diff --git a/docs/design/module/dit_module.md b/docs/design/module/dit_module.md
index 4390793e9..009df77ff 100644
--- a/docs/design/module/dit_module.md
+++ b/docs/design/module/dit_module.md
@@ -169,15 +169,13 @@ class DiffusionRequestStatus(enum.IntEnum):
 
 @dataclass
 class DiffusionRequestState:
-    sched_req_id: str
+    request_id: str
     req: OmniDiffusionRequest
     status: DiffusionRequestStatus = DiffusionRequestStatus.WAITING
 ```
 
 **Design Features**:
 
-- **Scheduler-owned ID**: Each `OmniDiffusionRequest` is tracked by an internal `sched_req_id`, separated from public `request_id` values.
-
 - **Explicit lifecycle**: Requests move through waiting, running, optional preemption, and terminal states.
 
 - **Centralized error handling**: Completion, abort, and error states are all normalized in the scheduler layer.
@@ -188,7 +186,6 @@ class DiffusionRequestState:
 class _BaseScheduler(SchedulerInterface):
     def __init__(self) -> None:
         self._request_states = {}
-        self._request_id_to_sched_req_id = {}
         self._waiting = deque()
         self._running = []
         self._finished_req_ids = set()
@@ -199,7 +196,8 @@ class _BaseScheduler(SchedulerInterface):
 
 - **Common state storage**: Shared request maps and waiting/running sets live in the base class.
 
-- **Shared cleanup logic**: Request-id registration, finish handling, and state removal are centralized instead of duplicated in each policy.
+- **Shared cleanup logic**: Duplicate-request checks, finish handling, and state removal are centralized instead of
+  duplicated in each policy.
 
 - **Current constraint boundary**: `_BaseScheduler` derives `max_num_running_reqs` from `max_num_seqs`, but request-mode diffusion is still clamped back to `1` by the engine. The step-wise path can keep this above `1` for compatible-request batching.
 
@@ -219,12 +217,12 @@ class RequestScheduler(_BaseScheduler):
 
 - **Single-request admission**: `RequestScheduler` still admits one active request at a time because request-mode execution completes a whole request per dispatch.
 
-- **Executor result feedback**: `update_from_output()` converts executor output into `FINISHED_COMPLETED` or `FINISHED_ERROR` and returns finished scheduler ids.
+- **Executor result feedback**: `update_from_output()` converts executor output into `FINISHED_COMPLETED` or `FINISHED_ERROR` and returns finished request ids.
 
 #### 2.5 Engine-Driven Execution Loop
 
 ```python
-sched_req_id = scheduler.add_request(request)
+request_id = scheduler.add_request(request)
 while True:
     sched_output = scheduler.schedule()
     output = executor.add_req(req)
diff --git a/examples/offline_inference/internvla_a1/end2end.py b/examples/offline_inference/internvla_a1/end2end.py
index 6bc69f4e0..72cdbff0c 100755
--- a/examples/offline_inference/internvla_a1/end2end.py
+++ b/examples/offline_inference/internvla_a1/end2end.py
@@ -127,7 +127,12 @@ def run_one_path(
             ),
             args.device,
         )
-        pred = run_pipeline_forward(pipeline, batch_inputs, noise)
+        pred = run_pipeline_forward(
+            pipeline,
+            batch_inputs,
+            noise,
+            request_id=f"internvla-a1-sample-{index}",
+        )
         pred = pred[:, :, : dataset.physical_action_dim].to(torch.float32).cpu()
         results.append(
             {
@@ -150,6 +155,7 @@ def run_pipeline_forward(
     pipeline,
     batch_inputs: dict[str, torch.Tensor],
     noise: torch.Tensor,
+    request_id: str,
 ) -> torch.Tensor:
     output = pipeline.forward(
         OmniDiffusionRequest(
@@ -161,6 +167,7 @@ def run_pipeline_forward(
                     "decode_image": False,
                 }
             ),
+            request_id=request_id,
         )
     )
     if output.error:
@@ -212,23 +219,38 @@ def benchmark_forward(
 
     _synchronize(args.device)
     cold_start_begin = time.perf_counter()
-    pred = run_pipeline_forward(pipeline, batch_inputs, noise)
+    pred = run_pipeline_forward(
+        pipeline,
+        batch_inputs,
+        noise,
+        request_id=f"internvla-a1-benchmark-{index}-cold",
+    )
     _synchronize(args.device)
     cold_start_ms = (time.perf_counter() - cold_start_begin) * 1000.0
 
     warmup_ms: list[float] = []
-    for _ in range(args.warmup_iters):
+    for iter_idx in range(args.warmup_iters):
         _synchronize(args.device)
         begin = time.perf_counter()
-        _ = run_pipeline_forward(pipeline, batch_inputs, noise)
+        _ = run_pipeline_forward(
+            pipeline,
+            batch_inputs,
+            noise,
+            request_id=f"internvla-a1-benchmark-{index}-warmup-{iter_idx}",
+        )
         _synchronize(args.device)
         warmup_ms.append((time.perf_counter() - begin) * 1000.0)
 
     benchmark_ms: list[float] = []
-    for _ in range(args.benchmark_iters):
+    for iter_idx in range(args.benchmark_iters):
         _synchronize(args.device)
         begin = time.perf_counter()
-        _ = run_pipeline_forward(pipeline, batch_inputs, noise)
+        _ = run_pipeline_forward(
+            pipeline,
+            batch_inputs,
+            noise,
+            request_id=f"internvla-a1-benchmark-{index}-iter-{iter_idx}",
+        )
         _synchronize(args.device)
         benchmark_ms.append((time.perf_counter() - begin) * 1000.0)
 
@@ -295,7 +317,12 @@ def main() -> None:
             dataset=dataset,
             train_meta=train_meta,
             collate_samples=collate_open_loop_samples,
-            run_sample_actions=lambda policy, batch_inputs, noise: run_pipeline_forward(policy, batch_inputs, noise),
+            run_sample_actions=lambda policy, batch_inputs, noise: run_pipeline_forward(
+                policy,
+                batch_inputs,
+                noise,
+                request_id="internvla-a1-open-loop",
+            ),
             num_episodes=args.num_episodes,
             seed=args.seed,
             device=args.device,
diff --git a/tests/diffusion/diffusion_backend/test_diffusers_backend.py b/tests/diffusion/diffusion_backend/test_diffusers_backend.py
index 92dd73358..b64d6f738 100644
--- a/tests/diffusion/diffusion_backend/test_diffusers_backend.py
+++ b/tests/diffusion/diffusion_backend/test_diffusers_backend.py
@@ -60,6 +60,7 @@ def _make_request(**overrides) -> OmniDiffusionRequest:
             output_type="pil",
             generator_device="cpu",
         ),
+        "request_id": "diffusers-backend",
     }
     defaults.update(overrides)
     return OmniDiffusionRequest(**defaults)
diff --git a/tests/diffusion/models/dmd2/test_dmd2_request_sanitization.py b/tests/diffusion/models/dmd2/test_dmd2_request_sanitization.py
index f7ada6ebf..1365a3477 100644
--- a/tests/diffusion/models/dmd2/test_dmd2_request_sanitization.py
+++ b/tests/diffusion/models/dmd2/test_dmd2_request_sanitization.py
@@ -48,6 +48,7 @@ def _make_request(prompts=None, **sp_kwargs) -> OmniDiffusionRequest:
     return OmniDiffusionRequest(
         prompts=prompts or [{"prompt": "a cat dancing"}],
         sampling_params=sp,
+        request_id="dmd2-sanitize",
     )
 
 
diff --git a/tests/diffusion/models/dmd2/test_dmd2_scheduler.py b/tests/diffusion/models/dmd2/test_dmd2_scheduler.py
index 7aac36970..e5a1b6d83 100644
--- a/tests/diffusion/models/dmd2/test_dmd2_scheduler.py
+++ b/tests/diffusion/models/dmd2/test_dmd2_scheduler.py
@@ -48,7 +48,7 @@ def _make_pipeline(cls):
 
 def _make_request(**sp_kwargs) -> OmniDiffusionRequest:
     sp = OmniDiffusionSamplingParams(**sp_kwargs)
-    return OmniDiffusionRequest(prompts=[{"prompt": "a cat"}], sampling_params=sp)
+    return OmniDiffusionRequest(prompts=[{"prompt": "a cat"}], sampling_params=sp, request_id="dmd2-scheduler")
 
 
 @pytest.fixture(
diff --git a/tests/diffusion/models/ernie_image/test_ernie_image_pe.py b/tests/diffusion/models/ernie_image/test_ernie_image_pe.py
index d1dc90715..a632ab3be 100644
--- a/tests/diffusion/models/ernie_image/test_ernie_image_pe.py
+++ b/tests/diffusion/models/ernie_image/test_ernie_image_pe.py
@@ -73,7 +73,7 @@ def test_should_apply_pe_respects_sampling_extra_args():
 
 
 def test_should_apply_pe_disables_dummy_warmup_request():
-    req = SimpleNamespace(request_ids=["dummy_req_id"], sampling_params=SimpleNamespace(extra_args={}))
+    req = SimpleNamespace(is_dummy_run=lambda: True, sampling_params=SimpleNamespace(extra_args={}))
 
     assert ErnieImagePipeline._should_apply_pe(req) is False
 
diff --git a/tests/diffusion/models/ovis_image/test_ovis_image.py b/tests/diffusion/models/ovis_image/test_ovis_image.py
index 6e7ed2f58..8e357e6c6 100644
--- a/tests/diffusion/models/ovis_image/test_ovis_image.py
+++ b/tests/diffusion/models/ovis_image/test_ovis_image.py
@@ -167,6 +167,7 @@ def test_basic_generation(ovis_pipeline):
     # Setup request
     req = OmniDiffusionRequest(
         prompts=["A photo of a cat"],
+        request_id="ovis-basic",
         sampling_params=OmniDiffusionSamplingParams(
             height=256,
             width=256,
@@ -206,6 +207,7 @@ def test_guidance_scale(ovis_pipeline, monkeypatch: pytest.MonkeyPatch):
                 "negative_prompt": "bad quality",
             }
         ],
+        request_id="ovis-guidance",
         sampling_params=OmniDiffusionSamplingParams(
             height=256,
             width=256,
@@ -225,6 +227,7 @@ def test_resolution_check(ovis_pipeline):
     # Pass odd resolution
     req = OmniDiffusionRequest(
         prompts=["test"],
+        request_id="ovis-resolution",
         sampling_params=OmniDiffusionSamplingParams(
             height=250,  # Not divisible by 16 (8*2)
             width=250,
diff --git a/tests/diffusion/test_diffusion_engine.py b/tests/diffusion/test_diffusion_engine.py
index dca9a001a..2d44f6a68 100644
--- a/tests/diffusion/test_diffusion_engine.py
+++ b/tests/diffusion/test_diffusion_engine.py
@@ -22,15 +22,15 @@ class DiffusionSchedulerOutput:
     num_waiting_reqs: int = 0
 
     @property
-    def scheduled_req_ids(self):
+    def scheduled_request_ids(self):
         ids = [req.request_id for req in self.scheduled_new_reqs]
         if self.scheduled_cached_reqs:
-            ids.extend(self.scheduled_cached_reqs.sched_req_ids)
+            ids.extend(self.scheduled_cached_reqs.request_ids)
         return ids
 
     @property
     def is_empty(self):
-        return len(self.scheduled_req_ids) == 0
+        return len(self.scheduled_request_ids) == 0
 
 
 class MockScheduler:
@@ -71,31 +71,36 @@ async def test_async_add_req_and_wait_for_response():
     engine.scheduler = MockScheduler()
     engine._out_queue = {}
     engine.abort_queue: queue.Queue[str] = queue.Queue()
-    engine._rpc_lock = threading.Lock()
+    engine._rpc_queue = queue.Queue()
+    engine._rpc_lock = threading.RLock()
+    engine._cv = threading.Condition(engine._rpc_lock)
+    engine._init_lock = asyncio.Lock()
+    engine._closed = False
+    engine._loop_started = False
+    engine.main_loop = None
 
     engine._finalize_finished_request = lambda rid, out, err: out.result
 
     def mock_execute_batch(sched_output):
-        req_ids = sched_output.scheduled_req_ids
+        request_ids = sched_output.scheduled_request_ids
 
         time.sleep(1)
 
         class MockRunnerOutput:
             def __init__(self, ids):
-                self.req_id = ids
+                self.request_id = ids
                 self.step_index = 0
                 self.finished = True
                 self._results = {rid: SimpleNamespace(result_data=f"data_{rid}") for rid in ids}
 
-            def get_req_output(self, rid):
+            def get_request_output(self, rid):
                 return SimpleNamespace(result=self._results[rid], step_index=0, finished=True)
 
-        return MockRunnerOutput(req_ids)
+        return MockRunnerOutput(request_ids)
 
     engine.execute_fn = mock_execute_batch
 
-    engine.stop_event = threading.Event()
-    engine.start_background_loop()
+    await engine._check_and_start_background_loop()
 
     async def run_task(rid):
         req = SimpleNamespace(request_id=rid)
@@ -105,10 +110,13 @@ async def test_async_add_req_and_wait_for_response():
 
     task_ids = [f"req_{i}" for i in range(5)]
     tasks = [run_task(rid) for rid in task_ids]
-    results = await asyncio.gather(*tasks)
-
-    engine.stop_event.set()
-    engine.worker_thread.join(timeout=5)
+    try:
+        results = await asyncio.gather(*tasks)
+    finally:
+        with engine._cv:
+            engine.stop_event.set()
+            engine._cv.notify_all()
+        engine.worker_thread.join(timeout=5)
     assert len(results) == 5
     for rid, res, elapsed in results:
         assert rid in res.result_data
diff --git a/tests/diffusion/test_diffusion_engine_cleanup.py b/tests/diffusion/test_diffusion_engine_cleanup.py
index a7b945eea..a8985f372 100644
--- a/tests/diffusion/test_diffusion_engine_cleanup.py
+++ b/tests/diffusion/test_diffusion_engine_cleanup.py
@@ -17,15 +17,10 @@ from vllm_omni.inputs.data import OmniDiffusionSamplingParams
 pytestmark = [pytest.mark.core_model, pytest.mark.cpu, pytest.mark.diffusion]
 
 
-def _make_request(
-    request_id: str,
-    *,
-    request_ids: list[str] | None = None,
-) -> OmniDiffusionRequest:
+def _make_request(request_id: str) -> OmniDiffusionRequest:
     return OmniDiffusionRequest(
         prompts=[f"prompt_{request_id}"],
         sampling_params=OmniDiffusionSamplingParams(num_inference_steps=1),
-        request_ids=request_ids or [request_id],
         request_id=request_id,
     )
 
@@ -79,15 +74,15 @@ def test_handle_finished_requests_ignores_already_drained_waiter() -> None:
     engine._finalize_finished_request.assert_not_called()
 
 
-def test_abort_parent_request_id_aborts_batched_scheduler_request() -> None:
+def test_abort_request_id_aborts_scheduler_request() -> None:
     engine = _make_engine()
-    request = _make_request("batch-parent", request_ids=["batch-parent-0", "batch-parent-1"])
-    sched_req_id = engine.scheduler.add_request(request)
+    request = _make_request("batch-parent")
+    request_id = engine.scheduler.add_request(request)
 
     engine.abort("batch-parent")
     engine._process_aborts_queue()
 
-    state = engine.scheduler.get_request_state(sched_req_id)
+    state = engine.scheduler.get_request_state(request_id)
     assert state is not None
     assert state.status == DiffusionRequestStatus.FINISHED_ABORTED
 
diff --git a/tests/diffusion/test_diffusion_engine_rpc_routing.py b/tests/diffusion/test_diffusion_engine_rpc_routing.py
index b1b63a1a2..852f6dc2e 100644
--- a/tests/diffusion/test_diffusion_engine_rpc_routing.py
+++ b/tests/diffusion/test_diffusion_engine_rpc_routing.py
@@ -89,7 +89,7 @@ class _ConcurrencyTrackingExecutor:
             if method in {"execute_model", "execute_stepwise", "generate"}:
                 # args[0] is the request-like object for execute_model.
                 req = args[0] if args else None
-                tag = req.request_ids[0] if req is not None and hasattr(req, "request_ids") else "unknown"
+                tag = req.request_id if req is not None and hasattr(req, "request_id") else "unknown"
                 return DiffusionOutput(error=f"result_for_{tag}")
             tag = args[0] if args else method
             return DiffusionOutput(error=f"rpc_result_for_{tag}")
@@ -108,7 +108,7 @@ class _ConcurrencyTrackingExecutor:
             exec_all_ranks=True,
         )
         return RunnerOutput(
-            req_id=new_req.sched_req_id,
+            request_id=new_req.request_id,
             step_index=None,
             finished=True,
             result=result,
@@ -120,7 +120,7 @@ class _ConcurrencyTrackingExecutor:
 
 def _make_request(tag: str):
     return SimpleNamespace(
-        request_ids=[tag],
+        request_id=tag,
         prompts=[f"prompt_{tag}"],
         sampling_params=SimpleNamespace(num_inference_steps=1, **_SAMPLING_KEY_DEFAULTS),
     )
@@ -148,6 +148,7 @@ def _make_engine_with_loop(
     engine._rpc_lock = threading.RLock()
     engine._cv = threading.Condition(engine._rpc_lock)
     engine._out_queue = {}
+    engine._closed = False
     engine.abort_queue = queue.Queue()
     engine._rpc_queue = queue.Queue()
 
diff --git a/tests/diffusion/test_diffusion_request.py b/tests/diffusion/test_diffusion_request.py
index 56ec95d0c..9087a6e2f 100644
--- a/tests/diffusion/test_diffusion_request.py
+++ b/tests/diffusion/test_diffusion_request.py
@@ -5,7 +5,7 @@ import random
 
 import pytest
 
-from vllm_omni.diffusion.request import OmniDiffusionRequest
+from vllm_omni.diffusion.request import DUMMY_DIFFUSION_REQUEST_ID, OmniDiffusionRequest
 from vllm_omni.inputs.data import OmniDiffusionSamplingParams
 
 pytestmark = [pytest.mark.core_model, pytest.mark.diffusion, pytest.mark.cpu]
@@ -15,9 +15,53 @@ def _make_request() -> OmniDiffusionRequest:
     return OmniDiffusionRequest(
         prompts=[{"prompt": "a cup of coffee on a table"}],
         sampling_params=OmniDiffusionSamplingParams(num_inference_steps=1),
+        request_id="request-test",
     )
 
 
+def test_request_id_is_required():
+    with pytest.raises(TypeError, match="request_id"):
+        OmniDiffusionRequest(
+            prompts=[{"prompt": "a cup of coffee on a table"}],
+            sampling_params=OmniDiffusionSamplingParams(num_inference_steps=1),
+        )
+
+
+def test_request_ids_identity_list_is_removed():
+    req = _make_request()
+
+    assert req.request_id == "request-test"
+    assert not hasattr(req, "request_ids")
+
+
+def test_request_id_must_be_non_empty():
+    with pytest.raises(ValueError, match="request_id must be a non-empty string"):
+        OmniDiffusionRequest(
+            prompts=[{"prompt": "a cup of coffee on a table"}],
+            sampling_params=OmniDiffusionSamplingParams(num_inference_steps=1),
+            request_id="",
+        )
+
+
+def test_dummy_run_request_is_identified_by_reserved_request_id():
+    req = OmniDiffusionRequest(
+        prompts=[{"prompt": "dummy run"}],
+        sampling_params=OmniDiffusionSamplingParams(num_inference_steps=1),
+        request_id=DUMMY_DIFFUSION_REQUEST_ID,
+    )
+
+    assert req.is_dummy_run()
+    assert OmniDiffusionRequest.is_dummy_run_request_id(DUMMY_DIFFUSION_REQUEST_ID)
+
+
+def test_non_dummy_request_is_not_identified_as_dummy_run():
+    req = _make_request()
+
+    assert not req.is_dummy_run()
+    assert not OmniDiffusionRequest.is_dummy_run_request_id(req.request_id)
+    assert not OmniDiffusionRequest.is_dummy_run_request_id(None)
+
+
 def test_tp_seed_same_across_ranks_and_varies_across_requests():
     random.seed(0)
     n_requests = 5
diff --git a/tests/diffusion/test_diffusion_scheduler.py b/tests/diffusion/test_diffusion_scheduler.py
index ca28b2629..85d2e45c9 100644
--- a/tests/diffusion/test_diffusion_scheduler.py
+++ b/tests/diffusion/test_diffusion_scheduler.py
@@ -31,13 +31,13 @@ def _make_request(req_id: str) -> OmniDiffusionRequest:
     return OmniDiffusionRequest(
         prompts=[f"prompt_{req_id}"],
         sampling_params=OmniDiffusionSamplingParams(num_inference_steps=1),
-        request_ids=[req_id],
+        request_id=req_id,
     )
 
 
 def _make_request_output(req_id: str, *, error: str | None = None, finished: bool = True):
     return RunnerOutput(
-        req_id=req_id,
+        request_id=req_id,
         step_index=None,
         finished=finished,
         result=DiffusionOutput(output=None, error=error),
@@ -52,7 +52,7 @@ def _make_step_output(
     error: str | None = None,
 ):
     return RunnerOutput(
-        req_id=req_id,
+        request_id=req_id,
         step_index=step_index,
         finished=finished,
         result=DiffusionOutput(output=None, error=error) if error is not None else None,
@@ -73,16 +73,16 @@ def _make_step_request(
             num_inference_steps=num_inference_steps,
             step_index=step_index,
         ),
-        request_ids=[req_id],
+        request_id=req_id,
     )
 
 
 def _new_ids(sched_output) -> list[str]:
-    return [req.sched_req_id for req in sched_output.scheduled_new_reqs]
+    return [req.request_id for req in sched_output.scheduled_new_reqs]
 
 
 def _cached_ids(sched_output) -> list[str]:
-    return list(sched_output.scheduled_cached_reqs.sched_req_ids)
+    return list(sched_output.scheduled_cached_reqs.request_ids)
 
 
 class _StubScheduler(SchedulerInterface):
@@ -90,7 +90,7 @@ class _StubScheduler(SchedulerInterface):
         self._request = request
         self._output = output
         self.initialized_with = None
-        self._sched_req_id = request.request_ids[0]
+        self._request_id = request.request_id
         self._state = None
         self._scheduled = False
         self.max_num_running_reqs = 1
@@ -100,22 +100,22 @@ class _StubScheduler(SchedulerInterface):
 
     def add_request(self, request: OmniDiffusionRequest) -> str:
         assert request is self._request
-        self._state = SimpleNamespace(sched_req_id=self._sched_req_id, req=request)
-        return self._sched_req_id
+        self._state = SimpleNamespace(request_id=self._request_id, req=request)
+        return self._request_id
 
     def schedule(self):
         if self._scheduled or self._state is None:
             return SimpleNamespace(
                 scheduled_new_reqs=[],
                 scheduled_cached_reqs=CachedRequestData.make_empty(),
-                scheduled_req_ids=[],
+                scheduled_request_ids=[],
                 is_empty=True,
             )
         self._scheduled = True
         return SimpleNamespace(
             scheduled_new_reqs=[NewRequestData.from_state(self._state)],
             scheduled_cached_reqs=CachedRequestData.make_empty(),
-            scheduled_req_ids=[self._state.sched_req_id],
+            scheduled_request_ids=[self._state.request_id],
             is_empty=False,
         )
 
@@ -123,30 +123,25 @@ class _StubScheduler(SchedulerInterface):
         del sched_output
         assert output is self._output
         self._state.status = DiffusionRequestStatus.FINISHED_COMPLETED
-        return {self._sched_req_id}
+        return {self._request_id}
 
     def has_requests(self) -> bool:
         return not self._scheduled
 
-    def get_request_state(self, sched_req_id: str):
-        del sched_req_id
+    def get_request_state(self, request_id: str):
+        del request_id
         return self._state
 
-    def get_sched_req_id(self, request_id: str) -> str | None:
-        if request_id in self._request.request_ids:
-            return self._sched_req_id
-        return None
-
-    def pop_request_state(self, sched_req_id: str):
-        del sched_req_id
+    def pop_request_state(self, request_id: str):
+        del request_id
         return self._state
 
-    def preempt_request(self, sched_req_id: str) -> bool:
-        del sched_req_id
+    def preempt_request(self, request_id: str) -> bool:
+        del request_id
         return False
 
-    def finish_requests(self, sched_req_ids, status) -> None:
-        del sched_req_ids, status
+    def finish_requests(self, request_ids, status) -> None:
+        del request_ids, status
         return None
 
     def close(self) -> None:
@@ -171,7 +166,7 @@ class TestGetSamplingParamsKey:
         return OmniDiffusionRequest(
             prompts=["prompt"],
             sampling_params=sp,
-            request_ids=[f"req-{lora_int_id}-{lora_scale}"],
+            request_id=f"req-{lora_int_id}-{lora_scale}",
         )
 
     def test_distinguishes_lora_id(self) -> None:
@@ -291,7 +286,7 @@ class TestRequestScheduler:
             OmniDiffusionRequest(
                 prompts=["prompt_b"],
                 sampling_params=OmniDiffusionSamplingParams(width=768),
-                request_ids=["b"],
+                request_id="b",
             )
         )
         scheduler.add_request(_make_request("c"))
@@ -333,7 +328,7 @@ class TestRequestScheduler:
         assert state_a.status == DiffusionRequestStatus.FINISHED_ABORTED
 
         assert self.scheduler.has_requests() is False
-        assert self.scheduler.schedule().scheduled_req_ids == []
+        assert self.scheduler.schedule().scheduled_request_ids == []
 
     def test_has_requests_state_transition(self) -> None:
         assert self.scheduler.has_requests() is False
@@ -348,60 +343,28 @@ class TestRequestScheduler:
         assert self.scheduler.get_request_state(req_id).status == DiffusionRequestStatus.FINISHED_COMPLETED
         assert self.scheduler.has_requests() is False
 
-    def test_request_id_mapping_lifecycle(self) -> None:
+    def test_request_id_is_scheduler_key(self) -> None:
         request = OmniDiffusionRequest(
             prompts=["prompt_map_a", "prompt_map_b"],
             sampling_params=OmniDiffusionSamplingParams(num_inference_steps=1),
-            request_ids=["map-a", "map-b"],
             request_id="map-parent",
         )
 
-        sched_req_id = self.scheduler.add_request(request)
+        request_id = self.scheduler.add_request(request)
 
-        assert self.scheduler.get_sched_req_id("map-a") == sched_req_id
-        assert self.scheduler.get_sched_req_id("map-b") == sched_req_id
-        assert self.scheduler.get_sched_req_id("map-parent") == sched_req_id
+        assert request_id == "map-parent"
+        state = self.scheduler.get_request_state("map-parent")
+        assert state.request_id == "map-parent"
 
-        self.scheduler.pop_request_state(sched_req_id)
+        self.scheduler.pop_request_state("map-parent")
 
-        assert self.scheduler.get_sched_req_id("map-a") is None
-        assert self.scheduler.get_sched_req_id("map-b") is None
-        assert self.scheduler.get_sched_req_id("map-parent") is None
+        assert self.scheduler.get_request_state("map-parent") is None
 
-    def test_parent_request_id_registration_failure_rolls_back_child_ids(self) -> None:
-        self.scheduler.add_request(
-            OmniDiffusionRequest(
-                prompts=["prompt_existing"],
-                sampling_params=OmniDiffusionSamplingParams(num_inference_steps=1),
-                request_ids=["existing-child"],
-                request_id="duplicate-parent",
-            )
-        )
+    def test_duplicate_request_id_is_rejected(self) -> None:
+        self.scheduler.add_request(_make_request("dup"))
 
-        colliding_request = OmniDiffusionRequest(
-            prompts=["prompt_unique"],
-            sampling_params=OmniDiffusionSamplingParams(num_inference_steps=1),
-            request_ids=["unique-child"],
-            request_id="duplicate-parent",
-        )
-
-        with pytest.raises(ValueError, match="duplicate-parent"):
-            self.scheduler.add_request(colliding_request)
-
-        assert self.scheduler.get_request_state("unique-child") is None
-        assert self.scheduler.get_sched_req_id("unique-child") is None
-
-        valid_request = OmniDiffusionRequest(
-            prompts=["prompt_unique"],
-            sampling_params=OmniDiffusionSamplingParams(num_inference_steps=1),
-            request_ids=["unique-child"],
-            request_id="unique-parent",
-        )
-        sched_req_id = self.scheduler.add_request(valid_request)
-
-        assert sched_req_id == "unique-child"
-        assert self.scheduler.get_sched_req_id("unique-child") == sched_req_id
-        assert self.scheduler.get_sched_req_id("unique-parent") == sched_req_id
+        with pytest.raises(ValueError, match="request_id 'dup' is already active"):
+            self.scheduler.add_request(_make_request("dup"))
 
 
 class TestDiffusionEngine:
@@ -662,7 +625,7 @@ class TestStepScheduler:
         finished = self.scheduler.update_from_output(
             sched_output,
             RunnerOutput(
-                req_id=req_id,
+                request_id=req_id,
                 step_index=None,
                 finished=True,
                 result=None,
@@ -934,7 +897,7 @@ class TestStepScheduler:
 
         for _ in range(expected_steps - 1):
             sched_output = self.scheduler.schedule()
-            assert sched_output.scheduled_req_ids == [req_id]
+            assert sched_output.scheduled_request_ids == [req_id]
             next_step = request.sampling_params.step_index + 1
             assert (
                 self.scheduler.update_from_output(
@@ -945,7 +908,7 @@ class TestStepScheduler:
             )
 
         final_output = self.scheduler.schedule()
-        assert final_output.scheduled_req_ids == [req_id]
+        assert final_output.scheduled_request_ids == [req_id]
         assert self.scheduler.update_from_output(
             final_output,
             _make_step_output(req_id, step_index=expected_steps, finished=True),
diff --git a/tests/diffusion/test_diffusion_step_pipeline.py b/tests/diffusion/test_diffusion_step_pipeline.py
index 2722de7e3..029fea120 100644
--- a/tests/diffusion/test_diffusion_step_pipeline.py
+++ b/tests/diffusion/test_diffusion_step_pipeline.py
@@ -206,7 +206,7 @@ class _DistributedStepPipeline(CFGParallelMixin):
 def _make_step_request(num_inference_steps: int = 2):
     return SimpleNamespace(
         prompts=["a prompt"],
-        request_ids=["req-1"],
+        request_id="req-1",
         sampling_params=SimpleNamespace(
             generator=None,
             seed=None,
@@ -227,7 +227,7 @@ def _make_engine_request(req_id: str = "req-1", num_inference_steps: int = 2) ->
     return OmniDiffusionRequest(
         prompts=[f"prompt-{req_id}"],
         sampling_params=OmniDiffusionSamplingParams(num_inference_steps=num_inference_steps),
-        request_ids=[req_id],
+        request_id=req_id,
     )
 
 
@@ -274,10 +274,10 @@ def _make_distributed_runner(mode: str, device: torch.device):
     return runner
 
 
-def _make_scheduler_output(req, sched_req_id="req-1", step_id=0, finished_req_ids=None):
+def _make_scheduler_output(req, request_id="req-1", step_id=0, finished_req_ids=None):
     return DiffusionSchedulerOutput(
         step_id=step_id,
-        scheduled_new_reqs=[NewRequestData(sched_req_id=sched_req_id, req=req)],
+        scheduled_new_reqs=[NewRequestData(request_id=request_id, req=req)],
         scheduled_cached_reqs=CachedRequestData.make_empty(),
         finished_req_ids=set() if finished_req_ids is None else set(finished_req_ids),
         num_running_reqs=1,
@@ -287,7 +287,7 @@ def _make_scheduler_output(req, sched_req_id="req-1", step_id=0, finished_req_id
 
 def _make_batch_scheduler_output(reqs, *, step_id=0, finished_req_ids=None):
     """Scheduler output for a homogeneous batch (one NewRequestData per req)."""
-    new_reqs = [NewRequestData(sched_req_id=r.request_ids[0], req=r) for r in reqs]
+    new_reqs = [NewRequestData(request_id=r.request_id, req=r) for r in reqs]
     return DiffusionSchedulerOutput(
         step_id=step_id,
         scheduled_new_reqs=new_reqs,
@@ -298,11 +298,11 @@ def _make_batch_scheduler_output(reqs, *, step_id=0, finished_req_ids=None):
     )
 
 
-def _make_cached_scheduler_output(sched_req_id="req-1", step_id=1, finished_req_ids=None):
+def _make_cached_scheduler_output(request_id="req-1", step_id=1, finished_req_ids=None):
     return DiffusionSchedulerOutput(
         step_id=step_id,
         scheduled_new_reqs=[],
-        scheduled_cached_reqs=CachedRequestData(sched_req_ids=[sched_req_id]),
+        scheduled_cached_reqs=CachedRequestData(request_ids=[request_id]),
         finished_req_ids=set() if finished_req_ids is None else set(finished_req_ids),
         num_running_reqs=1,
         num_waiting_reqs=0,
@@ -359,7 +359,7 @@ def _distributed_step_worker(local_rank: int, world_size: int, mode: str, master
             runner,
             _make_scheduler_output(_make_step_request(num_inference_steps=1), step_id=0),
         )
-        output = result.get_req_output("req-1")
+        output = result.get_request_output("req-1")
 
         assert output.finished is True
         assert output.result is not None
@@ -384,16 +384,16 @@ class TestRunner:
         monkeypatch.setattr(model_runner_module, "set_forward_context", _noop_forward_context)
 
         result = DiffusionModelRunner.execute_stepwise(runner, _make_scheduler_output(req, step_id=0))
-        first = result.get_req_output("req-1")
-        assert first.req_id == "req-1"
+        first = result.get_request_output("req-1")
+        assert first.request_id == "req-1"
         assert first.step_index == 1
         assert first.finished is False
         assert first.result is None
         assert "req-1" in runner.state_cache
 
         result = DiffusionModelRunner.execute_stepwise(runner, _make_cached_scheduler_output(step_id=1))
-        second = result.get_req_output("req-1")
-        assert second.req_id == "req-1"
+        second = result.get_request_output("req-1")
+        assert second.request_id == "req-1"
         assert second.step_index == 2
         assert second.finished is True
         assert second.result is not None
@@ -410,13 +410,13 @@ class TestRunner:
         runner = _make_runner()
         req_1 = _make_step_request()
         req_2 = _make_step_request()
-        req_2.request_ids = ["req-2"]
+        req_2.request_id = "req-2"
 
         scheduler_output = DiffusionSchedulerOutput(
             step_id=0,
             scheduled_new_reqs=[
-                NewRequestData(sched_req_id="req-1", req=req_1),
-                NewRequestData(sched_req_id="req-2", req=req_2),
+                NewRequestData(request_id="req-1", req=req_1),
+                NewRequestData(request_id="req-2", req=req_2),
             ],
             scheduled_cached_reqs=CachedRequestData.make_empty(),
             finished_req_ids=set(),
@@ -431,7 +431,7 @@ class TestRunner:
         runner = _make_runner()
 
         with pytest.raises(ValueError, match="Missing cached state"):
-            DiffusionModelRunner.execute_stepwise(runner, _make_cached_scheduler_output(sched_req_id="req-missing"))
+            DiffusionModelRunner.execute_stepwise(runner, _make_cached_scheduler_output(request_id="req-missing"))
 
     def test_interrupt_marks_request_finished_and_clears_state(self, monkeypatch):
         runner = _make_runner()
@@ -440,8 +440,8 @@ class TestRunner:
         monkeypatch.setattr(model_runner_module, "set_forward_context", _noop_forward_context)
 
         result = DiffusionModelRunner.execute_stepwise(runner, _make_scheduler_output(req, step_id=0))
-        output = result.get_req_output("req-1")
-        assert output.req_id == "req-1"
+        output = result.get_request_output("req-1")
+        assert output.request_id == "req-1"
         assert output.step_index == 0
         assert output.finished is True
         assert output.result is not None
@@ -515,7 +515,7 @@ def _make_step_worker(lora_manager=None, *, expected_output=None):
     worker = object.__new__(DiffusionWorker)
     worker.lora_manager = lora_manager
     worker._step_lora_state = {}
-    output = expected_output if expected_output is not None else RunnerOutput(req_id="req-1")
+    output = expected_output if expected_output is not None else RunnerOutput(request_id="req-1")
     worker.model_runner = SimpleNamespace(execute_stepwise=lambda arg: output)
     return worker
 
@@ -525,9 +525,9 @@ class TestWorker:
     """DiffusionWorker.execute_stepwise"""
 
     def test_delegates_to_model_runner(self):
-        expected = RunnerOutput(req_id="req-1", step_index=1, finished=False, result=None)
+        expected = RunnerOutput(request_id="req-1", step_index=1, finished=False, result=None)
         worker = _make_step_worker(expected_output=expected)
-        scheduler_output = _make_scheduler_output(_make_engine_request("req-1"), sched_req_id="req-1")
+        scheduler_output = _make_scheduler_output(_make_engine_request("req-1"), request_id="req-1")
 
         output = DiffusionWorker.execute_stepwise(worker, scheduler_output)
 
@@ -536,7 +536,7 @@ class TestWorker:
     def test_deactivates_lora_when_request_has_no_adapter(self):
         manager = _RecordingLoRAManager()
         worker = _make_step_worker(lora_manager=manager)
-        scheduler_output = _make_scheduler_output(_make_engine_request("req-1"), sched_req_id="req-1")
+        scheduler_output = _make_scheduler_output(_make_engine_request("req-1"), request_id="req-1")
 
         DiffusionWorker.execute_stepwise(worker, scheduler_output)
 
@@ -552,7 +552,7 @@ class TestWorker:
 
         manager = _RecordingLoRAManager()
         worker = _make_step_worker(lora_manager=manager)
-        scheduler_output = _make_scheduler_output(request, sched_req_id="req-1")
+        scheduler_output = _make_scheduler_output(request, request_id="req-1")
 
         DiffusionWorker.execute_stepwise(worker, scheduler_output)
 
@@ -568,8 +568,8 @@ class TestWorker:
 
         manager = _RecordingLoRAManager()
         worker = _make_step_worker(lora_manager=manager)
-        first = _make_scheduler_output(request, sched_req_id="req-1")
-        second = _make_cached_scheduler_output(sched_req_id="req-1", step_id=1)
+        first = _make_scheduler_output(request, request_id="req-1")
+        second = _make_cached_scheduler_output(request_id="req-1", step_id=1)
 
         DiffusionWorker.execute_stepwise(worker, first)
         DiffusionWorker.execute_stepwise(worker, second)
@@ -610,10 +610,10 @@ class TestWorker:
         next_request.sampling_params.lora_request = lora_request
 
         worker = _make_step_worker(lora_manager=_RecordingLoRAManager())
-        first = _make_scheduler_output(finishing, sched_req_id="req-1")
+        first = _make_scheduler_output(finishing, request_id="req-1")
         next_batch = _make_scheduler_output(
             next_request,
-            sched_req_id="req-2",
+            request_id="req-2",
             step_id=1,
             finished_req_ids={"req-1"},
         )
@@ -633,11 +633,11 @@ class TestExecutor:
     def test_execute_step_passes_through_runner_output(self, mocker: MockerFixture):
         executor = object.__new__(MultiprocDiffusionExecutor)
         executor._ensure_open = lambda: None
-        expected = RunnerOutput(req_id="req-step", step_index=1, finished=False, result=None)
+        expected = RunnerOutput(request_id="req-step", step_index=1, finished=False, result=None)
         executor.collective_rpc = mocker.Mock(return_value=expected)
 
         request = _make_engine_request("req-step", num_inference_steps=2)
-        scheduler_output = _make_scheduler_output(request, sched_req_id="req-step")
+        scheduler_output = _make_scheduler_output(request, request_id="req-step")
 
         output = MultiprocDiffusionExecutor.execute_step(executor, scheduler_output)
 
@@ -653,7 +653,7 @@ class TestEngine:
         [
             (
                 lambda _: RunnerOutput(
-                    req_id="req-error",
+                    request_id="req-error",
                     step_index=1,
                     finished=True,
                     result=DiffusionOutput(error="boom"),
@@ -688,7 +688,7 @@ class TestEngine:
             call_count["n"] += 1
             finished = call_count["n"] == 2
             return RunnerOutput(
-                req_id="req-step",
+                request_id="req-step",
                 step_index=call_count["n"],
                 finished=finished,
                 result=(DiffusionOutput(output=torch.tensor([2.0])) if finished else None),
@@ -714,7 +714,7 @@ class TestEngine:
             step["n"] += 1
             engine.abort("req-stop")
             return RunnerOutput(
-                req_id="req-stop",
+                request_id="req-stop",
                 step_index=1,
                 finished=False,
                 result=None,
@@ -741,7 +741,7 @@ class TestEngine:
                 assert sched_output == _make_cached_scheduler_output("req-mid", step_id=1)
                 engine.abort("req-mid")
             return RunnerOutput(
-                req_id="req-mid",
+                request_id="req-mid",
                 step_index=step["n"],
                 finished=False,
                 result=None,
@@ -760,7 +760,7 @@ class TestEngine:
         engine = _make_engine(
             scheduler,
             execute_fn=lambda _: RunnerOutput(
-                req_id="req-missing",
+                request_id="req-missing",
                 step_index=1,
                 finished=True,
                 result=None,
@@ -777,7 +777,7 @@ class TestEngine:
 class TestIPC:
     def test_pack_unpack_runner_output_shm(self):
         tensor = torch.zeros(300_000, dtype=torch.float32)
-        output = RunnerOutput(req_id="req-1", finished=True, result=DiffusionOutput(output=tensor))
+        output = RunnerOutput(request_id="req-1", finished=True, result=DiffusionOutput(output=tensor))
 
         packed = pack_diffusion_output_shm(output)
         assert isinstance(packed.result.output, dict)
diff --git a/tests/diffusion/test_multiproc_engine_concurrency.py b/tests/diffusion/test_multiproc_engine_concurrency.py
index aa2a74ac1..99d7a9c9c 100644
--- a/tests/diffusion/test_multiproc_engine_concurrency.py
+++ b/tests/diffusion/test_multiproc_engine_concurrency.py
@@ -36,7 +36,7 @@ def _tagged_output(tag: str) -> DiffusionOutput:
 def _mock_request(tag: str):
     """Return a lightweight request object identifiable by *tag*."""
     return SimpleNamespace(
-        request_ids=[tag],
+        request_id=tag,
         prompts=[f"prompt_{tag}"],
         sampling_params=OmniDiffusionSamplingParams(num_inference_steps=1),
     )
@@ -97,8 +97,8 @@ def _start_worker(req_q, res_q, count=2):
             req = req_q.get(timeout=10)
             method = req.get("method", "")
             args = req.get("args", ())
-            if method in {"generate", "execute_model"} and args and hasattr(args[0], "request_ids"):
-                tag = f"result_for_{args[0].request_ids[0]}"
+            if method in {"generate", "execute_model"} and args and hasattr(args[0], "request_id"):
+                tag = f"result_for_{args[0].request_id}"
             elif args:
                 tag = f"result_for_{args[0]}"
             else:
diff --git a/tests/diffusion/test_stage_diffusion_proc.py b/tests/diffusion/test_stage_diffusion_proc.py
index 36ceb6cfc..0419bb813 100644
--- a/tests/diffusion/test_stage_diffusion_proc.py
+++ b/tests/diffusion/test_stage_diffusion_proc.py
@@ -68,7 +68,7 @@ def test_process_batch_request_preserves_parent_request_id_and_kv_sender_info():
 
         request = captured["request"]
         assert request.request_id == "req-parent"
-        assert request.request_ids == ["req-parent-0", "req-parent-1"]
+        assert not hasattr(request, "request_ids")
         assert request.kv_sender_info == {0: {"host": "10.0.0.2", "zmq_port": 50151}}
         assert result.request_id == "req-parent"
         assert result.images == ["img-1", "img-2"]
diff --git a/tests/distributed/omni_connectors/test_kv_flow.py b/tests/distributed/omni_connectors/test_kv_flow.py
index cea186019..2cc19f1b3 100644
--- a/tests/distributed/omni_connectors/test_kv_flow.py
+++ b/tests/distributed/omni_connectors/test_kv_flow.py
@@ -384,7 +384,7 @@ def test_manager_reception(kv_config, mock_connector, common_constants):
     req = OmniDiffusionRequest(
         prompts=["test_recv"],
         sampling_params=OmniDiffusionSamplingParams(),
-        request_ids=[req_id],
+        request_id=req_id,
     )
     # req.need_kv_receive = True # Implicitly handled by receive_kv_cache check? No, manager doesn't check it, runner does.
     # But receive_kv_cache in manager checks request_id. Which we need to fix in manager next.
@@ -428,7 +428,6 @@ def test_manager_reception_prefers_parent_request_id_for_batched_request(kv_conf
     req = OmniDiffusionRequest(
         prompts=["prompt-a", "prompt-b"],
         sampling_params=OmniDiffusionSamplingParams(),
-        request_ids=[f"{parent_req_id}-0", f"{parent_req_id}-1"],
         request_id=parent_req_id,
     )
 
@@ -454,7 +453,6 @@ def test_receive_multi_kv_cache_uses_parent_request_id_for_cfg_collection(kv_con
     req = OmniDiffusionRequest(
         prompts=["prompt-a", "prompt-b"],
         sampling_params=OmniDiffusionSamplingParams(),
-        request_ids=["req-parent-0", "req-parent-1"],
         request_id="req-parent",
     )
     req.sampling_params.cfg_kv_request_ids = {"cfg_text": "req-parent__cfg_text"}
@@ -516,7 +514,7 @@ def test_integration_flow(common_constants):
     req = OmniDiffusionRequest(
         prompts=["test_integ"],
         sampling_params=OmniDiffusionSamplingParams(),
-        request_ids=[req_id],
+        request_id=req_id,
     )
 
     # Receive
diff --git a/vllm_omni/diffusion/cache/teacache/coefficient_estimator.py b/vllm_omni/diffusion/cache/teacache/coefficient_estimator.py
index 37ea454de..d8931b8da 100644
--- a/vllm_omni/diffusion/cache/teacache/coefficient_estimator.py
+++ b/vllm_omni/diffusion/cache/teacache/coefficient_estimator.py
@@ -202,6 +202,7 @@ class TeaCacheCoefficientEstimator:
         self.hook.start_collection()
         req = OmniDiffusionRequest(
             prompts=[prompt],
+            request_id="teacache-coefficient-estimator",
             sampling_params=OmniDiffusionSamplingParams(
                 num_inference_steps=generate_kwargs.get("num_inference_steps", 20),
                 seed=generate_kwargs.get("seed", 42),
diff --git a/vllm_omni/diffusion/diffusion_engine.py b/vllm_omni/diffusion/diffusion_engine.py
index 8fd85fd9e..8cb0d5296 100644
--- a/vllm_omni/diffusion/diffusion_engine.py
+++ b/vllm_omni/diffusion/diffusion_engine.py
@@ -30,10 +30,10 @@ from vllm_omni.diffusion.registry import (
     get_diffusion_post_process_func,
     get_diffusion_pre_process_func,
 )
-from vllm_omni.diffusion.request import OmniDiffusionRequest
+from vllm_omni.diffusion.request import DUMMY_DIFFUSION_REQUEST_ID, OmniDiffusionRequest
 from vllm_omni.diffusion.sched import RequestScheduler, SchedulerInterface, StepScheduler
 from vllm_omni.diffusion.sched.interface import DiffusionRequestStatus
-from vllm_omni.diffusion.worker.utils import BatchRunnerOutput, RunnerOutput
+from vllm_omni.diffusion.worker.utils import BaseRunnerOutput, BatchRunnerOutput, RunnerOutput
 from vllm_omni.inputs.data import OmniDiffusionSamplingParams, OmniTextPrompt
 from vllm_omni.outputs import OmniRequestOutput
 
@@ -217,7 +217,7 @@ class DiffusionEngine:
             logger.warning("Output is None, returning empty OmniRequestOutput")
             return [
                 OmniRequestOutput.from_diffusion(
-                    request_id=request.request_ids[i] if i < len(request.request_ids) else "",
+                    request_id=request.request_id,
                     images=[],
                     prompt=prompt,
                     metrics={},
@@ -304,7 +304,7 @@ class DiffusionEngine:
         if len(request.prompts) == 1:
             # Single request: return single OmniRequestOutput
             prompt = request.prompts[0]
-            request_id = request.request_ids[0] if request.request_ids else ""
+            request_id = request.request_id
 
             if is_text_output:
                 return [
@@ -368,10 +368,9 @@ class DiffusionEngine:
             # Split images based on num_outputs_per_prompt for each request
             results = []
             output_idx = 0
+            request_id = request.request_id
 
             for i, prompt in enumerate(request.prompts):
-                request_id = request.request_ids[i] if i < len(request.request_ids) else ""
-
                 # Get images for this request
                 num_outputs = request.sampling_params.num_outputs_per_prompt
                 start_idx = output_idx
@@ -467,17 +466,17 @@ class DiffusionEngine:
                 runner_output = self.execute_fn(sched_output)
             except Exception as exc:
                 logger.error(
-                    "Execution failed for diffusion requests %s", sched_output.scheduled_req_ids, exc_info=True
+                    "Execution failed for diffusion requests %s", sched_output.scheduled_request_ids, exc_info=True
                 )
                 runner_output = BatchRunnerOutput.from_list(
                     [
                         RunnerOutput(
-                            req_id=req_id,
+                            request_id=request_id,
                             step_index=None,
                             finished=True,
                             result=DiffusionOutput(error=str(exc)),
                         )
-                        for req_id in sched_output.scheduled_req_ids
+                        for request_id in sched_output.scheduled_request_ids
                     ]
                 )
 
@@ -544,7 +543,7 @@ class DiffusionEngine:
     def _handle_finished_requests(
         self,
         finished_ids: set[str],
-        runner_output: RunnerOutput | None = None,
+        runner_output: BaseRunnerOutput | None = None,
         missing_result_error: str = "Diffusion execution finished without a final output",
     ):
         for rid in finished_ids:
@@ -553,7 +552,7 @@ class DiffusionEngine:
             if fut is None:
                 continue
             if runner_output is not None:
-                _output = runner_output.get_req_output(rid)
+                _output = runner_output.get_request_output(rid)
             else:
                 _output = None
             out = self._finalize_finished_request(rid, _output, missing_result_error)
@@ -579,11 +578,11 @@ class DiffusionEngine:
             if self._closed:
                 raise RuntimeError("DiffusionEngine is closed.")
             fut = self.main_loop.create_future()
-            sched_req_id = self.scheduler.add_request(request)
-            self._out_queue[sched_req_id] = fut
+            request_id = self.scheduler.add_request(request)
+            self._out_queue[request_id] = fut
             self._cv.notify_all()
 
-        return sched_req_id
+        return request_id
 
     async def get_result(self, request_id: str) -> DiffusionOutput:
         fut = self._out_queue.get(request_id)
@@ -599,37 +598,37 @@ class DiffusionEngine:
     async def async_add_req_and_wait_for_response(self, request: OmniDiffusionRequest) -> DiffusionOutput:
         # No lock needed: add_request is already protected by self._cv, and
         # all executor calls are serialized inside the busy loop.
-        sched_req_id = self.add_request(request)
-        return await self.get_result(sched_req_id)
+        request_id = self.add_request(request)
+        return await self.get_result(request_id)
 
     def add_req_and_wait_for_response(self, request: OmniDiffusionRequest) -> DiffusionOutput:
         with self._rpc_lock:
             if self._closed:
                 raise RuntimeError("DiffusionEngine is closed.")
-            target_sched_req_id = self.scheduler.add_request(request)
+            target_request_id = self.scheduler.add_request(request)
 
             # keep scheduling and executing until the target request is finished
             while True:
                 self._process_aborts_queue()
                 sched_output = self.scheduler.schedule()
                 if sched_output.is_empty:
-                    if target_sched_req_id in sched_output.finished_req_ids:
-                        return self._finalize_finished_request(target_sched_req_id)
+                    if target_request_id in sched_output.finished_req_ids:
+                        return self._finalize_finished_request(target_request_id)
                     if not self.scheduler.has_requests():
                         raise RuntimeError("Diffusion scheduler has no runnable requests.")
                     continue
 
                 # NOTE: add_req_and_wait_for_response() is synchronous, will be only called
                 # within _dummy_run, only one request will be scheduled
-                sched_req_id = sched_output.scheduled_req_ids[0]
+                request_id = sched_output.scheduled_request_ids[0]
                 try:
                     runner_output = self.execute_fn(sched_output)
                 except EngineDeadError:
                     raise
                 except Exception as exc:
-                    logger.error("Execution failed for diffusion request %s", sched_req_id, exc_info=True)
+                    logger.error("Execution failed for diffusion request %s", request_id, exc_info=True)
                     runner_output = RunnerOutput(
-                        req_id=sched_req_id,
+                        request_id=request_id,
                         step_index=None,
                         finished=True,
                         result=DiffusionOutput(error=str(exc)),
@@ -642,10 +641,10 @@ class DiffusionEngine:
                 # sync func should receive one result
                 if not isinstance(runner_output, RunnerOutput) and not len(runner_output) == 1:
                     raise ValueError("Sync func should receive one result at one time")
-                if target_sched_req_id in finished_req_ids:
-                    runner_output = runner_output.get_req_output(target_sched_req_id)
+                if target_request_id in finished_req_ids:
+                    runner_output = runner_output.get_request_output(target_request_id)
                     return self._finalize_finished_request(
-                        target_sched_req_id,
+                        target_request_id,
                         runner_output=runner_output,
                         missing_result_error="Diffusion execution finished without a final output.",
                     )
@@ -697,7 +696,7 @@ class DiffusionEngine:
         num_frames = 2 if supports_audio_input or supports_audio_output(self.od_config.model_class_name) else 1
         req = OmniDiffusionRequest(
             prompts=[prompt],
-            request_ids=["dummy_req_id"],
+            request_id=DUMMY_DIFFUSION_REQUEST_ID,
             sampling_params=OmniDiffusionSamplingParams(
                 height=height,
                 width=width,
@@ -904,34 +903,27 @@ class DiffusionEngine:
     def _abort_requests(self, request_ids: str | Iterable[str]) -> None:
         request_ids = [request_ids] if isinstance(request_ids, str) else list(request_ids)
 
-        sched_req_ids: list[str] = []
         for request_id in dict.fromkeys(request_ids):
-            sched_req_id = self.scheduler.get_sched_req_id(request_id)
-            if sched_req_id is not None:
-                sched_req_ids.append(sched_req_id)
-
-        for sched_req_id in dict.fromkeys(sched_req_ids):
-            if self.scheduler.get_request_state(sched_req_id) is not None:
-                self.scheduler.finish_requests(sched_req_id, DiffusionRequestStatus.FINISHED_ABORTED)
+            if self.scheduler.get_request_state(request_id) is not None:
+                self.scheduler.finish_requests(request_id, DiffusionRequestStatus.FINISHED_ABORTED)
 
     def _finalize_finished_request(
         self,
-        sched_req_id: str,
+        request_id: str,
         runner_output: RunnerOutput | None = None,
         missing_result_error: str = "Diffusion scheduler finished target request without execution output.",
     ) -> DiffusionOutput:
-        state = self.scheduler.get_request_state(sched_req_id)
-        popped_state = self.scheduler.pop_request_state(sched_req_id)
+        state = self.scheduler.get_request_state(request_id)
+        popped_state = self.scheduler.pop_request_state(request_id)
         state = state or popped_state
 
         if state is None:
-            raise RuntimeError(f"Diffusion scheduler lost state for request {sched_req_id}.")
+            raise RuntimeError(f"Diffusion scheduler lost state for request {request_id}.")
 
         if state.status == DiffusionRequestStatus.FINISHED_ABORTED:
-            request_id = state.req.request_ids[0] if state.req.request_ids else sched_req_id
             return DiffusionOutput(
                 aborted=True,
-                abort_message=f"Request {request_id} aborted.",
+                abort_message=f"Request {state.req.request_id} aborted.",
             )
 
         if runner_output is not None and runner_output.result is not None:
diff --git a/vllm_omni/diffusion/executor/multiproc_executor.py b/vllm_omni/diffusion/executor/multiproc_executor.py
index 6727122d4..3aa409e14 100644
--- a/vllm_omni/diffusion/executor/multiproc_executor.py
+++ b/vllm_omni/diffusion/executor/multiproc_executor.py
@@ -311,7 +311,7 @@ class MultiprocDiffusionExecutor(DiffusionExecutor):
             raise RuntimeError(f"Unexpected response type for execute_request: {type(result)!r}")
 
         return RunnerOutput(
-            req_id=new_req.sched_req_id,
+            request_id=new_req.request_id,
             step_index=None,
             finished=True,
             result=result,
@@ -334,9 +334,9 @@ class MultiprocDiffusionExecutor(DiffusionExecutor):
         # TODO: Remove this fallback; DiffusionOutput cannot faithfully represent
         # failed multi-request step batches.
         if isinstance(result, DiffusionOutput):
-            req_id = scheduler_output.scheduled_req_ids[0] if scheduler_output.scheduled_req_ids else ""
+            request_id = scheduler_output.scheduled_request_ids[0] if scheduler_output.scheduled_request_ids else ""
             return RunnerOutput(
-                req_id=req_id,
+                request_id=request_id,
                 step_index=None,
                 finished=True,
                 result=result,
diff --git a/vllm_omni/diffusion/inline_stage_diffusion_client.py b/vllm_omni/diffusion/inline_stage_diffusion_client.py
index b6f881d1c..d8eb2ac53 100644
--- a/vllm_omni/diffusion/inline_stage_diffusion_client.py
+++ b/vllm_omni/diffusion/inline_stage_diffusion_client.py
@@ -128,7 +128,6 @@ class InlineStageDiffusionClient(StageClientBase):
             request = OmniDiffusionRequest(
                 prompts=[prompt],
                 sampling_params=sampling_params,
-                request_ids=[request_id],
                 request_id=request_id,
                 kv_sender_info=kv_sender_info,
             )
@@ -187,7 +186,6 @@ class InlineStageDiffusionClient(StageClientBase):
             request = OmniDiffusionRequest(
                 prompts=prompts,
                 sampling_params=sampling_params,
-                request_ids=[f"{request_id}-{i}" for i in range(len(prompts))],
                 request_id=request_id,
                 kv_sender_info=kv_sender_info,
             )
diff --git a/vllm_omni/diffusion/models/ernie_image/pipeline_ernie_image.py b/vllm_omni/diffusion/models/ernie_image/pipeline_ernie_image.py
index 7b5d80571..cd60cc93b 100644
--- a/vllm_omni/diffusion/models/ernie_image/pipeline_ernie_image.py
+++ b/vllm_omni/diffusion/models/ernie_image/pipeline_ernie_image.py
@@ -247,8 +247,10 @@ class ErnieImagePipeline(
 
     @staticmethod
     def _is_warmup_request(req: OmniDiffusionRequest) -> bool:
-        request_ids = getattr(req, "request_ids", None) or ()
-        return len(request_ids) == 1 and request_ids[0] == "dummy_req_id"
+        is_dummy_run = getattr(req, "is_dummy_run", None)
+        if callable(is_dummy_run):
+            return bool(is_dummy_run())
+        return OmniDiffusionRequest.is_dummy_run_request_id(getattr(req, "request_id", None))
 
     @staticmethod
     def _should_apply_pe(req: OmniDiffusionRequest) -> bool:
diff --git a/vllm_omni/diffusion/models/glm_image/pipeline_glm_image.py b/vllm_omni/diffusion/models/glm_image/pipeline_glm_image.py
index 97cba18c2..4cbd23c21 100644
--- a/vllm_omni/diffusion/models/glm_image/pipeline_glm_image.py
+++ b/vllm_omni/diffusion/models/glm_image/pipeline_glm_image.py
@@ -689,15 +689,11 @@ class GlmImagePipeline(nn.Module, DiffusionPipelineProfilerMixin):
         prompt = first_prompt if isinstance(first_prompt, str) else (first_prompt.get("prompt") or "")
 
         # NOTE: DiffusionEngine does an internal warmup "dummy run" during
-        # initialization. That request has no request_id and does not carry
+        # initialization. That request carries the fixed dummy request_id and does not carry
         # Stage-0 (AR) outputs via req.extra. For GLM-Image, we allow that
         # specific warmup request to proceed by synthesizing minimal prior
         # tokens, while still raising a clear error for real requests.
-        is_dummy_warmup = (
-            not getattr(req, "request_id", None)
-            and prompt == "dummy run"
-            and (req.sampling_params.num_inference_steps == 1)
-        )
+        is_dummy_warmup = req.is_dummy_run()
 
         # Get pre-computed prompt embeddings if provided
         if isinstance(first_prompt, str):
diff --git a/vllm_omni/diffusion/request.py b/vllm_omni/diffusion/request.py
index 4d4328d25..79198c3ec 100644
--- a/vllm_omni/diffusion/request.py
+++ b/vllm_omni/diffusion/request.py
@@ -3,10 +3,12 @@
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 import random
-from dataclasses import dataclass, field
+from dataclasses import dataclass
 
 from vllm_omni.inputs.data import OmniDiffusionSamplingParams, OmniPromptType
 
+DUMMY_DIFFUSION_REQUEST_ID = "dummy_req_id"
+
 
 @dataclass
 class OmniDiffusionRequest:
@@ -24,13 +26,14 @@ class OmniDiffusionRequest:
 
     prompts: list[OmniPromptType]  # Actually supporting str-based prompts
     sampling_params: OmniDiffusionSamplingParams
-
-    request_ids: list[str] = field(default_factory=list)
-    request_id: str | None = None
+    request_id: str
     kv_sender_info: dict | None = None
 
     def __post_init__(self):
         """Initialize dependent fields after dataclass initialization."""
+        if not isinstance(self.request_id, str) or not self.request_id:
+            raise ValueError("OmniDiffusionRequest.request_id must be a non-empty string.")
+
         # When neither a generator nor a seed is provided, assign a random seed
         # so that all ranks derive the same generator state.
         if self.sampling_params.generator is None and self.sampling_params.seed is None:
@@ -56,3 +59,10 @@ class OmniDiffusionRequest:
         # so downstream code always has a valid value.
         if self.sampling_params.guidance_scale_2 is None:
             self.sampling_params.guidance_scale_2 = self.sampling_params.guidance_scale
+
+    def is_dummy_run(self) -> bool:
+        return self.is_dummy_run_request_id(self.request_id)
+
+    @classmethod
+    def is_dummy_run_request_id(cls, request_id: str | None) -> bool:
+        return request_id == DUMMY_DIFFUSION_REQUEST_ID
diff --git a/vllm_omni/diffusion/sched/base_scheduler.py b/vllm_omni/diffusion/sched/base_scheduler.py
index 0bd16597f..812873a1c 100644
--- a/vllm_omni/diffusion/sched/base_scheduler.py
+++ b/vllm_omni/diffusion/sched/base_scheduler.py
@@ -46,7 +46,6 @@ class _BaseScheduler(SchedulerInterface):
     def __init__(self) -> None:
         self.od_config: OmniDiffusionConfig | None = None
         self._request_states: dict[str, DiffusionRequestState] = {}
-        self._request_id_to_sched_req_id: dict[str, str] = {}
         self._step_id: int = 0
         self._waiting: deque[str] = deque()
         self._running: list[str] = []
@@ -57,7 +56,6 @@ class _BaseScheduler(SchedulerInterface):
     def initialize(self, od_config: OmniDiffusionConfig) -> None:
         self.od_config = od_config
         self._request_states.clear()
-        self._request_id_to_sched_req_id.clear()
         self._step_id = 0
         self._waiting.clear()
         self._running.clear()
@@ -71,32 +69,31 @@ class _BaseScheduler(SchedulerInterface):
         self._reset_scheduler_state()
 
     def add_request(self, request: OmniDiffusionRequest) -> str:
-        sched_req_id = self._make_sched_req_id(request)
-        return self._add_request_with_sched_req_id(sched_req_id, request)
+        return self._add_request_with_request_id(request.request_id, request)
 
-    def _add_request_with_sched_req_id(self, sched_req_id: str, request: OmniDiffusionRequest) -> str:
-        state = self._make_request_state(sched_req_id, request)
-        request_ids = self._request_ids_for_mapping(request)
-        self._register_request_ids(request_ids, sched_req_id)
-        self._request_states[sched_req_id] = state
-        self._waiting.append(sched_req_id)
-        logger.debug("%s add_request: %s (waiting=%d)", self.__class__.__name__, sched_req_id, len(self._waiting))
-        return sched_req_id
+    def _add_request_with_request_id(self, request_id: str, request: OmniDiffusionRequest) -> str:
+        if request_id in self._request_states:
+            raise ValueError(f"request_id {request_id!r} is already active.")
+        state = self._make_request_state(request_id, request)
+        self._request_states[request_id] = state
+        self._waiting.append(request_id)
+        logger.debug("%s add_request: %s (waiting=%d)", self.__class__.__name__, request_id, len(self._waiting))
+        return request_id
 
     def schedule(self) -> DiffusionSchedulerOutput:
         scheduled_new_reqs: list[NewRequestData] = []
-        scheduled_cached_req_ids: list[str] = []
+        scheduled_cached_request_ids: list[str] = []
 
         # First, schedule the RUNNING request(s)
-        for sched_req_id in self._running:
-            state = self._request_states.get(sched_req_id)
+        for request_id in self._running:
+            state = self._request_states.get(request_id)
             if state is not None:
-                scheduled_cached_req_ids.append(sched_req_id)
+                scheduled_cached_request_ids.append(request_id)
 
         # Second, schedule WAITING requests while capacity remains.
         while self._waiting and len(self._running) < self.max_num_running_reqs:
-            sched_req_id = self._waiting[0]
-            state = self._request_states.get(sched_req_id)
+            request_id = self._waiting[0]
+            state = self._request_states.get(request_id)
             if state is None:
                 self._waiting.popleft()
                 continue
@@ -108,16 +105,16 @@ class _BaseScheduler(SchedulerInterface):
             if not self._running:
                 self._running_sampling_params_key = state.sampling_params_key
             state.status = DiffusionRequestStatus.RUNNING
-            self._running.append(sched_req_id)
+            self._running.append(request_id)
             if was_new_request:
                 scheduled_new_reqs.append(NewRequestData.from_state(state))
             else:
-                scheduled_cached_req_ids.append(sched_req_id)
+                scheduled_cached_request_ids.append(request_id)
 
         scheduler_output = DiffusionSchedulerOutput(
             step_id=self._step_id,
             scheduled_new_reqs=scheduled_new_reqs,
-            scheduled_cached_reqs=CachedRequestData(sched_req_ids=scheduled_cached_req_ids),
+            scheduled_cached_reqs=CachedRequestData(request_ids=scheduled_cached_request_ids),
             finished_req_ids=set(self._finished_req_ids),
             num_running_reqs=len(self._running),
             num_waiting_reqs=len(self._waiting),
@@ -131,40 +128,33 @@ class _BaseScheduler(SchedulerInterface):
     def has_requests(self) -> bool:
         return bool(self._waiting or self._running)
 
-    def get_request_state(self, sched_req_id: str) -> DiffusionRequestState | None:
-        return self._request_states.get(sched_req_id)
+    def get_request_state(self, request_id: str) -> DiffusionRequestState | None:
+        return self._request_states.get(request_id)
 
-    def get_sched_req_id(self, request_id: str) -> str | None:
-        return self._request_id_to_sched_req_id.get(request_id)
+    def pop_request_state(self, request_id: str) -> DiffusionRequestState | None:
+        self._pop_extra_request_state(request_id)
+        return self._request_states.pop(request_id, None)
 
-    def pop_request_state(self, sched_req_id: str) -> DiffusionRequestState | None:
-        self._pop_extra_request_state(sched_req_id)
-        state = self._request_states.pop(sched_req_id, None)
-        if state is not None:
-            self._unregister_request_ids(self._request_ids_for_mapping(state.req), sched_req_id)
-        return state
-
-    def preempt_request(self, sched_req_id: str) -> bool:
-        if sched_req_id not in self._request_states:
+    def preempt_request(self, request_id: str) -> bool:
+        if request_id not in self._request_states:
             return False
-        if sched_req_id in self._running:
-            self._running.remove(sched_req_id)
+        if request_id in self._running:
+            self._running.remove(request_id)
             if not self._running:
                 self._running_sampling_params_key = None
-            self._waiting.appendleft(sched_req_id)
-            self._request_states[sched_req_id].status = DiffusionRequestStatus.PREEMPTED
+            self._waiting.appendleft(request_id)
+            self._request_states[request_id].status = DiffusionRequestStatus.PREEMPTED
             return True
         return False
 
-    def finish_requests(self, sched_req_ids: str | list[str], status: DiffusionRequestStatus) -> None:
+    def finish_requests(self, request_ids: str | list[str], status: DiffusionRequestStatus) -> None:
         assert DiffusionRequestStatus.is_finished(status)
-        if isinstance(sched_req_ids, str):
-            sched_req_ids = [sched_req_ids]
-        self._finish_requests({sched_req_id: status for sched_req_id in sched_req_ids})
+        if isinstance(request_ids, str):
+            request_ids = [request_ids]
+        self._finish_requests({request_id: status for request_id in request_ids})
 
     def close(self) -> None:
         self._request_states.clear()
-        self._request_id_to_sched_req_id.clear()
         self._waiting.clear()
         self._running.clear()
         self._running_sampling_params_key = None
@@ -183,33 +173,31 @@ class _BaseScheduler(SchedulerInterface):
         running_to_remove: set[str] = set()
         waiting_to_remove: set[str] = set()
 
-        for sched_req_id, status in statuses.items():
+        for request_id, status in statuses.items():
             assert DiffusionRequestStatus.is_finished(status)
-            state = self._request_states.get(sched_req_id)
+            state = self._request_states.get(request_id)
             if state is None or state.is_finished():
                 continue
 
-            finished_req_ids.add(sched_req_id)
-            if sched_req_id in self._running:
-                running_to_remove.add(sched_req_id)
-            if sched_req_id in self._waiting:
-                waiting_to_remove.add(sched_req_id)
+            finished_req_ids.add(request_id)
+            if request_id in self._running:
+                running_to_remove.add(request_id)
+            if request_id in self._waiting:
+                waiting_to_remove.add(request_id)
 
         if running_to_remove:
-            self._running = [sched_req_id for sched_req_id in self._running if sched_req_id not in running_to_remove]
+            self._running = [request_id for request_id in self._running if request_id not in running_to_remove]
             if not self._running:
                 self._running_sampling_params_key = None
         if waiting_to_remove:
-            self._waiting = deque(
-                sched_req_id for sched_req_id in self._waiting if sched_req_id not in waiting_to_remove
-            )
+            self._waiting = deque(request_id for request_id in self._waiting if request_id not in waiting_to_remove)
 
-        for sched_req_id in finished_req_ids:
-            state = self._request_states[sched_req_id]
-            status = statuses[sched_req_id]
+        for request_id in finished_req_ids:
+            state = self._request_states[request_id]
+            status = statuses[request_id]
             state.status = status
             if status == DiffusionRequestStatus.FINISHED_ERROR:
-                state.error = None if errors is None else errors.get(sched_req_id)
+                state.error = None if errors is None else errors.get(request_id)
             else:
                 state.error = None
 
@@ -227,7 +215,7 @@ class _BaseScheduler(SchedulerInterface):
         # marked finished at that point, but we still need to surface its id
         # in this update so the engine can observe the terminal state.
         finished_req_ids = {
-            sched_req_id for sched_req_id in sched_output.scheduled_req_ids if sched_req_id in self._finished_req_ids
+            request_id for request_id in sched_output.scheduled_request_ids if request_id in self._finished_req_ids
         }
         finished_req_ids |= self._finish_requests(statuses, errors)
         return finished_req_ids
@@ -235,12 +223,12 @@ class _BaseScheduler(SchedulerInterface):
     def _reset_scheduler_state(self) -> None:
         """Reset subclass-owned state during initialize()/close()."""
 
-    def _pop_extra_request_state(self, sched_req_id: str) -> None:
+    def _pop_extra_request_state(self, request_id: str) -> None:
         """Remove subclass-owned per-request state before popping request state."""
 
-    def _make_request_state(self, sched_req_id: str, request: OmniDiffusionRequest) -> DiffusionRequestState:
+    def _make_request_state(self, request_id: str, request: OmniDiffusionRequest) -> DiffusionRequestState:
         return DiffusionRequestState(
-            sched_req_id=sched_req_id,
+            request_id=request_id,
             req=request,
             sampling_params_key=get_sampling_params_key(request),
         )
@@ -258,24 +246,3 @@ class _BaseScheduler(SchedulerInterface):
         state = self._request_states.get(self._running[0])
         self._running_sampling_params_key = None if state is None else state.sampling_params_key
         return self._running_sampling_params_key
-
-    def _register_request_ids(self, request_ids: list[str], sched_req_id: str) -> None:
-        unique_request_ids = list(dict.fromkeys(request_ids))
-        for request_id in unique_request_ids:
-            existing = self._request_id_to_sched_req_id.get(request_id)
-            if existing is not None and existing != sched_req_id:
-                raise ValueError(f"request_id {request_id!r} is already mapped to active sched_req_id {existing!r}.")
-        for request_id in unique_request_ids:
-            self._request_id_to_sched_req_id[request_id] = sched_req_id
-
-    def _unregister_request_ids(self, request_ids: list[str], sched_req_id: str) -> None:
-        for request_id in request_ids:
-            if self._request_id_to_sched_req_id.get(request_id) == sched_req_id:
-                self._request_id_to_sched_req_id.pop(request_id, None)
-
-    @staticmethod
-    def _request_ids_for_mapping(request: OmniDiffusionRequest) -> list[str]:
-        request_ids = list(request.request_ids)
-        if request_id := getattr(request, "request_id", None):
-            request_ids.append(request_id)
-        return list(dict.fromkeys(request_ids))
diff --git a/vllm_omni/diffusion/sched/interface.py b/vllm_omni/diffusion/sched/interface.py
index 1bfb69458..b50e3555a 100644
--- a/vllm_omni/diffusion/sched/interface.py
+++ b/vllm_omni/diffusion/sched/interface.py
@@ -4,22 +4,17 @@
 from __future__ import annotations
 
 import enum
-import uuid
 from abc import ABC, abstractmethod
 from dataclasses import dataclass
 from functools import cached_property
 from typing import TYPE_CHECKING
 
-from vllm.logger import init_logger
-
 from vllm_omni.diffusion.data import OmniDiffusionConfig
 from vllm_omni.diffusion.request import OmniDiffusionRequest
 
 if TYPE_CHECKING:
     from vllm_omni.diffusion.worker.utils import RunnerOutput
 
-logger = init_logger(__name__)
-
 
 class DiffusionRequestStatus(enum.IntEnum):
     """Request status tracked by diffusion scheduler."""
@@ -75,10 +70,7 @@ class SamplingParamsKey:
 class DiffusionRequestState:
     """Scheduler-owned state for one queued OmniDiffusionRequest."""
 
-    # Unique scheduler-owned request ID.
-    # NOTE: This identifies one OmniDiffusionRequest, which may contain multiple request_ids.
-    # TODO: Align this with OmniDiffusionRequest.request_ids once scheduler batching is supported.
-    sched_req_id: str
+    request_id: str
     req: OmniDiffusionRequest
     sampling_params_key: SamplingParamsKey | None = None
     status: DiffusionRequestStatus = DiffusionRequestStatus.WAITING
@@ -92,23 +84,23 @@ class DiffusionRequestState:
 class NewRequestData:
     """Full request payload for a newly scheduled diffusion request."""
 
-    sched_req_id: str
+    request_id: str
     req: OmniDiffusionRequest
 
     @classmethod
     def from_state(cls, state: DiffusionRequestState) -> NewRequestData:
-        return cls(sched_req_id=state.sched_req_id, req=state.req)
+        return cls(request_id=state.request_id, req=state.req)
 
 
 @dataclass
 class CachedRequestData:
-    """Cached diffusion requests that only need their scheduler ids resent."""
+    """Cached diffusion requests that only need their request ids resent."""
 
-    sched_req_ids: list[str]
+    request_ids: list[str]
 
     @classmethod
     def make_empty(cls) -> CachedRequestData:
-        return cls(sched_req_ids=[])
+        return cls(request_ids=[])
 
 
 @dataclass
@@ -123,21 +115,18 @@ class DiffusionSchedulerOutput:
     num_waiting_reqs: int
 
     @cached_property
-    def scheduled_req_ids(self) -> list[str]:
+    def scheduled_request_ids(self) -> list[str]:
         """
         All scheduled request ids in this cycle, including both new and cached ones.
-        NOTE:
-            This id is generated and owned by the scheduler,
-            and may be different from the OmniDiffusionRequest.request_ids.
         """
         return [
-            *(req.sched_req_id for req in self.scheduled_new_reqs),
-            *self.scheduled_cached_reqs.sched_req_ids,
+            *(req.request_id for req in self.scheduled_new_reqs),
+            *self.scheduled_cached_reqs.request_ids,
         ]
 
     @property
     def num_scheduled_reqs(self) -> int:
-        return len(self.scheduled_req_ids)
+        return len(self.scheduled_request_ids)
 
     @property
     def is_empty(self) -> bool:
@@ -147,25 +136,6 @@ class DiffusionSchedulerOutput:
 class SchedulerInterface(ABC):
     """Abstract lifecycle contract for diffusion schedulers."""
 
-    def _make_sched_req_id(self, request: OmniDiffusionRequest) -> str:
-        """
-        Generate a unique scheduler request ID for the given request.
-            The default implementation uses the first request_id from the request if available,
-            otherwise generates a random one.
-        """
-        if request.request_ids:
-            base = request.request_ids[0]
-        else:
-            logger.warning("Request has no request_ids, generating a random one. Request: %s", request)
-            base = f"req_{uuid.uuid4().hex[:8]}"
-
-        sched_req_id = base
-        suffix = 1
-        while self.get_request_state(sched_req_id) is not None:
-            sched_req_id = f"{base}#{suffix}"
-            suffix += 1
-        return sched_req_id
-
     @abstractmethod
     def initialize(self, od_config: OmniDiffusionConfig) -> None:
         """Initialize or reset scheduler state."""
@@ -183,7 +153,7 @@ class SchedulerInterface(ABC):
         """Update scheduler state from executor output."""
 
     @abstractmethod
-    def get_request_state(self, sched_req_id: str) -> DiffusionRequestState | None:
+    def get_request_state(self, request_id: str) -> DiffusionRequestState | None:
         """Return request state if present."""
 
     @abstractmethod
@@ -191,19 +161,15 @@ class SchedulerInterface(ABC):
         """Return whether the scheduler still owns runnable requests."""
 
     @abstractmethod
-    def get_sched_req_id(self, request_id: str) -> str | None:
-        """Resolve a public request_id to the active scheduler request id."""
-
-    @abstractmethod
-    def pop_request_state(self, sched_req_id: str) -> DiffusionRequestState | None:
+    def pop_request_state(self, request_id: str) -> DiffusionRequestState | None:
         """Remove and return request state if present."""
 
     @abstractmethod
-    def preempt_request(self, sched_req_id: str) -> bool:
+    def preempt_request(self, request_id: str) -> bool:
         """Preempt a running request back to waiting."""
 
     @abstractmethod
-    def finish_requests(self, sched_req_ids: str | list[str], status: DiffusionRequestStatus) -> None:
+    def finish_requests(self, request_ids: str | list[str], status: DiffusionRequestStatus) -> None:
         """Mark one or more requests finished."""
 
     @abstractmethod
diff --git a/vllm_omni/diffusion/sched/request_scheduler.py b/vllm_omni/diffusion/sched/request_scheduler.py
index 5029e3593..ba9cda616 100644
--- a/vllm_omni/diffusion/sched/request_scheduler.py
+++ b/vllm_omni/diffusion/sched/request_scheduler.py
@@ -26,26 +26,26 @@ class RequestScheduler(_BaseScheduler):
         return super().schedule()
 
     def update_from_output(self, sched_output: DiffusionSchedulerOutput, output: RunnerOutput) -> set[str]:
-        scheduled_req_ids = sched_output.scheduled_req_ids
-        if not scheduled_req_ids:
+        scheduled_request_ids = sched_output.scheduled_request_ids
+        if not scheduled_request_ids:
             return set()
 
         terminal_statuses: dict[str, DiffusionRequestStatus] = {}
         terminal_errors: dict[str, str | None] = {}
-        for sched_req_id in scheduled_req_ids:
-            state = self._request_states.get(sched_req_id)
+        for request_id in scheduled_request_ids:
+            state = self._request_states.get(request_id)
             if state is None or state.is_finished():
                 continue
-            req_output = output.get_req_output(sched_req_id)
+            req_output = output.get_request_output(request_id)
             result = req_output.result if req_output is not None else None
             if result is None:
-                terminal_statuses[sched_req_id] = DiffusionRequestStatus.FINISHED_ERROR
-                terminal_errors[sched_req_id] = "No output result"
+                terminal_statuses[request_id] = DiffusionRequestStatus.FINISHED_ERROR
+                terminal_errors[request_id] = "No output result"
             elif result.error:
-                terminal_statuses[sched_req_id] = DiffusionRequestStatus.FINISHED_ERROR
-                terminal_errors[sched_req_id] = result.error
+                terminal_statuses[request_id] = DiffusionRequestStatus.FINISHED_ERROR
+                terminal_errors[request_id] = result.error
             else:
-                terminal_statuses[sched_req_id] = DiffusionRequestStatus.FINISHED_COMPLETED
-                terminal_errors[sched_req_id] = None
+                terminal_statuses[request_id] = DiffusionRequestStatus.FINISHED_COMPLETED
+                terminal_errors[request_id] = None
 
         return self._finalize_update_from_output(sched_output, terminal_statuses, terminal_errors)
diff --git a/vllm_omni/diffusion/sched/step_scheduler.py b/vllm_omni/diffusion/sched/step_scheduler.py
index 58449281b..0bc2d4a3c 100644
--- a/vllm_omni/diffusion/sched/step_scheduler.py
+++ b/vllm_omni/diffusion/sched/step_scheduler.py
@@ -38,84 +38,84 @@ class StepScheduler(_BaseScheduler):
         self._request_progress.clear()
 
     def add_request(self, request: OmniDiffusionRequest) -> str:
-        sched_req_id = self._make_sched_req_id(request)
+        request_id = request.request_id
         total_steps = self._get_total_steps(request)
         if total_steps <= 0:
-            raise ValueError(f"Diffusion request {sched_req_id} must have positive total_steps, got {total_steps}")
+            raise ValueError(f"Diffusion request {request_id} must have positive total_steps, got {total_steps}")
 
         current_step = request.sampling_params.step_index or 0
         if current_step < 0 or current_step >= total_steps:
             raise ValueError(
-                f"Diffusion request {sched_req_id} has invalid initial step_index {current_step} "
+                f"Diffusion request {request_id} has invalid initial step_index {current_step} "
                 f"for total_steps={total_steps}"
             )
 
         request.sampling_params.step_index = current_step
-        sched_req_id = self._add_request_with_sched_req_id(sched_req_id, request)
-        self._request_progress[sched_req_id] = _StepProgress(current_step=current_step, total_steps=total_steps)
+        request_id = self._add_request_with_request_id(request_id, request)
+        self._request_progress[request_id] = _StepProgress(current_step=current_step, total_steps=total_steps)
         logger.debug(
             "StepScheduler add_request: %s (step=%d/%d, waiting=%d)",
-            sched_req_id,
+            request_id,
             current_step,
             total_steps,
             len(self._waiting),
         )
-        return sched_req_id
+        return request_id
 
     def schedule(self) -> DiffusionSchedulerOutput:
         return super().schedule()
 
     def update_from_output(self, sched_output: DiffusionSchedulerOutput, output: RunnerOutput) -> set[str]:
-        scheduled_req_ids = sched_output.scheduled_req_ids
-        if not scheduled_req_ids:
+        scheduled_request_ids = sched_output.scheduled_request_ids
+        if not scheduled_request_ids:
             return set()
 
         terminal_statuses: dict[str, DiffusionRequestStatus] = {}
         terminal_errors: dict[str, str | None] = {}
-        for sched_req_id in scheduled_req_ids:
-            state = self._request_states.get(sched_req_id)
-            progress = self._request_progress.get(sched_req_id)
+        for request_id in scheduled_request_ids:
+            state = self._request_states.get(request_id)
+            progress = self._request_progress.get(request_id)
             if state is None or progress is None or state.is_finished():
                 continue
-            req_output = output.get_req_output(sched_req_id)
+            req_output = output.get_request_output(request_id)
             if req_output is None:
                 logger.warning(
                     "No RunnerOutput for request %s, treating as error",
-                    sched_req_id,
+                    request_id,
                 )
-                terminal_statuses[sched_req_id] = DiffusionRequestStatus.FINISHED_ERROR
-                terminal_errors[sched_req_id] = "No output for request"
+                terminal_statuses[request_id] = DiffusionRequestStatus.FINISHED_ERROR
+                terminal_errors[request_id] = "No output for request"
                 continue
 
             req_result = req_output.result
             output_error = req_result.error if req_result is not None else None
             if output_error is not None:
-                terminal_statuses[sched_req_id] = DiffusionRequestStatus.FINISHED_ERROR
-                terminal_errors[sched_req_id] = output_error
+                terminal_statuses[request_id] = DiffusionRequestStatus.FINISHED_ERROR
+                terminal_errors[request_id] = output_error
                 continue
 
             if req_output.step_index is None:
                 logger.warning(
                     "Received RunnerOutput with no step_index for request %s, treating as error",
-                    sched_req_id,
+                    request_id,
                 )
-                terminal_statuses[sched_req_id] = DiffusionRequestStatus.FINISHED_ERROR
-                terminal_errors[sched_req_id] = "Missing step_index in RunnerOutput"
+                terminal_statuses[request_id] = DiffusionRequestStatus.FINISHED_ERROR
+                terminal_errors[request_id] = "Missing step_index in RunnerOutput"
                 continue
 
             # We assume that the decoding stage is executed immediately after the denoising stage completes.
             progress.current_step = req_output.step_index
             state.req.sampling_params.step_index = req_output.step_index
             if req_output.finished:
-                terminal_statuses[sched_req_id] = DiffusionRequestStatus.FINISHED_COMPLETED
-                terminal_errors[sched_req_id] = None
+                terminal_statuses[request_id] = DiffusionRequestStatus.FINISHED_COMPLETED
+                terminal_errors[request_id] = None
             else:
                 state.error = None
 
         return self._finalize_update_from_output(sched_output, terminal_statuses, terminal_errors)
 
-    def _pop_extra_request_state(self, sched_req_id: str) -> None:
-        self._request_progress.pop(sched_req_id, None)
+    def _pop_extra_request_state(self, request_id: str) -> None:
+        self._request_progress.pop(request_id, None)
 
     def _get_total_steps(self, request: OmniDiffusionRequest) -> int:
         sampling = request.sampling_params
diff --git a/vllm_omni/diffusion/stage_diffusion_proc.py b/vllm_omni/diffusion/stage_diffusion_proc.py
index 19e890abb..07489d4c9 100644
--- a/vllm_omni/diffusion/stage_diffusion_proc.py
+++ b/vllm_omni/diffusion/stage_diffusion_proc.py
@@ -159,7 +159,6 @@ class StageDiffusionProc:
         request = OmniDiffusionRequest(
             prompts=[prompt],
             sampling_params=sampling_params,
-            request_ids=[request_id],
             request_id=request_id,
             kv_sender_info=kv_sender_info,
         )
@@ -189,7 +188,6 @@ class StageDiffusionProc:
         request = OmniDiffusionRequest(
             prompts=prompts,
             sampling_params=sampling_params,
-            request_ids=[f"{request_id}-{i}" for i in range(len(prompts))],
             request_id=request_id,
             kv_sender_info=kv_sender_info,
         )
diff --git a/vllm_omni/diffusion/worker/diffusion_model_runner.py b/vllm_omni/diffusion/worker/diffusion_model_runner.py
index ab6dbb79a..2720de038 100644
--- a/vllm_omni/diffusion/worker/diffusion_model_runner.py
+++ b/vllm_omni/diffusion/worker/diffusion_model_runner.py
@@ -322,50 +322,44 @@ class DiffusionModelRunner(OmniConnectorModelRunnerMixin):
         self, scheduler_output: DiffusionSchedulerOutput
     ) -> tuple[list[DiffusionRequestState], list[str]]:
         """Step-before update: cleanup finished requests and get/create one running state."""
-        for req_id in scheduler_output.finished_req_ids:
-            self.state_cache.pop(req_id, None)
+        for request_id in scheduler_output.finished_req_ids:
+            self.state_cache.pop(request_id, None)
 
         resolved: list[DiffusionRequestState] = []
-        new_req_id: list[str] = []
+        new_request_ids: list[str] = []
         try:
             # process new requests
             for sched_new_req in scheduler_output.scheduled_new_reqs:
-                # new_req_data = scheduler_output.scheduled_new_reqs[0]
-                req_id = sched_new_req.sched_req_id
+                request_id = sched_new_req.request_id
                 req = sched_new_req.req
-                new_req_id.append(req_id)
-                if req_id in self.state_cache:
-                    raise ValueError(f"Received duplicate new-request payload for cached request {req_id}.")
-                request_ids = req.request_ids or [req_id]
-                if len(request_ids) != len(req.prompts):
-                    raise ValueError(
-                        f"request_ids length ({len(request_ids)}) does not match prompts length ({len(req.prompts)})"
-                    )
+                new_request_ids.append(request_id)
+                if request_id in self.state_cache:
+                    raise ValueError(f"Received duplicate new-request payload for cached request {request_id}.")
                 new_state = DiffusionRequestState(
-                    req_id=req_id,
+                    request_id=request_id,
                     sampling=copy.deepcopy(req.sampling_params),
                     prompts=req.prompts,
                 )
-                self.state_cache[req_id] = new_state
+                self.state_cache[request_id] = new_state
                 resolved.append(new_state)
 
             # process cached requests
-            for req_id in scheduler_output.scheduled_cached_reqs.sched_req_ids:
-                state = self.state_cache.get(req_id)
+            for request_id in scheduler_output.scheduled_cached_reqs.request_ids:
+                state = self.state_cache.get(request_id)
                 if state is None:
-                    raise ValueError(f"Missing cached state for request {req_id}.")
+                    raise ValueError(f"Missing cached state for request {request_id}.")
                 resolved.append(state)
         except Exception:
-            for req_id in new_req_id:
-                self.state_cache.pop(req_id, None)
+            for request_id in new_request_ids:
+                self.state_cache.pop(request_id, None)
             raise
 
-        return resolved, new_req_id
+        return resolved, new_request_ids
 
     def _prepare_batch_inputs(self, states: list[DiffusionRequestState], new_request_ids: list[str]) -> InputBatch:
         # process new reqs
         for state in states:
-            if state.req_id in new_request_ids:
+            if state.request_id in new_request_ids:
                 # set generator
                 if state.sampling.generator is None and state.sampling.seed is not None:
                     if state.sampling.generator_device is not None:
@@ -407,7 +401,7 @@ class DiffusionModelRunner(OmniConnectorModelRunnerMixin):
 
         for state in states:
             if interrupted or state.denoise_completed:
-                self.state_cache.pop(state.req_id, None)
+                self.state_cache.pop(state.request_id, None)
 
     def _prepare_attn_metadata(self, input_batch: InputBatch) -> Any:
         model_state = getattr(self, "model_state", None)
@@ -449,7 +443,7 @@ class DiffusionModelRunner(OmniConnectorModelRunnerMixin):
                     for state in states:
                         runner_output_list.append(
                             RunnerOutput(
-                                req_id=state.req_id,
+                                request_id=state.request_id,
                                 step_index=state.step_index,
                                 finished=True,
                                 result=DiffusionOutput(error="stepwise denoise interrupted"),
@@ -470,7 +464,7 @@ class DiffusionModelRunner(OmniConnectorModelRunnerMixin):
                             result = None
                         runner_output_list.append(
                             RunnerOutput(
-                                req_id=req.req_id,
+                                request_id=req.request_id,
                                 step_index=req.step_index,
                                 finished=req.denoise_completed,
                                 result=result,
diff --git a/vllm_omni/diffusion/worker/diffusion_worker.py b/vllm_omni/diffusion/worker/diffusion_worker.py
index 782e79855..8f0577b49 100644
--- a/vllm_omni/diffusion/worker/diffusion_worker.py
+++ b/vllm_omni/diffusion/worker/diffusion_worker.py
@@ -189,7 +189,7 @@ class DiffusionWorker:
         self.lora_manager: DiffusionLoRAManager | None = None
         # Worker-side cache of (lora_request, lora_scale) per scheduled
         # request id. Used by step mode to recover LoRA identity for cached
-        # requests, which only carry their sched_req_id in subsequent ticks.
+        # requests, which only carry their request_id in subsequent ticks.
         self._step_lora_state: dict[str, tuple[LoRARequest | None, float]] = {}
         self.stage_id = getattr(od_config, "stage_id", 0)
         self.init_device()
@@ -391,12 +391,12 @@ class DiffusionWorker:
         homogeneity is enforced by the scheduler via ``SamplingParamsKey``,
         so any scheduled request id resolves to the active LoRA identity.
         """
-        for sched_req_id in scheduler_output.finished_req_ids:
-            self._step_lora_state.pop(sched_req_id, None)
+        for request_id in scheduler_output.finished_req_ids:
+            self._step_lora_state.pop(request_id, None)
 
         for new_req in scheduler_output.scheduled_new_reqs:
             sampling = new_req.req.sampling_params
-            self._step_lora_state[new_req.sched_req_id] = (
+            self._step_lora_state[new_req.request_id] = (
                 sampling.lora_request,
                 sampling.lora_scale,
             )
@@ -406,8 +406,8 @@ class DiffusionWorker:
 
         lora_request: LoRARequest | None = None
         lora_scale = 1.0
-        for sched_req_id in scheduler_output.scheduled_req_ids:
-            entry = self._step_lora_state.get(sched_req_id)
+        for request_id in scheduler_output.scheduled_request_ids:
+            entry = self._step_lora_state.get(request_id)
             if entry is not None:
                 lora_request, lora_scale = entry
                 break
diff --git a/vllm_omni/diffusion/worker/input_batch.py b/vllm_omni/diffusion/worker/input_batch.py
index 48c5bb57b..82033d9dc 100644
--- a/vllm_omni/diffusion/worker/input_batch.py
+++ b/vllm_omni/diffusion/worker/input_batch.py
@@ -81,8 +81,8 @@ def _select_states(
     return selected_states, idx_mapping, idx_mapping.detach().cpu().numpy()
 
 
-def _prepare_req_ids(states: Sequence[DiffusionRequestState]) -> list[str]:
-    return [state.req_id for state in states]
+def _prepare_request_ids(states: Sequence[DiffusionRequestState]) -> list[str]:
+    return [state.request_id for state in states]
 
 
 def _prepare_prompt_field_on_state(
@@ -192,11 +192,13 @@ def _get_request_prompt_seq_lens(
         mask_attr=mask_attr,
     )
     if embeds is None:
-        raise ValueError(f"{embeds_attr} is not initialized on request {state.req_id}.")
+        raise ValueError(f"{embeds_attr} is not initialized on request {state.request_id}.")
 
     if mask is not None:
         if mask.shape[0] != embeds.shape[0]:
-            raise ValueError(f"{mask_attr} batch dimension does not match {embeds_attr} for request {state.req_id}.")
+            raise ValueError(
+                f"{mask_attr} batch dimension does not match {embeds_attr} for request {state.request_id}."
+            )
         return _get_seq_lens_from_mask(mask)
 
     seq_lens = getattr(state, seq_lens_attr)
@@ -220,7 +222,7 @@ def _prepare_request_prompt_field(
         mask_attr=mask_attr,
     )
     if embeds is None:
-        raise ValueError(f"{embeds_attr} is not initialized on request {state.req_id}.")
+        raise ValueError(f"{embeds_attr} is not initialized on request {state.request_id}.")
 
     actual_seq_lens = _get_request_prompt_seq_lens(
         state,
@@ -248,7 +250,7 @@ def _prepare_request_prompt_field(
     if current_seq_len > target_seq_len:
         if max_actual_seq_len > target_seq_len:
             raise ValueError(
-                f"{embeds_attr} for request {state.req_id} requires seq_len "
+                f"{embeds_attr} for request {state.request_id} requires seq_len "
                 f"{max_actual_seq_len}, got target {target_seq_len}."
             )
         return embeds[:, :target_seq_len], None if mask is None else mask[:, :target_seq_len]
@@ -349,7 +351,7 @@ def _require_state_latents(
 ) -> torch.Tensor:
     latents = state.latents
     if latents is None:
-        raise ValueError(f"Request {state.req_id} has no latents while preparing {for_field}.")
+        raise ValueError(f"Request {state.request_id} has no latents while preparing {for_field}.")
     return latents
 
 
@@ -526,12 +528,12 @@ def _prepare_negative_prompt_embeds(
 
 def _same_composition(
     cached_batch: InputBatch | None,
-    req_ids: list[str],
+    request_ids: list[str],
     idx_mapping_np: np.ndarray,
 ) -> bool:
     if cached_batch is None:
         return False
-    if cached_batch.req_ids != req_ids:
+    if cached_batch.request_ids != request_ids:
         return False
     return np.array_equal(cached_batch.idx_mapping_np, idx_mapping_np)
 
@@ -581,7 +583,7 @@ class InputBatch:
     unchanged.
     """
 
-    req_ids: list[str]
+    request_ids: list[str]
     num_reqs: int
     num_reqs_after_padding: int
     idx_mapping: torch.Tensor
@@ -604,9 +606,9 @@ class InputBatch:
     negative_txt_seq_lens: list[int] | None = None
 
     def __post_init__(self) -> None:
-        if len(self.req_ids) != int(self.idx_mapping.numel()):
-            raise ValueError("`req_ids` and `idx_mapping` must have the same length.")
-        if self.num_reqs != len(self.req_ids):
+        if len(self.request_ids) != int(self.idx_mapping.numel()):
+            raise ValueError("`request_ids` and `idx_mapping` must have the same length.")
+        if self.num_reqs != len(self.request_ids):
             raise ValueError("`num_reqs` must match the number of request ids.")
         if self.num_reqs_after_padding < self.num_reqs:
             raise ValueError("`num_reqs_after_padding` must be >= `num_reqs`.")
@@ -653,11 +655,11 @@ class InputBatch:
         selected_states: Sequence[DiffusionRequestState],
         idx_mapping: torch.Tensor,
         idx_mapping_np: np.ndarray,
-        req_ids: list[str],
+        request_ids: list[str],
     ) -> InputBatch:
-        self.req_ids = req_ids
-        self.num_reqs = len(req_ids)
-        self.num_reqs_after_padding = len(req_ids)
+        self.request_ids = request_ids
+        self.num_reqs = len(request_ids)
+        self.num_reqs_after_padding = len(request_ids)
         self.idx_mapping = idx_mapping
         self.idx_mapping_np = idx_mapping_np
         self.latents = _prepare_latents(selected_states, out=self.latents)
@@ -675,9 +677,9 @@ class InputBatch:
     ) -> InputBatch:
         """Build a temporary step-local batch view from request states."""
         selected_states, idx_mapping, idx_mapping_np = _select_states(states, idx_mapping)
-        req_ids = _prepare_req_ids(selected_states)
+        request_ids = _prepare_request_ids(selected_states)
 
-        if _same_composition(cached_batch, req_ids, idx_mapping_np):
+        if _same_composition(cached_batch, request_ids, idx_mapping_np):
             assert cached_batch is not None
             cached_batch._repack_dynamic_fields(selected_states)
             return cached_batch
@@ -687,14 +689,14 @@ class InputBatch:
                 selected_states,
                 idx_mapping,
                 idx_mapping_np,
-                req_ids,
+                request_ids,
             )
 
         prompt_embeds, prompt_embeds_mask = _prepare_prompt_embeds(selected_states)
         negative_prompt_embeds, negative_prompt_embeds_mask = _prepare_negative_prompt_embeds(selected_states)
         do_true_cfg, true_cfg_scale, cfg_normalize = _prepare_cfg_scalars(selected_states)
         return cls(
-            req_ids=req_ids,
+            request_ids=request_ids,
             num_reqs=len(selected_states),
             num_reqs_after_padding=len(selected_states),
             idx_mapping=idx_mapping,
diff --git a/vllm_omni/diffusion/worker/utils.py b/vllm_omni/diffusion/worker/utils.py
index 1e98a7784..a0bfcea9b 100644
--- a/vllm_omni/diffusion/worker/utils.py
+++ b/vllm_omni/diffusion/worker/utils.py
@@ -38,7 +38,7 @@ class DiffusionRequestState:
     """
 
     # ── Identity / request-level inputs ──
-    req_id: str
+    request_id: str
     sampling: OmniDiffusionSamplingParams
     prompts: list[OmniPromptType] | None = None
 
@@ -112,7 +112,7 @@ class DiffusionRequestState:
 
 class BaseRunnerOutput(ABC):
     @abstractmethod
-    def get_req_output(self, sched_req_id: str) -> RunnerOutput | None:
+    def get_request_output(self, request_id: str) -> RunnerOutput | None:
         pass
 
 
@@ -125,13 +125,13 @@ class RunnerOutput(BaseRunnerOutput):
     _request_state_cache.
     """
 
-    req_id: str
+    request_id: str
     step_index: int | None = None
     finished: bool = False
     result: DiffusionOutput | None = None
 
-    def get_req_output(self, sched_req_id: str) -> RunnerOutput | None:
-        return self if self.req_id == sched_req_id else None
+    def get_request_output(self, request_id: str) -> RunnerOutput | None:
+        return self if self.request_id == request_id else None
 
 
 @dataclass
@@ -140,18 +140,18 @@ class BatchRunnerOutput(BaseRunnerOutput):
     _id_to_idx: dict[str, int] = field(init=False, repr=False)
 
     def __post_init__(self) -> None:
-        self._id_to_idx = {out.req_id: i for i, out in enumerate(self.runner_outputs)}
+        self._id_to_idx = {out.request_id: i for i, out in enumerate(self.runner_outputs)}
 
-    def __getitem__(self, req_id: str) -> RunnerOutput | None:
-        """access single RunnerOutput by req_id"""
-        idx = self._id_to_idx.get(req_id)
+    def __getitem__(self, request_id: str) -> RunnerOutput | None:
+        """access single RunnerOutput by request_id"""
+        idx = self._id_to_idx.get(request_id)
         return self.runner_outputs[idx] if idx is not None else None
 
-    def get_req_output(self, sched_req_id: str) -> RunnerOutput | None:
-        return self[sched_req_id]
+    def get_request_output(self, request_id: str) -> RunnerOutput | None:
+        return self[request_id]
 
     @property
-    def req_ids(self) -> list[str]:
+    def request_ids(self) -> list[str]:
         return list(self._id_to_idx.keys())
 
     def __len__(self) -> int:
diff --git a/vllm_omni/distributed/omni_connectors/kv_transfer_manager.py b/vllm_omni/distributed/omni_connectors/kv_transfer_manager.py
index 372c2cb3d..3b234ad1c 100644
--- a/vllm_omni/distributed/omni_connectors/kv_transfer_manager.py
+++ b/vllm_omni/distributed/omni_connectors/kv_transfer_manager.py
@@ -12,6 +12,8 @@ from typing import Any
 import torch
 from vllm.logger import init_logger
 
+from vllm_omni.diffusion.request import OmniDiffusionRequest
+
 from .factory import OmniConnectorFactory
 from .utils.config import TRANSFER_ENGINE_CONNECTOR_NAMES, ConnectorSpec
 from .utils.env import expand_env_int
@@ -1014,7 +1016,7 @@ class OmniKVTransferManager:
             return None, 0
 
         # Skip during warmup dummy run — no sender is available.
-        if request_id == "dummy_req_id":
+        if OmniDiffusionRequest.is_dummy_run_request_id(request_id):
             logger.info("Skip receiving KV cache for dummy warmup request")
             return None, 0
 
@@ -1171,12 +1173,7 @@ class OmniKVTransferManager:
     @staticmethod
     def _resolve_request_id(req: Any) -> str | None:
         """Resolve the logical request ID used for KV transfer lookups."""
-        request_id = getattr(req, "request_id", None)
-        if request_id:
-            return request_id
-        if hasattr(req, "request_ids") and req.request_ids:
-            return req.request_ids[0]
-        return None
+        return getattr(req, "request_id", None)
 
     # Legacy compatibility method
     def receive_kv_cache(self, req: Any, target_device: torch.device | None = None) -> bool:
diff --git a/vllm_omni/worker/omni_connector_model_runner_mixin.py b/vllm_omni/worker/omni_connector_model_runner_mixin.py
index 64b7e60e2..6d991d0f2 100644
--- a/vllm_omni/worker/omni_connector_model_runner_mixin.py
+++ b/vllm_omni/worker/omni_connector_model_runner_mixin.py
@@ -1245,9 +1245,7 @@ class OmniConnectorModelRunnerMixin:
         if self._kv_transfer_manager is None:
             return False
 
-        request_id = getattr(req, "request_id", None) or (
-            req.request_ids[0] if hasattr(req, "request_ids") and req.request_ids else None
-        )
+        request_id = getattr(req, "request_id", None)
         if not request_id:
             logger.warning("Request has no ID, cannot receive KV cache")
             return False