diff --git a/crates/spacesh-proto/src/lib.rs b/crates/spacesh-proto/src/lib.rs
index 328a525..cef3834 100644
--- a/crates/spacesh-proto/src/lib.rs
+++ b/crates/spacesh-proto/src/lib.rs
@@ -2,7 +2,9 @@ pub mod codec;
 pub mod ids;
 pub mod layout;
 pub mod message;
+pub mod workspace;
 
 pub use ids::{GroupId, SurfaceId, WorkspaceId};
 pub use layout::{LayoutNode, Orient};
 pub use message::{Cmd, Envelope, ErrorBody, Evt};
+pub use workspace::{Group, SurfaceSpec, SurfaceView, Workspace, WorkspaceView};
diff --git a/crates/spacesh-proto/src/workspace.rs b/crates/spacesh-proto/src/workspace.rs
new file mode 100644
index 0000000..23ffea7
--- /dev/null
+++ b/crates/spacesh-proto/src/workspace.rs
@@ -0,0 +1,104 @@
+use std::collections::HashMap;
+use serde::{Deserialize, Serialize};
+use crate::ids::{GroupId, SurfaceId, WorkspaceId};
+use crate::layout::LayoutNode;
+
+/// Everything needed to (re)create a panel's process.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct SurfaceSpec {
+    pub command: String,
+    #[serde(default)]
+    pub args: Vec<String>,
+    pub cwd: String,
+    #[serde(default)]
+    pub agent_label: Option<String>,
+    pub cols: u16,
+    pub rows: u16,
+    #[serde(default)]
+    pub autostart: bool,
+}
+
+/// A colored, ordered collection of workspaces.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct Group {
+    pub id: GroupId,
+    pub name: String,
+    pub color: String,
+    pub order: u32,
+}
+
+/// Persisted workspace: structure only (no live process state).
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct Workspace {
+    pub id: WorkspaceId,
+    pub path: String,
+    pub name: String,
+    #[serde(default)]
+    pub group_id: Option<GroupId>,
+    pub order: u32,
+    #[serde(default)]
+    pub unread: bool,
+    /// None = empty workspace (no panels yet).
+    #[serde(default)]
+    pub layout: Option<LayoutNode>,
+    pub surfaces: HashMap<SurfaceId, SurfaceSpec>,
+}
+
+/// Per-surface view in `status` — spec plus live lifecycle flag.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct SurfaceView {
+    pub spec: SurfaceSpec,
+    /// true = has a live actor/PTY; false = stopped (in tree, no process).
+    pub running: bool,
+}
+
+/// Workspace view in `status` / `workspace_changed`: structure + per-surface state.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct WorkspaceView {
+    pub id: WorkspaceId,
+    pub path: String,
+    pub name: String,
+    pub group_id: Option<GroupId>,
+    pub order: u32,
+    pub unread: bool,
+    pub layout: Option<LayoutNode>,
+    pub surfaces: HashMap<SurfaceId, SurfaceView>,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn surface_spec_round_trips() {
+        let s = SurfaceSpec {
+            command: "claude".into(),
+            args: vec![],
+            cwd: "/tmp".into(),
+            agent_label: Some("claude".into()),
+            cols: 80,
+            rows: 24,
+            autostart: false,
+        };
+        let j = serde_json::to_string(&s).unwrap();
+        let back: SurfaceSpec = serde_json::from_str(&j).unwrap();
+        assert_eq!(back, s);
+    }
+
+    #[test]
+    fn workspace_round_trips_with_empty_layout() {
+        let w = Workspace {
+            id: WorkspaceId("w_1".into()),
+            path: "/tmp/p".into(),
+            name: "p".into(),
+            group_id: None,
+            order: 0,
+            unread: false,
+            layout: None,
+            surfaces: HashMap::new(),
+        };
+        let j = serde_json::to_string(&w).unwrap();
+        let back: Workspace = serde_json::from_str(&j).unwrap();
+        assert_eq!(back, w);
+    }
+}