Add command interface and status indicator.

CLAUDE.md

@@ -61,7 +61,7 @@ Events use parent IDs forming a tree (not a flat list). This enables future bran
 
 - Unit tests go in the same file as the code (`#[cfg(test)] mod tests`)
 - Integration tests go in `tests/`
-- TUI widget tests use `ratatui::backend::TestBackend` + `insta` snapshots
+- TUI widget tests use `ratatui::backend::TestBackend`
 - Provider tests replay recorded SSE fixtures from `tests/fixtures/`
 - Sandbox tests use `tempdir` and skip Landlock-specific assertions if kernel < 5.13
 - Run `cargo test` before every commit

DESIGN.md

@@ -67,7 +67,7 @@
 - **`sandbox`:** Landlock policy construction, path validation logic (without applying kernel rules)
 - **`core`:** Conversation tree operations (insert, query by parent, turn computation, token totals), orchestrator state machine transitions against mock `StreamEvent` sequences
 - **`session`:** JSONL serialization roundtrips, parent ID chain reconstruction
-- **`tui`:** Widget rendering via Ratatui `TestBackend`, snapshot tests with `insta` crate for layout/mode indicator/token display
+- **`tui`:** Widget rendering via Ratatui `TestBackend`
 
 ### Integration Tests — Component Boundaries
 - **Core ↔ Provider:** Mock `ModelProvider` replaying recorded API sessions (full SSE streams with tool use). Tests the complete orchestration loop deterministically without network.
@@ -78,11 +78,6 @@
 - **Recorded session replay:** Capture real Claude API HTTP request/response pairs, replay deterministically. Exercises full stack (core + channel + mock TUI) without cost or network dependency. Primary E2E test strategy.
 - **Live API tests:** Small suite behind feature flag / env var. Verifies real API integration. Run manually before releases, not in CI.
 
-### Snapshot Testing
-- `insta` crate for TUI visual regression testing from Phase 2 onward
-- Capture rendered `TestBackend` buffers as string snapshots
-- Catches layout, mode indicator, and token display regressions
-
 ### Benchmarking — SWE-bench
 - **Target:** SWE-bench Verified (500 curated problems) as primary benchmark
 - **Secondary:** SWE-bench Pro for testing planning mode on longer-horizon tasks
@@ -93,7 +88,6 @@
 
 ### Test Sequencing
 - Phase 1: Unit tests for SSE parser, event types, message serialization
-- Phase 2: Snapshot tests for TUI with `insta`
 - Phase 4: Recorded session replay infrastructure (core loop complex enough to warrant it)
 - Phase 6-7: Headless mode + first SWE-bench Verified run
 

PLAN.md

@@ -28,7 +28,6 @@
 - Key dispatch: correct handler called per mode
 - Command parser: `:quit`, `:clear`, `:q`, unknown command
 - Scroll clamping: j/k at boundaries, G/gg
-- `insta` snapshot tests: mode indicator rendering for each mode, layout with status bar
 - Existing Phase 1 input tests still pass (insert mode behavior unchanged)
 
 ## Phase 3: Tool Execution

src/core/history.rs

@@ -34,6 +34,11 @@ impl ConversationHistory {
     pub fn messages(&self) -> &[ConversationMessage] {
         &self.messages
     }
+
+    /// Remove all messages from the history.
+    pub fn clear(&mut self) {
+        self.messages.clear();
+    }
 }
 
 impl Default for ConversationHistory {
@@ -73,6 +78,17 @@ mod tests {
         assert_eq!(msgs[1].content, "hi there");
     }
 
+    #[test]
+    fn clear_empties_history() {
+        let mut history = ConversationHistory::new();
+        history.push(ConversationMessage {
+            role: Role::User,
+            content: "hello".to_string(),
+        });
+        history.clear();
+        assert!(history.messages().is_empty());
+    }
+
     #[test]
     fn messages_preserves_insertion_order() {
         let mut history = ConversationHistory::new();

src/core/orchestrator.rs

@@ -65,6 +65,9 @@ impl<P: ModelProvider> Orchestrator<P> {
         while let Some(action) = self.action_rx.recv().await {
             match action {
                 UserAction::Quit => break,
+                UserAction::ClearHistory => {
+                    self.history.clear();
+                }
 
                 UserAction::SendMessage(text) => {
                     // Push the user message before snapshotting, so providers

src/core/types.rs

@@ -20,6 +20,8 @@ pub enum UserAction {
     SendMessage(String),
     /// The user has requested to quit.
     Quit,
+    /// The user has requested to clear conversation history.
+    ClearHistory,
 }
 
 /// An event sent from the core orchestrator to the TUI.

src/tui/mod.rs

@@ -20,7 +20,7 @@ use crossterm::terminal::{
 use futures::StreamExt;
 use ratatui::backend::CrosstermBackend;
 use ratatui::layout::{Constraint, Layout, Rect};
-use ratatui::style::{Color, Style};
+use ratatui::style::{Color, Modifier, Style};
 use ratatui::text::{Line, Span};
 use ratatui::widgets::{Block, Paragraph, Wrap};
 use ratatui::{Frame, Terminal};
@@ -70,6 +70,8 @@ pub struct AppState {
     pub pending_keys: Vec<char>,
     /// Last-known viewport height (output pane lines). Updated each frame by `update_scroll`.
     pub viewport_height: u16,
+    /// Transient error message shown in the status bar, cleared on next keypress.
+    pub status_error: Option<String>,
 }
 
 impl AppState {
@@ -81,6 +83,7 @@ impl AppState {
             mode: Mode::Insert,
             pending_keys: Vec::new(),
             viewport_height: 0,
+            status_error: None,
         }
     }
 }
@@ -125,6 +128,8 @@ enum LoopControl {
     SendMessage(String),
     /// The user pressed Ctrl+C or Ctrl+D; exit the event loop.
     Quit,
+    /// The user ran `:clear`; wipe the conversation.
+    ClearHistory,
 }
 
 /// Map a key event to a [`LoopControl`] signal, mutating `state` as a side-effect.
@@ -133,6 +138,8 @@ enum LoopControl {
 /// handler for the current [`Mode`].
 fn handle_key(key: Option<KeyEvent>, state: &mut AppState) -> Option<LoopControl> {
     let key = key?;
+    // Clear any transient status error on the next keypress.
+    state.status_error = None;
     // Ctrl+C quits from any mode.
     if key.modifiers.contains(KeyModifiers::CONTROL) && key.code == KeyCode::Char('c') {
         return Some(LoopControl::Quit);
@@ -269,6 +276,28 @@ fn handle_insert_key(key: KeyEvent, state: &mut AppState) -> Option<LoopControl>
     }
 }
 
+/// Execute a parsed command string and return the appropriate control signal.
+///
+/// | Command       | Effect                                          |
+/// |---------------|-------------------------------------------------|
+/// | `quit` / `q`  | Return `LoopControl::Quit`                      |
+/// | `clear`       | Clear messages and scroll, return `ClearHistory` |
+/// | anything else | Set `status_error` on state                     |
+fn execute_command(buf: &str, state: &mut AppState) -> Option<LoopControl> {
+    match buf.trim() {
+        "quit" | "q" => Some(LoopControl::Quit),
+        "clear" => {
+            state.messages.clear();
+            state.scroll = 0;
+            Some(LoopControl::ClearHistory)
+        }
+        other => {
+            state.status_error = Some(format!("Unknown command: {other}"));
+            None
+        }
+    }
+}
+
 /// Handle a keypress in Command mode (ex-style `:` command entry).
 ///
 /// | Key       | Effect                                              |
@@ -289,14 +318,11 @@ fn handle_command_key(key: KeyEvent, state: &mut AppState) -> Option<LoopControl
             // Already set to Normal above.
         }
         KeyCode::Enter => {
-            // Command execution deferred to phase 2.3; just return to Normal.
+            return execute_command(&buf, state);
         }
         KeyCode::Backspace => {
             buf.pop();
-            if !buf.is_empty() {
+            state.mode = Mode::Command(buf);
-                state.mode = Mode::Command(buf);
-            }
-            // else stay in Normal (already set)
         }
         KeyCode::Char(c) => {
             buf.push(c);
@@ -351,8 +377,8 @@ fn drain_ui_events(event_rx: &mut mpsc::Receiver<UIEvent>, state: &mut AppState)
 /// - `ceil(chars / width).max(1)` lines per newline-separated content line
 /// - 1 blank separator line
 fn update_scroll(state: &mut AppState, area: Rect) {
-    // 3 = height of the input pane (border top + content + border bottom)
+    // 4 = input pane (3: border top + content + border bottom) + status bar (1)
-    let viewport_height = area.height.saturating_sub(3);
+    let viewport_height = area.height.saturating_sub(4);
     state.viewport_height = viewport_height;
     let width = area.width.max(1) as usize;
 
@@ -392,11 +418,19 @@ fn update_scroll(state: &mut AppState, area: Rect) {
 /// |  Input                         |  Length(3)
 /// |  > _                           |
 /// +--------------------------------+
+/// | NORMAL          tokens: --     |  Length(1)
+/// +--------------------------------+
 /// ```
 ///
 /// Role headers are coloured: `"You:"` in cyan, `"Assistant:"` in green.
+/// In Command mode, a one-line overlay appears at row 1 of the output pane.
 fn render(frame: &mut Frame, state: &AppState) {
-    let chunks = Layout::vertical([Constraint::Fill(1), Constraint::Length(3)]).split(frame.area());
+    let chunks = Layout::vertical([
+        Constraint::Fill(1),
+        Constraint::Length(3),
+        Constraint::Length(1),
+    ])
+    .split(frame.area());
 
     // --- Output pane ---
     let mut lines: Vec<Line> = Vec::new();
@@ -417,10 +451,108 @@ fn render(frame: &mut Frame, state: &AppState) {
         .scroll((state.scroll, 0));
     frame.render_widget(output, chunks[0]);
 
+    // --- Command overlay (floating box centered on output pane) ---
+    if let Mode::Command(ref buf) = state.mode {
+        let out = chunks[0];
+        let overlay_w = (out.width / 2).max(80).min(out.width);
+        let overlay_h = 3; // border + content + border
+        let overlay_x = out.x + (out.width.saturating_sub(overlay_w)) / 2;
+        let overlay_y = out.y + (out.height.saturating_sub(overlay_h)) / 2;
+        let overlay_area = Rect {
+            x: overlay_x,
+            y: overlay_y,
+            width: overlay_w,
+            height: overlay_h.min(out.height),
+        };
+        // Clear the area behind the overlay so it appears floating.
+        let clear = Paragraph::new("");
+        frame.render_widget(clear, overlay_area);
+        let overlay = Paragraph::new(format!(":{buf}")).block(
+            Block::bordered()
+                .border_style(Style::default().fg(Color::Yellow))
+                .title("Command"),
+        );
+        frame.render_widget(overlay, overlay_area);
+    }
+
     // --- Input pane ---
+    let (input_title, input_style) = match state.mode {
+        Mode::Normal | Mode::Command(_) => (
+            "Input (normal)",
+            Style::default()
+                .fg(Color::DarkGray)
+                .add_modifier(Modifier::ITALIC),
+        ),
+        Mode::Insert => ("Input", Style::default()),
+    };
     let input_text = format!("> {}", state.input);
-    let input_widget = Paragraph::new(input_text).block(Block::bordered().title("Input"));
+    let input_widget = Paragraph::new(input_text)
+        .style(input_style)
+        .block(Block::bordered().title(input_title));
     frame.render_widget(input_widget, chunks[1]);
+
+    // --- Cursor positioning ---
+    match state.mode {
+        Mode::Insert => {
+            // Cursor at end of input text: border(1) + "> " (2) + input len
+            let cursor_x = chunks[1].x + 1 + 2 + state.input.len() as u16;
+            let cursor_y = chunks[1].y + 1; // inside the border
+            frame.set_cursor_position((cursor_x, cursor_y));
+        }
+        Mode::Command(ref buf) => {
+            // Cursor in the floating overlay: recalculate overlay position
+            let out = chunks[0];
+            let overlay_w = (out.width / 2).max(80).min(out.width);
+            let overlay_x = out.x + (out.width.saturating_sub(overlay_w)) / 2;
+            let overlay_y = out.y + (out.height.saturating_sub(3)) / 2;
+            // border(1) + ":" (1) + buf len
+            let cursor_x = overlay_x + 1 + 1 + buf.len() as u16;
+            let cursor_y = overlay_y + 1; // inside the border
+            frame.set_cursor_position((cursor_x, cursor_y));
+        }
+        Mode::Normal => {} // no cursor
+    }
+
+    // --- Status bar ---
+    let (mode_label, mode_style) = match state.mode {
+        Mode::Normal => (
+            " NORMAL ",
+            Style::default().bg(Color::Blue).fg(Color::White),
+        ),
+        Mode::Insert => (
+            " INSERT ",
+            Style::default().bg(Color::Green).fg(Color::White),
+        ),
+        Mode::Command(_) => (
+            " COMMAND ",
+            Style::default().bg(Color::Yellow).fg(Color::Black),
+        ),
+    };
+
+    let right_text = if let Some(ref err) = state.status_error {
+        err.clone()
+    } else {
+        "tokens: --".to_string()
+    };
+
+    let right_style = if state.status_error.is_some() {
+        Style::default().fg(Color::Red)
+    } else {
+        Style::default()
+    };
+
+    let bar_width = chunks[2].width as usize;
+    let left_len = mode_label.len();
+    let right_len = right_text.len();
+    let pad = bar_width.saturating_sub(left_len + right_len);
+
+    let status_line = Line::from(vec![
+        Span::styled(mode_label, mode_style),
+        Span::raw(" ".repeat(pad)),
+        Span::styled(right_text, right_style),
+    ]);
+    let status_widget = Paragraph::new(status_line);
+    frame.render_widget(status_widget, chunks[2]);
 }
 
 /// Run the TUI event loop.
@@ -482,6 +614,9 @@ pub async fn run(
                 let _ = action_tx.send(UserAction::Quit).await;
                 break;
             }
+            Some(LoopControl::ClearHistory) => {
+                let _ = action_tx.send(UserAction::ClearHistory).await;
+            }
             None => {}
         }
     }
@@ -694,11 +829,17 @@ mod tests {
     }
 
     #[test]
-    fn command_backspace_empty_exits() {
+    fn command_backspace_empty_stays_in_command() {
         let mut state = AppState::new();
-        state.mode = Mode::Command(String::new());
+        state.mode = Mode::Command("ab".to_string());
         handle_key(make_key(KeyCode::Backspace), &mut state);
-        assert_eq!(state.mode, Mode::Normal);
+        assert_eq!(state.mode, Mode::Command("a".to_string()));
+        handle_key(make_key(KeyCode::Backspace), &mut state);
+        assert_eq!(state.mode, Mode::Command(String::new()));
+        handle_key(make_key(KeyCode::Backspace), &mut state);
+        assert_eq!(state.mode, Mode::Command(String::new()));
+        handle_key(make_key(KeyCode::Backspace), &mut state);
+        assert_eq!(state.mode, Mode::Command(String::new()));
     }
 
     #[test]
@@ -804,4 +945,185 @@ mod tests {
         handle_key(ctrl_key('u'), &mut state);
         assert_eq!(state.scroll, 0);
     }
+
+    // --- execute_command tests ---
+
+    #[test]
+    fn command_quit_returns_quit() {
+        let mut state = AppState::new();
+        let result = execute_command("quit", &mut state);
+        assert!(matches!(result, Some(LoopControl::Quit)));
+    }
+
+    #[test]
+    fn command_q_returns_quit() {
+        let mut state = AppState::new();
+        let result = execute_command("q", &mut state);
+        assert!(matches!(result, Some(LoopControl::Quit)));
+    }
+
+    #[test]
+    fn command_clear_empties_messages() {
+        let mut state = AppState::new();
+        state.messages.push((Role::User, "hi".to_string()));
+        state.messages.push((Role::Assistant, "hello".to_string()));
+        state.scroll = 10;
+        let result = execute_command("clear", &mut state);
+        assert!(matches!(result, Some(LoopControl::ClearHistory)));
+        assert!(state.messages.is_empty());
+        assert_eq!(state.scroll, 0);
+    }
+
+    #[test]
+    fn command_unknown_sets_status_error() {
+        let mut state = AppState::new();
+        let result = execute_command("foo", &mut state);
+        assert!(result.is_none());
+        assert_eq!(state.status_error.as_deref(), Some("Unknown command: foo"));
+    }
+
+    #[test]
+    fn status_error_cleared_on_next_keypress() {
+        let mut state = AppState::new();
+        state.status_error = Some("some error".to_string());
+        handle_key(make_key(KeyCode::Char('h')), &mut state);
+        assert!(state.status_error.is_none());
+    }
+
+    #[test]
+    fn command_enter_executes_quit() {
+        let mut state = AppState::new();
+        state.mode = Mode::Command("q".to_string());
+        let result = handle_key(make_key(KeyCode::Enter), &mut state);
+        assert!(matches!(result, Some(LoopControl::Quit)));
+        assert_eq!(state.mode, Mode::Normal);
+    }
+
+    // --- render snapshot tests ---
+
+    #[test]
+    fn render_status_bar_normal_mode() {
+        let backend = TestBackend::new(80, 24);
+        let mut terminal = Terminal::new(backend).unwrap();
+        let mut state = AppState::new();
+        state.mode = Mode::Normal;
+        terminal.draw(|frame| render(frame, &state)).unwrap();
+        let buf = terminal.backend().buffer().clone();
+        let all_text: String = buf
+            .content()
+            .iter()
+            .map(|c| c.symbol().to_string())
+            .collect();
+        assert!(all_text.contains("NORMAL"), "expected 'NORMAL' in buffer");
+        assert!(
+            all_text.contains("tokens: --"),
+            "expected 'tokens: --' in buffer"
+        );
+    }
+
+    #[test]
+    fn render_status_bar_insert_mode() {
+        let backend = TestBackend::new(80, 24);
+        let mut terminal = Terminal::new(backend).unwrap();
+        let state = AppState::new(); // starts in Insert
+        terminal.draw(|frame| render(frame, &state)).unwrap();
+        let buf = terminal.backend().buffer().clone();
+        let all_text: String = buf
+            .content()
+            .iter()
+            .map(|c| c.symbol().to_string())
+            .collect();
+        assert!(all_text.contains("INSERT"), "expected 'INSERT' in buffer");
+    }
+
+    #[test]
+    fn render_status_bar_command_mode() {
+        let backend = TestBackend::new(80, 24);
+        let mut terminal = Terminal::new(backend).unwrap();
+        let mut state = AppState::new();
+        state.mode = Mode::Command("quit".to_string());
+        terminal.draw(|frame| render(frame, &state)).unwrap();
+        let buf = terminal.backend().buffer().clone();
+        let all_text: String = buf
+            .content()
+            .iter()
+            .map(|c| c.symbol().to_string())
+            .collect();
+        assert!(all_text.contains("COMMAND"), "expected 'COMMAND' in buffer");
+    }
+
+    #[test]
+    fn render_command_overlay_visible_in_command_mode() {
+        let backend = TestBackend::new(80, 24);
+        let mut terminal = Terminal::new(backend).unwrap();
+        let mut state = AppState::new();
+        state.mode = Mode::Command("quit".to_string());
+        terminal.draw(|frame| render(frame, &state)).unwrap();
+        let buf = terminal.backend().buffer().clone();
+        let all_text: String = buf
+            .content()
+            .iter()
+            .map(|c| c.symbol().to_string())
+            .collect();
+        assert!(
+            all_text.contains(":quit"),
+            "expected ':quit' overlay in buffer"
+        );
+    }
+
+    #[test]
+    fn render_no_overlay_in_normal_mode() {
+        let backend = TestBackend::new(80, 24);
+        let mut terminal = Terminal::new(backend).unwrap();
+        let mut state = AppState::new();
+        state.mode = Mode::Normal;
+        terminal.draw(|frame| render(frame, &state)).unwrap();
+        let buf = terminal.backend().buffer().clone();
+        // Row 1 should not have a ":" prefix from the overlay
+        let row1: String = (0..80)
+            .map(|x| buf.cell((x, 1)).unwrap().symbol().to_string())
+            .collect();
+        assert!(
+            !row1.starts_with(':'),
+            "overlay should not appear in Normal mode"
+        );
+    }
+
+    #[test]
+    fn render_input_pane_dimmed_in_normal() {
+        let backend = TestBackend::new(80, 24);
+        let mut terminal = Terminal::new(backend).unwrap();
+        let mut state = AppState::new();
+        state.mode = Mode::Normal;
+        terminal.draw(|frame| render(frame, &state)).unwrap();
+        let buf = terminal.backend().buffer().clone();
+        let all_text: String = buf
+            .content()
+            .iter()
+            .map(|c| c.symbol().to_string())
+            .collect();
+        assert!(
+            all_text.contains("Input (normal)"),
+            "expected 'Input (normal)' title in Normal mode"
+        );
+    }
+
+    #[test]
+    fn render_status_bar_shows_error() {
+        let backend = TestBackend::new(80, 24);
+        let mut terminal = Terminal::new(backend).unwrap();
+        let mut state = AppState::new();
+        state.status_error = Some("Unknown command: foo".to_string());
+        terminal.draw(|frame| render(frame, &state)).unwrap();
+        let buf = terminal.backend().buffer().clone();
+        let all_text: String = buf
+            .content()
+            .iter()
+            .map(|c| c.symbol().to_string())
+            .collect();
+        assert!(
+            all_text.contains("Unknown command: foo"),
+            "expected error in status bar"
+        );
+    }
 }