diff --git a/vllm/worker/cpu_model_runner.py b/vllm/worker/cpu_model_runner.py
index f1531e0fc0675..e3f502cdc14e6 100644
--- a/vllm/worker/cpu_model_runner.py
+++ b/vllm/worker/cpu_model_runner.py
@@ -142,12 +142,11 @@ def __init__(self,
         self.chunked_prefill = (runner.scheduler_config.chunked_prefill_enabled
                                 or runner.cache_config.enable_prefix_caching)
         self.model_input_cls = self.runner._model_input_cls
-        self.attn_backend = self.runner.attn_backend
+        self.attn_backend: AttentionBackend = self.runner.attn_backend
         self.multi_modal_input_mapper = self.runner.multi_modal_input_mapper
         self.input_data = ModelInputForCPUBuilder.ModelInputData(
             self.runner.model_config.uses_mrope)
-        self.att_metadata_builder = self.runner.attn_backend.get_builder_cls()(
-            self)
+        self.att_metadata_builder = self.attn_backend.get_builder_cls()(self)
 
     def add_seq_group(self, seq_group_metadata: SequenceGroupMetadata):
         self.seq_group_metadata_list.append(seq_group_metadata)
diff --git a/vllm/worker/model_runner.py b/vllm/worker/model_runner.py
index 2b545d1b28bd2..51e1aced2f8c4 100644
--- a/vllm/worker/model_runner.py
+++ b/vllm/worker/model_runner.py
@@ -448,7 +448,7 @@ def __init__(self,
 
         self.runner = runner
         self.model_input_cls = self.runner._model_input_cls
-        self.attn_backend = self.runner.attn_backend
+        self.attn_backend: AttentionBackend = self.runner.attn_backend
         self.scheduler_config = self.runner.scheduler_config
         self.sliding_window = self.runner.sliding_window
         self.block_size = self.runner.block_size
@@ -1048,14 +1048,14 @@ def __init__(
         needs_attn_backend = (num_attn_heads != 0
                               or self.model_config.is_attention_free)
 
-        self.attn_backend = get_attn_backend(
+        self.attn_backend: Optional[AttentionBackend] = get_attn_backend(
             self.model_config.get_head_size(),
             self.model_config.dtype,
             self.kv_cache_dtype,
             self.block_size,
             self.model_config.is_attention_free,
         ) if needs_attn_backend else None
-        if self.attn_backend:
+        if self.attn_backend is not None:
             self.attn_state = self.attn_backend.get_state_cls()(
                 weakref.proxy(self))
         else:
@@ -1481,6 +1481,7 @@ def capture_model(self, kv_caches: List[List[torch.Tensor]]) -> None:
                         )
                         self.set_active_prompt_adapters(
                             set(), prompt_adapter_mapping)
+                    assert isinstance(self.attn_backend, AttentionBackend)
                     graph_runner = CUDAGraphRunner(
                         self.model, self.attn_backend.get_name(),
                         self.attn_state.graph_clone(batch_size),
diff --git a/vllm/worker/multi_step_model_runner.py b/vllm/worker/multi_step_model_runner.py
index dee63a75c0605..1dac08d4e1c73 100644
--- a/vllm/worker/multi_step_model_runner.py
+++ b/vllm/worker/multi_step_model_runner.py
@@ -313,6 +313,8 @@ def __init__(self, base_model_runner: GPUModelRunnerBase, *args, **kwargs):
         supported_attention_backends: List[str] = \
             _get_supported_attention_backends(
                 self.scheduler_config.chunked_prefill_enabled)
+
+        assert isinstance(self.attn_backend, AttentionBackend)
         if self.attn_backend.get_name() not in supported_attention_backends:
             ms_config_str: str = "Multi-Step + Chunked-Prefill" \
                 if self.scheduler_config.chunked_prefill_enabled \
diff --git a/vllm/worker/openvino_worker.py b/vllm/worker/openvino_worker.py
index 0bf522d5333ed..782eca9ccdb6d 100644
--- a/vllm/worker/openvino_worker.py
+++ b/vllm/worker/openvino_worker.py
@@ -371,10 +371,14 @@ def execute_model(
         else:
             seq_group_metadata_list = execute_model_req.seq_group_metadata_list
 
+        blocks_to_copy: List[Tuple[int, int]]
+        blocks_to_swap_in: List[Tuple[int, int]]
+        blocks_to_swap_out: List[Tuple[int, int]]
+
         if self.is_driver_worker:
             assert seq_group_metadata_list is not None
             num_seq_groups: int = len(seq_group_metadata_list)
-            assert execute_model_req is not None
+            assert isinstance(execute_model_req, ExecuteModelRequest)
             blocks_to_copy = execute_model_req.blocks_to_copy
             blocks_to_swap_in = execute_model_req.blocks_to_swap_in
             blocks_to_swap_out = execute_model_req.blocks_to_swap_out
@@ -393,8 +397,8 @@ def execute_model(
             blocks_to_swap_out = data["blocks_to_swap_out"]
 
         if current_platform.is_openvino_cpu():
-            assert len(execute_model_req.blocks_to_swap_in) == 0
-            assert len(execute_model_req.blocks_to_swap_out) == 0
+            assert len(blocks_to_swap_in) == 0
+            assert len(blocks_to_swap_out) == 0
         else:
             self.cache_swap_in(blocks_to_swap_in)
             self.cache_swap_out(blocks_to_swap_out)