Threads monitor background shells: a turn that ends with a shell, monitor or workflow still running shows Monitoring, not Complete

src/core/hub.bend

@@ -893,24 +893,41 @@ def Bg.started(agent: Bool, +s: M.State, +th: String, +now: Nat, +o: J.Json) ->
     case False{}:
       Nil{}
 
-def Bg.ended(done: Bool, +s: M.State, +th: String, +now: Nat, +id: String) -> List<&2, M.Change>:
+# a foreground shell Claude moved to the background when it ran past its
+# timeout (task_updated sets is_backgrounded; the patch has no description)
+def Bg.moved(bg: Bool, +s: M.State, +th: String, +now: Nat, +id: String) -> List<&2, M.Change>:
+  match bg:
+    case True{}:
+      Bg.put(s, th, now, M.Bg.add(M.Bg.of(s, th), id, "Background shell"))
+    case False{}:
+      Nil{}
+
+def Bg.ended(done: Bool, bg: Bool, +s: M.State, +th: String, +now: Nat, +id: String) -> List<&2, M.Change>:
   match done:
     case True{}:
       Bg.put(s, th, now, M.Bg.drop(M.Bg.of(s, th), id))
     case False{}:
-      Nil{}
+      Bg.moved(bg, s, th, now, id)
+
+# a task the agent left running: a subagent, a background shell or
+# monitor, a workflow; not one a subagent runs for itself, and not a
+# foreground shell (listed only if Claude moves it to the background,
+# Bg.moved)
+def Bg.listed(+o: J.Json) -> Bool:
+  Bool.and(Nat.is_lt(C.Codec.pos(["local_agent", "local_bash", "local_workflow", "remote_agent", "monitor_mcp", "monitor_ws", "in_process_teammate"], J.Json.get_str(o, "task_type", "")), 7n),
+    Bool.and(Bool.not(J.Json.get_bool(o, "owned_by_subagent", False{})), J.Json.get_bool(o, "is_backgrounded", True{})))
 
 def Bg.system.k(i: Nat, +s: M.State, +th: String, +now: Nat, +o: J.Json) -> List<&2, M.Change>:
   match i:
     case 0n:
-      Bg.started(String.eq(J.Json.get_str(o, "task_type", ""), "local_agent"), s, th, now, o)
+      Bg.started(Bg.listed(o), s, th, now, o)
     case 1n:
       Bg.put(s, th, now, M.Bg.set(M.Bg.of(s, th), J.Json.get_str(o, "task_id", ""), J.Json.get_str(o, "description", "")))
     case 2n:
       Bg.put(s, th, now, M.Bg.drop(M.Bg.of(s, th), J.Json.get_str(o, "task_id", "")))
     case 3n:
       Bg.ended(Nat.is_lt(C.Codec.pos(["completed", "failed", "killed", "stopped", "cancelled"], J.Json.get_str(J.Json.get_obj(o, "patch"), "status", "")), 5n),
-        s, th, now, J.Json.get_str(o, "task_id", ""))
+        J.Json.get_bool(J.Json.get_obj(o, "patch"), "is_backgrounded", False{}), s, th, now, J.Json.get_str(o, "task_id", ""))
     case _:
       Nil{}
 

src/core/model.bend

@@ -2101,10 +2101,10 @@ def Phase.label(p: Phase) -> String:
 
 # Subagents
 # ---------
-# The subagents an agent has at work (Claude's task_started, task_progress
-# and task_notification lines), kept as the setting "bg.<thread>": one
-# "id\tdoing" line each. They can run on after the agent's own turn ends,
-# so the thread still shows them working.
+# The subagents, background shells and monitors an agent has at work
+# (Claude's task_started, task_progress and task_notification lines), kept
+# as the setting "bg.<thread>": one "id\tdoing" line each. They can run on
+# after the agent's own turn ends, so the thread shows it monitoring them.
 
 def Bg.key(+th: String) -> String:
   "bg." ++ th

test/subagents_test.bend

@@ -4,7 +4,7 @@ import ../src/core/model.bend as M
 import ../src/core/hub.bend as H
 import ../src/core/client.bend as U
 
-# Claude's subagents: a background one started, said what it does, and
+# Claude's subagents and background shells: a background one started, said what it does, and
 # ended (lines as Claude Code 2.1 writes them); the thread waits on it
 # after its own turn ends, and an agent that exits leaves none at work.
 
@@ -38,6 +38,21 @@ def progressed() -> List<&2, M.Change>:
 def ended() -> List<&2, M.Change>:
   after(progressed(), 105n, "{\"type\":\"system\",\"subtype\":\"task_notification\",\"task_id\":\"a847\",\"tool_use_id\":\"toolu_1\",\"status\":\"completed\",\"session_id\":\"s\"}")
 
+# a shell the agent put in the background (or Claude moved there when it
+# ran past its timeout)
+def shell() -> List<&2, M.Change>:
+  after(made(), 102n, "{\"type\":\"system\",\"subtype\":\"task_started\",\"task_id\":\"b3\",\"description\":\"scripts/check.sh\",\"task_type\":\"local_bash\",\"is_backgrounded\":true}")
+
+def shell.done() -> List<&2, M.Change>:
+  List.append(&2, M.Change, shell(), [M.TurnChanged{"t100-1", M.Completed{}, 103n}])
+
+# a foreground shell (Claude names it once it has run 30 s) that ran past
+# its timeout and was moved to the background (lines as Claude Code 2.1.285
+# writes them)
+def moved() -> List<&2, M.Change>:
+  after(after(made(), 102n, "{\"type\":\"system\",\"subtype\":\"task_started\",\"task_id\":\"b5\",\"task_type\":\"local_bash\",\"is_backgrounded\":false,\"description\":\"Run checks\"}"),
+    103n, "{\"type\":\"system\",\"subtype\":\"task_updated\",\"task_id\":\"b5\",\"patch\":{\"is_backgrounded\":true}}")
+
 def status(+es: List<&2, M.Change>) -> String:
   M.Status.name(U.Side.status(state(es), H.Hub.thread(state(es), "t100-1")))
 
@@ -63,7 +78,16 @@ def main() -> IO(Unit):
     C.Check.str("progress", doing(progressed()), "Running Sleep for 20 seconds")
     C.Check.str("progress again writes nothing", Nat.show(List.length(&2, M.Change, progressed())), Nat.show(List.length(&2, M.Change,
       after(progressed(), 106n, "{\"type\":\"system\",\"subtype\":\"task_progress\",\"task_id\":\"a847\",\"description\":\"Running Sleep for 20 seconds\",\"session_id\":\"s\"}"))))
-    C.Check.str("a subagent's bash is not listed", doing(after(done(), 104n, "{\"type\":\"system\",\"subtype\":\"task_started\",\"task_id\":\"b1\",\"description\":\"Sleep\",\"task_type\":\"local_bash\"}")), "Run bash command and report output")
+    C.Check.str("a subagent's bash is not listed", doing(after(done(), 104n, "{\"type\":\"system\",\"subtype\":\"task_started\",\"task_id\":\"b1\",\"description\":\"Sleep\",\"task_type\":\"local_bash\",\"owned_by_subagent\":true}")), "Run bash command and report output")
+    C.Check.str("a foreground shell is not listed", doing(after(made(), 102n, "{\"type\":\"system\",\"subtype\":\"task_started\",\"task_id\":\"b2\",\"description\":\"sleep 4\",\"task_type\":\"local_bash\",\"is_backgrounded\":false}")), "")
+    C.Check.str("a background shell is listed", doing(shell()), "scripts/check.sh")
+    C.Check.str("the turn over, it monitors the shell", status(shell.done()), "waiting")
+    C.Check.str("monitoring phase", phase(shell.done()), "Monitoring 1 task")
+    C.Check.str("the shell ends: ready", status(after(shell.done(), 105n, "{\"type\":\"system\",\"subtype\":\"task_notification\",\"task_id\":\"b3\",\"status\":\"completed\"}")), "ready")
+    C.Check.str("a shell moved to the background past its timeout is listed", doing(moved()), "Background shell")
+    C.Check.str("moved, the turn over: monitoring", phase(List.append(&2, M.Change, moved(), [M.TurnChanged{"t100-1", M.Completed{}, 104n}])), "Monitoring 1 task")
+    C.Check.str("moved, then done", doing(after(moved(), 105n, "{\"type\":\"system\",\"subtype\":\"task_updated\",\"task_id\":\"b5\",\"patch\":{\"status\":\"completed\",\"end_time\":1}}")), "")
+    C.Check.str("a monitor is listed", doing(after(made(), 102n, "{\"type\":\"system\",\"subtype\":\"task_started\",\"task_id\":\"b4\",\"description\":\"CI\",\"task_type\":\"monitor_mcp\"}")), "CI")
     C.Check.str("ended", doing(ended()), "")
     C.Check.str("ready after", status(ended()), "ready")
     C.Check.str("updated to completed ends it", doing(after(progressed(), 105n, "{\"type\":\"system\",\"subtype\":\"task_updated\",\"task_id\":\"a847\",\"patch\":{\"status\":\"completed\"}}")), "")