fix: discover running subgraph lifecycle events

libs/sdk-py/integration/scripts/test_subgraphs.py

@@ -37,7 +37,7 @@ async def _drain_subgraphs(thread) -> list:
         # Just count handle paths; deep message iteration on scoped
         # handles has its own draining pattern and isn't the goal of
         # this test (which exercises subgraph discovery via
-        # child-namespace ``lifecycle: started``).
+        # child-namespace `lifecycle: started/running`).
         children.append({"path": child.path})
     return children
 

libs/sdk-py/langgraph_sdk/_async/stream.py

@@ -537,12 +537,11 @@ def _is_direct_child(namespace: list[str], scope: tuple[str, ...]) -> bool:
 def _subgraph_subscription_params(scope: tuple[str, ...]) -> SubscribeParams:
     # Subscribe to tasks + messages + tools + lifecycle without a depth limit
     # so all descendant-namespace events are captured in one SSE and buffered
-    # into each child handle's inbox. ``lifecycle`` is included so child-
-    # namespace ``started`` events (the canonical signal for
-    # ``create_deep_agent``-style subagent discovery, matching JS behavior)
-    # reach ``_subgraphs_iter``; servers that surface child invocations via
-    # ``tasks`` events instead are also handled via the existing ``method ==
-    # "tasks"`` branch.
+    # into each child handle's inbox. `lifecycle` is included so child
+    # started/running events (the canonical signal for `create_deep_agent`-
+    # style subagent discovery, matching JS behavior) reach `_subgraphs_iter`;
+    # servers that surface child invocations via `tasks` events instead are
+    # also handled via the existing `method == "tasks"` branch.
     return {
         "channels": ["messages", "tasks", "tools", "lifecycle"],
         "namespaces": [list(scope)],
@@ -1991,7 +1990,9 @@ class AsyncThreadStream:
             params = event.get("params") or {}
             data = params.get("data") if isinstance(params, dict) else None
             phase = data.get("event") if isinstance(data, dict) else None
-            payload_namespace = data.get("namespace") if isinstance(data, dict) else None
+            payload_namespace = (
+                data.get("namespace") if isinstance(data, dict) else None
+            )
             if isinstance(payload_namespace, list) and payload_namespace:
                 return
             if phase in ("started", "running"):

libs/sdk-py/langgraph_sdk/_sync/stream.py

@@ -114,9 +114,9 @@ def _is_direct_child(namespace: list[str], scope: tuple[str, ...]) -> bool:
 
 
 def _subgraph_subscription_params(scope: tuple[str, ...]) -> SubscribeParams:
-    # Includes ``lifecycle`` so child-namespace ``started`` events (the
-    # ``create_deep_agent`` subagent discovery signal, matching JS)
-    # reach ``_subgraphs_iter`` alongside ``tasks``-based discovery.
+    # Includes `lifecycle` so child started/running events (the
+    # `create_deep_agent` subagent discovery signal, matching JS) reach
+    # `_subgraphs_iter` alongside `tasks`-based discovery.
     return {
         "channels": ["messages", "tasks", "tools", "lifecycle"],
         "namespaces": [list(scope)],
@@ -1624,7 +1624,9 @@ class SyncThreadStream:
             params = event.get("params") or {}
             data = params.get("data") if isinstance(params, dict) else None
             phase = data.get("event") if isinstance(data, dict) else None
-            payload_namespace = data.get("namespace") if isinstance(data, dict) else None
+            payload_namespace = (
+                data.get("namespace") if isinstance(data, dict) else None
+            )
             if isinstance(payload_namespace, list) and payload_namespace:
                 return
             if phase in ("started", "running"):

libs/sdk-py/langgraph_sdk/stream/decoders.py

@@ -9,7 +9,7 @@ which drives multiple decoders from one shared subscription.
 from __future__ import annotations
 
 from collections.abc import Callable, Iterable, Mapping
-from typing import Any, Literal, Protocol
+from typing import Any, Literal, Protocol, cast
 
 #: Channel names the public ``interleave_projections`` API accepts as built-ins.
 SUPPORTED_INTERLEAVE_CHANNELS = (
@@ -61,7 +61,7 @@ def _lifecycle_payload_namespace(
 ) -> list[str]:
     namespace = data.get("namespace")
     if isinstance(namespace, list):
-        return list(namespace)
+        return cast(list[str], list(namespace))
     return _event_namespace(params_field)
 
 
@@ -310,7 +310,9 @@ class SubgraphsDecoder:
                 yield from self._discover(namespace)
         elif method == "lifecycle":
             event_type = data.get("event")
-            if event_type == "started" and _is_direct_child(namespace, self._scope):
+            if event_type in ("started", "running") and _is_direct_child(
+                namespace, self._scope
+            ):
                 yield from self._discover(namespace)
             elif event_type in ("completed", "failed", "interrupted"):
                 self._apply_lifecycle_terminal(namespace, data)

libs/sdk-py/tests/streaming/test_decoders.py

@@ -375,6 +375,24 @@ def test_subgraphs_decoder_discovers_on_forwarded_lifecycle_payload_namespace():
     assert h.trigger_call_id == "call-1"
 
 
+def test_subgraphs_decoder_discovers_on_forwarded_lifecycle_running_status():
+    decoder = SubgraphsDecoder(scope=(), handle_factory=_scoped_factory)
+    [h] = list(
+        decoder.feed(
+            _forwarded_lifecycle_event(
+                seq=1,
+                event="running",
+                namespace=["child:call-1"],
+                graph_name="child",
+                trigger_call_id="call-1",
+            )
+        )
+    )
+    assert h.path == ("child:call-1",)
+    assert h.graph_name == "child"
+    assert h.trigger_call_id == "call-1"
+
+
 def test_subgraphs_decoder_completes_on_forwarded_lifecycle_payload_namespace():
     decoder = SubgraphsDecoder(scope=(), handle_factory=_scoped_factory)
     [h] = list(

libs/sdk-py/tests/streaming/test_scoped_handles.py

@@ -81,7 +81,7 @@ async def test_subgraphs_yields_handle_from_forwarded_lifecycle_namespace():
             lifecycle_started_event(seq=0),
             _forwarded_lifecycle_event(
                 seq=1,
-                event="started",
+                event="running",
                 namespace=["worker:abc"],
                 graph_name="worker",
                 trigger_call_id="abc",

libs/sdk-py/tests/streaming/test_sync_scoped_handles.py

@@ -140,7 +140,7 @@ def test_sync_subgraphs_yields_handle_from_forwarded_lifecycle_namespace():
             lifecycle_started_event(seq=0),
             _forwarded_lifecycle_event(
                 seq=1,
-                event="started",
+                event="running",
                 namespace=["worker:abc"],
                 graph_name="worker",
                 trigger_call_id="abc",