Show live background task counts

server/src/session/echo.rs

@@ -124,6 +124,9 @@ pub struct EchoDriver {
     /// says it recovered, and a clear leaves it unmeasured. What is real is
     /// which way the numbers move.
     context: Arc<AtomicU64>,
+    /// Live background commands, for the same count a real provider reports.
+    /// This is the deterministic UI/session-lifecycle rig for that state.
+    background_tasks: Arc<Mutex<usize>>,
     /// This session's subagents -- see `SUBAGENTS.md`. `/subagent` is the
     /// test rig for the same registry the claude driver routes real Task
     /// calls into.
@@ -500,6 +503,12 @@ impl EchoDriver {
                 id: id.clone(),
                 output: format!("Command running in background with ID: {id}"),
             });
+            let background_tasks = Arc::clone(&self.background_tasks);
+            {
+                let mut count = background_tasks.lock().unwrap();
+                *count += 1;
+                self.emit(Event::BackgroundTasks { count: *count });
+            }
             for word in "Started it; I'll pick this up when it lands.".split_inclusive(' ') {
                 self.emit(Event::AssistantText {
                     delta: word.to_string(),
@@ -513,6 +522,11 @@ impl EchoDriver {
             let sink = self.sink.clone();
             tokio::spawn(async move {
                 tokio::time::sleep(Duration::from_secs(seconds)).await;
+                {
+                    let mut count = background_tasks.lock().unwrap();
+                    *count -= 1;
+                    let _ = sink.send(Event::BackgroundTasks { count: *count });
+                }
                 let _ = sink.send(Event::ToolUpdate {
                     id,
                     output: format!(r#"Background command "{command}" completed (exit code 0)"#),
@@ -526,9 +540,16 @@ impl EchoDriver {
                     });
                     tokio::time::sleep(DELTA_DELAY).await;
                 }
-                let _ = sink.send(Event::Status {
-                    state: SessionStatus::Idle,
-                });
+                {
+                    let count = background_tasks.lock().unwrap();
+                    let _ = sink.send(Event::Status {
+                        state: if *count == 0 {
+                            SessionStatus::Idle
+                        } else {
+                            SessionStatus::Waiting
+                        },
+                    });
+                }
             });
             return;
         }
@@ -855,6 +876,7 @@ impl EchoDriver {
             sink,
             pending_questions: Mutex::new(Vec::new()),
             context: Arc::new(AtomicU64::new(0)),
+            background_tasks: Arc::new(Mutex::new(0)),
             busy: Arc::new(AtomicBool::new(false)),
             queued: Arc::new(Mutex::new(Vec::new())),
             session_dir,
@@ -1165,6 +1187,10 @@ fn finish_turn(sink: &EventSink, queued: &Mutex<Vec<Held>>, busy: &AtomicBool) {
 }
 
 impl Driver for EchoDriver {
+    fn background_tasks(&self) -> Option<usize> {
+        Some(*self.background_tasks.lock().unwrap())
+    }
+
     fn between_turns(&self) -> bool {
         !self.busy.load(Ordering::SeqCst)
     }