diff --git a/crates/maestro-tui/src/action.rs b/crates/maestro-tui/src/action.rs
index 0efba87..c3a3403 100644
--- a/crates/maestro-tui/src/action.rs
+++ b/crates/maestro-tui/src/action.rs
@@ -34,6 +34,7 @@ pub enum Action {
     // Sidebar highlight movement
     SidebarNext,
     SidebarPrev,
+    ToggleSidebarGroup,
 
     // Catalog actions on the highlighted sidebar row
     AttachHighlighted,
@@ -81,6 +82,7 @@ impl Action {
             "FocusSidebar" => return Ok(Action::FocusSidebar),
             "SidebarNext" => return Ok(Action::SidebarNext),
             "SidebarPrev" => return Ok(Action::SidebarPrev),
+            "ToggleSidebarGroup" => return Ok(Action::ToggleSidebarGroup),
             "AttachHighlighted" => return Ok(Action::AttachHighlighted),
             "ToggleAttachHighlighted" => return Ok(Action::ToggleAttachHighlighted),
             "NewDraftPane" => return Ok(Action::NewDraftPane),
diff --git a/crates/maestro-tui/src/app.rs b/crates/maestro-tui/src/app.rs
index 245a628..b08547b 100644
--- a/crates/maestro-tui/src/app.rs
+++ b/crates/maestro-tui/src/app.rs
@@ -30,14 +30,16 @@ use crate::catalog::CatalogStore;
 use crate::config::TuiConfig;
 use crate::draft::DraftInputResult;
 use crate::emulators::SessionEmulators;
-use crate::input::{canonicalise, ChordResult, ChordState, ClickTracker, InputKey};
+use crate::input::{
+    canonicalise, ChordResult, ChordState, ClickTracker, InputKey, MouseKind, Region,
+};
 use crate::keymap::Mode;
 use crate::overlays::HelpOverlay;
 use crate::pane::{Pane, PaneStatus};
 use crate::render::{draw, RegionMap, RenderInputs};
 use crate::session_task::{SessionInput, SessionTask};
 use crate::sidebar::Sidebar;
-use crate::state::{AppState, Focus, OverlayKind, PaneRef};
+use crate::state::{AppState, Focus, OverlayKind, PaneRef, SidebarItem};
 use crate::tabs::TabBar;
 use crate::worktrees::WorktreesView;
 use crate::TuiError;
@@ -52,6 +54,7 @@ enum OverlayDecision {
 
 pub struct App {
     cfg: TuiConfig,
+    home_dir: String,
     catalog: CatalogStore,
     emulators: SessionEmulators,
     state: AppState,
@@ -137,6 +140,7 @@ impl App {
             .expect("build reqwest client");
         Self {
             cfg,
+            home_dir: std::env::var("HOME").unwrap_or_default(),
             catalog,
             emulators: SessionEmulators::default(),
             state: AppState::new(),
@@ -158,6 +162,9 @@ impl App {
         mut self,
         terminal: &mut Terminal<CrosstermBackend<Stdout>>,
     ) -> Result<(), TuiError> {
+        if let Ok(info) = self.daemon.daemon_info().await {
+            self.home_dir = info.home_dir;
+        }
         let mut events = EventStream::new();
         loop {
             self.redraw(terminal)?;
@@ -190,6 +197,10 @@ impl App {
         };
         let key = self.clicks.promote(key, std::time::Instant::now());
 
+        if self.handle_sidebar_mouse(&key) {
+            return Ok(false);
+        }
+
         // Overlay intercept first.
         let (decision, effects) = self.handle_overlay_input(&key);
         self.perform(effects).await;
@@ -224,6 +235,34 @@ impl App {
         }
     }
 
+    /// Clicks select rendered sidebar items directly. Double-clicks continue
+    /// through the keymap so the configured attach binding remains intact.
+    fn handle_sidebar_mouse(&mut self, key: &InputKey) -> bool {
+        let InputKey::Mouse {
+            kind: MouseKind::Click,
+            region: Region::SidebarRow,
+            row,
+            ..
+        } = key
+        else {
+            return false;
+        };
+        let Some(item) = self.region.sidebar_item_at(*row) else {
+            return true;
+        };
+        match item {
+            SidebarItem::Group(key) => {
+                self.state.sidebar_highlight = Some(SidebarItem::Group(key.clone()));
+                self.toggle_sidebar_group(key);
+            }
+            SidebarItem::Session(id) => {
+                self.state.sidebar_highlight = Some(SidebarItem::Session(id));
+                self.state.focus = Focus::Sidebar;
+            }
+        }
+        true
+    }
+
     /// Carry out what `dispatch` decided. The only place in `App` that talks to
     /// the daemon.
     async fn perform(&mut self, effects: Vec<Effect>) {
@@ -330,15 +369,22 @@ impl App {
                 self.state.focus = Focus::Pane;
             }
             Action::SidebarNext => {
-                let order = visible_sidebar_order(&self.catalog.snapshot());
+                let order = visible_sidebar_order(
+                    &self.catalog.snapshot(),
+                    &self.state.collapsed_sidebar_groups,
+                );
                 self.state.move_sidebar_highlight(&order, 1);
                 self.state.focus = Focus::Sidebar;
             }
             Action::SidebarPrev => {
-                let order = visible_sidebar_order(&self.catalog.snapshot());
+                let order = visible_sidebar_order(
+                    &self.catalog.snapshot(),
+                    &self.state.collapsed_sidebar_groups,
+                );
                 self.state.move_sidebar_highlight(&order, -1);
                 self.state.focus = Focus::Sidebar;
             }
+            Action::ToggleSidebarGroup => self.toggle_highlighted_sidebar_group(),
             Action::NewTab => self.state.new_tab(),
             Action::CloseTab => {
                 if let Some(sid) = self.state.close_tab() {
@@ -403,13 +449,50 @@ impl App {
     /// Return the session under the sidebar highlight, falling back to the
     /// first listed session so the user can attach without arrowing first.
     fn pick_sidebar_target(&self) -> Option<Uuid> {
-        if let Some(sid) = self.state.sidebar_highlight {
+        if let Some(SidebarItem::Session(sid)) = self.state.sidebar_highlight {
             return Some(sid);
         }
+        if self.state.sidebar_highlight.is_some() {
+            return None;
+        }
         let snap = self.catalog.snapshot();
         snap.sessions.first().map(|s| s.id)
     }
 
+    fn toggle_highlighted_sidebar_group(&mut self) {
+        let key = match self.state.sidebar_highlight.clone() {
+            Some(SidebarItem::Group(key)) => Some(key),
+            Some(SidebarItem::Session(id)) => self
+                .catalog
+                .snapshot()
+                .sessions
+                .into_iter()
+                .find(|s| s.id == id)
+                .and_then(|s| maestro_protocol::display::session_tree_path(&s)),
+            None => None,
+        };
+        if let Some(key) = key {
+            self.toggle_sidebar_group(key);
+        }
+    }
+
+    fn toggle_sidebar_group(&mut self, key: PathBuf) {
+        let contains_highlight = match self.state.sidebar_highlight {
+            Some(SidebarItem::Session(id)) => {
+                self.catalog
+                    .snapshot()
+                    .sessions
+                    .iter()
+                    .find(|s| s.id == id)
+                    .and_then(maestro_protocol::display::session_tree_path)
+                    .as_ref()
+                    == Some(&key)
+            }
+            _ => false,
+        };
+        self.state.toggle_sidebar_group(key, contains_highlight);
+    }
+
     /// Encode a keystroke for the focused pane. `None` when there is nothing
     /// attached to send it to.
     fn forward_to_session(&mut self, key: &InputKey) -> Option<Effect> {
@@ -811,7 +894,7 @@ impl App {
             .collect();
         let sidebar = Sidebar {
             sessions: snap.sessions.clone(),
-            highlight: self.state.sidebar_highlight,
+            highlight: self.state.sidebar_highlight.clone(),
             attached,
         };
         let tab_bar = TabBar {
@@ -833,6 +916,7 @@ impl App {
 
         let inputs = RenderInputs {
             sidebar: &sidebar,
+            home_dir: &self.home_dir,
             tab_bar: &tab_bar,
             pane: pane.as_ref(),
             state: &self.state,
@@ -881,8 +965,16 @@ impl App {
 /// Order the sidebar walks for `j`/`k`: the sessions in the same order
 /// [`crate::sidebar::Sidebar::render`] emits them. Keeps highlight movement in
 /// visual sync with what the user sees.
-fn visible_sidebar_order(snap: &crate::catalog::CatalogSnapshot) -> Vec<Uuid> {
-    snap.sessions.iter().map(|s| s.id).collect()
+fn visible_sidebar_order(
+    snap: &crate::catalog::CatalogSnapshot,
+    collapsed: &std::collections::HashSet<PathBuf>,
+) -> Vec<SidebarItem> {
+    Sidebar {
+        sessions: snap.sessions.clone(),
+        highlight: None,
+        attached: HashSet::new(),
+    }
+    .rendered_items_with_collapsed(collapsed)
 }
 
 /// Wire encoding for a keystroke headed to a session's PTY. `None` for keys
@@ -1134,9 +1226,32 @@ mod tests {
             }],
         });
         app.dispatch(Action::SidebarNext);
+        app.dispatch(Action::SidebarNext);
         app
     }
 
+    fn test_session(sid: Uuid, cwd: &str) -> maestro_protocol::Session {
+        use chrono::Utc;
+        use maestro_protocol::{Session, SessionStatus};
+        Session {
+            id: sid,
+            command: "bash".into(),
+            cwd: cwd.into(),
+            env: Default::default(),
+            metadata: Default::default(),
+            worktree: None,
+            status: SessionStatus::Running,
+            created_at: Utc::now(),
+            foreground: None,
+            activity: Default::default(),
+            activity_detail: None,
+            last_activity_at: Utc::now(),
+            activity_since: Utc::now(),
+            current_cwd: None,
+            blocked_work: None,
+        }
+    }
+
     #[test]
     fn attach_highlighted_asks_for_an_attach() {
         let sid = Uuid::from_u128(11);
@@ -1148,6 +1263,64 @@ mod tests {
         assert_eq!(app.state.active_tab().session(), Some(sid));
     }
 
+    #[test]
+    fn group_highlight_is_not_a_session_action_target() {
+        use maestro_protocol::CatalogEvent;
+
+        let sid = Uuid::from_u128(14);
+        let mut app = make_app();
+        app.catalog.apply_event(CatalogEvent::Snapshot {
+            sessions: vec![test_session(sid, "/repo")],
+        });
+        app.dispatch(Action::SidebarNext);
+        assert_eq!(
+            app.state.sidebar_highlight,
+            Some(SidebarItem::Group(PathBuf::from("/repo")))
+        );
+        assert!(app.dispatch(Action::AttachHighlighted).is_empty());
+        assert!(app.dispatch(Action::KillHighlighted).is_empty());
+        assert!(app.state.overlay().is_none());
+    }
+
+    #[test]
+    fn collapsing_the_group_containing_a_card_highlight_keeps_a_visible_group_highlight() {
+        let sid = Uuid::from_u128(15);
+        let mut app = app_with_highlighted_session(sid);
+        assert_eq!(app.state.sidebar_highlight, Some(SidebarItem::Session(sid)));
+        assert!(app.dispatch(Action::ToggleSidebarGroup).is_empty());
+        assert_eq!(
+            app.state.sidebar_highlight,
+            Some(SidebarItem::Group(PathBuf::from("/")))
+        );
+        assert!(app
+            .state
+            .collapsed_sidebar_groups
+            .contains(&PathBuf::from("/")));
+    }
+
+    #[test]
+    fn clicking_a_group_toggles_it_and_selects_the_group() {
+        let sid = Uuid::from_u128(16);
+        let mut app = app_with_highlighted_session(sid);
+        app.region.sidebar = Some(ratatui::layout::Rect::new(0, 0, 28, 10));
+        app.region.sidebar_items = vec![SidebarItem::Group(PathBuf::from("/"))];
+        let click = InputKey::Mouse {
+            kind: MouseKind::Click,
+            region: Region::SidebarRow,
+            col: 3,
+            row: 2,
+        };
+        assert!(app.handle_sidebar_mouse(&click));
+        assert_eq!(
+            app.state.sidebar_highlight,
+            Some(SidebarItem::Group(PathBuf::from("/")))
+        );
+        assert!(app
+            .state
+            .collapsed_sidebar_groups
+            .contains(&PathBuf::from("/")));
+    }
+
     #[test]
     fn confirming_a_kill_asks_for_the_kill() {
         let sid = Uuid::from_u128(12);
diff --git a/crates/maestro-tui/src/config.rs b/crates/maestro-tui/src/config.rs
index 4b305ea..494278c 100644
--- a/crates/maestro-tui/src/config.rs
+++ b/crates/maestro-tui/src/config.rs
@@ -45,6 +45,7 @@ const DEFAULT_NORMAL: &[(&str, &str)] = &[
     ("k", "SidebarPrev"),
     ("down", "SidebarNext"),
     ("up", "SidebarPrev"),
+    ("c", "ToggleSidebarGroup"),
     // Catalog actions
     ("enter", "AttachHighlighted"),
     ("s", "NewDraftPane"),
diff --git a/crates/maestro-tui/src/render.rs b/crates/maestro-tui/src/render.rs
index d222420..86d0b04 100644
--- a/crates/maestro-tui/src/render.rs
+++ b/crates/maestro-tui/src/render.rs
@@ -14,7 +14,7 @@ use crate::overlays::{HelpOverlay, KillConfirm, Toast};
 use crate::palette;
 use crate::pane::Pane;
 use crate::sidebar::Sidebar;
-use crate::state::{AppState, Focus, OverlayKind};
+use crate::state::{AppState, Focus, OverlayKind, SidebarItem};
 use crate::tabs::TabBar;
 use crate::worktrees::{ReclaimConfirm, WorktreesView};
 
@@ -23,6 +23,7 @@ use crate::worktrees::{ReclaimConfirm, WorktreesView};
 #[derive(Debug, Default, Clone)]
 pub struct RegionMap {
     pub sidebar: Option<Rect>,
+    pub sidebar_items: Vec<SidebarItem>,
     pub tab_bar: Option<Rect>,
     pub pane: Option<Rect>,
     pub modal: Option<Rect>,
@@ -52,6 +53,24 @@ impl RegionMap {
         }
         Region::Unknown
     }
+
+    /// Resolve a mouse row against the rendered sidebar sequence. The title
+    /// occupies one inner row; groups occupy one row and visible cards two.
+    pub fn sidebar_item_at(&self, row: u16) -> Option<SidebarItem> {
+        let area = self.sidebar?;
+        let mut cursor = area.y.saturating_add(2);
+        for item in &self.sidebar_items {
+            let height = match item {
+                SidebarItem::Group(_) => 1,
+                SidebarItem::Session(_) => 2,
+            };
+            if row >= cursor && row < cursor.saturating_add(height) {
+                return Some(item.clone());
+            }
+            cursor = cursor.saturating_add(height);
+        }
+        None
+    }
 }
 
 fn inside(r: Rect, col: u16, row: u16) -> bool {
@@ -63,6 +82,7 @@ fn inside(r: Rect, col: u16, row: u16) -> bool {
 #[derive(Debug)]
 pub struct RenderInputs<'a> {
     pub sidebar: &'a Sidebar,
+    pub home_dir: &'a str,
     pub tab_bar: &'a TabBar,
     pub pane: Option<&'a Pane>,
     /// Inline spawn form when the active tab's pane is a draft (issue #63).
@@ -102,10 +122,17 @@ pub fn draw(f: &mut Frame, inputs: RenderInputs<'_>) -> RegionMap {
     let right = cols[1];
 
     if inputs.state.sidebar_visible {
-        inputs
-            .sidebar
-            .render_with_focus(f, sidebar_area, inputs.state.focus == Focus::Sidebar);
+        inputs.sidebar.render_with_focus_and_collapsed_home(
+            f,
+            sidebar_area,
+            inputs.state.focus == Focus::Sidebar,
+            &inputs.state.collapsed_sidebar_groups,
+            inputs.home_dir,
+        );
         map.sidebar = Some(sidebar_area);
+        map.sidebar_items = inputs
+            .sidebar
+            .rendered_items_with_collapsed(&inputs.state.collapsed_sidebar_groups);
     }
 
     // The pane always owns its full border, so focus changes only recolour
@@ -233,6 +260,7 @@ mod tests {
                 width: 10,
                 height: 20,
             }),
+            sidebar_items: Vec::new(),
             tab_bar: Some(Rect {
                 x: 10,
                 y: 0,
@@ -262,6 +290,7 @@ mod tests {
                 width: 10,
                 height: 20,
             }),
+            sidebar_items: Vec::new(),
             tab_bar: Some(Rect {
                 x: 10,
                 y: 0,
@@ -286,6 +315,40 @@ mod tests {
         assert_eq!(map.region_at(3, 12), Region::SidebarRow); // outside modal
     }
 
+    #[test]
+    fn sidebar_mouse_rows_follow_group_and_two_line_card_heights() {
+        use std::path::PathBuf;
+        use uuid::Uuid;
+
+        let group_a = SidebarItem::Group(PathBuf::from("/a"));
+        let card_a = SidebarItem::Session(Uuid::from_u128(1));
+        let group_b = SidebarItem::Group(PathBuf::from("/b"));
+        let card_b = SidebarItem::Session(Uuid::from_u128(2));
+        let map = RegionMap {
+            sidebar: Some(Rect::new(0, 0, 28, 10)),
+            sidebar_items: vec![group_a.clone(), card_a.clone(), group_b.clone(), card_b],
+            ..RegionMap::default()
+        };
+        assert_eq!(map.sidebar_item_at(2), Some(group_a));
+        assert_eq!(map.sidebar_item_at(3), Some(card_a.clone()));
+        assert_eq!(map.sidebar_item_at(4), Some(card_a));
+        assert_eq!(map.sidebar_item_at(5), Some(group_b));
+
+        let collapsed = RegionMap {
+            sidebar: Some(Rect::new(0, 0, 28, 10)),
+            sidebar_items: vec![
+                SidebarItem::Group(PathBuf::from("/a")),
+                SidebarItem::Group(PathBuf::from("/b")),
+                SidebarItem::Session(Uuid::from_u128(2)),
+            ],
+            ..RegionMap::default()
+        };
+        assert_eq!(
+            collapsed.sidebar_item_at(3),
+            Some(SidebarItem::Group(PathBuf::from("/b")))
+        );
+    }
+
     /// Issue #63: an empty pane is a draft — the frame must show the spawn
     /// form where the terminal would otherwise be.
     #[test]
@@ -312,6 +375,7 @@ mod tests {
         let help = HelpOverlay { lines: Vec::new() };
         let inputs = RenderInputs {
             sidebar: &sidebar,
+            home_dir: "",
             tab_bar: &tab_bar,
             pane: None,
             draft: Some(draft),
@@ -368,6 +432,7 @@ mod tests {
             state.focus = focus;
             let inputs = RenderInputs {
                 sidebar: &sidebar,
+                home_dir: "",
                 tab_bar: &tab_bar,
                 pane: None,
                 draft: None,
@@ -411,6 +476,7 @@ mod tests {
             state.focus = focus;
             let inputs = RenderInputs {
                 sidebar: &sidebar,
+                home_dir: "",
                 tab_bar: &tab_bar,
                 pane: None,
                 draft: None,
diff --git a/crates/maestro-tui/src/sidebar.rs b/crates/maestro-tui/src/sidebar.rs
index 84ddbb9..77eb7a3 100644
--- a/crates/maestro-tui/src/sidebar.rs
+++ b/crates/maestro-tui/src/sidebar.rs
@@ -4,9 +4,11 @@
 //! Line 2: activity dot + duration in the state's colour, plus the
 //! adaptive detail, blocked-work, exited, and command fragments.
 
-use std::collections::HashSet;
+use std::collections::{BTreeMap, HashSet};
+use std::path::PathBuf;
 
 use chrono::Utc;
+use maestro_protocol::display::{abbreviate_dir, abbreviate_folder_name, session_tree_path};
 use maestro_protocol::{ActivityState, Session, SessionStatus};
 use ratatui::layout::Rect;
 use ratatui::style::{Color, Modifier, Style};
@@ -16,6 +18,7 @@ use ratatui::Frame;
 use uuid::Uuid;
 
 use crate::palette;
+use crate::state::SidebarItem;
 
 /// Time-in-state earns a duration fragment once the session has sat in its
 /// current activity state this long (docs/SIDEBAR.md).
@@ -44,10 +47,17 @@ fn card_base(highlighted: bool, focused: bool) -> Style {
 #[derive(Debug, Clone)]
 pub struct Sidebar {
     pub sessions: Vec<Session>,
-    pub highlight: Option<Uuid>,
+    pub highlight: Option<SidebarItem>,
     pub attached: HashSet<Uuid>,
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct SidebarGroup {
+    pub key: PathBuf,
+    pub sessions: Vec<Session>,
+    pub collapsed: bool,
+}
+
 impl Sidebar {
     pub fn render(&self, f: &mut Frame, area: Rect) {
         self.render_with_focus(f, area, false);
@@ -57,6 +67,27 @@ impl Sidebar {
     /// and whether the highlighted card claims the selection surface, never
     /// its geometry.
     pub fn render_with_focus(&self, f: &mut Frame, area: Rect, focused: bool) {
+        self.render_with_focus_and_collapsed(f, area, focused, &HashSet::new());
+    }
+
+    pub fn render_with_focus_and_collapsed(
+        &self,
+        f: &mut Frame,
+        area: Rect,
+        focused: bool,
+        collapsed: &HashSet<PathBuf>,
+    ) {
+        self.render_with_focus_and_collapsed_home(f, area, focused, collapsed, &home_dir());
+    }
+
+    pub fn render_with_focus_and_collapsed_home(
+        &self,
+        f: &mut Frame,
+        area: Rect,
+        focused: bool,
+        collapsed: &HashSet<PathBuf>,
+        home: &str,
+    ) {
         let border_style = palette::active().border_style(focused);
         let block = Block::default()
             .borders(Borders::ALL)
@@ -69,23 +100,110 @@ impl Sidebar {
             "sessions",
             Style::default().add_modifier(Modifier::BOLD),
         ))];
-        for s in &self.sessions {
-            let highlighted = self.highlight == Some(s.id);
-            let base = card_base(highlighted, focused);
-            lines.push(Line::from(self.name_row(s, width, focused)));
-            let meta = self.meta_row(s, width, focused);
-            lines.push(Line::from(pad_to_width(meta, width, base)));
+        for group in self.groups(collapsed) {
+            lines.push(Line::from(self.group_row(&group, width, focused, home)));
+            if !group.collapsed {
+                for s in &group.sessions {
+                    let highlighted = self.highlight == Some(SidebarItem::Session(s.id));
+                    let base = card_base(highlighted, focused);
+                    lines.push(Line::from(self.name_row(s, width, focused)));
+                    let meta = self.meta_row(s, width, focused);
+                    lines.push(Line::from(pad_to_width(meta, width, base)));
+                }
+            }
         }
         f.render_widget(Paragraph::new(lines), inner);
     }
 
+    /// Items in exactly the order and height they occupy on screen.
+    pub fn rendered_items(&self) -> Vec<SidebarItem> {
+        self.rendered_items_with_collapsed(&HashSet::new())
+    }
+
+    pub fn rendered_items_with_collapsed(&self, collapsed: &HashSet<PathBuf>) -> Vec<SidebarItem> {
+        self.groups(collapsed)
+            .into_iter()
+            .flat_map(|group| {
+                let mut items = vec![SidebarItem::Group(group.key)];
+                if !group.collapsed {
+                    items.extend(
+                        group
+                            .sessions
+                            .into_iter()
+                            .map(|s| SidebarItem::Session(s.id)),
+                    );
+                }
+                items
+            })
+            .collect()
+    }
+
+    pub fn groups(&self, collapsed: &HashSet<PathBuf>) -> Vec<SidebarGroup> {
+        let mut grouped: BTreeMap<PathBuf, Vec<Session>> = BTreeMap::new();
+        for session in &self.sessions {
+            if let Some(key) = session_tree_path(session) {
+                grouped.entry(key).or_default().push(session.clone());
+            }
+        }
+        grouped
+            .into_iter()
+            .map(|(key, mut sessions)| {
+                sessions
+                    .sort_by(|a, b| name_for(a).cmp(&name_for(b)).then_with(|| a.id.cmp(&b.id)));
+                SidebarGroup {
+                    collapsed: collapsed.contains(&key),
+                    key,
+                    sessions,
+                }
+            })
+            .collect()
+    }
+
+    fn group_row(
+        &self,
+        group: &SidebarGroup,
+        width: usize,
+        focused: bool,
+        home: &str,
+    ) -> Vec<Span<'static>> {
+        let highlighted = self.highlight == Some(SidebarItem::Group(group.key.clone()));
+        let palette = palette::active();
+        let surface = palette.surface(highlighted && focused);
+        let base = Style::default().bg(surface.bg).fg(if highlighted {
+            surface.fg
+        } else {
+            palette.group_row
+        });
+        let edge = highlighted && !focused;
+        let prefix = if edge { "▏ " } else { "  " };
+        let chevron = if group.collapsed { "▸ " } else { "▾ " };
+        let path = abbreviate_dir(&group.key, home);
+        let name = abbreviate_folder_name(&path);
+        let count = format!(" ({})", group.sessions.len());
+        let mut spans = vec![Span::styled(
+            prefix,
+            if edge {
+                base.fg(palette.focus_accent)
+            } else {
+                base
+            },
+        )];
+        spans.push(Span::styled(chevron, base));
+        if let Some(stem) = name.stem {
+            spans.push(Span::styled(format!("{stem}/"), surface.dim_style()));
+        }
+        spans.push(Span::styled(name.last, base));
+        spans.push(Span::styled(count, surface.muted_style()));
+        pad_to_width(fit_to_width(spans, width), width, base)
+    }
+
     fn name_row(&self, s: &Session, width: usize, focused: bool) -> Vec<Span<'static>> {
         let glyph = match (s.status, self.attached.contains(&s.id)) {
             (SessionStatus::Dead, _) => "✗",
             (SessionStatus::Running, true) => "●",
             (SessionStatus::Running, false) => "○",
         };
-        let highlighted = self.highlight == Some(s.id);
+        let highlighted = self.highlight == Some(SidebarItem::Session(s.id));
         let base = card_base(highlighted, focused);
         // Line-1 actions are keyboard affordances shown on the highlighted
         // row only; they reserve their width so the name truncates with `…`
@@ -138,7 +256,7 @@ impl Sidebar {
         // on line 1; the kill confirm names the specifics.
         let blocked = s.blocked_work.filter(|b| !b.is_clear());
         let dead = s.status == SessionStatus::Dead;
-        let highlighted = self.highlight == Some(s.id);
+        let highlighted = self.highlight == Some(SidebarItem::Session(s.id));
         let base = card_base(highlighted, focused);
         let dot_style =
             base.patch(Style::default().fg(activity_color(s.activity, highlighted, focused)));
@@ -269,6 +387,10 @@ fn name_for(s: &Session) -> String {
     }
 }
 
+fn home_dir() -> String {
+    std::env::var("HOME").unwrap_or_default()
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -314,6 +436,15 @@ mod tests {
         terminal.backend().buffer().clone()
     }
 
+    fn draw_collapsed(sidebar: &Sidebar, w: u16, h: u16, collapsed: &HashSet<PathBuf>) -> Buffer {
+        let backend = TestBackend::new(w, h);
+        let mut terminal = Terminal::new(backend).unwrap();
+        terminal
+            .draw(|f| sidebar.render_with_focus_and_collapsed(f, f.area(), true, collapsed))
+            .unwrap();
+        terminal.backend().buffer().clone()
+    }
+
     fn rows(buf: &Buffer) -> Vec<String> {
         (0..buf.area.height)
             .map(|y| {
@@ -360,6 +491,82 @@ mod tests {
         );
     }
 
+    #[test]
+    fn groups_worktrees_under_their_base_repository() {
+        let mut s = session_named(1, "claude");
+        s.cwd = "/home/u/repos/worktrees/feature".into();
+        s.worktree = Some(maestro_protocol::SessionWorktree {
+            path: s.cwd.clone(),
+            base_repo: "/home/u/repos/maestro".into(),
+        });
+        let groups = (Sidebar {
+            sessions: vec![s],
+            highlight: None,
+            attached: Default::default(),
+        })
+        .groups(&HashSet::new());
+        assert_eq!(groups[0].key, PathBuf::from("/home/u/repos/maestro"));
+    }
+
+    #[test]
+    fn does_not_render_groups_without_sessions() {
+        let sidebar = Sidebar {
+            sessions: Vec::new(),
+            highlight: None,
+            attached: Default::default(),
+        };
+        assert!(sidebar.groups(&HashSet::new()).is_empty());
+        assert!(sidebar.rendered_items().is_empty());
+    }
+
+    #[test]
+    fn collapsing_a_group_hides_cards_but_keeps_the_count_and_item() {
+        let sidebar = Sidebar {
+            sessions: vec![session_named(1, "claude"), session_named(2, "bash")],
+            highlight: None,
+            attached: Default::default(),
+        };
+        let key = PathBuf::from("/tmp");
+        let mut collapsed = HashSet::new();
+        collapsed.insert(key.clone());
+        let groups = sidebar.groups(&collapsed);
+        assert_eq!(groups[0].sessions.len(), 2);
+        assert!(groups[0].collapsed);
+        assert_eq!(
+            sidebar.rendered_items_with_collapsed(&collapsed),
+            vec![SidebarItem::Group(key)]
+        );
+        let rendered = render_to_string(&draw_collapsed(&sidebar, 40, 6, &collapsed));
+        assert!(rendered.contains("(2)"));
+        assert!(!rendered.contains("claude"));
+    }
+
+    #[test]
+    fn shared_display_helpers_abbreviate_group_labels() {
+        let path = maestro_protocol::display::abbreviate_dir(
+            std::path::Path::new("/home/u/git.naps.pt/naps62/maestro"),
+            "/home/u",
+        );
+        let name = maestro_protocol::display::abbreviate_folder_name(&path);
+        assert_eq!(path, "~/git.naps.pt/naps62/maestro");
+        assert_eq!(name.stem.as_deref(), Some("~/g/n"));
+        assert_eq!(name.last, "maestro");
+    }
+
+    #[test]
+    fn rendered_cards_are_always_two_lines_after_one_group_row() {
+        let sidebar = Sidebar {
+            sessions: vec![session_named(1, "claude")],
+            highlight: None,
+            attached: Default::default(),
+        };
+        let all = rows(&draw(&sidebar, 40, 8));
+        assert!(all[2].contains("/tmp"));
+        assert!(all[3].contains("claude"));
+        assert!(all[4].contains("bash"));
+        assert!(!all[5].contains("bash"));
+    }
+
     #[test]
     fn attached_session_uses_filled_glyph() {
         let sid = Uuid::from_u128(1);
@@ -450,17 +657,17 @@ mod tests {
         assert_eq!(content(&all[1]), "sessions");
         assert!(row_containing(&all, "claude").contains('○'));
         assert!(
-            all[3].contains('●'),
+            all[4].contains('●'),
             "line 2 must carry the dot: {:?}",
             all[3]
         );
         assert!(
-            all[3].contains("bash"),
+            all[4].contains("bash"),
             "line 2 must carry the command: {:?}",
             all[3]
         );
         assert!(
-            !all[3].contains("10s"),
+            !all[4].contains("10s"),
             "fresh cards have no duration: {:?}",
             all[3]
         );
@@ -541,7 +748,7 @@ mod tests {
             s.activity_since = Utc::now() - Duration::seconds(120);
             let sb = Sidebar {
                 sessions: vec![s],
-                highlight: Some(Uuid::from_u128(1)),
+                highlight: Some(SidebarItem::Session(Uuid::from_u128(1))),
                 attached: Default::default(),
             };
             let buf = draw(&sb, 28, 8);
@@ -782,12 +989,12 @@ mod tests {
         };
         let all = rows(&draw(&sb, 40, 6));
         assert!(
-            all[2].contains("friendly name"),
+            all[3].contains("friendly name"),
             "name must stay on line 1: {:?}",
             all[2]
         );
         assert!(
-            all[3].contains("bash"),
+            all[4].contains("bash"),
             "command must be on line 2: {:?}",
             all[3]
         );
@@ -803,12 +1010,12 @@ mod tests {
         };
         let all = rows(&draw(&sb, 10, 6));
         assert!(
-            all[3].contains('●'),
+            all[4].contains('●'),
             "dot must survive narrow cards: {:?}",
             all[3]
         );
         assert!(
-            all[3].contains('…'),
+            all[4].contains('…'),
             "command should truncate: {:?}",
             all[3]
         );
@@ -828,8 +1035,8 @@ mod tests {
             attached: Default::default(),
         };
         let all = rows(&draw(&sb, 29, 6));
-        assert!(all[3].contains("⚠ 1 uncommitted file"), "{:?}", all[3]);
-        let meta = content(&all[3]);
+        assert!(all[4].contains("⚠ 1 uncommitted file"), "{:?}", all[4]);
+        let meta = content(&all[4]);
         assert!(meta.ends_with('…'), "command must truncate: {meta:?}");
     }
 
@@ -847,13 +1054,13 @@ mod tests {
             attached: Default::default(),
         };
         let all = rows(&draw(&sb, 40, 6));
-        assert!(all[3].contains("⚠ 1 uncommitted file"), "{:?}", all[3]);
+        assert!(all[4].contains("⚠ 1 uncommitted file"), "{:?}", all[4]);
         assert!(
-            all[3].contains("bash"),
+            all[4].contains("bash"),
             "command must survive: {:?}",
             all[3]
         );
-        assert!(all[3].contains('…'), "detail must truncate: {:?}", all[3]);
+        assert!(all[4].contains('…'), "detail must truncate: {:?}", all[4]);
     }
 
     /// Reversed video makes a card unreadable against a background; cards
@@ -864,7 +1071,7 @@ mod tests {
         highlighted.activity_since = Utc::now() - Duration::seconds(120);
         let sb = Sidebar {
             sessions: vec![highlighted],
-            highlight: Some(Uuid::from_u128(1)),
+            highlight: Some(SidebarItem::Session(Uuid::from_u128(1))),
             attached: Default::default(),
         };
         let buf = draw(&sb, 28, 8);
@@ -889,7 +1096,7 @@ mod tests {
         let two = session_named(2, "bash");
         let sb = Sidebar {
             sessions: vec![one, two],
-            highlight: Some(Uuid::from_u128(1)),
+            highlight: Some(SidebarItem::Session(Uuid::from_u128(1))),
             attached: Default::default(),
         };
         let buf = draw(&sb, 28, 8);
@@ -924,7 +1131,7 @@ mod tests {
     fn highlighted_card_is_hollow_when_sidebar_is_unfocused() {
         let sb = Sidebar {
             sessions: vec![session_named(1, "claude")],
-            highlight: Some(Uuid::from_u128(1)),
+            highlight: Some(SidebarItem::Session(Uuid::from_u128(1))),
             attached: Default::default(),
         };
         let buf = draw_with_focus(&sb, 28, 8, false);
@@ -982,7 +1189,7 @@ mod tests {
     fn highlighted_row_anchors_the_actions_top_right() {
         let sb = Sidebar {
             sessions: vec![session_named(1, "claude")],
-            highlight: Some(Uuid::from_u128(1)),
+            highlight: Some(SidebarItem::Session(Uuid::from_u128(1))),
             attached: Default::default(),
         };
         let all = rows(&draw(&sb, 28, 8));
@@ -999,7 +1206,7 @@ mod tests {
         let two = session_named(2, "bash");
         let sb = Sidebar {
             sessions: vec![one, two],
-            highlight: Some(Uuid::from_u128(1)),
+            highlight: Some(SidebarItem::Session(Uuid::from_u128(1))),
             attached: Default::default(),
         };
         let all = rows(&draw(&sb, 28, 8));
@@ -1020,7 +1227,7 @@ mod tests {
         }
         let sb = Sidebar {
             sessions: vec![s],
-            highlight: Some(Uuid::from_u128(1)),
+            highlight: Some(SidebarItem::Session(Uuid::from_u128(1))),
             attached: Default::default(),
         };
         let all = rows(&draw(&sb, 28, 8));
diff --git a/crates/maestro-tui/src/state.rs b/crates/maestro-tui/src/state.rs
index 4e487c8..85e4d13 100644
--- a/crates/maestro-tui/src/state.rs
+++ b/crates/maestro-tui/src/state.rs
@@ -8,6 +8,9 @@
 //!
 //! v1.5 will replace `Tab::pane`'s single slot with a split tree.
 
+use std::collections::HashSet;
+use std::path::PathBuf;
+
 use uuid::Uuid;
 
 use crate::draft::DraftPane;
@@ -19,6 +22,16 @@ pub enum Focus {
     Pane,
 }
 
+/// One selectable item in the rendered sidebar sequence.
+///
+/// Group paths, unlike a session's position in the catalog, survive catalog
+/// redraws and make a highlighted collapsed group unambiguous.
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub enum SidebarItem {
+    Group(PathBuf),
+    Session(Uuid),
+}
+
 /// What a tab's pane slot holds: a live session, or an inline draft form.
 // The draft variant dwarfs `Session(Uuid)`; tabs are moved rarely enough
 // that boxing every access costs more than the copy does.
@@ -70,7 +83,10 @@ pub struct AppState {
     pub focus: Focus,
     pub mode: Mode,
     pub sidebar_visible: bool,
-    pub sidebar_highlight: Option<Uuid>,
+    pub sidebar_highlight: Option<SidebarItem>,
+    /// Group paths whose cards are hidden. This is UI state rather than
+    /// catalog state, so it survives every catalog redraw.
+    pub collapsed_sidebar_groups: HashSet<PathBuf>,
     /// Private: every transition goes through [`AppState::show_overlay`],
     /// [`AppState::dismiss_overlay`] or [`AppState::toast`]. Poking the field
     /// from four call sites is what left a toast on screen with no way to
@@ -96,6 +112,7 @@ impl AppState {
             mode: Mode::Normal,
             sidebar_visible: true,
             sidebar_highlight: None,
+            collapsed_sidebar_groups: HashSet::new(),
             overlay: None,
         }
     }
@@ -213,19 +230,32 @@ impl AppState {
     }
 
     /// Move the sidebar highlight by `delta` (positive = down) within the
-    /// given ordered list of selectable session ids. Wraps. No-op on empty.
-    pub fn move_sidebar_highlight(&mut self, order: &[Uuid], delta: i32) {
+    /// rendered item sequence. Wraps. No-op on empty.
+    pub fn move_sidebar_highlight(&mut self, order: &[SidebarItem], delta: i32) {
         if order.is_empty() {
             return;
         }
         let len = order.len() as i32;
         let cur = self
             .sidebar_highlight
-            .and_then(|id| order.iter().position(|x| *x == id))
+            .as_ref()
+            .and_then(|id| order.iter().position(|x| x == id))
             .map(|i| i as i32)
             .unwrap_or(-1);
         let next = (cur + delta).rem_euclid(len) as usize;
-        self.sidebar_highlight = Some(order[next]);
+        self.sidebar_highlight = Some(order[next].clone());
+    }
+
+    /// Toggle a group. When collapsing a group containing the current card,
+    /// leave the highlight on the group row that remains visible.
+    pub fn toggle_sidebar_group(&mut self, key: PathBuf, contains_highlight: bool) {
+        if self.collapsed_sidebar_groups.remove(&key) {
+            return;
+        }
+        self.collapsed_sidebar_groups.insert(key.clone());
+        if contains_highlight {
+            self.sidebar_highlight = Some(SidebarItem::Group(key));
+        }
     }
 
     /// Toggle sidebar visibility.
@@ -318,22 +348,30 @@ mod tests {
         let a = Uuid::from_u128(1);
         let b = Uuid::from_u128(2);
         let c = Uuid::from_u128(3);
-        let order = vec![a, b, c];
+        let order = vec![
+            SidebarItem::Session(a),
+            SidebarItem::Group("repo".into()),
+            SidebarItem::Session(b),
+            SidebarItem::Session(c),
+        ];
 
         // No prior highlight + delta +1 lands on first item.
         state.move_sidebar_highlight(&order, 1);
-        assert_eq!(state.sidebar_highlight, Some(a));
+        assert_eq!(state.sidebar_highlight, Some(SidebarItem::Session(a)));
 
         state.move_sidebar_highlight(&order, 1);
-        assert_eq!(state.sidebar_highlight, Some(b));
+        assert_eq!(
+            state.sidebar_highlight,
+            Some(SidebarItem::Group("repo".into()))
+        );
         state.move_sidebar_highlight(&order, 1);
-        assert_eq!(state.sidebar_highlight, Some(c));
+        assert_eq!(state.sidebar_highlight, Some(SidebarItem::Session(b)));
         // Wraps forward.
         state.move_sidebar_highlight(&order, 1);
-        assert_eq!(state.sidebar_highlight, Some(a));
+        assert_eq!(state.sidebar_highlight, Some(SidebarItem::Session(c)));
         // Wraps backward.
         state.move_sidebar_highlight(&order, -1);
-        assert_eq!(state.sidebar_highlight, Some(c));
+        assert_eq!(state.sidebar_highlight, Some(SidebarItem::Session(b)));
     }
 
     #[test]
@@ -343,6 +381,22 @@ mod tests {
         assert_eq!(state.sidebar_highlight, None);
     }
 
+    #[test]
+    fn collapsing_highlighted_group_moves_a_card_highlight_to_the_group() {
+        let key = PathBuf::from("/repo");
+        let mut state = AppState::new();
+        state.sidebar_highlight = Some(SidebarItem::Session(Uuid::from_u128(9)));
+        state.toggle_sidebar_group(key.clone(), true);
+        assert_eq!(
+            state.sidebar_highlight,
+            Some(SidebarItem::Group(key.clone()))
+        );
+        assert!(state.collapsed_sidebar_groups.contains(&key));
+        state.toggle_sidebar_group(key.clone(), false);
+        assert!(!state.collapsed_sidebar_groups.contains(&key));
+        assert_eq!(state.sidebar_highlight, Some(SidebarItem::Group(key)));
+    }
+
     #[test]
     fn attach_binds_focuses_pane_and_enters_insert_mode() {
         let mut state = AppState::new();