diff --git a/crates/spaceshd/src/registry.rs b/crates/spaceshd/src/registry.rs
index 872696b..cc0aefe 100644
--- a/crates/spaceshd/src/registry.rs
+++ b/crates/spaceshd/src/registry.rs
@@ -1,24 +1,24 @@
 use std::collections::HashMap;
 use std::path::PathBuf;
 use std::sync::atomic::{AtomicU64, Ordering};
-use spacesh_proto::{SurfaceId, WorkspaceId};
+
+use spacesh_proto::ids::{GroupId, SurfaceId, WorkspaceId};
+use spacesh_proto::layout::LayoutNode;
+use spacesh_proto::workspace::{Group, SurfaceSpec, SurfaceView, Workspace, WorkspaceView};
+
+use crate::state_store::PersistState;
 use crate::surface::SurfaceHandle;
 
-#[derive(Clone)]
-pub struct WorkspaceMeta {
-    pub id: WorkspaceId,
-    pub path: PathBuf,
-}
-
-/// Single-threaded owner of all live surfaces and workspaces.
-/// Lives inside the server task; not shared across threads.
+/// Single-threaded owner of structure (workspaces/groups/trees + per-surface
+/// specs) and the live actor map. Lives in the server router task.
 #[derive(Default)]
 pub struct Registry {
     counter: AtomicU64,
-    workspaces: HashMap<WorkspaceId, WorkspaceMeta>,
-    /// path → workspace, so `open` is idempotent.
-    by_path: HashMap<PathBuf, WorkspaceId>,
-    surfaces: HashMap<SurfaceId, SurfaceHandle>,
+    groups: HashMap<GroupId, Group>,
+    workspaces: HashMap<WorkspaceId, Workspace>,
+    by_path: HashMap<String, WorkspaceId>,
+    /// Live actors only. Absent id that exists in a workspace's `surfaces` = stopped.
+    live: HashMap<SurfaceId, SurfaceHandle>,
 }
 
 impl Registry {
@@ -31,75 +31,217 @@ impl Registry {
         format!("{prefix}_{n:x}")
     }
 
-    /// Idempotent: opening the same canonicalized path returns the existing workspace.
-    pub fn open_workspace(&mut self, path: PathBuf) -> WorkspaceMeta {
-        let canonical = path.canonicalize().unwrap_or(path);
-        if let Some(id) = self.by_path.get(&canonical) {
-            return self.workspaces[id].clone();
-        }
-        let id = WorkspaceId(self.next_id("w"));
-        let meta = WorkspaceMeta { id: id.clone(), path: canonical.clone() };
-        self.workspaces.insert(id.clone(), meta.clone());
-        self.by_path.insert(canonical, id);
-        meta
-    }
-
-    pub fn workspace(&self, id: &WorkspaceId) -> Option<&WorkspaceMeta> {
-        self.workspaces.get(id)
-    }
-
     pub fn new_surface_id(&self) -> SurfaceId {
         SurfaceId(self.next_id("s"))
     }
 
-    pub fn insert_surface(&mut self, handle: SurfaceHandle) {
-        self.surfaces.insert(handle.id.clone(), handle);
+    // ---- workspaces ----
+
+    /// Idempotent by canonicalized path. Returns (workspace_id, created?).
+    pub fn open_workspace(&mut self, path: PathBuf) -> (WorkspaceId, bool) {
+        let canonical = path.canonicalize().unwrap_or(path);
+        let key = canonical.to_string_lossy().to_string();
+        if let Some(id) = self.by_path.get(&key) {
+            return (id.clone(), false);
+        }
+        let id = WorkspaceId(self.next_id("w"));
+        let name = canonical.file_name().map(|s| s.to_string_lossy().to_string()).unwrap_or_else(|| key.clone());
+        let order = self.workspaces.len() as u32;
+        self.workspaces.insert(id.clone(), Workspace {
+            id: id.clone(), path: key.clone(), name, group_id: None, order,
+            unread: false, layout: None, surfaces: HashMap::new(),
+        });
+        self.by_path.insert(key, id.clone());
+        (id, true)
     }
 
-    pub fn surface(&self, id: &SurfaceId) -> Option<&SurfaceHandle> {
-        self.surfaces.get(id)
+    pub fn workspace(&self, id: &WorkspaceId) -> Option<&Workspace> {
+        self.workspaces.get(id)
+    }
+    pub fn workspace_mut(&mut self, id: &WorkspaceId) -> Option<&mut Workspace> {
+        self.workspaces.get_mut(id)
+    }
+    pub fn close_workspace(&mut self, id: &WorkspaceId) -> Vec<SurfaceId> {
+        let Some(ws) = self.workspaces.remove(id) else { return vec![] };
+        self.by_path.retain(|_, v| v != id);
+        let ids: Vec<SurfaceId> = ws.surfaces.keys().cloned().collect();
+        for sid in &ids {
+            self.live.remove(sid);
+        }
+        ids
     }
 
-    pub fn remove_surface(&mut self, id: &SurfaceId) -> Option<SurfaceHandle> {
-        self.surfaces.remove(id)
+    /// The workspace that owns a surface id, if any.
+    pub fn workspace_of(&self, sid: &SurfaceId) -> Option<WorkspaceId> {
+        self.workspaces.values().find(|w| w.surfaces.contains_key(sid)).map(|w| w.id.clone())
     }
 
-    /// Snapshot for the `status` command: (workspace, its surface ids).
-    pub fn status(&self) -> Vec<(WorkspaceMeta, Vec<SurfaceId>)> {
-        self.workspaces
-            .values()
-            .map(|w| {
-                let sids = self
-                    .surfaces
-                    .values()
-                    .filter(|s| s.workspace_id == w.id)
-                    .map(|s| s.id.clone())
-                    .collect();
-                (w.clone(), sids)
-            })
-            .collect()
+    // ---- surfaces (structure) ----
+
+    pub fn add_surface_spec(&mut self, ws: &WorkspaceId, sid: SurfaceId, spec: SurfaceSpec) {
+        if let Some(w) = self.workspaces.get_mut(ws) {
+            w.surfaces.insert(sid, spec);
+        }
+    }
+    pub fn surface_spec(&self, sid: &SurfaceId) -> Option<SurfaceSpec> {
+        self.workspaces.values().find_map(|w| w.surfaces.get(sid).cloned())
+    }
+    /// Remove a surface from its workspace's spec map and the tree.
+    pub fn remove_surface(&mut self, sid: &SurfaceId) {
+        self.live.remove(sid);
+        if let Some(ws) = self.workspace_of(sid) {
+            if let Some(w) = self.workspaces.get_mut(&ws) {
+                w.surfaces.remove(sid);
+                w.layout = w.layout.take().and_then(|l| spacesh_core::ops::remove_leaf(l, sid));
+            }
+        }
+    }
+
+    // ---- live actors ----
+
+    pub fn set_live(&mut self, handle: SurfaceHandle) {
+        self.live.insert(handle.id.clone(), handle);
+    }
+    pub fn live(&self, sid: &SurfaceId) -> Option<&SurfaceHandle> {
+        self.live.get(sid)
+    }
+    pub fn mark_stopped(&mut self, sid: &SurfaceId) {
+        self.live.remove(sid);
+    }
+    pub fn is_running(&self, sid: &SurfaceId) -> bool {
+        self.live.contains_key(sid)
+    }
+
+    // ---- groups ----
+
+    pub fn create_group(&mut self, name: String, color: String) -> GroupId {
+        let id = GroupId(self.next_id("g"));
+        let order = self.groups.len() as u32;
+        self.groups.insert(id.clone(), Group { id: id.clone(), name, color, order });
+        id
+    }
+    pub fn group_mut(&mut self, id: &GroupId) -> Option<&mut Group> {
+        self.groups.get_mut(id)
+    }
+    pub fn delete_group(&mut self, id: &GroupId) {
+        self.groups.remove(id);
+        for w in self.workspaces.values_mut() {
+            if w.group_id.as_ref() == Some(id) {
+                w.group_id = None;
+            }
+        }
+    }
+    pub fn groups(&self) -> Vec<Group> {
+        let mut g: Vec<Group> = self.groups.values().cloned().collect();
+        g.sort_by_key(|x| x.order);
+        g
+    }
+
+    // ---- views & persistence ----
+
+    pub fn workspace_view(&self, id: &WorkspaceId) -> Option<WorkspaceView> {
+        let w = self.workspaces.get(id)?;
+        Some(self.to_view(w))
+    }
+    fn to_view(&self, w: &Workspace) -> WorkspaceView {
+        let surfaces = w.surfaces.iter().map(|(sid, spec)| {
+            (sid.clone(), SurfaceView { spec: spec.clone(), running: self.live.contains_key(sid) })
+        }).collect();
+        WorkspaceView {
+            id: w.id.clone(), path: w.path.clone(), name: w.name.clone(),
+            group_id: w.group_id.clone(), order: w.order, unread: w.unread,
+            layout: w.layout.clone(), surfaces,
+        }
+    }
+    pub fn status(&self) -> (Vec<Group>, Vec<WorkspaceView>) {
+        let mut ws: Vec<WorkspaceView> = self.workspaces.values().map(|w| self.to_view(w)).collect();
+        ws.sort_by_key(|w| w.order);
+        (self.groups(), ws)
+    }
+    pub fn persist_state(&self) -> PersistState {
+        let mut workspaces: Vec<Workspace> = self.workspaces.values().cloned().collect();
+        workspaces.sort_by_key(|w| w.order);
+        PersistState { version: 1, groups: self.groups(), workspaces }
+    }
+    /// Replace all structure from a loaded snapshot (cold start). Clears live map.
+    pub fn restore(&mut self, state: PersistState) {
+        self.groups = state.groups.into_iter().map(|g| (g.id.clone(), g)).collect();
+        self.workspaces.clear();
+        self.by_path.clear();
+        self.live.clear();
+        for w in state.workspaces {
+            self.by_path.insert(w.path.clone(), w.id.clone());
+            self.workspaces.insert(w.id.clone(), w);
+        }
     }
 }
 
 #[cfg(test)]
 mod tests {
     use super::*;
+    use spacesh_proto::layout::{LayoutNode as LN, Orient};
 
-    #[test]
-    fn open_is_idempotent_per_path() {
-        let mut reg = Registry::new();
-        let dir = std::env::temp_dir();
-        let a = reg.open_workspace(dir.clone());
-        let b = reg.open_workspace(dir.clone());
-        assert_eq!(a.id, b.id);
+    fn spec() -> SurfaceSpec {
+        SurfaceSpec { command: "/bin/sh".into(), args: vec![], cwd: "/tmp".into(),
+            agent_label: None, cols: 80, rows: 24, autostart: false }
     }
 
     #[test]
-    fn ids_are_unique_and_prefixed() {
-        let reg = Registry::new();
-        let s1 = reg.new_surface_id();
-        let s2 = reg.new_surface_id();
-        assert!(s1.0.starts_with("s_"));
-        assert_ne!(s1, s2);
+    fn open_is_idempotent() {
+        let mut r = Registry::new();
+        let (a, c1) = r.open_workspace(std::env::temp_dir());
+        let (b, c2) = r.open_workspace(std::env::temp_dir());
+        assert_eq!(a, b);
+        assert!(c1 && !c2);
+    }
+
+    #[test]
+    fn surface_running_then_stopped() {
+        let mut r = Registry::new();
+        let (ws, _) = r.open_workspace(std::env::temp_dir());
+        let sid = r.new_surface_id();
+        r.add_surface_spec(&ws, sid.clone(), spec());
+        assert!(!r.is_running(&sid)); // spec present, no live actor = stopped
+        let v = r.workspace_view(&ws).unwrap();
+        assert_eq!(v.surfaces.get(&sid).unwrap().running, false);
+    }
+
+    #[test]
+    fn remove_surface_updates_tree() {
+        let mut r = Registry::new();
+        let (ws, _) = r.open_workspace(std::env::temp_dir());
+        let s1 = r.new_surface_id();
+        let s2 = r.new_surface_id();
+        r.add_surface_spec(&ws, s1.clone(), spec());
+        r.add_surface_spec(&ws, s2.clone(), spec());
+        r.workspace_mut(&ws).unwrap().layout = Some(LN::Split {
+            orient: Orient::H, ratios: vec![0.5, 0.5],
+            children: vec![LN::leaf(s1.clone()), LN::leaf(s2.clone())],
+        });
+        r.remove_surface(&s2);
+        let w = r.workspace(&ws).unwrap();
+        assert!(!w.surfaces.contains_key(&s2));
+        assert_eq!(w.layout, Some(LN::leaf(s1))); // split collapsed
+    }
+
+    #[test]
+    fn restore_round_trips_through_persist_state() {
+        let mut r = Registry::new();
+        let (ws, _) = r.open_workspace(std::env::temp_dir());
+        r.add_surface_spec(&ws, r.new_surface_id(), spec());
+        let state = r.persist_state();
+        let mut r2 = Registry::new();
+        r2.restore(state.clone());
+        assert_eq!(r2.persist_state().workspaces.len(), state.workspaces.len());
+    }
+
+    #[test]
+    fn delete_group_ungroups_members() {
+        let mut r = Registry::new();
+        let (ws, _) = r.open_workspace(std::env::temp_dir());
+        let g = r.create_group("prod".into(), "#fff".into());
+        r.workspace_mut(&ws).unwrap().group_id = Some(g.clone());
+        r.delete_group(&g);
+        assert!(r.workspace(&ws).unwrap().group_id.is_none());
     }
 }