diff --git a/crates/spacesh-proto/src/lib.rs b/crates/spacesh-proto/src/lib.rs
index cef3834..987b410 100644
--- a/crates/spacesh-proto/src/lib.rs
+++ b/crates/spacesh-proto/src/lib.rs
@@ -2,9 +2,11 @@ pub mod codec;
 pub mod ids;
 pub mod layout;
 pub mod message;
+pub mod status;
 pub mod workspace;
 
 pub use ids::{GroupId, SurfaceId, WorkspaceId};
 pub use layout::{LayoutNode, Orient};
 pub use message::{Cmd, Envelope, ErrorBody, Evt};
+pub use status::SurfaceState;
 pub use workspace::{Group, SurfaceSpec, SurfaceView, Workspace, WorkspaceView};
diff --git a/crates/spacesh-proto/src/message.rs b/crates/spacesh-proto/src/message.rs
index b8187a2..dc26265 100644
--- a/crates/spacesh-proto/src/message.rs
+++ b/crates/spacesh-proto/src/message.rs
@@ -1,6 +1,7 @@
 use serde::{Deserialize, Serialize};
 use crate::ids::{GroupId, SurfaceId, WorkspaceId};
 use crate::layout::LayoutNode;
+use crate::status::SurfaceState;
 use crate::workspace::{Group, WorkspaceView};
 
 /// Wire envelope. `kind` is the serde tag.
@@ -114,6 +115,7 @@ pub enum Cmd {
         order: Option<u32>,
     },
     DeleteGroup { group_id: GroupId },
+    SetState { surface_id: SurfaceId, state: SurfaceState },
     Status,
     Shutdown,
 }
@@ -131,6 +133,7 @@ pub enum Evt {
     WorkspaceClosed { workspace_id: WorkspaceId },
     GroupsChanged { groups: Vec<Group> },
     SurfaceRestarted { surface_id: SurfaceId },
+    State { surface_id: SurfaceId, state: SurfaceState },
 }
 
 #[cfg(test)]
@@ -240,4 +243,23 @@ mod tests {
         let back: Envelope = serde_json::from_str(&serde_json::to_string(&evt).unwrap()).unwrap();
         assert_eq!(back, evt);
     }
+
+    #[test]
+    fn set_state_round_trips() {
+        let env = Envelope::Req {
+            id: 1,
+            cmd: Cmd::SetState { surface_id: SurfaceId("s_1".into()), state: crate::status::SurfaceState::Done },
+        };
+        let back: Envelope = serde_json::from_str(&serde_json::to_string(&env).unwrap()).unwrap();
+        assert_eq!(back, env);
+    }
+
+    #[test]
+    fn state_event_round_trips() {
+        let evt = Envelope::Evt(Evt::State { surface_id: SurfaceId("s_1".into()), state: crate::status::SurfaceState::Wait });
+        let j = serde_json::to_string(&evt).unwrap();
+        assert!(j.contains(r#""evt":"state""#));
+        let back: Envelope = serde_json::from_str(&j).unwrap();
+        assert_eq!(back, evt);
+    }
 }
diff --git a/crates/spacesh-proto/src/status.rs b/crates/spacesh-proto/src/status.rs
new file mode 100644
index 0000000..ee14d64
--- /dev/null
+++ b/crates/spacesh-proto/src/status.rs
@@ -0,0 +1,39 @@
+use serde::{Deserialize, Serialize};
+
+/// Ephemeral agent-activity status of a running surface (orthogonal to the
+/// running/stopped process lifecycle). Defaults to `Idle`.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default, Serialize, Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum SurfaceState {
+    Work,
+    Wait,
+    Done,
+    Error,
+    #[default]
+    Idle,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn serializes_snake_case() {
+        assert_eq!(serde_json::to_string(&SurfaceState::Work).unwrap(), r#""work""#);
+        assert_eq!(serde_json::to_string(&SurfaceState::Idle).unwrap(), r#""idle""#);
+    }
+
+    #[test]
+    fn default_is_idle() {
+        assert_eq!(SurfaceState::default(), SurfaceState::Idle);
+    }
+
+    #[test]
+    fn round_trips() {
+        for s in [SurfaceState::Work, SurfaceState::Wait, SurfaceState::Done, SurfaceState::Error, SurfaceState::Idle] {
+            let j = serde_json::to_string(&s).unwrap();
+            let back: SurfaceState = serde_json::from_str(&j).unwrap();
+            assert_eq!(back, s);
+        }
+    }
+}
diff --git a/crates/spacesh-proto/src/workspace.rs b/crates/spacesh-proto/src/workspace.rs
index 23ffea7..5a0c28a 100644
--- a/crates/spacesh-proto/src/workspace.rs
+++ b/crates/spacesh-proto/src/workspace.rs
@@ -2,6 +2,7 @@ use std::collections::HashMap;
 use serde::{Deserialize, Serialize};
 use crate::ids::{GroupId, SurfaceId, WorkspaceId};
 use crate::layout::LayoutNode;
+use crate::status::SurfaceState;
 
 /// Everything needed to (re)create a panel's process.
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
@@ -50,6 +51,9 @@ pub struct SurfaceView {
     pub spec: SurfaceSpec,
     /// true = has a live actor/PTY; false = stopped (in tree, no process).
     pub running: bool,
+    /// Ephemeral agent-activity status (meaningful while running).
+    #[serde(default)]
+    pub state: SurfaceState,
 }
 
 /// Workspace view in `status` / `workspace_changed`: structure + per-surface state.