route those APIs

src/wf_core/runtime/lineage.py

@@ -6,6 +6,7 @@ from dataclasses import dataclass
 from typing import Any
 
 from wf_core.run_state import ExecutionFrame, LineageState, RunState, StateWrite
+from wf_core.run_state import ROOT_LINEAGE_ID, ROOT_SCOPE_ID
 from wf_core.runtime.foreach_state import ForeachBarrierState, item_frame_owner
 from wf_core.runtime.ops.state import StatePatch
 from wf_core.runtime.ops.state import safe_set_nested_value
@@ -69,6 +70,16 @@ def lineage_writes_for_frame(
     return pending.patch.writes
 
 
+def is_root_lineage_frame(frame: ExecutionFrame) -> bool:
+    """Return whether a frame currently commits directly to root run state.
+
+    This is a migration shortcut, not the final commit policy. Once native
+    subgraphs can complete, direct commits should be decided by an explicit
+    scope/lineage commit target rather than only by root ids.
+    """
+    return frame.scope_id == ROOT_SCOPE_ID and frame.lineage_id == ROOT_LINEAGE_ID
+
+
 def scope_state_for_frame(run: RunState, frame: ExecutionFrame) -> dict[str, Any]:
     """Return the committed state root for the frame's runtime scope."""
     scope = run.scopes.get(frame.scope_id)

src/wf_core/runtime/ops/nodes.py

@@ -18,6 +18,7 @@ from wf_core.run_state import (
     StepExecutionResult,
 )
 from wf_core.runtime.foreach_state import ForeachBarrierState, item_frame_owner
+from wf_core.runtime.lineage import append_lineage_writes, is_root_lineage_frame
 from wf_core.runtime.ops.frames import frame_context_values
 from wf_core.runtime.ops.merges import ReducerDefinition
 from wf_core.runtime.ops.overlays import state_view_for_frame
@@ -120,7 +121,16 @@ def _finalize_node_execution(
     )
     owner = item_frame_owner(frame)
     if owner is None:
-        state_changes = commit_state_patch(run.state, patch)
+        if is_root_lineage_frame(frame):
+            state_changes = commit_state_patch(run.state, patch)
+        else:
+            append_lineage_writes(
+                run,
+                scope_id=frame.scope_id,
+                lineage_id=frame.lineage_id,
+                writes=patch.writes,
+            )
+            state_changes = {}
     else:
         parent_frame_id, foreach_node_id, item_index = owner
         parent_frame = run.frames[parent_frame_id]

src/wf_core/runtime/ops/runs.py

@@ -8,6 +8,9 @@ from wf_core.run_state import (
     ExecutionFrame,
     FrameStatus,
     LineageState,
+    ROOT_FRAME_ID,
+    ROOT_LINEAGE_ID,
+    ROOT_SCOPE_ID,
     RunState,
     RunStatus,
     RuntimeScope,
@@ -27,20 +30,25 @@ def create_run_state(workflow: Workflow, workflow_input: dict[str, object]) -> R
         workflow_input=dict(workflow_input),
         state=state,
         scopes={
-            "root": RuntimeScope(
-                id="root",
+            ROOT_SCOPE_ID: RuntimeScope(
+                id=ROOT_SCOPE_ID,
                 workflow_name=workflow.name,
                 committed_state=state,
             )
         },
-        lineages={"root": LineageState(id="root", scope_id="root")},
-        current_frame_id="root",
+        lineages={
+            ROOT_LINEAGE_ID: LineageState(
+                id=ROOT_LINEAGE_ID,
+                scope_id=ROOT_SCOPE_ID,
+            )
+        },
+        current_frame_id=ROOT_FRAME_ID,
         current_node_id=workflow.start,
     )
     add_frame(
         run,
         ExecutionFrame(
-            id="root",
+            id=ROOT_FRAME_ID,
             kind="workflow",
             node_id=workflow.start,
             status=FrameStatus.PENDING,