feat(claudbg-nypt): Space/PageDown page down, Shift+Space/PageUp page up in TUI

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.beans/claudbg-nypt--spacepagedown-scrolls-down-shiftspacepageup-scroll.md

@@ -0,0 +1,13 @@
+---
+# claudbg-nypt
+title: Space/PageDown scrolls down, Shift+Space/PageUp scrolls up in TUI
+status: completed
+type: feature
+priority: normal
+created_at: 2026-03-31T22:44:51Z
+updated_at: 2026-03-31T22:51:43Z
+---
+
+Pressing Space should scroll down one page in TUI (like less/more). Shift+Space scrolls up one page. PageDown/PageUp should also scroll by page.
+
+## Summary\n\n- Added  to , set each frame via \n- / scroll down one page; / scroll up one page\n- Updated block title hint and help modal (⇧Spc/PgUp entry)\n- 6 new tests

src/tui/modals/help_modal.rs

@@ -16,7 +16,7 @@ use crate::tui::state::AppState;
 
 /// Dialog dimensions.
 const DIALOG_WIDTH: u16 = 32;
-const DIALOG_HEIGHT: u16 = 15;
+const DIALOG_HEIGHT: u16 = 17;
 
 /// Compute a centered [`Rect`] of the given size within `area`.
 fn centered_rect(width: u16, height: u16, area: Rect) -> Rect {
@@ -37,6 +37,8 @@ fn centered_rect(width: u16, height: u16, area: Rect) -> Rect {
 const HELP_TEXT: &str = "\
  Navigation\n\
   \u{2191}/\u{2193} k/j  scroll up/dn\n\
+  Spc/PgDn  page down\n\
+  \u{21e7}Spc/PgUp  page up\n\
   \u{2190}/\u{2192} h/l  scroll lr\n\
   Tab       cycle panes\n\
   Enter     open/select\n\

src/tui/run.rs

@@ -226,6 +226,14 @@ pub fn run_tui() -> Result<()> {
         // Load transcript data lazily when entering a transcript screen.
         maybe_load_transcript(&mut state);
 
+        // Record the visible chat-log height before rendering so that
+        // Space / PageDown / PageUp can scroll by exactly one page.
+        // Layout: 4-row stats header + 2 border rows = 6 fixed rows.
+        state.transcript_page_height = guard
+            .terminal
+            .size()
+            .map(|s| s.height.saturating_sub(6))
+            .unwrap_or(0);
         guard.terminal.draw(|f| render(f, &state))?;
 
         if event::poll(Duration::from_millis(50))? {

src/tui/screens/transcript.rs

@@ -5,7 +5,7 @@
 //! a scrollable chat log below.
 
 use ratatui::Frame;
-use ratatui::crossterm::event::{Event, KeyCode, KeyEventKind};
+use ratatui::crossterm::event::{Event, KeyCode, KeyEventKind, KeyModifiers};
 use ratatui::layout::{Constraint, Direction, Layout, Rect};
 use ratatui::style::{Color, Modifier, Style};
 use ratatui::text::{Line, Span, Text};
@@ -301,7 +301,7 @@ pub fn render_transcript(f: &mut Frame, area: Rect, state: &AppState) {
     };
 
     let chat_block = Block::default()
-        .title(" Transcript  [↑/↓ scroll · ←/→ h-scroll · Tab focus · Esc back · ? help] ")
+        .title(" Transcript  [↑/↓ scroll · Spc/PgDn page · ←/→ h-scroll · Tab · Esc · ?] ")
         .borders(Borders::ALL)
         .border_style(chat_border_style);
 
@@ -423,6 +423,23 @@ pub fn handle_transcript_event(event: Event, state: &mut AppState) -> bool {
                 true
             }
         },
+        // Page scrolling — always acts on the chat log, matching less/more.
+        // Shift+Space must come before the plain-Space arm so the guard fires first.
+        KeyCode::Char(' ') if key.modifiers.contains(KeyModifiers::SHIFT) => {
+            let page = (state.transcript_page_height as usize).max(1);
+            state.transcript_scroll = state.transcript_scroll.saturating_sub(page);
+            true
+        }
+        KeyCode::PageUp => {
+            let page = (state.transcript_page_height as usize).max(1);
+            state.transcript_scroll = state.transcript_scroll.saturating_sub(page);
+            true
+        }
+        KeyCode::PageDown | KeyCode::Char(' ') => {
+            let page = (state.transcript_page_height as usize).max(1);
+            state.transcript_scroll = state.transcript_scroll.saturating_add(page);
+            true
+        }
         // Horizontal scroll — only meaningful in ChatLog.
         KeyCode::Left | KeyCode::Char('h') => {
             state.transcript_h_scroll = state.transcript_h_scroll.saturating_sub(1);
@@ -947,6 +964,69 @@ mod tests {
         assert!(state.show_help);
     }
 
+    fn press_with_mod(code: KeyCode, mods: KeyModifiers) -> Event {
+        Event::Key(KeyEvent {
+            code,
+            modifiers: mods,
+            kind: KeyEventKind::Press,
+            state: KeyEventState::NONE,
+        })
+    }
+
+    #[test]
+    fn space_scrolls_down_by_page() {
+        let mut state = transcript_state();
+        state.transcript_page_height = 20;
+        handle_transcript_event(press(KeyCode::Char(' ')), &mut state);
+        assert_eq!(state.transcript_scroll, 20);
+    }
+
+    #[test]
+    fn pagedown_scrolls_down_by_page() {
+        let mut state = transcript_state();
+        state.transcript_page_height = 15;
+        handle_transcript_event(press(KeyCode::PageDown), &mut state);
+        assert_eq!(state.transcript_scroll, 15);
+    }
+
+    #[test]
+    fn shift_space_scrolls_up_by_page() {
+        let mut state = transcript_state();
+        state.transcript_page_height = 10;
+        state.transcript_scroll = 25;
+        handle_transcript_event(
+            press_with_mod(KeyCode::Char(' '), KeyModifiers::SHIFT),
+            &mut state,
+        );
+        assert_eq!(state.transcript_scroll, 15);
+    }
+
+    #[test]
+    fn pageup_scrolls_up_by_page() {
+        let mut state = transcript_state();
+        state.transcript_page_height = 10;
+        state.transcript_scroll = 25;
+        handle_transcript_event(press(KeyCode::PageUp), &mut state);
+        assert_eq!(state.transcript_scroll, 15);
+    }
+
+    #[test]
+    fn pageup_clamps_at_zero() {
+        let mut state = transcript_state();
+        state.transcript_page_height = 20;
+        state.transcript_scroll = 5;
+        handle_transcript_event(press(KeyCode::PageUp), &mut state);
+        assert_eq!(state.transcript_scroll, 0);
+    }
+
+    #[test]
+    fn page_scroll_uses_one_when_height_is_zero() {
+        let mut state = transcript_state();
+        state.transcript_page_height = 0;
+        handle_transcript_event(press(KeyCode::Char(' ')), &mut state);
+        assert_eq!(state.transcript_scroll, 1);
+    }
+
     #[test]
     fn unhandled_key_not_consumed() {
         let mut state = transcript_state();

src/tui/state.rs

@@ -109,6 +109,11 @@ pub struct AppState {
     pub transcript_scroll: usize,
     /// Horizontal scroll offset (columns from the left edge of the chat log).
     pub transcript_h_scroll: usize,
+    /// Height of the visible chat-log content area in rows (set each frame).
+    ///
+    /// Used by Space / PageDown / PageUp to scroll by exactly one page.
+    /// Zero until the first frame is drawn.
+    pub transcript_page_height: u16,
 
     // ── Sub-agents panel ────────────────────────────────────────────────────
     /// Sub-agent references for the currently viewed session.
@@ -207,6 +212,7 @@ impl AppState {
             transcript_entries: Vec::new(),
             transcript_scroll: 0,
             transcript_h_scroll: 0,
+            transcript_page_height: 0,
             subagents: Vec::new(),
             subagent_selected: 0,
             focus: Focus::default(),