diff --git a/MEMORY.md b/MEMORY.md
index 6303b40..4966414 100644
--- a/MEMORY.md
+++ b/MEMORY.md
@@ -182,3 +182,7 @@
 - OpenAI 연결(사용자 요청, 2026-11-03): rc.6 설치 후 OpenAI preset으로 어떤 model도 setup을 통과하지 못했다. 원인 3가지를 실제 api.openai.com 요청으로 확정했다. (1) 추론 model은 `max_tokens`·`temperature: 0` 거절 (2) preset의 `json_schema`는 strict 모드가 모든 schema node에 `type`을 요구해 Step `arguments`에서 모든 model이 400 (3) 별칭 model은 응답 `model`이 날짜 붙은 snapshot이라 identity 검사에서 닫힘.
 - OpenAI parameter style(ADR-0086, 구현·실제 OpenAI 검증 완료): `--parameter-style compatible|openai`, `openai`는 `max_completion_tokens`·temperature 생략. OpenAI preset은 `json_object`+`openai`. compatible은 digest·profile 파일 바이트가 그대로다. 별칭 identity 검사는 완화하지 않고 snapshot ID 선택을 안내한다. setup PASS gpt-6-luna·gpt-5.5-2026-04-23·gpt-4.1-2025-04-14, run 파일 수정 3/3, 테스트 생성+README 수정 2/2(pytest 4 passed), 출력 한도 1024에서 잘림 0.
 - 다음(제안, 미구현): setup/run의 `request_rejected`·`chat_completions_incompatible`에 provider 거절 이유와 응답 model ID를 보여 준다. 지금은 code 한 줄뿐이라 사용자가 원인을 알 수 없다.
+- TUI 깜빡임(사용자 보고, 2026-11-03, iTerm2·한글 IME): 대기 중에도 100ms마다 커서를 구석으로 보내 크기를 묻고(`ESC[6n`) 입력창 4줄을 지웠다 다시 그렸다. tmux 실측 대기 5초 61KB. IME 조합 글자가 입력줄 아래에 그려졌다. 수정(구현·tmux 검증): 시간 재그리기는 spinner가 돌 때와 resize 뒤 1초만, 크기 조회는 PTY 보고 크기가 바뀌었거나 resize 직후만, 같은 프레임은 건너뛰고 `?2026` 동기화 출력으로 감쌌다. 대기 5초 0바이트, 스모크 3종(rapid-resize·PTY 지연 포함) 통과. 입력창 아래에 시작 안내 줄이 다시 보이던 증상은 iTerm2에서 재현 못 함(사용자 확인 대기). 첫 CI 실패는 resize 직후 "같은 프레임 건너뛰기"가 tmux reflow로 바뀐 화면을 못 본 탓이라, resize 뒤 2초는 건너뛰지 않게 고쳤다.
+- 알려진 흔들림(기존 main에도 있음): `smoke-inline-tui.py --rapid-resize`의 `heldout-burst-restored`가 burst 중간 크기의 입력창 조각이 화면에 남아 가끔 시간 초과한다. 맥 로컬 main 8회 중 1회, 수정본 14회 중 1회. 원인은 연속 reflow를 프런트엔드가 다 따라가지 못해 지울 위치를 잘못 잡는 것(미해결). 같은 스크립트의 `stty.txt` 읽기 경합(파일 생성 직후 빈 내용 읽음)은 고쳤다.
+- TUI 사용성(사용자 요청, 2026-11-03, 미구현): Claude Code `/model`처럼 화살표로 고르는 model 선택기. opencode는 TypeScript/Go라 그대로 못 가져온다. 같은 Rust인 OpenAI Codex CLI TUI(ratatui, Apache-2.0)가 참고·이식 후보 — 셀 단위 diff 렌더링이라 지우고 다시 그리는 깜빡임 구조 자체가 없다. 한 단계씩: 깜빡임 수정 → `/model` 선택기 → 렌더러 교체 여부는 ADR로 따로 판단.
+- 18초 응답(사용자 보고, 2026-11-03): 시간 전부가 한 번의 HTTP 호출 안이었다(usage elapsedMillis 18324, 출력 52 token). 같은 경로를 tmux TUI·`xgen run`으로 다시 재면 2~5초, 직접 호출 1.5~2초라 일회성 provider 지연으로 본다(원인 확정 아님).
diff --git a/crates/xgen-cli/src/tui.rs b/crates/xgen-cli/src/tui.rs
index fa7db0f..3ea4782 100644
--- a/crates/xgen-cli/src/tui.rs
+++ b/crates/xgen-cli/src/tui.rs
@@ -36,7 +36,10 @@ const MAX_EVENTS_PER_TICK: usize = 256;
 /// Input rows the box shows before it scrolls with the caret.
 const MAX_INPUT_ROWS: usize = 8;
 const SPINNER: [char; 4] = ['|', '/', '-', '\\'];
+/// Timed repaints only animate the spinner or settle a resize; an idle pane is never repainted.
 const REDRAW_INTERVAL: Duration = Duration::from_millis(100);
+/// After a resize, keep asking the screen for its size while a lagging PTY catches up.
+const RESIZE_SETTLE: Duration = Duration::from_secs(2);
 const MAX_DEFERRED_BYTES: usize = 8 * 1024 * 1024;
 static ALTERNATE_ACTIVE: AtomicBool = AtomicBool::new(false);
 
@@ -178,10 +181,15 @@ struct Frontend {
     deferred: Vec<Vec<u8>>,
     deferred_bytes: usize,
     viewer_frame: Option<((u16, u16), Vec<String>)>,
+    /// The PTY-reported size at the last screen probe, and the screen size that probe found.
+    probed: Option<((u16, u16), (u16, u16))>,
+    last_resize: Option<Instant>,
 }
 
 #[derive(Default)]
 struct DrawnPane {
+    /// The rows as last written, so an unchanged frame is not erased and written again.
+    rows: Vec<String>,
     /// Row of the cursor inside the pane, counted from the pane's first row.
     caret_row: u16,
     caret_column: u16,
@@ -206,6 +214,13 @@ impl DrawnPane {
         u16::try_from(above + usize::from(self.caret_column) / width).unwrap_or(u16::MAX)
     }
 
+    fn shows(&self, pane: &Pane, size: (u16, u16)) -> bool {
+        self.size == Some(size)
+            && self.rows == pane.rows
+            && usize::from(self.caret_row) == pane.caret_row
+            && usize::from(self.caret_column) == pane.caret_column
+    }
+
     fn physical_rows(&self, width: u16) -> usize {
         let width = usize::from(width.max(1));
         self.line_widths
@@ -246,6 +261,8 @@ impl Frontend {
             deferred: Vec::new(),
             deferred_bytes: 0,
             viewer_frame: None,
+            probed: None,
+            last_resize: None,
         }
     }
 
@@ -253,9 +270,13 @@ impl Frontend {
         let mut finished = Vec::new();
         let mut last_draw = Instant::now();
         loop {
+            // Any message can change the pane (the prompt, the progress line, the Run state).
+            let mut dirty = false;
             // Drain everything the REPL produced before looking at the keyboard.
             loop {
-                match receiver.try_recv() {
+                let message = receiver.try_recv();
+                dirty |= message.is_ok();
+                match message {
                     Ok(Message::Output(bytes)) => finished.extend(self.screen.push(&bytes)),
                     Ok(Message::Section(kind, bytes)) => {
                         let lines = self.screen.push(&bytes);
@@ -278,7 +299,7 @@ impl Frontend {
                     Err(mpsc::TryRecvError::Empty) => break,
                 }
             }
-            let mut dirty = !finished.is_empty();
+            dirty |= !finished.is_empty();
             let event = event::poll(Duration::from_millis(25))
                 .and_then(|ready| ready.then(event::read).transpose());
             let Ok(event) = event else {
@@ -296,7 +317,16 @@ impl Frontend {
                     dirty |= self.on_event(event, &mut finished);
                 }
             }
-            if dirty || last_draw.elapsed() >= REDRAW_INTERVAL {
+            // A cancelled Run is over once the REPL asks for input again.
+            if self.requested && self.cancelling {
+                self.cancelling = false;
+                dirty = true;
+            }
+            // Repainting an idle pane erases and rewrites it, which terminals show as flicker
+            // and which moves the caret under an IME composition.
+            let timed = (self.animating() || self.settling_resize())
+                && last_draw.elapsed() >= REDRAW_INTERVAL;
+            if dirty || timed {
                 if self.draw(&finished, true).is_err() {
                     let _ = self.lines.send(InputMessage::Unavailable);
                     return;
@@ -304,13 +334,19 @@ impl Frontend {
                 finished.clear();
                 last_draw = Instant::now();
             }
-            // A cancelled Run is over once the REPL asks for input again.
-            if self.requested {
-                self.cancelling = false;
-            }
         }
     }
 
+    /// The pane shows a spinner only while a Run is in flight or being cancelled.
+    fn animating(&self) -> bool {
+        self.viewer.is_none() && (self.cancelling || (!self.requested && !self.prompt().is_empty()))
+    }
+
+    fn settling_resize(&self) -> bool {
+        self.last_resize
+            .is_some_and(|resized| resized.elapsed() < RESIZE_SETTLE)
+    }
+
     fn prompt(&self) -> String {
         strip_controls(self.screen.tail())
     }
@@ -345,7 +381,10 @@ impl Frontend {
                     .insert_str(&text.replace("\r\n", "\n").replace('\r', "\n"));
                 true
             }
-            Event::Resize(..) => true,
+            Event::Resize(..) => {
+                self.last_resize = Some(Instant::now());
+                true
+            }
             _ => false,
         }
     }
@@ -518,9 +557,71 @@ impl Frontend {
 
     fn draw(&mut self, finished: &[Vec<u8>], with_pane: bool) -> io::Result<()> {
         let mut stdout = io::stdout().lock();
-        let (width, height) = screen_size(&mut stdout, !self.alternate)?;
-        if with_pane && self.draw_result_viewer(&mut stdout, finished, (width, height))? {
-            return stdout.flush();
+        let size = self.size(&mut stdout)?;
+        if with_pane && self.unchanged(finished, size) {
+            return Ok(());
+        }
+        // Terminals that support synchronized output show the erased and rewritten pane at once.
+        queue!(stdout, terminal::BeginSynchronizedUpdate)?;
+        let painted = self.paint(&mut stdout, finished, with_pane, size);
+        queue!(stdout, terminal::EndSynchronizedUpdate)?;
+        stdout.flush()?;
+        painted
+    }
+
+    /// Whether the screen still shows exactly the frame that would be written now.
+    fn unchanged(&self, finished: &[Vec<u8>], size: (u16, u16)) -> bool {
+        finished.is_empty()
+            && self.deferred.is_empty()
+            && self.viewer.is_none()
+            && !self.alternate
+            // The terminal reflows and clips the screen behind the pane while it resizes,
+            // so a matching last frame does not prove the screen still shows it.
+            && !self.settling_resize()
+            && self.drawn.shows(&self.pane(size), size)
+    }
+
+    /// The screen size, probed only when the PTY size moved or a resize may still be settling.
+    /// Probing parks the caret in the corner for a round trip, which an IME composition shows.
+    fn size(&mut self, output: &mut impl Write) -> io::Result<(u16, u16)> {
+        let reported = terminal::size().ok();
+        if !self.settling_resize()
+            && let Some((probed_report, screen)) = self.probed
+            && reported == Some(probed_report)
+        {
+            return Ok(screen);
+        }
+        let screen = screen_size(output, !self.alternate)?;
+        self.probed = reported.map(|reported| (reported, screen));
+        Ok(screen)
+    }
+
+    fn pane(&self, (width, height): (u16, u16)) -> Pane {
+        let view = PaneView {
+            width: usize::from(width),
+            height: usize::from(height),
+            prompt: self.prompt(),
+            requested: self.requested,
+            cancelling: self.cancelling,
+            queue: &self.queue,
+            footer: &self.footer,
+            has_results: self.results.latest().is_some(),
+            spinner: SPINNER[usize::try_from(self.started.elapsed().as_millis() / 250)
+                .unwrap_or(0)
+                % SPINNER.len()],
+        };
+        layout(&view, &self.editor)
+    }
+
+    fn paint(
+        &mut self,
+        stdout: &mut impl Write,
+        finished: &[Vec<u8>],
+        with_pane: bool,
+        (width, height): (u16, u16),
+    ) -> io::Result<()> {
+        if with_pane && self.draw_result_viewer(stdout, finished, (width, height))? {
+            return Ok(());
         }
         self.viewer = None;
         if self.alternate {
@@ -534,29 +635,16 @@ impl Frontend {
         self.deferred_bytes = 0;
         lines.extend_from_slice(finished);
         let finished = &lines;
-        let origin = erase_pane(&mut stdout, &self.drawn, (width, height))?;
+        let origin = erase_pane(stdout, &self.drawn, (width, height))?;
         for line in finished {
             stdout.write_all(line)?;
             stdout.write_all(b"\x1b[0m\r\n")?;
         }
         if !with_pane {
             self.drawn = DrawnPane::default();
-            return stdout.flush();
+            return Ok(());
         }
-        let view = PaneView {
-            width: usize::from(width),
-            height: usize::from(height),
-            prompt: self.prompt(),
-            requested: self.requested,
-            cancelling: self.cancelling,
-            queue: &self.queue,
-            footer: &self.footer,
-            has_results: self.results.latest().is_some(),
-            spinner: SPINNER[usize::try_from(self.started.elapsed().as_millis() / 250)
-                .unwrap_or(0)
-                % SPINNER.len()],
-        };
-        let pane = layout(&view, &self.editor);
+        let pane = self.pane((width, height));
         let row = if finished.is_empty()
             && let Some(origin) = origin
         {
@@ -589,7 +677,8 @@ impl Frontend {
             .iter()
             .map(|row| display_width(&strip_controls(row.as_bytes())))
             .collect();
-        stdout.flush()
+        self.drawn.rows = pane.rows;
+        Ok(())
     }
 }
 
@@ -1306,6 +1395,7 @@ mod tests {
             caret_row: 1,
             caret_column: 9,
             line_widths: vec![80, 80, 80, 79],
+            ..DrawnPane::default()
         };
         let mut output = Vec::new();
         assert_eq!(erase_pane(&mut output, &drawn, (80, 24)).unwrap(), Some(20));
@@ -1317,6 +1407,73 @@ mod tests {
         assert_eq!(drawn.physical_rows(40), 8);
     }
 
+    #[test]
+    fn only_a_running_or_resizing_pane_is_repainted_on_a_timer() {
+        let (lines, _received) = mpsc::sync_channel(1);
+        let mut frontend =
+            Frontend::new(Cancellation::default(), None, "fixture".to_owned(), lines);
+        let mut finished = Vec::new();
+        frontend.screen.push(GOAL_PROMPT.as_bytes());
+        frontend.on_request(&mut finished);
+        assert!(
+            !frontend.animating(),
+            "an idle goal prompt must not repaint"
+        );
+        assert!(!frontend.settling_resize());
+
+        frontend.on_event(Event::Resize(80, 24), &mut finished);
+        assert!(
+            frontend.settling_resize(),
+            "a resize keeps probing while the PTY settles"
+        );
+
+        frontend.editor.insert_str("goal");
+        frontend.on_key(
+            KeyEvent::new(KeyCode::Enter, KeyModifiers::NONE),
+            &mut finished,
+        );
+        frontend.screen.push(b"Reading... 1s");
+        assert!(
+            frontend.animating(),
+            "the spinner turns while a Run is in flight"
+        );
+
+        let pane = frontend.pane((80, 24));
+        let mut drawn = DrawnPane {
+            size: Some((80, 24)),
+            rows: pane.rows.clone(),
+            caret_row: u16::try_from(pane.caret_row).unwrap(),
+            caret_column: u16::try_from(pane.caret_column).unwrap(),
+            ..DrawnPane::default()
+        };
+        assert!(drawn.shows(&pane, (80, 24)));
+        assert!(
+            !drawn.shows(&pane, (100, 24)),
+            "a new size is always repainted"
+        );
+        drawn.caret_column += 1;
+        assert!(
+            !drawn.shows(&pane, (80, 24)),
+            "a moved caret is always repainted"
+        );
+        drawn.caret_column -= 1;
+
+        // Spinner frames change every 250ms; restart the clock so both panes are the same frame.
+        frontend.started = Instant::now();
+        frontend.drawn = DrawnPane {
+            rows: frontend.pane((80, 24)).rows,
+            ..drawn
+        };
+        frontend.last_resize = Some(Instant::now());
+        assert!(
+            !frontend.unchanged(&[], (80, 24)),
+            "a resize reflows the screen, so a matching last frame is repainted"
+        );
+        frontend.last_resize = None;
+        assert!(frontend.unchanged(&[], (80, 24)));
+        assert!(!frontend.unchanged(&[b"output".to_vec()], (80, 24)));
+    }
+
     #[test]
     fn resizing_preserves_drafts_queued_goals_and_pending_approval_answers() {
         let (lines, received) = mpsc::sync_channel(1);
diff --git a/scripts/smoke-inline-tui.py b/scripts/smoke-inline-tui.py
index 6b628f5..9c2f6cd 100644
--- a/scripts/smoke-inline-tui.py
+++ b/scripts/smoke-inline-tui.py
@@ -298,7 +298,9 @@ def lagged_input_updated():
         recalled = "│ > Inspect viewer background" if args.results else "│ > queued after resize"
         wait_for(lambda: recalled in capture(), "history after resize")
         tmux("send-keys", "-t", "fixture", "C-c", "C-d")
-        wait_for(lambda: (root / "stty.txt").exists(), "terminal restoration")
+        # The shell creates stty.txt before stty writes it; wait for the mode list itself.
+        wait_for(lambda: (root / "stty.txt").exists()
+                 and "icanon" in (root / "stty.txt").read_text(), "terminal restoration")
         modes = (root / "stty.txt").read_text().split()
         assert "icanon" in modes and "-icanon" not in modes, "raw mode not restored"
         print(json.dumps({"status": "passed", "results": args.results, "modelCalls": len(requests), "artifacts": str(root)}))