Problem

The TUI's "edit queued message" shortcut (Alt+Up) is either silently swallowed or recognized as another key combination by Apple Terminal, Warp, and VSCode's integrated terminal on macOS. Users in those environments see the hint but pressing the keys does nothing.

Mental model

When a model turn is in progress the user can still type follow-up messages. These are queued and displayed below the composer with a hint line showing how to pop the most recent one back into the editor. The hint text and the actual key handler must agree on which shortcut is used, and that shortcut must actually reach the TUI—i.e. it must not be intercepted by the host terminal.

Three terminals are known to intercept Alt+Up: Apple Terminal (remaps it to cursor movement), Warp (consumes it for its own command palette), and VSCode (maps it to "move line up"). For these we use Shift+Left instead.

macOS Native Terminal	Warp	VSCode Terminal

Non-goals

• Making the binding user-configurable at runtime (deferred to a broader keybinding-config effort).
• Remapping any other shortcuts that might be terminal-specific.

Tradeoffs

• Exhaustive match instead of a wildcard default. The queued_message_edit_binding_for_terminal function explicitly lists every TerminalName variant. This is intentional: adding a new terminal to the enum will produce a compile error, forcing the author to decide which binding that terminal should use.

• Binding lives on ChatWidget, hint lives on QueuedUserMessages. The key event handler that actually acts on the press is in ChatWidget, but the rendered hint text is inside QueuedUserMessages. These are kept in sync by ChatWidget calling bottom_pane.set_queued_message_edit_binding(self.queued_message_edit_binding) during construction. A mismatch would show the wrong hint but would not lose data.

Architecture

  graph TD
      TI["terminal_info().name"] --> FN["queued_message_edit_binding_for_terminal(name)"]
      FN --> KB["KeyBinding"]
      KB --> CW["ChatWidget.queued_message_edit_binding<br/><i>key event matching</i>"]
      KB --> BP["BottomPane.set_queued_message_edit_binding()"]
      BP --> QUM["QueuedUserMessages.edit_binding<br/><i>rendered in hint line</i>"]

      subgraph "Special terminals (Shift+Left)"
          AT["Apple Terminal"]
          WT["Warp"]
          VS["VSCode"]
      end

      subgraph "Default (Alt+Up)"
          GH["Ghostty"]
          IT["iTerm2"]
          OT["Others…"]
      end

      AT --> FN
      WT --> FN
      VS --> FN
      GH --> FN
      IT --> FN
      OT --> FN

No new crates or public API surface. The only cross-crate dependency added is codex_core::terminal::{TerminalName, terminal_info}, which already existed for telemetry.

Observability

No new logging. Terminal detection already emits a tracing::debug! log line at startup with the detected terminal name, which is sufficient to diagnose binding mismatches.

Tests

• Existing alt_up_edits_most_recent_queued_message test is preserved and explicitly sets the Alt+Up binding to isolate from the host terminal.
• New parameterized async tests verify Shift+Left works for Apple Terminal, Warp, and VSCode.
• A sync unit test asserts the mapping table covers the three special terminals (Shift+Left) and that iTerm2 still gets Alt+Up.

Fixes #4490