Feature: Pin prompt/composer input box to bottom of terminal pane (CLI)

Variant

CLI (terminal TUI)

Feature request

Add an option to pin the prompt/composer input box to the bottom of the terminal viewport so it stays visible while the conversation/transcript scrolls above it.

Problem

In long Codex CLI sessions, the transcript grows quickly. When reviewing earlier output or scrolling through tool results, the input area can scroll out of view or feel detached from the active viewport. Users must scroll back down to compose the next message, which breaks flow during debugging and multi-step tasks.

This is especially painful when:

• Reading tool output or diffs above while drafting the next instruction
• Comparing earlier assistant messages with current terminal state
• Working in shorter terminal windows (split panes, laptop screens)

Proposed behavior

• Pinned input region: Reserve a fixed bottom band of the terminal for the composer/prompt UI (text input, model indicator, approval hints, etc.).
• Scrollable transcript only: Session history, tool calls, and command output scroll in the area above; the input box never leaves the viewport.
• No overlap: Pinned UI should not obscure transcript content at the bottom (clear separator, optional reduced font size for chrome).
• Configurable (suggested): e.g. in ~/.codex/config.toml or equivalent:

[tui]
pin_composer_to_bottom = true   # default: true (or false for legacy behavior)
composer_height_lines = 4       # optional: min rows reserved for input chrome

Reference / parity

IDE-style agent UIs (including Cursor’s composer) keep the prompt anchored at the bottom while content scrolls above. Bringing the same layout to the Codex CLI would improve ergonomics for power users living in the terminal.

Environment

• OS: macOS (Darwin 25.4.0)
• Terminal: standard macOS terminal / iTerm2-style split panes

Additional notes

Related UX improvements that pair well with this:

• Optional status/footer line pinned just above the input (model, cwd, sandbox mode)
• Smarter auto-scroll: only follow output when user is already at bottom (see also scroll-behavior requests in other agent CLIs)

Happy to test a beta build or provide screen recordings if helpful.