feat(claudbg-agi7): transcript search panel with highlight and n/N navigation

- Bottom search bar (3 rows, always visible), press 't' to focus
- Case-insensitive match highlighting (yellow bg) across all spans
- Panel title shows current/total match count (e.g. "2/7")
- 'n'/'N' navigate next/previous match, wrapping around
- Enter applies search and returns focus to chat log
- Esc clears search and returns focus to chat log
- Tab cycles ChatLog → SubagentsPanel → SearchInput → ChatLog
- Help modal updated with search keybindings

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

.beans/claudbg-agi7--tui-transcript-search-panel-with-highlight-and-nn.md

@@ -0,0 +1,11 @@
+---
+# claudbg-agi7
+title: TUI transcript search panel with highlight and n/N navigation
+status: completed
+type: feature
+priority: normal
+created_at: 2026-03-31T22:51:54Z
+updated_at: 2026-03-31T23:02:42Z
+---
+
+Add a search panel to transcript screens (bottom, like filter panel). Press 't' to focus search input. Highlights all case-insensitive matches. Press 'n'/'N' to jump to next/previous match. Panel shows match count. Enter returns focus to transcript.

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 = 17;
+const DIALOG_HEIGHT: u16 = 20;
 
 /// Compute a centered [`Rect`] of the given size within `area`.
 fn centered_rect(width: u16, height: u16, area: Rect) -> Rect {
@@ -43,6 +43,12 @@ const HELP_TEXT: &str = "\
   Tab       cycle panes\n\
   Enter     open/select\n\
   Esc       go back\n\
+\n\
+ Search (transcript)\n\
+  t         open search\n\
+  n / N     next/prev match\n\
+  Enter     apply & close\n\
+  Esc       clear & close\n\
 \n\
  Global\n\
   q/Q       quit\n\

src/tui/run.rs

@@ -228,11 +228,11 @@ pub fn run_tui() -> Result<()> {
 
         // 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.
+        // Layout: 4-row stats header + 3-row search bar + 2 border rows = 9 fixed rows.
         state.transcript_page_height = guard
             .terminal
             .size()
-            .map(|s| s.height.saturating_sub(6))
+            .map(|s| s.height.saturating_sub(9))
             .unwrap_or(0);
         guard.terminal.draw(|f| render(f, &state))?;
 

src/tui/screens/transcript.rs

@@ -238,6 +238,102 @@ pub fn build_chat_lines(entries: &[RawEntry], color_enabled: bool) -> Vec<Line<'
     lines
 }
 
+// ---------------------------------------------------------------------------
+// Search helpers
+// ---------------------------------------------------------------------------
+
+/// Style applied to matched substrings in search mode.
+const SEARCH_HIGHLIGHT: Style = Style::new().bg(Color::Yellow).fg(Color::Black);
+
+/// Split a single [`Span`] around all case-insensitive occurrences of `query_lower`,
+/// returning a vec of spans where matches are styled with [`SEARCH_HIGHLIGHT`].
+///
+/// Only operates on ASCII-safe byte positions — if `text` and its lowercase
+/// counterpart have different byte lengths (multi-byte Unicode edge case) the
+/// original span is returned unchanged.
+fn split_span_with_search(span: Span<'static>, query_lower: &str) -> Vec<Span<'static>> {
+    let original_style = span.style;
+    let text = span.content.into_owned();
+    let text_lower = text.to_lowercase();
+
+    // Guard: only byte-level slice when lengths match (safe for ASCII / common Unicode).
+    if text.len() != text_lower.len() || !text_lower.contains(query_lower) {
+        return vec![Span::styled(text, original_style)];
+    }
+
+    let mut result: Vec<Span<'static>> = Vec::new();
+    let mut pos = 0usize;
+    while pos < text.len() {
+        match text_lower[pos..].find(query_lower) {
+            None => {
+                result.push(Span::styled(text[pos..].to_string(), original_style));
+                break;
+            }
+            Some(rel) => {
+                let abs = pos + rel;
+                if abs > pos {
+                    result.push(Span::styled(text[pos..abs].to_string(), original_style));
+                }
+                result.push(Span::styled(
+                    text[abs..abs + query_lower.len()].to_string(),
+                    SEARCH_HIGHLIGHT,
+                ));
+                pos = abs + query_lower.len();
+            }
+        }
+    }
+    if result.is_empty() {
+        result.push(Span::styled(text, original_style));
+    }
+    result
+}
+
+/// Post-process rendered chat lines to highlight all case-insensitive matches
+/// of `query`.  Returns lines unchanged when `query` is empty.
+fn apply_search_highlights(lines: Vec<Line<'static>>, query: &str) -> Vec<Line<'static>> {
+    if query.is_empty() {
+        return lines;
+    }
+    let query_lower = query.to_lowercase();
+    lines
+        .into_iter()
+        .map(|line| {
+            // Quick check: does the plain text of this line contain the query?
+            let plain: String = line.spans.iter().map(|s| s.content.as_ref()).collect();
+            if !plain.to_lowercase().contains(&*query_lower) {
+                return line;
+            }
+            // Rebuild spans, splitting around matches.
+            let new_spans: Vec<Span<'static>> = line
+                .spans
+                .into_iter()
+                .flat_map(|sp| split_span_with_search(sp, &query_lower))
+                .collect();
+            Line::from(new_spans)
+        })
+        .collect()
+}
+
+/// Return the indices of chat-log lines that contain `query` (case-insensitive).
+///
+/// Calls [`build_chat_lines`] to get the rendered lines, then filters by text content.
+/// Returns an empty vec when `query` is empty.
+pub fn find_match_lines(entries: &[RawEntry], query: &str, color_enabled: bool) -> Vec<usize> {
+    if query.is_empty() {
+        return Vec::new();
+    }
+    let query_lower = query.to_lowercase();
+    build_chat_lines(entries, color_enabled)
+        .iter()
+        .enumerate()
+        .filter(|(_, line)| {
+            let text: String = line.spans.iter().map(|s| s.content.as_ref()).collect();
+            text.to_lowercase().contains(&*query_lower)
+        })
+        .map(|(i, _)| i)
+        .collect()
+}
+
 /// Truncate a string to at most `max_chars` chars (Unicode-safe).
 fn truncate_str(s: &str, max_chars: usize) -> String {
     let char_count = s.chars().count();
@@ -252,11 +348,60 @@ fn truncate_str(s: &str, max_chars: usize) -> String {
 // Rendering
 // ---------------------------------------------------------------------------
 
+/// Draw the search bar at the bottom of the transcript area.
+fn render_search_bar(f: &mut Frame, area: Rect, state: &AppState) {
+    let focused = state.focus == Focus::SearchInput;
+
+    let border_style = if focused {
+        Style::default().fg(Color::Yellow)
+    } else {
+        Style::default()
+    };
+
+    let match_info = if !state.search_active.is_empty() {
+        let total = state.search_match_lines.len();
+        if total == 0 {
+            "  no matches".to_string()
+        } else {
+            let cur = state.search_current_match + 1;
+            format!("  {cur}/{total}")
+        }
+    } else {
+        String::new()
+    };
+
+    let block = Block::default()
+        .title(format!(" Search{match_info} "))
+        .borders(Borders::ALL)
+        .border_style(border_style);
+
+    let label = Span::styled("Search: ", Style::default().add_modifier(Modifier::BOLD));
+    let input_line = if focused {
+        let mut spans = vec![label, Span::raw(state.search_input.clone())];
+        spans.push(Span::styled("█", Style::default().fg(Color::Yellow)));
+        Line::from(spans)
+    } else if state.search_input.is_empty() && state.search_active.is_empty() {
+        Line::from(vec![
+            label,
+            Span::styled(
+                "Press 't' to search — type and press Enter to highlight matches",
+                Style::default().fg(Color::DarkGray),
+            ),
+        ])
+    } else {
+        Line::from(vec![label, Span::raw(state.search_input.clone())])
+    };
+
+    let paragraph = Paragraph::new(input_line).block(block);
+    f.render_widget(paragraph, area);
+}
+
 /// Draw the transcript screen onto `area` of the given frame.
 ///
 /// Layout:
 /// - Top 4 lines: stats header (inside a bordered block).
-/// - Remaining lines: scrollable chat log.
+/// - Middle: scrollable chat log (left) + sub-agents panel (right).
+/// - Bottom 3 lines: search bar.
 pub fn render_transcript(f: &mut Frame, area: Rect, state: &AppState) {
     // Determine the session_id for the header.
     let session_id = match &state.screen {
@@ -265,12 +410,11 @@ pub fn render_transcript(f: &mut Frame, area: Rect, state: &AppState) {
         _ => String::new(),
     };
 
-    // Split area: header (fixed) | chat log (min).
-    // Header block: 2 content lines + 2 border lines = 4 rows total.
-    let header_height: u16 = 4;
+    // Split area: header (fixed) | body (min) | search bar (fixed).
     let chunks = Layout::vertical([
-        Constraint::Length(header_height),
-        Constraint::Min(1),
+        Constraint::Length(4),  // stats header
+        Constraint::Min(1),     // chat log + sub-agents
+        Constraint::Length(3),  // search bar
     ])
     .split(area);
 
@@ -292,7 +436,10 @@ pub fn render_transcript(f: &mut Frame, area: Rect, state: &AppState) {
         .split(chunks[1]);
 
     // ── Chat log ─────────────────────────────────────────────────────────────
-    let chat_lines = build_chat_lines(&state.transcript_entries, state.color_enabled);
+    let mut chat_lines = build_chat_lines(&state.transcript_entries, state.color_enabled);
+    if !state.search_active.is_empty() {
+        chat_lines = apply_search_highlights(chat_lines, &state.search_active);
+    }
 
     let chat_border_style = if state.focus == Focus::ChatLog {
         Style::default().fg(Color::Yellow)
@@ -300,8 +447,15 @@ pub fn render_transcript(f: &mut Frame, area: Rect, state: &AppState) {
         Style::default()
     };
 
+    let search_hint = if !state.search_active.is_empty() {
+        " · n/N match"
+    } else {
+        ""
+    };
     let chat_block = Block::default()
-        .title(" Transcript  [↑/↓ scroll · Spc/PgDn page · ←/→ h-scroll · Tab · Esc · ?] ")
+        .title(format!(
+            " Transcript  [↑/↓ scroll · Spc/PgDn page · t search{search_hint} · Tab · Esc · ?] "
+        ))
         .borders(Borders::ALL)
         .border_style(chat_border_style);
 
@@ -357,6 +511,9 @@ pub fn render_transcript(f: &mut Frame, area: Rect, state: &AppState) {
         .block(subagents_block);
 
     f.render_widget(subagents_paragraph, body_chunks[1]);
+
+    // ── Search bar ───────────────────────────────────────────────────────────
+    render_search_bar(f, chunks[2], state);
 }
 
 // ---------------------------------------------------------------------------
@@ -374,12 +531,18 @@ pub fn handle_transcript_event(event: Event, state: &mut AppState) -> bool {
         return false;
     }
 
+    // When the search bar is focused, route all input there.
+    if state.focus == Focus::SearchInput {
+        return handle_search_input_event(key.code, state);
+    }
+
     match key.code {
-        // Toggle focus between ChatLog and SubagentsPanel.
+        // Toggle focus: ChatLog → SubagentsPanel → SearchInput → ChatLog.
         KeyCode::Tab => {
             state.focus = match state.focus {
                 Focus::ChatLog => Focus::SubagentsPanel,
-                Focus::SubagentsPanel | Focus::FilterInput => Focus::ChatLog,
+                Focus::SubagentsPanel => Focus::SearchInput,
+                Focus::SearchInput | Focus::FilterInput => Focus::ChatLog,
             };
             true
         }
@@ -398,13 +561,40 @@ pub fn handle_transcript_event(event: Event, state: &mut AppState) -> bool {
             state.show_help = true;
             true
         }
+        // Jump directly to the search input.
+        KeyCode::Char('t') => {
+            state.focus = Focus::SearchInput;
+            true
+        }
+        // Next match.
+        KeyCode::Char('n') => {
+            if !state.search_match_lines.is_empty() {
+                state.search_current_match =
+                    (state.search_current_match + 1) % state.search_match_lines.len();
+                state.transcript_scroll =
+                    state.search_match_lines[state.search_current_match];
+            }
+            true
+        }
+        // Previous match (Shift+N).
+        KeyCode::Char('N') => {
+            if !state.search_match_lines.is_empty() {
+                state.search_current_match = state
+                    .search_current_match
+                    .checked_sub(1)
+                    .unwrap_or(state.search_match_lines.len() - 1);
+                state.transcript_scroll =
+                    state.search_match_lines[state.search_current_match];
+            }
+            true
+        }
         // Directional keys are routed based on the focused panel.
         KeyCode::Up | KeyCode::Char('k') => match state.focus {
             Focus::SubagentsPanel => {
                 state.subagent_selected = state.subagent_selected.saturating_sub(1);
                 true
             }
-            Focus::ChatLog | Focus::FilterInput => {
+            Focus::ChatLog | Focus::FilterInput | Focus::SearchInput => {
                 state.transcript_scroll = state.transcript_scroll.saturating_sub(1);
                 true
             }
@@ -418,7 +608,7 @@ pub fn handle_transcript_event(event: Event, state: &mut AppState) -> bool {
                 }
                 true
             }
-            Focus::ChatLog | Focus::FilterInput => {
+            Focus::ChatLog | Focus::FilterInput | Focus::SearchInput => {
                 state.transcript_scroll = state.transcript_scroll.saturating_add(1);
                 true
             }
@@ -469,6 +659,53 @@ pub fn handle_transcript_event(event: Event, state: &mut AppState) -> bool {
     }
 }
 
+/// Handle a key event while the search input bar is focused.
+///
+/// Returns `true` when the event is consumed.
+fn handle_search_input_event(code: KeyCode, state: &mut AppState) -> bool {
+    match code {
+        // Character input: append to search_input.
+        KeyCode::Char(c) => {
+            state.search_input.push(c);
+            true
+        }
+        // Backspace: remove last char.
+        KeyCode::Backspace => {
+            state.search_input.pop();
+            true
+        }
+        // Enter: apply the search, compute match lines, return focus to ChatLog.
+        KeyCode::Enter => {
+            let query = state.search_input.trim().to_string();
+            state.search_active = query.clone();
+            state.search_match_lines =
+                find_match_lines(&state.transcript_entries, &query, state.color_enabled);
+            state.search_current_match = 0;
+            // Scroll to first match if any.
+            if let Some(&first) = state.search_match_lines.first() {
+                state.transcript_scroll = first;
+            }
+            state.focus = Focus::ChatLog;
+            true
+        }
+        // Escape: clear search and return focus to ChatLog.
+        KeyCode::Esc => {
+            state.search_input.clear();
+            state.search_active.clear();
+            state.search_match_lines.clear();
+            state.search_current_match = 0;
+            state.focus = Focus::ChatLog;
+            true
+        }
+        // Tab: cycle focus back to ChatLog.
+        KeyCode::Tab => {
+            state.focus = Focus::ChatLog;
+            true
+        }
+        _ => true, // consume all other keys while search is focused
+    }
+}
+
 // ---------------------------------------------------------------------------
 // Data loading
 // ---------------------------------------------------------------------------
@@ -923,12 +1160,14 @@ mod tests {
     }
 
     #[test]
-    fn tab_toggles_focus() {
+    fn tab_cycles_focus() {
         let mut state = transcript_state();
         assert_eq!(state.focus, Focus::ChatLog);
         handle_transcript_event(press(KeyCode::Tab), &mut state);
         assert_eq!(state.focus, Focus::SubagentsPanel);
         handle_transcript_event(press(KeyCode::Tab), &mut state);
+        assert_eq!(state.focus, Focus::SearchInput);
+        handle_transcript_event(press(KeyCode::Tab), &mut state);
         assert_eq!(state.focus, Focus::ChatLog);
     }
 
@@ -1019,6 +1258,155 @@ mod tests {
         assert_eq!(state.transcript_scroll, 0);
     }
 
+    // ── Search input focus ───────────────────────────────────────────────────
+
+    #[test]
+    fn t_key_focuses_search_input() {
+        let mut state = transcript_state();
+        let consumed = handle_transcript_event(press(KeyCode::Char('t')), &mut state);
+        assert!(consumed);
+        assert_eq!(state.focus, Focus::SearchInput);
+    }
+
+    #[test]
+    fn search_char_input_appends() {
+        let mut state = transcript_state();
+        state.focus = Focus::SearchInput;
+        handle_transcript_event(press(KeyCode::Char('h')), &mut state);
+        handle_transcript_event(press(KeyCode::Char('i')), &mut state);
+        assert_eq!(state.search_input, "hi");
+    }
+
+    #[test]
+    fn search_backspace_removes_char() {
+        let mut state = transcript_state();
+        state.focus = Focus::SearchInput;
+        state.search_input = "hi".to_string();
+        handle_transcript_event(press(KeyCode::Backspace), &mut state);
+        assert_eq!(state.search_input, "h");
+    }
+
+    #[test]
+    fn search_enter_applies_query_and_returns_focus() {
+        let mut state = transcript_state();
+        state.focus = Focus::SearchInput;
+        state.search_input = "user".to_string();
+        handle_transcript_event(press(KeyCode::Enter), &mut state);
+        assert_eq!(state.search_active, "user");
+        assert_eq!(state.focus, Focus::ChatLog);
+    }
+
+    #[test]
+    fn search_esc_clears_and_returns_focus() {
+        let mut state = transcript_state();
+        state.focus = Focus::SearchInput;
+        state.search_input = "hi".to_string();
+        state.search_active = "hi".to_string();
+        state.search_match_lines = vec![1, 3];
+        handle_transcript_event(press(KeyCode::Esc), &mut state);
+        assert_eq!(state.search_input, "");
+        assert_eq!(state.search_active, "");
+        assert!(state.search_match_lines.is_empty());
+        assert_eq!(state.focus, Focus::ChatLog);
+    }
+
+    // ── n/N match navigation ─────────────────────────────────────────────────
+
+    #[test]
+    fn n_advances_to_next_match() {
+        let mut state = transcript_state();
+        state.search_match_lines = vec![2, 5, 9];
+        state.search_current_match = 0;
+        handle_transcript_event(press(KeyCode::Char('n')), &mut state);
+        assert_eq!(state.search_current_match, 1);
+        assert_eq!(state.transcript_scroll, 5);
+    }
+
+    #[test]
+    fn n_wraps_to_first_match() {
+        let mut state = transcript_state();
+        state.search_match_lines = vec![2, 5, 9];
+        state.search_current_match = 2; // last
+        handle_transcript_event(press(KeyCode::Char('n')), &mut state);
+        assert_eq!(state.search_current_match, 0);
+        assert_eq!(state.transcript_scroll, 2);
+    }
+
+    #[test]
+    fn big_n_goes_to_previous_match() {
+        let mut state = transcript_state();
+        state.search_match_lines = vec![2, 5, 9];
+        state.search_current_match = 2;
+        handle_transcript_event(press(KeyCode::Char('N')), &mut state);
+        assert_eq!(state.search_current_match, 1);
+        assert_eq!(state.transcript_scroll, 5);
+    }
+
+    #[test]
+    fn big_n_wraps_to_last_match() {
+        let mut state = transcript_state();
+        state.search_match_lines = vec![2, 5, 9];
+        state.search_current_match = 0; // first
+        handle_transcript_event(press(KeyCode::Char('N')), &mut state);
+        assert_eq!(state.search_current_match, 2);
+        assert_eq!(state.transcript_scroll, 9);
+    }
+
+    #[test]
+    fn n_with_no_matches_does_nothing() {
+        let mut state = transcript_state();
+        state.search_match_lines = vec![];
+        state.transcript_scroll = 3;
+        handle_transcript_event(press(KeyCode::Char('n')), &mut state);
+        assert_eq!(state.transcript_scroll, 3); // unchanged
+    }
+
+    // ── find_match_lines + highlight helpers ─────────────────────────────────
+
+    #[test]
+    fn find_match_lines_empty_query_returns_empty() {
+        let result = find_match_lines(&[], "", false);
+        assert!(result.is_empty());
+    }
+
+    #[test]
+    fn find_match_lines_finds_case_insensitive() {
+        let entries = vec![
+            user_text_entry("Hello Claude"),
+            user_text_entry("world"),
+            user_text_entry("hello again"),
+        ];
+        let lines = find_match_lines(&entries, "hello", false);
+        // Lines 0 and 2 (from entries 0 and 2) should match.
+        assert_eq!(lines.len(), 2);
+    }
+
+    #[test]
+    fn apply_search_highlights_empty_query_unchanged() {
+        let original = vec![Line::from("some text")];
+        let result = apply_search_highlights(original.clone(), "");
+        assert_eq!(result.len(), original.len());
+    }
+
+    #[test]
+    fn split_span_with_search_no_match_unchanged() {
+        let span = Span::raw("hello world");
+        let result = split_span_with_search(span, "xyz");
+        assert_eq!(result.len(), 1);
+        assert_eq!(result[0].content, "hello world");
+    }
+
+    #[test]
+    fn split_span_with_search_highlights_match() {
+        let span = Span::raw("hello world");
+        let result = split_span_with_search(span, "world");
+        // Expect: "hello " + highlighted "world"
+        assert_eq!(result.len(), 2);
+        assert_eq!(result[0].content, "hello ");
+        assert_eq!(result[1].content, "world");
+        assert_eq!(result[1].style, SEARCH_HIGHLIGHT);
+    }
+
     #[test]
     fn page_scroll_uses_one_when_height_is_zero() {
         let mut state = transcript_state();

src/tui/state.rs

@@ -80,6 +80,8 @@ pub enum Focus {
     SubagentsPanel,
     /// The filter input bar at the bottom of the session-list screen.
     FilterInput,
+    /// The search input bar at the bottom of the transcript screen.
+    SearchInput,
 }
 
 // ---------------------------------------------------------------------------
@@ -121,6 +123,18 @@ pub struct AppState {
     /// Index of the highlighted row in the sub-agents panel.
     pub subagent_selected: usize,
 
+    // ── Search ──────────────────────────────────────────────────────────────
+    /// Text currently being typed in the transcript search box.
+    pub search_input: String,
+    /// The last applied search query (highlights all case-insensitive matches).
+    /// Empty string means no search is active.
+    pub search_active: String,
+    /// Line indices (in the rendered chat lines) where `search_active` matches.
+    /// Populated on Enter; used for n/N navigation.
+    pub search_match_lines: Vec<usize>,
+    /// Index into `search_match_lines` for the match currently centred by n/N.
+    pub search_current_match: usize,
+
     // ── Focus ───────────────────────────────────────────────────────────────
     /// Which panel currently holds keyboard focus.
     pub focus: Focus,
@@ -213,6 +227,10 @@ impl AppState {
             transcript_scroll: 0,
             transcript_h_scroll: 0,
             transcript_page_height: 0,
+            search_input: String::new(),
+            search_active: String::new(),
+            search_match_lines: Vec::new(),
+            search_current_match: 0,
             subagents: Vec::new(),
             subagent_selected: 0,
             focus: Focus::default(),
@@ -240,6 +258,10 @@ impl AppState {
         self.transcript_entries.clear();
         self.transcript_scroll = 0;
         self.transcript_h_scroll = 0;
+        self.search_input.clear();
+        self.search_active.clear();
+        self.search_match_lines.clear();
+        self.search_current_match = 0;
         self.subagents.clear();
         self.subagent_selected = 0;
         self.focus = Focus::ChatLog;
@@ -261,6 +283,10 @@ impl AppState {
         self.transcript_entries.clear();
         self.transcript_scroll = 0;
         self.transcript_h_scroll = 0;
+        self.search_input.clear();
+        self.search_active.clear();
+        self.search_match_lines.clear();
+        self.search_current_match = 0;
         self.focus = Focus::ChatLog;
     }
 
@@ -274,6 +300,10 @@ impl AppState {
         self.transcript_entries.clear();
         self.transcript_scroll = 0;
         self.transcript_h_scroll = 0;
+        self.search_input.clear();
+        self.search_active.clear();
+        self.search_match_lines.clear();
+        self.search_current_match = 0;
         self.subagents.clear();
         self.subagent_selected = 0;
         self.focus = Focus::ChatLog;