Codex CLI — UI Layout Reference

Agent-specific layout reference for Codex CLI (OpenAI). See agent-ui-analysis.md for shared concepts.

Observed version: v0.116.0 (2026-03-21) Rendering engine: Ink (React for terminals) Rendering approach: ANSI absolute positioning (\033[row;colH) + scroll regions

Layout Anatomy

Codex uses a fundamentally different approach from Claude Code:

• No separator-framed prompt box — uses background color instead
• Absolute cursor positioning — \033[12;2H (row 12, col 2)
• Terminal scroll regions — \033[12;41r to define scrollable content area
• Reverse index — \033M to scroll content upward

[agent output with • bullet prefix]
[empty line]
 ← dark background (rgb 57,57,57) starts here
› [user input]                       (prompt, bold ›, dark bg)
                                     (dark bg continues)
                                     (dark bg continues)
  gpt-5.4 high · 100% left · ~/project   (status line, dim, normal bg)

Real-world Examples (live session, 2026-03-21)

Startup banner

╭────────────────────────────────────────────╮
│ >_ OpenAI Codex (v0.116.0)                 │
│                                            │
│ model:     gpt-5.4 high   /model to change │
│ directory: ~/Gits/personal/tuicommander    │
╰────────────────────────────────────────────╯
  Tip: Use /mcp to list configured MCP tools.

Idle (waiting for input)

› Summarize recent commits           (ghost text, dim)
  gpt-5.4 high · 100% left · ~/Gits/personal/tuicommander

After tool execution

› create a file called /tmp/codex-test.txt with "hello"
• Creating /tmp/codex-test.txt with the requested contents.
• Added /tmp/codex-test.txt (+1 -0)
    1 +hello
───────────────────────────────────────────────────────────────────────────────
• Created /tmp/codex-test.txt with hello.
› Summarize recent commits
  gpt-5.4 high · 98% left · ~/Gits/personal/tuicommander

After interrupt (Escape)

■ Conversation interrupted - tell the model what to do differently.
› Summarize recent commits
  esc again to edit previous message

Key Differences from Claude Code

Prompt Line

• Character: › (U+203A) — bold \033[1m
• Background: dark gray rgb(57,57,57) — \033[48;2;57;57;57m
• The prompt area spans multiple rows with dark background
• Ghost text (placeholder) shown in dim: \033[2m

Multiline input: Codex supports multiline prompts where Enter adds a newline. Submit is also Enter (single line). This makes programmatic input tricky — sending text + Enter may add a newline instead of submitting.

Status Line

Single line below the prompt area, always present:

  gpt-5.4 high · 100% left · ~/Gits/personal/tuicommander

Format: <model> <effort> · <quota>% left · <directory>

Rendered in dim (\033[2m) with normal background (not dark bg).

Separator Usage

Codex uses ──── separators differently from CC — they appear between tool output and the agent’s summary response, not as a prompt box frame:

• Added /tmp/codex-test.txt (+1 -0)
    1 +hello
───────────────────────────────────────────────────────────────────────────
• Created /tmp/codex-test.txt with hello.

Spinner

Codex uses • (U+2022) as a spinner/working indicator:

• Working (10s • esc to interrupt)

The • is already in is_chrome_row’s marker set.

OSC Sequences

\033]10;?\033\\    — query terminal foreground color
\033]11;?\033\\    — query terminal background color
\033]0;...\007     — window title updates

No \033]777;notify; observed — Codex does not emit terminal notifications for approval prompts.

Approval Modes

CLI flag: -a or --ask-for-approval <POLICY>

Note: In untrusted mode, Codex auto-approves tool use within the sandbox. No interactive approval prompt was observed. The approval UI may only appear in specific edge cases or with on-request mode.

Slash Commands Observed

• Unrecognized command '/mode'. Type "/" for a list of supported commands.

Available: /model, /mcp, /fast, /feedback, /help, and others. Not observed: /stats, /status (CC-specific).

Known Issues

Enter key handling

Codex likely uses the kitty keyboard protocol to distinguish Enter (submit) from Enter (newline in multiline prompt). The TUICommander session action=input special_key=enter sends \r which Codex may interpret as newline. Workaround: send text and Enter in separate calls, but this is unreliable for multiline content.

ask_user_question tool (proposed)

GitHub issue openai/codex#9926 proposes a tabbed questionnaire UI similar to Claude Code’s skill menus. Currently available via request_user_input tool with collaboration_modes = true in config, but only in plan mode (Shift+Tab).

Rendering Mechanics (raw ANSI)

Absolute positioning

\033[12;2H     — cursor to row 12, col 2 (absolute)
\033[K         — erase to end of line

Scroll regions

\033[12;41r    — set scroll region rows 12-41
\033M          — reverse index (scroll content up within region)
\033[r         — reset scroll region

Prompt area rendering

\033[48;2;57;57;57m  — dark background starts
\033[1m›\033[22m     — bold › then unbold
\033[2m...          — dim ghost text
\033[49m             — background reset for status line

Unlike CC which uses relative cursor movement (\033[8A), Codex uses absolute positioning. This means changed_rows detection works differently — Codex updates specific rows by address rather than painting top-down.