tui: overlay screens via F-keys (F1=context, F2=agents)

Replaced debug_visible bool with an Overlay enum. F1 shows the
context/debug screen (Ctrl+D still works as alias), F2 shows the
agents screen (placeholder for now — will show surface, observe,
reflect, journal status). Esc closes any overlay.

Co-Authored-By: Proof of Concept <poc@bcachefs.org>

src/agent/tui.rs

@@ -9,6 +9,8 @@
 // Uses ratatui + crossterm. The App struct holds all TUI state and
 // handles rendering. Input is processed from crossterm key events.
 
+const SCREEN_LEGEND: &str = " F1=main  F2=agents  F10=context ";
+
 use crossterm::{
     event::{EnableMouseCapture, DisableMouseCapture, KeyCode, KeyEvent, KeyModifiers, MouseEvent, MouseEventKind, MouseButton},
     terminal::{self, EnterAlternateScreen, LeaveAlternateScreen},
@@ -328,8 +330,8 @@ pub struct App {
     pub hotkey_actions: Vec<HotkeyAction>,
     /// Pane areas from last draw (for mouse click → pane selection).
     pane_areas: [Rect; 3], // [autonomous, conversation, tools]
-    /// Debug screen visible (Ctrl+D toggle).
+    /// Active overlay screen (F1=context, F2=agents, Ctrl+D=context).
-    debug_visible: bool,
+    overlay: Option<Overlay>,
     /// Debug screen scroll offset.
     debug_scroll: u16,
     /// Index of selected context section in debug view (for expand/collapse).
@@ -342,6 +344,15 @@ pub struct App {
     shared_context: SharedContextState,
 }
 
+/// Overlay screens toggled by F-keys.
+#[derive(Debug, Clone, Copy, PartialEq)]
+enum Overlay {
+    /// F1 / Ctrl+D — context window, model info, budget
+    Context,
+    /// F2 — subconscious agent status
+    Agents,
+}
+
 /// Actions triggered by hotkeys, consumed by the main loop.
 #[derive(Debug)]
 pub enum HotkeyAction {
@@ -385,7 +396,7 @@ impl App {
             submitted: Vec::new(),
             hotkey_actions: Vec::new(),
             pane_areas: [Rect::default(); 3],
-            debug_visible: false,
+            overlay: None,
             debug_scroll: 0,
             debug_selected: None,
             debug_expanded: std::collections::HashSet::new(),
@@ -510,8 +521,8 @@ impl App {
                     return;
                 }
                 KeyCode::Char('d') => {
-                    self.debug_visible = !self.debug_visible;
+                    // Legacy alias for F10
-                    self.debug_scroll = 0;
+                    self.set_overlay(Overlay::Context);
                     return;
                 }
                 KeyCode::Char('p') => {
@@ -522,13 +533,15 @@ impl App {
             }
         }
 
-        // Debug screen captures scroll keys and Esc
+        // Overlay screen captures scroll keys and Esc
-        if self.debug_visible {
+        if self.overlay.is_some() {
             match key.code {
-                KeyCode::Esc => {
+                KeyCode::F(1) => {
-                    self.debug_visible = false;
+                    self.overlay = None;
                     return;
                 }
+                KeyCode::F(10) => { self.set_overlay(Overlay::Context); return; }
+                KeyCode::F(2) => { self.set_overlay(Overlay::Agents); return; }
                 KeyCode::Up => {
                     let cs = self.read_context_state();
                     let n = self.debug_item_count(&cs);
@@ -574,6 +587,8 @@ impl App {
         }
 
         match key.code {
+            KeyCode::F(10) => { self.set_overlay(Overlay::Context); return; }
+            KeyCode::F(2) => { self.set_overlay(Overlay::Agents); return; }
             KeyCode::Esc => {
                 self.hotkey_actions.push(HotkeyAction::Interrupt);
             }
@@ -695,9 +710,10 @@ impl App {
     pub fn draw(&mut self, frame: &mut Frame) {
         let size = frame.area();
 
-        if self.debug_visible {
+        match self.overlay {
-            self.draw_debug(frame, size);
+            Some(Overlay::Context) => { self.draw_debug(frame, size); return; }
-            return;
+            Some(Overlay::Agents) => { self.draw_agents(frame, size); return; }
+            None => {}
         }
 
         // Main layout: content area + active tools overlay + status bar
@@ -744,11 +760,12 @@ impl App {
 
         // Draw autonomous pane
         let auto_active = self.active_pane == ActivePane::Autonomous;
-        draw_pane(frame, auto_area, "autonomous", &mut self.autonomous, auto_active);
+        draw_pane(frame, auto_area, "autonomous", &mut self.autonomous, auto_active,
+            Some(SCREEN_LEGEND));
 
         // Draw tools pane
         let tools_active = self.active_pane == ActivePane::Tools;
-        draw_pane(frame, right_col, "tools", &mut self.tools, tools_active);
+        draw_pane(frame, right_col, "tools", &mut self.tools, tools_active, None);
 
         // Draw conversation pane (with input line)
         let conv_active = self.active_pane == ActivePane::Conversation;
@@ -849,7 +866,7 @@ impl App {
             String::new()
         };
         let right_legend = format!(
-            "{}{} ^P:pause ^D:debug ^R:reason ^K:kill | {} ",
+            "{}{} ^P:pause ^R:reason ^K:kill | {} ",
             reason_indicator,
             proc_indicator,
             self.status.model,
@@ -961,15 +978,35 @@ impl App {
         }
     }
 
-    fn draw_debug(&self, frame: &mut Frame, size: Rect) {
+    fn set_overlay(&mut self, screen: Overlay) {
+        self.overlay = Some(screen);
+        self.debug_scroll = 0;
+    }
+
+    fn draw_agents(&self, frame: &mut Frame, size: Rect) {
         let mut lines: Vec<Line> = Vec::new();
         let section = Style::default().fg(Color::Yellow);
 
-        lines.push(Line::styled(
-            " Debug  (Ctrl+D or Esc to close, arrows/PgUp/PgDn to scroll)",
-            Style::default().fg(Color::Cyan).add_modifier(Modifier::BOLD),
-        ));
         lines.push(Line::raw(""));
+        lines.push(Line::styled("── Subconscious Agents ──", section));
+        lines.push(Line::raw(""));
+        lines.push(Line::raw("  (not yet wired — will show surface, observe, reflect, journal status)"));
+
+        let block = Block::default()
+            .title_top(Line::from(SCREEN_LEGEND).left_aligned())
+            .title_top(Line::from(" agents ").right_aligned())
+            .borders(Borders::ALL)
+            .border_style(Style::default().fg(Color::Cyan));
+
+        let para = Paragraph::new(lines)
+            .block(block)
+            .scroll((self.debug_scroll, 0));
+        frame.render_widget(para, size);
+    }
+
+    fn draw_debug(&self, frame: &mut Frame, size: Rect) {
+        let mut lines: Vec<Line> = Vec::new();
+        let section = Style::default().fg(Color::Yellow);
 
         // Model
         lines.push(Line::styled("── Model ──", section));
@@ -1024,7 +1061,8 @@ impl App {
         lines.push(Line::raw(format!("  Active tools: {}", self.active_tools.len())));
 
         let block = Block::default()
-            .title(" Debug ")
+            .title_top(Line::from(SCREEN_LEGEND).left_aligned())
+            .title_top(Line::from(" context ").right_aligned())
             .borders(Borders::ALL)
             .border_style(Style::default().fg(Color::Cyan));
 
@@ -1142,6 +1180,7 @@ fn draw_pane(
     title: &str,
     pane: &mut PaneState,
     is_active: bool,
+    left_title: Option<&str>,
 ) {
     let inner_height = area.height.saturating_sub(2);
 
@@ -1151,10 +1190,16 @@ fn draw_pane(
         Style::default().fg(Color::DarkGray)
     };
 
-    let block = Block::default()
+    let mut block = Block::default()
-        .title(format!(" {} ", title))
         .borders(Borders::ALL)
         .border_style(border_style);
+    if let Some(left) = left_title {
+        block = block
+            .title_top(Line::from(left).left_aligned())
+            .title_top(Line::from(format!(" {} ", title)).right_aligned());
+    } else {
+        block = block.title(format!(" {} ", title));
+    }
 
     let lines = pane.all_lines();
     let paragraph = Paragraph::new(lines)

src/bin/poc-agent.rs

@@ -628,7 +628,7 @@ impl Session {
                     "Keys: Tab=pane  ^Up/Down=scroll  PgUp/PgDn=scroll  Mouse=click/scroll".into(),
                 ));
                 let _ = self.ui_tx.send(UiMessage::Info(
-                    "      Alt+Enter=newline  Esc=interrupt  ^P=pause  ^R=reasoning  ^K=kill  ^D=debug".into(),
+                    "      Alt+Enter=newline  Esc=interrupt  ^P=pause  ^R=reasoning  ^K=kill  F10=context  F2=agents".into(),
                 ));
                 let _ = self.ui_tx.send(UiMessage::Info(
                     "      Shift+click for native text selection (copy/paste)".into(),