly.co.