diff --git a/CLAUDE.md b/CLAUDE.md
index 70bc60c6..f8f7bf40 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -82,8 +82,8 @@ CQRS, a repository/DI framework, a router library, a generic CRUD-router factory
 | Admin gate import       | `app.auth`                                                   | the `app.routes.admin` re-export                       |
 | Upstream failure status | `422` with JSON detail                                       | `502` (reserve 502 for raw byte-proxies)               |
 | User-facing error       | structured `detail` (`{code, reason}`)                       | a bare English string under a bilingual UI             |
-| Mutation response       | `{"ok": true, …}` (`{"deleted": id}`)                        | ad-hoc `{"unsubscribed"}`/`{"cleared": n}`/echo        |
-| Transaction commit      | the handler/job-wrapper commits; helpers `flush`             | helpers that commit (only `quota` owns its session)    |
+| Mutation response       | `{"ok": true, …}` (`{"deleted": id}`), test-held             | a bare `{"unsubscribed"}`/`{"cleared": n}`, no `ok`    |
+| Transaction commit      | the handler commits; helpers `flush` (test-held list)        | helpers that commit (only `quota` owns its session)    |
 | Admin knob storage      | `sysconfig` (values)                                         | env / `app_state` / `scheduler_settings` scatter       |
 | Job status word         | the `downloads/status.py` StrEnum                            | loose `"canceled"`/`"cancelled"` literals              |
 | Current time            | inline `datetime.now(timezone.utc)`                          | new `now_utc`/`_now` helpers                           |
diff --git a/backend/app/routes/admin.py b/backend/app/routes/admin.py
index c77f40b3..43fad55d 100644
--- a/backend/app/routes/admin.py
+++ b/backend/app/routes/admin.py
@@ -170,7 +170,7 @@ def _activate_user_by_email(db: Session, email: str) -> None:
     user = next((u for u in candidates if u.email == email), None) or next(iter(candidates), None)
     if user is not None and not user.is_active:
         user.is_active = True
-        db.commit()
+        db.flush()  # the handler commits (CLAUDE.md: helpers flush)
 
 
 def _decide(db: Session, invite_id: int, admin: User, approved: bool) -> Invite:
@@ -192,7 +192,7 @@ def _decide(db: Session, invite_id: int, admin: User, approved: bool) -> Invite:
         target_id=inv.id,
         summary=inv.email,
     )
-    db.commit()
+    db.flush()  # the handler commits, with the activation that goes with it
     return inv
 
 
@@ -211,6 +211,9 @@ def approve_invite(
     link, has_account, hours = _welcome_mail_parts(db, inv.email)
     lang = mailtext.lang_for_email(db, inv.email)
     background.add_task(email_mod.send_access_approved, inv.email, lang, link, has_account, hours)
+    # Before the response, so the mail (a background task, after it) never describes a decision
+    # the database does not hold yet.
+    db.commit()
     return _serialize(inv, has_account=bool(_accounts_for(db, [inv.email])))
 
 
@@ -227,6 +230,7 @@ def deny_invite(
     background.add_task(
         email_mod.send_access_denied, inv.email, mailtext.lang_for_email(db, inv.email)
     )
+    db.commit()
     return _serialize(inv, has_account=bool(_accounts_for(db, [inv.email])))
 
 
@@ -265,6 +269,7 @@ def add_invite(
     )
     db.commit()
     _activate_user_by_email(db, email)
+    db.commit()
     return _serialize(inv, has_account=bool(_accounts_for(db, [email])))
 
 
@@ -831,7 +836,7 @@ def reset_demo(admin: User = Depends(admin_user), db: Session = Depends(get_db))
         db, admin.id, AuditAction.DEMO_RESET, summary=f"{seeded} sample playlists re-seeded"
     )
     db.commit()
-    return {"reset": True, "playlists_seeded": seeded}
+    return {"ok": True, "reset": True, "playlists_seeded": seeded}
 
 
 @router.post("/purge-discovery")
diff --git a/backend/app/routes/audit.py b/backend/app/routes/audit.py
index 6562e3cf..d9a907b9 100644
--- a/backend/app/routes/audit.py
+++ b/backend/app/routes/audit.py
@@ -68,4 +68,4 @@ def clear_audit(admin: User = Depends(admin_user), db: Session = Depends(get_db)
     n = db.execute(delete(AuditLog)).rowcount or 0
     audit.record(db, admin.id, AuditAction.AUDIT_CLEAR, summary=f"Cleared {n} audit entries")
     db.commit()
-    return {"cleared": n}
+    return {"ok": True, "cleared": n}
diff --git a/backend/app/routes/auth.py b/backend/app/routes/auth.py
index 0b614648..c3bbd32f 100644
--- a/backend/app/routes/auth.py
+++ b/backend/app/routes/auth.py
@@ -673,7 +673,7 @@ def demo_login(body: EmailIn, request: Request, db: Session = Depends(get_db)) -
     exactly like a non-match (authenticated=false) so the field can't be hammered as an
     enumeration oracle. On a match it sets the session and the client reloads into the app."""
     if not _demo_limiter.allow(client_key(request)):
-        return {"authenticated": False}
+        return {"ok": True, "authenticated": False}
     email = (body.email or "").strip().lower()
     if valid_email(email) and is_demo_allowed(db, email):
         demo = get_or_create_demo_user(db)
@@ -684,8 +684,8 @@ def demo_login(body: EmailIn, request: Request, db: Session = Depends(get_db)) -
         _remember_epoch(request, demo)
         # The demo key IS an address, so it is not in the line — see the denied branch above.
         log.info("signed in", extra=logs.event("auth.login.ok", method="demo", uid=demo.id))
-        return {"authenticated": True}
-    return {"authenticated": False}
+        return {"ok": True, "authenticated": True}
+    return {"ok": True, "authenticated": False}
 
 
 def _establish_session(request: Request, user: User) -> None:
@@ -822,14 +822,14 @@ def register(
     if not sysconfig.get_bool(db, "allow_registration"):
         raise refused(403, "registration_closed")
     if not _register_limiter.allow(client_key(request)):
-        return {"status": "ok"}  # silently throttle; uniform response
+        return {"ok": True, "status": "ok"}  # silently throttle; uniform response
 
     # Do the existence check + account creation OFF the response path (a background task with its own
     # session). The create path hashes the password + writes several rows + schedules emails; doing it
     # inline would make a NEW email respond measurably slower than an already-registered one (which
     # skips all that) — a timing oracle for enumeration. Off-path, any valid email responds the same.
     background.add_task(_register_account, email, password, body.lang)
-    return {"status": "ok"}
+    return {"ok": True, "status": "ok"}
 
 
 def _register_account(email: str, password: str, lang: str | None = None) -> None:
@@ -995,11 +995,11 @@ def verify_email_resend(
     mail had no way back. Uniform response + timing regardless of whether the email has a pending
     account (the lookup runs off the response path), so it can't probe for registered emails."""
     if not _verify_resend_limiter.allow(client_key(request)):
-        return {"status": "ok"}  # silently throttle; uniform response
+        return {"ok": True, "status": "ok"}  # silently throttle; uniform response
     email = (body.email or "").strip().lower()
     if valid_email(email):
         background.add_task(_resend_verify_if_eligible, email)
-    return {"status": "ok"}
+    return {"ok": True, "status": "ok"}
 
 
 def _resend_verify_if_eligible(email: str) -> None:
@@ -1089,14 +1089,14 @@ def password_reset_request(
     """Request a password-reset link. Uniform response + timing regardless of whether the email has a
     password account (the lookup runs off the response path), so it can't probe for registered emails."""
     if not _reset_limiter.allow(client_key(request)):
-        return {"status": "ok"}
+        return {"ok": True, "status": "ok"}
     email = (body.email or "").strip().lower()
     # Do the account lookup + token issue + email OFF the response path (a background task with its
     # own session), so the endpoint takes the same time for any valid email whether or not it has a
     # password account — no timing-based enumeration. Any valid email schedules the same task.
     if valid_email(email):
         background.add_task(_send_reset_if_eligible, email)
-    return {"status": "ok"}
+    return {"ok": True, "status": "ok"}
 
 
 def _send_reset_if_eligible(email: str) -> None:
diff --git a/backend/app/routes/channels.py b/backend/app/routes/channels.py
index 87e1623d..5fdd68e8 100644
--- a/backend/app/routes/channels.py
+++ b/backend/app/routes/channels.py
@@ -424,6 +424,7 @@ def explore_channel(
     except YouTubeError as exc:
         raise youtube_refusal(exc)
     return {
+        "ok": True,
         "channel_id": channel_id,
         "ingested": result["ingested"],
         "next_page_token": result["next_page_token"],
@@ -505,6 +506,7 @@ def update_channel(
         background.add_task(backfill_channel_now, channel_id, user.id)
 
     return {
+        "ok": True,
         "id": channel_id,
         "priority": sub.priority,
         "hidden": sub.hidden,
@@ -539,7 +541,7 @@ def reset_backfill(
     db.commit()
     with quota.attribute(user.id, quota.QuotaAction.VIDEOS_BACKFILL_RECENT):
         run_recent_backfill(db, [channel], max_channels=1)
-    return {"id": channel_id, "reset": True}
+    return {"ok": True, "id": channel_id, "reset": True}
 
 
 @router.post("/{channel_id}/subscribe")
@@ -618,7 +620,7 @@ def subscribe(
             .values(via_explore=False)
         )
     db.commit()
-    return {"subscribed": channel_id}
+    return {"ok": True, "subscribed": channel_id}
 
 
 @router.delete("/{channel_id}/subscription")
@@ -645,7 +647,7 @@ def unsubscribe(
         raise youtube_refusal(exc)
     db.delete(sub)
     db.commit()
-    return {"unsubscribed": channel_id}
+    return {"ok": True, "unsubscribed": channel_id}
 
 
 @router.get("/blocked/list")
@@ -686,7 +688,7 @@ def block_channel(
             )
         )
         db.commit()
-    return {"blocked": channel_id}
+    return {"ok": True, "blocked": channel_id}
 
 
 @router.delete("/{channel_id}/block")
@@ -701,7 +703,7 @@ def unblock_channel(
         )
     )
     db.commit()
-    return {"unblocked": channel_id}
+    return {"ok": True, "unblocked": channel_id}
 
 
 class AttachTagIn(BaseModel):
@@ -736,7 +738,7 @@ def attach_tag(
             )
         )
         db.commit()
-    return {"channel_id": channel_id, "tag_id": body.tag_id}
+    return {"ok": True, "channel_id": channel_id, "tag_id": body.tag_id}
 
 
 @router.delete("/{channel_id}/tags/{tag_id}")
@@ -756,4 +758,4 @@ def detach_tag(
     if row is not None:
         db.delete(row)
         db.commit()
-    return {"channel_id": channel_id, "tag_id": tag_id}
+    return {"ok": True, "channel_id": channel_id, "tag_id": tag_id}
diff --git a/backend/app/routes/config.py b/backend/app/routes/config.py
index b5f68bf7..fbbc0e24 100644
--- a/backend/app/routes/config.py
+++ b/backend/app/routes/config.py
@@ -130,4 +130,4 @@ def send_test_email(
     sent = email_mod.send_test(user.email, mailtext.lang_for_user(user))
     if not sent:
         raise refused(422, "smtp_failed")
-    return {"sent": True, "to": user.email}
+    return {"ok": True, "sent": True, "to": user.email}
diff --git a/backend/app/routes/downloads.py b/backend/app/routes/downloads.py
index 20dc24ff..90e36197 100644
--- a/backend/app/routes/downloads.py
+++ b/backend/app/routes/downloads.py
@@ -847,7 +847,7 @@ def share_download(
             commit=False,
         )
         db.commit()
-    return {"shared_with": recipient.email}
+    return {"ok": True, "shared_with": recipient.email}
 
 
 @router.delete("/{job_id}/share/{email}")
@@ -891,7 +891,7 @@ def remove_shared_with_me(
     if row is not None:
         db.delete(row)
         db.commit()
-    return {"removed": job_id}
+    return {"ok": True, "removed": job_id}
 
 
 # --- recipients (for the internal "share with a user" picker) ------------------------------
diff --git a/backend/app/routes/feed.py b/backend/app/routes/feed.py
index 940199c8..fb5edcb3 100644
--- a/backend/app/routes/feed.py
+++ b/backend/app/routes/feed.py
@@ -261,7 +261,7 @@ def set_video_state(
             # or moved this row. The state the caller asked for is the state that holds either way.
             except StaleDataError:
                 db.rollback()
-        return {"video_id": video_id, "status": "new"}
+        return {"ok": True, "video_id": video_id, "status": "new"}
 
     # watched / hidden: atomic upsert. The player marks "watched" at end-of-playback at
     # the same instant a progress checkpoint may DELETE the in-progress row; a plain
@@ -282,7 +282,7 @@ def set_video_state(
     )
     db.execute(stmt)
     db.commit()
-    return {"video_id": video_id, "status": status}
+    return {"ok": True, "video_id": video_id, "status": status}
 
 
 @router.delete("/videos/{video_id}/state")
@@ -304,7 +304,7 @@ def clear_video_state(
         # silent-ok: the row went under the delete, which is the outcome the delete wanted.
         except StaleDataError:
             db.rollback()
-    return {"video_id": video_id, "status": "new", "position_seconds": 0}
+    return {"ok": True, "video_id": video_id, "status": "new", "position_seconds": 0}
 
 
 class VideoProgressIn(BaseModel):
@@ -362,7 +362,7 @@ def set_video_progress(
             # silent-ok: exactly the race the comment above describes; the response stays true.
             except StaleDataError:
                 db.rollback()
-        return {"video_id": video_id, "position_seconds": 0}
+        return {"ok": True, "video_id": video_id, "position_seconds": 0}
 
     if row is None:
         row = VideoState(user_id=user.id, video_id=video_id)
@@ -370,7 +370,7 @@ def set_video_progress(
     row.position_seconds = position
     row.progress_updated_at = datetime.now(timezone.utc)
     db.commit()
-    return {"video_id": video_id, "position_seconds": position}
+    return {"ok": True, "video_id": video_id, "position_seconds": position}
 
 
 @router.get("/videos/{video_id}")
diff --git a/backend/app/routes/me.py b/backend/app/routes/me.py
index ce6fab67..6f1784cf 100644
--- a/backend/app/routes/me.py
+++ b/backend/app/routes/me.py
@@ -214,7 +214,7 @@ def update_preferences(
     user.preferences = merged
     db.add(user)
     db.commit()
-    return {"preferences": merged}
+    return {"ok": True, "preferences": merged}
 
 
 class DiagnosticsIn(BaseModel):
diff --git a/backend/app/routes/messages.py b/backend/app/routes/messages.py
index 64156870..1cbe96fd 100644
--- a/backend/app/routes/messages.py
+++ b/backend/app/routes/messages.py
@@ -166,7 +166,7 @@ def setup_keys(
         )
     )
     db.commit()
-    return {"configured": True}
+    return {"ok": True, "configured": True}
 
 
 @router.post("/keys/reset")
@@ -204,7 +204,7 @@ def reset_keys(
     if key is not None:
         db.delete(key)
     db.commit()
-    return {"configured": False}
+    return {"ok": True, "configured": False}
 
 
 @router.get("/keys/{user_id}")
diff --git a/backend/app/routes/playlists.py b/backend/app/routes/playlists.py
index 1256a6e1..95a0b2b1 100644
--- a/backend/app/routes/playlists.py
+++ b/backend/app/routes/playlists.py
@@ -106,7 +106,7 @@ def _add_item(db: Session, pl: Playlist, video_id: str, *, mark_dirty: bool) ->
     if mark_dirty:
         recompute_dirty(db, pl)
     _touch(pl)
-    db.commit()
+    db.flush()  # the handler commits (CLAUDE.md: helpers flush)
     return True
 
 
@@ -124,7 +124,7 @@ def _remove_item(db: Session, pl: Playlist, video_id: str, *, mark_dirty: bool)
     if mark_dirty:
         recompute_dirty(db, pl)
     _touch(pl)
-    db.commit()
+    db.flush()  # the handler commits (CLAUDE.md: helpers flush)
     return True
 
 
@@ -278,7 +278,7 @@ def _watch_later(db: Session, user: User) -> Playlist:
             position=_next_playlist_position(db, user.id),
         )
         db.add(pl)
-        db.commit()
+        db.flush()  # the id, for the item the caller adds next; the handler commits
     return pl
 
 
@@ -293,7 +293,8 @@ def add_watch_later(
     get_or_404(db, Video, video_id, what="video")
     pl = _watch_later(db, user)
     _add_item(db, pl, video_id, mark_dirty=False)
-    return {"saved": True, "playlist_id": pl.id}
+    db.commit()
+    return {"ok": True, "saved": True, "playlist_id": pl.id}
 
 
 @router.delete("/watch-later/{video_id}")
@@ -307,7 +308,8 @@ def remove_watch_later(
     )
     if pl is not None:
         _remove_item(db, pl, video_id, mark_dirty=False)
-    return {"saved": False}
+        db.commit()
+    return {"ok": True, "saved": False}
 
 
 @router.post("/sync-youtube")
@@ -516,7 +518,8 @@ def add_item(
     video_id = body.video_id
     get_or_404(db, Video, video_id, what="video")
     _add_item(db, pl, video_id, mark_dirty=True)
-    return {"playlist_id": pl.id, "video_id": video_id}
+    db.commit()
+    return {"ok": True, "playlist_id": pl.id, "video_id": video_id}
 
 
 @router.delete("/{playlist_id}/items/{video_id}")
@@ -528,7 +531,8 @@ def remove_item(
 ) -> dict:
     pl = owned_or_404(db, Playlist, playlist_id, user, what="playlist")
     _remove_item(db, pl, video_id, mark_dirty=True)
-    return {"playlist_id": pl.id, "video_id": video_id}
+    db.commit()
+    return {"ok": True, "playlist_id": pl.id, "video_id": video_id}
 
 
 class MoveItemIn(BaseModel):
@@ -641,4 +645,4 @@ def reorder_items(
     recompute_dirty(db, pl)
     _touch(pl)
     db.commit()
-    return {"playlist_id": pl.id, "count": pos}
+    return {"ok": True, "playlist_id": pl.id, "count": pos}
diff --git a/backend/app/routes/plex/admin.py b/backend/app/routes/plex/admin.py
index e9a2af74..f724bc7f 100644
--- a/backend/app/routes/plex/admin.py
+++ b/backend/app/routes/plex/admin.py
@@ -149,7 +149,7 @@ def watch_link_set(
     result: dict = {}
     if enabled and not link.initial_import_done:
         result = plex_watch.import_owner_watch_state(db, link)
-    return {**_link_dict(link), "import": result or None}
+    return {"ok": True, **_link_dict(link), "import": result or None}
 
 
 @router.post("/watch/import")
@@ -160,4 +160,4 @@ def watch_import_now(user: User = Depends(admin_user), db: Session = Depends(get
     if link is None or not link.sync_enabled:
         raise refused(409, "watch_sync_off")
     result = plex_watch.import_owner_watch_state(db, link)
-    return {**_link_dict(link), "import": result}
+    return {"ok": True, **_link_dict(link), "import": result}
diff --git a/backend/app/routes/plex/playback.py b/backend/app/routes/plex/playback.py
index 4114b6e5..635c2b47 100644
--- a/backend/app/routes/plex/playback.py
+++ b/backend/app/routes/plex/playback.py
@@ -385,7 +385,7 @@ def item_progress(
         # item — or a second one racing this one — would otherwise bump Plex's viewCount again.
         if flipped:
             _push_watch(background, db, user.id, it.id, rating_key, "watched")
-        return {"status": "watched", "position_seconds": 0}
+        return {"ok": True, "status": "watched", "position_seconds": 0}
 
     st = (
         db.execute(
@@ -402,7 +402,7 @@ def item_progress(
             st.position_seconds = 0
             st.progress_updated_at = now
         db.commit()
-        return {"position_seconds": 0}
+        return {"ok": True, "position_seconds": 0}
 
     if st is None:
         st = PlexState(user_id=user.id, item_id=it.id)
@@ -427,7 +427,7 @@ def item_progress(
             duration * 1000,
             intent=now,
         )
-    return {"position_seconds": position}
+    return {"ok": True, "position_seconds": position}
 
 
 class ItemStateIn(BaseModel):
@@ -473,7 +473,7 @@ def item_state(
             db.commit()
         if mirrored_on_plex:
             _push_watch(background, db, user.id, it.id, rating_key, "unwatched")
-        return {"status": "new"}
+        return {"ok": True, "status": "new"}
     if st is None:
         st = PlexState(user_id=user.id, item_id=it.id)
         db.add(st)
@@ -485,7 +485,7 @@ def item_state(
     db.commit()
     if status == "watched" and prev_status != "watched":
         _push_watch(background, db, user.id, it.id, rating_key, "watched")
-    return {"status": status}
+    return {"ok": True, "status": status}
 
 
 def _bulk_state(
@@ -527,7 +527,9 @@ def _bulk_state(
                 db.delete(st)
                 if prev != "new":
                     to_push.append((e.id, e.rating_key, "unwatched"))
-    db.commit()
+    # Flush, not commit: the handler commits, and it does so before the response — which is when
+    # the background push below runs, so the push always reads the committed marks.
+    db.flush()
     if pushable and to_push:
         # One coalesced background task for the whole batch (reuses a single session + Plex client),
         # not one task per episode — a 200-ep show mark is 1 task, not 200.
@@ -558,7 +560,8 @@ def show_state(
         .all()
     )
     changed = _bulk_state(background, db, user.id, eps, watched)
-    return {"changed": changed, "watched": watched}
+    db.commit()
+    return {"ok": True, "changed": changed, "watched": watched}
 
 
 @router.post("/season/{rating_key}/state")
@@ -580,7 +583,8 @@ def season_state(
         .all()
     )
     changed = _bulk_state(background, db, user.id, eps, watched)
-    return {"changed": changed, "watched": watched}
+    db.commit()
+    return {"ok": True, "changed": changed, "watched": watched}
 
 
 @router.post("/stream/{rating_key}/session")
@@ -605,6 +609,7 @@ def stream_session(
     # the client can switch audio without a restart — even for otherwise direct-playable files.
     if it.playable == "direct" and audio is None and not aoff and not multi:
         return {
+            "ok": True,
             "mode": "direct",
             "url": f"/api/plex/stream/{it.rating_key}/file",
             "start_s": 0.0,
@@ -620,6 +625,7 @@ def stream_session(
     # surface the active mode + encoder in the stats overlay (`tonemap` = the HW HDR→SDR path); both
     # segment streams are otherwise identical.
     return {
+        "ok": True,
         "mode": "hls",
         "start_s": s.media_start_s,
         # The session id is part of the path (not a query param) so the playlist's RELATIVE segment
diff --git a/backend/app/routes/plex/playlists.py b/backend/app/routes/plex/playlists.py
index 9cd61fd5..8786584d 100644
--- a/backend/app/routes/plex/playlists.py
+++ b/backend/app/routes/plex/playlists.py
@@ -325,7 +325,7 @@ def playlist_add_bulk(
         )
         or 0
     )
-    return {"added": added, "item_count": total}
+    return {"ok": True, "added": added, "item_count": total}
 
 
 @router.post("/playlists/{pid}/items/remove-bulk")
@@ -356,7 +356,7 @@ def playlist_remove_bulk(
         )
         or 0
     )
-    return {"removed": removed, "item_count": total}
+    return {"ok": True, "removed": removed, "item_count": total}
 
 
 @router.put("/playlists/{pid}/order")
diff --git a/backend/app/routes/public.py b/backend/app/routes/public.py
index 7dafd1fb..fa2a2107 100644
--- a/backend/app/routes/public.py
+++ b/backend/app/routes/public.py
@@ -107,6 +107,7 @@ def watch_unlock(
         # Not a password link — nothing to unlock; just hand back the plain meta.
         job, asset = _ready_target(db, link)
         return {
+            "ok": True,
             "needs_password": False,
             **linksmod.public_meta(link, job, asset, _file_url(token), _poster_url(token, asset)),
         }
@@ -118,6 +119,7 @@ def watch_unlock(
     db.commit()
     grant = linksmod.make_grant(token, link.password_version)
     return {
+        "ok": True,
         "needs_password": False,
         **linksmod.public_meta(
             link, job, asset, _file_url(token, grant), _poster_url(token, asset, grant)
diff --git a/backend/app/routes/scheduler.py b/backend/app/routes/scheduler.py
index 70e786db..2a84dddc 100644
--- a/backend/app/routes/scheduler.py
+++ b/backend/app/routes/scheduler.py
@@ -60,7 +60,7 @@ def set_job_interval(
         after={"interval_minutes": applied},
     )
     db.commit()
-    return {"id": job_id, "interval_minutes": applied}
+    return {"ok": True, "id": job_id, "interval_minutes": applied}
 
 
 @router.post("/jobs/{job_id}/run")
@@ -77,13 +77,13 @@ def run_job_now(
         raise not_found("job")
     if result == "already_running":
         raise refused(409, "job_running")
-    return {"id": job_id, "started": True}
+    return {"ok": True, "id": job_id, "started": True}
 
 
 @router.post("/run-all")
 def run_all_now(user: User = Depends(admin_user)) -> dict:
     """Trigger every job that isn't already running. Returns the ids actually started."""
-    return {"started": trigger_all(actor_id=user.id)}
+    return {"ok": True, "started": trigger_all(actor_id=user.id)}
 
 
 class MaintenanceSettingsIn(BaseModel):
@@ -112,7 +112,7 @@ def set_maintenance_settings(
         after={"revalidate_batch": new},
     )
     db.commit()
-    return {"revalidate_batch": new}
+    return {"ok": True, "revalidate_batch": new}
 
 
 @router.get("")
diff --git a/backend/app/routes/search.py b/backend/app/routes/search.py
index 3936dbaf..7fa9af3b 100644
--- a/backend/app/routes/search.py
+++ b/backend/app/routes/search.py
@@ -411,7 +411,7 @@ def clear_search(
     find. Kept videos and organically-owned ones are left untouched."""
     ids = body.video_ids
     if not ids:
-        return {"removed": 0}
+        return {"ok": True, "removed": 0}
     db.execute(
         delete(SearchFind).where(SearchFind.user_id == user.id, SearchFind.video_id.in_(ids))
     )
@@ -431,4 +431,4 @@ def clear_search(
         )
     ).rowcount
     db.commit()
-    return {"removed": removed}
+    return {"ok": True, "removed": removed}
diff --git a/backend/app/routes/setup.py b/backend/app/routes/setup.py
index d9a6d996..6ce2c20b 100644
--- a/backend/app/routes/setup.py
+++ b/backend/app/routes/setup.py
@@ -106,7 +106,7 @@ def setup_config(settings_map: dict[str, Any], db: Session = Depends(require_set
             raise setting_refused(exc) from None
         saved.append(key)
     db.commit()  # sysconfig.set_value only flushes now — persist the wizard's config in one commit
-    return {"saved": saved}
+    return {"ok": True, "saved": saved}
 
 
 class SetupTestEmailIn(BaseModel):
diff --git a/backend/app/routes/sync.py b/backend/app/routes/sync.py
index 6cdbadfa..baed9463 100644
--- a/backend/app/routes/sync.py
+++ b/backend/app/routes/sync.py
@@ -143,7 +143,7 @@ def deep_all(
         update(Subscription).where(Subscription.user_id == user.id).values(deep_requested=on)
     )
     db.commit()
-    return {"updated": result.rowcount, "deep_requested": on}
+    return {"ok": True, "updated": result.rowcount, "deep_requested": on}
 
 
 @router.post("/pause")
@@ -151,7 +151,7 @@ def pause_sync(admin: User = Depends(admin_user), db: Session = Depends(get_db))
     state.set_sync_paused(db, True)
     audit.record(db, admin.id, AuditAction.SYNC_PAUSE, summary="Background sync paused")
     db.commit()
-    return {"paused": True}
+    return {"ok": True, "paused": True}
 
 
 @router.post("/resume")
@@ -159,4 +159,4 @@ def resume_sync(admin: User = Depends(admin_user), db: Session = Depends(get_db)
     state.set_sync_paused(db, False)
     audit.record(db, admin.id, AuditAction.SYNC_RESUME, summary="Background sync resumed")
     db.commit()
-    return {"paused": False}
+    return {"ok": True, "paused": False}
diff --git a/backend/app/routes/tags.py b/backend/app/routes/tags.py
index cfd5b58f..7e2c23c9 100644
--- a/backend/app/routes/tags.py
+++ b/backend/app/routes/tags.py
@@ -76,7 +76,13 @@ def create_tag(
     except IntegrityError:
         db.rollback()
         raise refused(409, "tag_name_taken", name=name)
-    return {"id": tag.id, "name": tag.name, "color": tag.color, "category": tag.category}
+    return {
+        "ok": True,
+        "id": tag.id,
+        "name": tag.name,
+        "color": tag.color,
+        "category": tag.category,
+    }
 
 
 class TagUpdateIn(BaseModel):
@@ -108,7 +114,13 @@ def update_tag(
     except IntegrityError:
         db.rollback()
         raise refused(409, "tag_name_taken", name=tag.name)
-    return {"id": tag.id, "name": tag.name, "color": tag.color, "category": tag.category}
+    return {
+        "ok": True,
+        "id": tag.id,
+        "name": tag.name,
+        "color": tag.color,
+        "category": tag.category,
+    }
 
 
 @router.delete("/{tag_id}")
diff --git a/backend/tests/test_auth_session.py b/backend/tests/test_auth_session.py
index 72fff9e6..040fd48f 100644
--- a/backend/tests/test_auth_session.py
+++ b/backend/tests/test_auth_session.py
@@ -447,7 +447,7 @@ def test_register_route_creates_the_account_end_to_end(client, db, monkeypatch):
 
     r = client.post("/auth/register", json={"email": "newbie@example.com", "password": _PW})
 
-    assert r.status_code == 200 and r.json() == {"status": "ok"}
+    assert r.status_code == 200 and r.json() == {"ok": True, "status": "ok"}
     db.expire_all()
     user = db.execute(_select(User).where(User.email == "newbie@example.com")).scalar_one_or_none()
     assert user is not None, "POST /auth/register answered ok but created nothing"
diff --git a/backend/tests/test_last_login.py b/backend/tests/test_last_login.py
index 8b6b2973..02256d04 100644
--- a/backend/tests/test_last_login.py
+++ b/backend/tests/test_last_login.py
@@ -79,7 +79,7 @@ def test_the_demo_entry_does_not_stamp_the_shared_account(client, db):
 
     r = client.post("/auth/demo", json={"email": "visitor@example.com"})
 
-    assert r.json() == {"authenticated": True}
+    assert r.json() == {"ok": True, "authenticated": True}
     demo = auth_routes.get_or_create_demo_user(db)
     db.refresh(demo)
     assert demo.last_login_at is None
diff --git a/backend/tests/test_plex_finish.py b/backend/tests/test_plex_finish.py
index 464e695a..43e890da 100644
--- a/backend/tests/test_plex_finish.py
+++ b/backend/tests/test_plex_finish.py
@@ -76,5 +76,5 @@ def test_the_finish_supersedes_a_resume_push_still_in_flight(db, as_user, make_u
     r = as_user(user).post(
         "/api/plex/item/m1/progress", json={"position_seconds": 2995, "duration_seconds": 3000}
     )
-    assert r.json() == {"status": "watched", "position_seconds": 0}
+    assert r.json() == {"ok": True, "status": "watched", "position_seconds": 0}
     assert playback._resume_push_superseded(user.id, item.id, earlier) is True
diff --git a/backend/tests/test_plex_query_conversion.py b/backend/tests/test_plex_query_conversion.py
index a0300882..602fe810 100644
--- a/backend/tests/test_plex_query_conversion.py
+++ b/backend/tests/test_plex_query_conversion.py
@@ -436,7 +436,7 @@ class TestPlaylistAndCollectionEndpoints:
             {"item_rating_keys": ["m1", "m2", "m3"]},
         )
         assert added.status_code == 200, added.text
-        assert added.json() == {"added": 3, "item_count": 3}
+        assert added.json() == {"ok": True, "added": 3, "item_count": 3}
 
         removed = _request(
             db,
@@ -448,7 +448,7 @@ class TestPlaylistAndCollectionEndpoints:
             {"item_rating_keys": ["m2"]},
         )
         assert removed.status_code == 200, removed.text
-        assert removed.json() == {"removed": 1, "item_count": 2}
+        assert removed.json() == {"ok": True, "removed": 1, "item_count": 2}
 
         detail = _get(db, user, monkeypatch, override_dep, f"/api/plex/playlists/{pid}").json()
         assert [it["id"] for it in detail["items"]] == [
diff --git a/backend/tests/test_route_conventions.py b/backend/tests/test_route_conventions.py
new file mode 100644
index 00000000..b0b6b988
--- /dev/null
+++ b/backend/tests/test_route_conventions.py
@@ -0,0 +1,68 @@
+"""Two rows of CLAUDE.md's canonical-patterns table, held in code rather than prose.
+
+A rule stated only in a comment drifts: this one had — 63 mutation responses without `ok`, and
+twelve route helpers that committed on their own, among them an approval whose decision, activation
+and token landed in three separate transactions. The debt burn of 2026-09 fixed the drift; these keep
+it fixed.
+"""
+
+import ast
+from pathlib import Path
+
+ROUTES = Path(__file__).parent.parent / "app" / "routes"
+MUTATING = {"post", "put", "patch", "delete"}
+
+# A route helper that commits where it stands, and why the commit has to be there rather than in
+# the handler. Anything else flushes and leaves the commit to its handler.
+COMMITTING_HELPERS = {
+    "auth.py:_issue_token": "the token must be durable before the link that carries it is mailed",
+    "auth.py:_consume_token": "burning a single-use token is its own unit: a later failure must "
+    "not hand the token back",
+    "auth.py:_complete_link": "the tail of the Google callback route, which answers with its result",
+    "auth.py:_register_account": "a background task with its own session, i.e. a job wrapper",
+    "search.py:_ingest_candidates": "stages around YouTube calls: the stubs must survive an enrich "
+    "that fails",
+    "search.py:_classify_shorts": "the last stage of that ingest, after its probes",
+}
+
+
+def _modules():
+    for path in sorted(ROUTES.rglob("*.py")):
+        yield path.relative_to(ROUTES).as_posix(), ast.parse(path.read_text(encoding="utf-8"))
+
+
+def _is_mutation_route(fn: ast.FunctionDef) -> bool:
+    return any(
+        isinstance(d, ast.Call) and getattr(d.func, "attr", "") in MUTATING
+        for d in fn.decorator_list
+    )
+
+
+def test_every_mutation_answers_ok():
+    """`{"ok": true, …}` (or `{"deleted": id}`) for every mutation that answers with a literal —
+    one field a client can read the same way everywhere. A serializer's return is exempt: it
+    describes a resource, not an acknowledgement."""
+    missing = []
+    for name, tree in _modules():
+        for fn in ast.walk(tree):
+            if not (isinstance(fn, ast.FunctionDef) and _is_mutation_route(fn)):
+                continue
+            for node in ast.walk(fn):
+                if isinstance(node, ast.Return) and isinstance(node.value, ast.Dict):
+                    keys = {k.value for k in node.value.keys if isinstance(k, ast.Constant)}
+                    if not keys & {"ok", "deleted"}:
+                        missing.append(f"{name}:{node.lineno} {fn.name}")
+    assert missing == []
+
+
+def test_route_helpers_flush_and_leave_the_commit_to_the_handler():
+    committing = set()
+    for name, tree in _modules():
+        for fn in ast.walk(tree):
+            if isinstance(fn, ast.FunctionDef) and fn.name.startswith("_"):
+                if any(
+                    isinstance(n, ast.Call) and getattr(n.func, "attr", "") == "commit"
+                    for n in ast.walk(fn)
+                ):
+                    committing.add(f"{name}:{fn.name}")
+    assert committing == set(COMMITTING_HELPERS)
diff --git a/backend/tests/test_welcome_mail.py b/backend/tests/test_welcome_mail.py
index 2984cb1e..4d92acfe 100644
--- a/backend/tests/test_welcome_mail.py
+++ b/backend/tests/test_welcome_mail.py
@@ -220,7 +220,7 @@ def test_registering_again_re_sends_the_link_instead_of_sending_nothing(db, clie
     # The old behaviour was to return in silence: same cheerful "check your inbox", no mail. That is
     # the most likely explanation for the 2026-09-03 confirmation mail that "never arrived" — none
     # was ever sent. The response stays uniform; only the dead end is gone.
-    assert r.status_code == 200 and r.json() == {"status": "ok"}
+    assert r.status_code == 200 and r.json() == {"ok": True, "status": "ok"}
     assert len(sent) == 2
     assert sent[1][0][0] == "twice@example.com"