fix(tui): clear scrollback and redraw history on resize to avoid terminal glitches

- Clear scrollback and screen via ANSI/OSC 1337 before re-rendering history, reducing chopped or re-drawn text
  outside the scroll area on resize.
- Handle resize explicitly, rebuilding transcript cells at the new width and redrawing, and treat onboarding resize
  like draw to ensure a full clear.
- Add ClearScrollback command leveraging ESC[3J][H][2J plus iTerm’s 1337 code; works on Ghostty/WezTerm/Kitty,
  partial on Terminal.app, not on Alacritty.
- Note: may introduce resize flicker; debouncing/notification parity still TBD.

codex-rs/Cargo.lock

@@ -4450,7 +4450,7 @@ checksum = "3af6b589e163c5a788fab00ce0c0366f6efbb9959c2f9874b224936af7fce7e1"
 dependencies = [
  "base64",
  "indexmap 2.12.0",
- "quick-xml",
+ "quick-xml 0.38.0",
  "serde",
  "time",
 ]
@@ -7093,7 +7093,7 @@ version = "0.31.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c66a47e840dc20793f2264eb4b3e4ecb4b75d91c0dd4af04b456128e0bdd449d"
 dependencies = [
- "bitflags 2.9.1",
+ "bitflags 2.10.0",
  "rustix 1.0.8",
  "wayland-backend",
  "wayland-scanner",
@@ -7105,7 +7105,7 @@ version = "0.32.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "efa790ed75fbfd71283bd2521a1cfdc022aabcc28bdcff00851f9e4ae88d9901"
 dependencies = [
- "bitflags 2.9.1",
+ "bitflags 2.10.0",
  "wayland-backend",
  "wayland-client",
  "wayland-scanner",
@@ -7117,7 +7117,7 @@ version = "0.3.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "efd94963ed43cf9938a090ca4f7da58eb55325ec8200c3848963e98dc25b78ec"
 dependencies = [
- "bitflags 2.9.1",
+ "bitflags 2.10.0",
  "wayland-backend",
  "wayland-client",
  "wayland-protocols",
@@ -7726,7 +7726,7 @@ dependencies = [
  "os_pipe",
  "rustix 0.38.44",
  "tempfile",
- "thiserror 2.0.16",
+ "thiserror 2.0.17",
  "tree_magic_mini",
  "wayland-backend",
  "wayland-client",

codex-rs/tui/src/app.rs

@@ -268,6 +268,34 @@ impl App {
                         },
                     )?;
                 }
+                TuiEvent::Resize(size) => {
+                    // This code change addresses visual artifacts that can occur during terminal
+                    // resize events by completely redrawing the scrollback history instead of
+                    // attempting to incrementally adjust it. This approach helps ensure that the
+                    // display remains consistent and free of glitches as the terminal dimensions
+                    // change.
+                    //
+                    // TODO (joshka). This can cause flicker during resize, so we likely need to
+                    // investigate debouncing resize events or optimizing the redraw.
+                    //
+                    // TODO (joshka). I'm unsure whether this also needs to post notifications like
+                    // in the normal Draw case above.
+                    //
+                    // TODO (joshka). `size` is the size that comes from the event, which may differ
+                    // from the terminal's actual size. Some parts of the draw path use the terminal
+                    // size directly. We should standardize on one or the other so that there's no
+                    // mismatch, but debouncing first seems more important.
+                    tui.clear_scrollback()?;
+                    for cell in &self.transcript_cells {
+                        tui.insert_history_lines(cell.display_lines(size.width));
+                    }
+                    tui.draw(self.chat_widget.desired_height(size.width), |frame| {
+                        self.chat_widget.render(frame.area(), frame.buffer);
+                        if let Some((x, y)) = self.chat_widget.cursor_pos(frame.area()) {
+                            frame.set_cursor_position((x, y));
+                        }
+                    })?;
+                }
             }
         }
         Ok(true)

codex-rs/tui/src/onboarding/onboarding_screen.rs

@@ -411,7 +411,7 @@ pub(crate) async fn run_onboarding_app(
                 TuiEvent::Paste(text) => {
                     onboarding_screen.handle_paste(text);
                 }
-                TuiEvent::Draw => {
+                TuiEvent::Draw | TuiEvent::Resize(_) => {
                     if !did_full_clear_after_success
                         && onboarding_screen.steps.iter().any(|step| {
                             if let Step::Auth(w) = step {

codex-rs/tui/src/tui.rs

@@ -12,6 +12,7 @@ use std::time::Duration;
 use std::time::Instant;
 
 use crossterm::Command;
+use crossterm::ExecutableCommand;
 use crossterm::SynchronizedUpdate;
 use crossterm::event::DisableBracketedPaste;
 use crossterm::event::DisableFocusChange;
@@ -31,6 +32,7 @@ use ratatui::crossterm::execute;
 use ratatui::crossterm::terminal::disable_raw_mode;
 use ratatui::crossterm::terminal::enable_raw_mode;
 use ratatui::layout::Offset;
+use ratatui::layout::Size;
 use ratatui::text::Line;
 use tokio::select;
 use tokio_stream::Stream;
@@ -152,6 +154,7 @@ pub enum TuiEvent {
     Key(KeyEvent),
     Paste(String),
     Draw,
+    Resize(Size),
 }
 
 pub struct Tui {
@@ -270,8 +273,8 @@ impl Tui {
                                 }
                                 yield TuiEvent::Key(key_event);
                             }
-                            Event::Resize(_, _) => {
-                                yield TuiEvent::Draw;
+                            Event::Resize(columns, rows) => {
+                                yield TuiEvent::Resize(Size::new(columns, rows));
                             }
                             Event::Paste(pasted) => {
                                 yield TuiEvent::Paste(pasted);
@@ -436,6 +439,47 @@ impl Tui {
             })
         })?
     }
+
+    pub(crate) fn clear_scrollback(&mut self) -> Result<()> {
+        self.terminal.backend_mut().execute(ClearScrollback)?;
+        Ok(())
+    }
+}
+
+/// Command that emits an OSC 1337 ClearScrollback sequence.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+struct ClearScrollback;
+
+impl Command for ClearScrollback {
+    fn write_ansi(&self, f: &mut impl fmt::Write) -> fmt::Result {
+        // This sequence clears the scrollback and the screen. It aligns to the standard that the clear command currently outputs.
+        // - ESC[3J clears the scrollback buffer
+        // - ESC[H moves the cursor to the home position
+        // - ESC[2J clears the screen
+        //
+        // works on ghostty, wezterm, kitty
+        // does not work on alacritty, iterm
+        // sort of works on terminal.app (leftover content above the viewport)
+        write!(f, "\x1b[3J\x1b[H\x1b[2J")?;
+
+        // iterm specific sequence to clear scrollback
+        // see https://iterm2.com/documentation-escape-codes.html
+        write!(f, "\x1b]1337;ClearScrollback=yes\x07")?;
+
+        Ok(())
+    }
+
+    #[cfg(windows)]
+    fn execute_winapi(&self) -> Result<()> {
+        Err(std::io::Error::other(
+            "tried to execute ClearScrollback using WinAPI; use ANSI instead",
+        ))
+    }
+
+    #[cfg(windows)]
+    fn is_ansi_code_supported(&self) -> bool {
+        true
+    }
 }
 
 /// Spawn background scheduler to coalesce frame requests and emit draws at deadlines.