diff --git a/webui/src/features/board/harness/graph/subtree.test.ts b/webui/src/features/board/harness/graph/subtree.test.ts
index 9567559a..bf38da04 100644
--- a/webui/src/features/board/harness/graph/subtree.test.ts
+++ b/webui/src/features/board/harness/graph/subtree.test.ts
@@ -1,18 +1,21 @@
 import { afterEach, describe, expect, it } from "vitest"
-import { asNodeId } from "@canvas-harness/core"
+import { asNodeId, type OpBatch } from "@canvas-harness/core"
 import { addEdge, freshStore, resetIdb } from "@/test/canvas"
 import type { DimNode } from "@/features/board/model"
 import { getLocalStores } from "@/features/local-stores"
 import { BoardPersistence } from "@/features/board/persist/local/board-persistence"
 import { InMemoryEngine } from "@/features/board/persist/local/in-memory-engine"
 import { setBoardPersistenceRef } from "@/features/board/persist/local/board-persistence-ref"
+import { setBoardSyncRef } from "@/features/board/harness/sync/board-sync-ref"
+import type { BoardSyncHandle } from "@/features/board/harness/sync/board-sync"
 import { useBoardAppStore } from "@/features/board/harness/store/board-app-store"
 import { collectSubtreeIds, removeNodeSubtree, removeNodesSubtreeAsync } from "./subtree"
 
 
 afterEach(() => {
-  // The persistence ref is a module singleton — isolate tests.
+  // The refs are module singletons — isolate tests.
   setBoardPersistenceRef(null)
+  setBoardSyncRef(null)
   useBoardAppStore.setState({ boardId: null })
 })
 
@@ -191,4 +194,39 @@ describe("removeNodeSubtree", () => {
     // Whole board: the deeper descendants were swept from the oplog too.
     expect((await persistence.load()).nodes.map((n) => n.id).sort()).toEqual(["s"])
   })
+
+
+  it("routes the deep-layer sweep through the sync intake (scene:false) on a synced board", async () => {
+    const engine = new InMemoryEngine()
+    const persistence = new BoardPersistence("b", { engine })
+
+    // Seed the whole board: F at root, a deeper child c1 (an unloaded layer).
+    const full = freshStore("seed")
+    const unsub = persistence.attach(full)
+    addChild(full, "F")
+    addChild(full, "c1", "F")
+    await persistence.flush()
+    unsub()
+
+    const live = freshStore("live")
+    addChild(live, "F") // only the folder is loaded at the parent layer
+    persistence.attach(live)
+    setBoardPersistenceRef(persistence)
+
+    // Spy sync ref: capture how the deep-layer batch enters the coordinator.
+    const submitted: { batch: { ops: { type: string }[] }; scene?: boolean }[] = []
+    setBoardSyncRef({
+      submitLocalBatch: (batch: OpBatch, opts?: { scene?: boolean }) =>
+        submitted.push({ batch: batch as unknown as { ops: { type: string }[] }, scene: opts?.scene }),
+    } as unknown as BoardSyncHandle)
+
+    await removeNodesSubtreeAsync(live, [asNodeId("F")])
+
+    // The deep sweep entered submitLocalBatch exactly once, off-scene (not
+    // rebase-tracked), carrying the deeper node's removal — so a synced board
+    // pumps it to the relay instead of leaving it to ship opportunistically.
+    expect(submitted).toHaveLength(1)
+    expect(submitted[0].scene).toBe(false)
+    expect(submitted[0].batch.ops.some((op) => op.type === "node.remove")).toBe(true)
+  })
 })
diff --git a/webui/src/features/board/harness/graph/subtree.ts b/webui/src/features/board/harness/graph/subtree.ts
index 3e6575ce..5727ed35 100644
--- a/webui/src/features/board/harness/graph/subtree.ts
+++ b/webui/src/features/board/harness/graph/subtree.ts
@@ -7,7 +7,9 @@
  *      store, in one batch (so a single undo restores them, edges included).
  *   2. Deeper layers — a folder's children live in a deeper layer that isn't in
  *      the store. Sweep them from the WHOLE board via persistence (the oplog
- *      covers every layer), recording their removal so they don't orphan.
+ *      covers every layer), recording their removal so they don't orphan, then
+ *      enter the sync intake (`submitLocalBatch`, off-scene) so a synced board
+ *      pumps them to the relay promptly instead of only on the next edit.
  *
  * On backend boards there's no local persistence ref, so only step 1 runs and the
  * server performs its own cascade (unchanged behaviour).
@@ -16,6 +18,7 @@ import type { CanvasStore, NodeId, Op } from "@canvas-harness/core"
 import type { OpBatch } from "@canvas-harness/core"
 import type { DimNode } from "@/features/board/model"
 import { getBoardPersistenceRef } from "@/features/board/persist/local/board-persistence-ref"
+import { getBoardSyncRef } from "@/features/board/harness/sync/board-sync-ref"
 import { makeBatch } from "@/features/board/harness/make-batch"
 import { isDurableDelete } from "@/features/board/harness/node-types/durable-delete"
 import { cascadeRemovedDocs } from "@/features/board/harness/agent/use-doc-node-cascade"
@@ -96,8 +99,16 @@ const sweepDeepDescendants = async (
       ...removeEdges.map((edge) => ({ type: "edge.remove", edge }) as Op),
       ...removeNodes.map((node) => ({ type: "node.remove", node }) as Op),
     ]
-    persistence.record(makeBatch(store, origin, ops))
+    const batch = makeBatch(store, origin, ops)
+    persistence.record(batch)
     await persistence.flush()
+    // On a synced board, enter the sync-correct intake so the batch pumps to the
+    // relay promptly (and is serverSeq-stamped on ack) instead of shipping only
+    // opportunistically on the next unrelated edit. `scene: false` — these ops
+    // target unloaded layers, so they must NOT join the in-scene rebase set. On a
+    // local board there's no sync ref (null) and the oplog record alone is
+    // sync-correct (no outbox to desync).
+    getBoardSyncRef()?.submitLocalBatch(batch, { scene: false })
     return removeNodes.filter((n) => n.type === "document").map((n) => String(n.id))
   } catch (err) {
     console.warn("[harness] deep subtree cascade failed", err)