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Codex CLI: Optional Fullscreen Terminal UI

CodexView original changelog

Codex CLI 0.156.0 introduced an optional fullscreen terminal interface, switched on with the new /tui command, giving the agent its first alternate display mode since launch. The fullscreen view adds transcript search, mouse-driven text selection, and right-click copying, replacing the plain scrolling log that previously required manual scrollback to review earlier output. The same release brought six new terminal color themes plus inline rendering of Mermaid diagrams and mathematical equations directly in Codex's responses. Developers who prefer the classic scrollback view can keep using it since fullscreen mode remains opt-in.

Key Takeaways

  • Codex CLI's /tui command switches on its first-ever alternate interface, moving from a plain scrolling log to a dedicated fullscreen view.
  • The fullscreen mode adds transcript search, letting developers jump straight to an earlier exchange instead of scrolling manually.
  • Mouse support arrives in the terminal for the first time, with click-and-drag selection and right-click copy.
  • Fullscreen mode is opt-in, so developers who prefer the classic scrollback view lose nothing by staying on it.
  • The same release adds inline Mermaid diagram and equation rendering, useful for architecture sketches and formulas without leaving the terminal.
  • Fullscreen UI shipped as one of three major features in CLI 0.156.0, alongside voice-by-default and worktree-by-default, making it one of the densest Codex CLI releases in months.

Codex CLI Gets Its First Alternate Interface

Codex CLI 0.156.0, released September 22, 2026, introduced the terminal agent's first genuinely different way of displaying a session: an optional fullscreen mode. Since its earliest versions, Codex CLI has presented conversations as a continuously scrolling log in the terminal, which works well for short sessions but becomes unwieldy once a task runs long or a developer needs to search back through what the agent already did. The new /tui command switches the next launch into a dedicated fullscreen view built to solve exactly that problem.

What Fullscreen Mode Adds

Inside the fullscreen interface, developers gain transcript search, letting them jump directly to a specific exchange instead of scrolling manually. Mouse support arrives for the first time as well: text can be selected with a click-and-drag, and right-click copies it straight to the clipboard, mirroring the conventions of a standard terminal application rather than requiring keyboard-only navigation. The feature is opt-in rather than a forced replacement, so developers who prefer the original scrollback view can continue using it exactly as before.

Bundled Visual Improvements

The same release rounded out the terminal's visual toolkit with six new color themes and the ability to render Mermaid diagrams and mathematical equations inline in Codex's responses, useful for anyone asking Codex to sketch an architecture diagram or explain a formula without leaving the terminal for a browser.

Part of a Bigger Release

Fullscreen mode shipped alongside two other substantial 0.156.0 features: voice conversations turning on by default and worktree sessions becoming the default git-isolation mode, making this one of the CLI's more feature-dense releases in recent months. OpenAI has not yet published performance or adoption details for the new interface.