diff --git a/packages/freecut-editor/package.json b/packages/freecut-editor/package.json
index aa3d2f303..a702a3d65 100644
--- a/packages/freecut-editor/package.json
+++ b/packages/freecut-editor/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@quantfive/freecut-editor-surface",
-  "version": "0.3.0",
+  "version": "0.3.1",
   "description": "The host-backed FreeCut browser editor surface.",
   "license": "MIT",
   "repository": {
diff --git a/src/features/preview/utils/decoder-prewarm.test.ts b/src/features/preview/utils/decoder-prewarm.test.ts
index 4f4777f94..55acd50fe 100644
--- a/src/features/preview/utils/decoder-prewarm.test.ts
+++ b/src/features/preview/utils/decoder-prewarm.test.ts
@@ -22,6 +22,15 @@ import {
   clearObjectUrlRegistry,
   registerObjectUrl,
 } from '@/infrastructure/browser/object-url-registry'
+import { blobUrlManager } from '@/infrastructure/browser/blob-url-manager'
+import { updateMedia } from '@/infrastructure/storage'
+import { setWorkspaceRoot } from '@/infrastructure/storage/workspace-fs/root'
+import { clearKeyframeIndex, getKeyframeTimestamps } from '@/shared/utils/keyframe-index-registry'
+
+vi.mock('@/infrastructure/storage', async (importOriginal) => {
+  const actual = await importOriginal<typeof import('@/infrastructure/storage')>()
+  return { ...actual, updateMedia: vi.fn() }
+})
 
 type MockWorkerMessage = {
   type: string
@@ -94,6 +103,7 @@ beforeEach(() => {
   mockBitmap = { close: vi.fn() } as unknown as ImageBitmap
   fetchMock = vi.fn()
   autoRespondPreseek = true
+  vi.mocked(updateMedia).mockClear()
 
   vi.stubGlobal('fetch', fetchMock)
   class WorkerStub extends MockWorker {
@@ -109,6 +119,9 @@ beforeEach(() => {
 afterEach(() => {
   disposePrewarmWorker()
   clearObjectUrlRegistry()
+  blobUrlManager.releaseAll()
+  setWorkspaceRoot(null)
+  clearKeyframeIndex()
   vi.unstubAllGlobals()
 })
 
@@ -711,4 +724,48 @@ describe('decoder prewarm', () => {
 
     expect(mockBitmap.close).toHaveBeenCalledTimes(1)
   })
+
+  it('skips keyframe persistence when no workspace root is set (host-mounted surface)', () => {
+    // Host-mounted consumers (e.g. CodePress) never render <WorkspaceGate>, so
+    // requireWorkspaceRoot() inside updateMedia would throw on every decoded
+    // play/pause cycle. Persistence must be gated off; in-session registration
+    // still happens.
+    setWorkspaceRoot(null)
+    blobUrlManager.registerUrl('media-host-mounted', 'blob:kf-no-root')
+    warmDecoderPrewarmWorkerPool()
+    const worker = createdWorkers[0]!
+
+    expect(() =>
+      worker.onmessage?.({
+        data: {
+          type: 'keyframes_extracted',
+          src: 'blob:kf-no-root',
+          keyframeTimestamps: [0, 1.5, 3],
+        },
+      } as MessageEvent),
+    ).not.toThrow()
+
+    expect(getKeyframeTimestamps('blob:kf-no-root')).toEqual([0, 1.5, 3])
+    expect(updateMedia).not.toHaveBeenCalled()
+  })
+
+  it('persists extracted keyframes to storage when a workspace root is set', () => {
+    setWorkspaceRoot({ name: 'workspace' } as FileSystemDirectoryHandle)
+    blobUrlManager.registerUrl('media-persisted', 'blob:kf-with-root')
+    warmDecoderPrewarmWorkerPool()
+    const worker = createdWorkers[0]!
+
+    worker.onmessage?.({
+      data: {
+        type: 'keyframes_extracted',
+        src: 'blob:kf-with-root',
+        keyframeTimestamps: [0, 2],
+      },
+    } as MessageEvent)
+
+    expect(getKeyframeTimestamps('blob:kf-with-root')).toEqual([0, 2])
+    expect(updateMedia).toHaveBeenCalledWith('media-persisted', {
+      keyframeTimestamps: [0, 2],
+    })
+  })
 })
diff --git a/src/features/preview/utils/decoder-prewarm.ts b/src/features/preview/utils/decoder-prewarm.ts
index 7f6ffe757..e044b2c8b 100644
--- a/src/features/preview/utils/decoder-prewarm.ts
+++ b/src/features/preview/utils/decoder-prewarm.ts
@@ -22,6 +22,7 @@ import {
 } from '@/infrastructure/browser/object-url-registry'
 import { blobUrlManager } from '@/infrastructure/browser/blob-url-manager'
 import { updateMedia } from '@/infrastructure/storage'
+import { getWorkspaceRoot } from '@/infrastructure/storage/workspace-fs/root'
 import {
   getKeyframeTimestamps,
   registerKeyframeIndex,
@@ -229,9 +230,12 @@ function handleWorkerMessage(event: MessageEvent): void {
     // Register in main-thread registry for the export/edit overlay path.
     registerKeyframeIndex(msg.src, msg.keyframeTimestamps)
     keyframesSentForSrc.add(msg.src)
-    // Persist to IndexedDB so future sessions don't need re-extraction
+    // Persist to IndexedDB so future sessions don't need re-extraction.
+    // Host-mounted surfaces (no <WorkspaceGate>) have no workspace root, so
+    // cross-session keyframe persistence is skipped there — the in-session
+    // registry above still serves the export/edit overlay path.
     const mediaId = blobUrlManager.getMediaIdByUrl(msg.src)
-    if (mediaId) {
+    if (mediaId && getWorkspaceRoot()) {
       void updateMedia(mediaId, { keyframeTimestamps: msg.keyframeTimestamps })
     }
     return