diff --git a/litellm/proxy/_lazy_openapi_snapshot.json b/litellm/proxy/_lazy_openapi_snapshot.json
index 545b317055a..84e12bdfa9d 100644
--- a/litellm/proxy/_lazy_openapi_snapshot.json
+++ b/litellm/proxy/_lazy_openapi_snapshot.json
@@ -28238,6 +28238,9 @@
                       {
                         "$ref": "#/components/schemas/CustomToolCallOutputItem"
                       },
+                      {
+                        "$ref": "#/components/schemas/ResponseReasoningItem"
+                      },
                       {
                         "$ref": "#/components/schemas/OutputToolSearchCall"
                       }
diff --git a/litellm/responses/litellm_completion_transformation/transformation.py b/litellm/responses/litellm_completion_transformation/transformation.py
index d9ebf50cc1a..f2b1abbe236 100644
--- a/litellm/responses/litellm_completion_transformation/transformation.py
+++ b/litellm/responses/litellm_completion_transformation/transformation.py
@@ -28,8 +28,13 @@ from openai.types.chat.chat_completion_named_tool_choice_param import (
 from openai.types.chat.chat_completion_named_tool_choice_param import (
     Function as NamedToolChoiceFunction,
 )
-from openai.types.responses import ResponseFunctionToolCall, ResponseFunctionWebSearch
+from openai.types.responses import (
+    ResponseFunctionToolCall,
+    ResponseFunctionWebSearch,
+    ResponseReasoningItem,
+)
 from openai.types.responses.response_create_params import ResponseInputParam
+from openai.types.responses.response_reasoning_item import Content as ReasoningContent
 from openai.types.responses.tool_choice_custom_param import ToolChoiceCustomParam
 from openai.types.responses.tool_choice_function_param import ToolChoiceFunctionParam
 from openai.types.responses.tool_param import FunctionToolParam
@@ -3037,6 +3042,7 @@ class LiteLLMCompletionResponsesConfig:
         | ResponseFunctionToolCall
         | ResponseFunctionWebSearch
         | CustomToolCallOutputItem
+        | ResponseReasoningItem
         | OutputToolSearchCall
     ]:
         responses_output: list[
@@ -3047,6 +3053,7 @@ class LiteLLMCompletionResponsesConfig:
             | ResponseFunctionToolCall
             | ResponseFunctionWebSearch
             | CustomToolCallOutputItem
+            | ResponseReasoningItem
             | OutputToolSearchCall
         ] = []
 
@@ -3124,7 +3131,7 @@ class LiteLLMCompletionResponsesConfig:
     def _extract_reasoning_output_items(
         chat_completion_response: ModelResponse,
         choices: list[Choices],
-    ) -> list[GenericResponseOutputItem]:
+    ) -> list[ResponseReasoningItem]:
         for choice in choices:
             if hasattr(choice, "message") and choice.message:
                 message = choice.message
@@ -3133,22 +3140,23 @@ class LiteLLMCompletionResponsesConfig:
                 if reasoning_content or encrypted_content:
                     # Only check the first choice for reasoning content
                     return [
-                        GenericResponseOutputItem(
+                        ResponseReasoningItem(
                             type="reasoning",
                             id=mint_reasoning_item_id(),
-                            status=LiteLLMCompletionResponsesConfig._map_chat_completion_finish_reason_to_responses_status(
-                                choice.finish_reason
-                            ),
-                            role="assistant",
+                            # summary is required by the SDK/spec; the bridge has
+                            # no summarized reasoning, so it stays empty
+                            summary=[],
                             content=[
-                                OutputText(
-                                    type="output_text",
-                                    text=text,
-                                    annotations=[],
-                                )
+                                ReasoningContent(type="reasoning_text", text=text)
                                 for text in (reasoning_content,)
                                 if text
                             ],
+                            status=cast(  # cast-ok: the map only returns completed/incomplete, both valid for a reasoning item's narrower status union
+                                "Literal['in_progress', 'completed', 'incomplete']",
+                                LiteLLMCompletionResponsesConfig._map_chat_completion_finish_reason_to_responses_status(
+                                    choice.finish_reason
+                                ),
+                            ),
                             encrypted_content=encrypted_content,
                         )
                     ]
diff --git a/litellm/types/llms/openai.py b/litellm/types/llms/openai.py
index 8dbc0d97d54..cf3e4ec5c4f 100644
--- a/litellm/types/llms/openai.py
+++ b/litellm/types/llms/openai.py
@@ -64,6 +64,7 @@ from openai.types.responses.response_create_params import (
 )
 from openai.types.responses.response_function_tool_call import ResponseFunctionToolCall
 from openai.types.responses.response_function_web_search import ResponseFunctionWebSearch
+from openai.types.responses.response_reasoning_item import ResponseReasoningItem
 from pydantic import (
     ConfigDict,
     Discriminator,
@@ -1487,6 +1488,7 @@ class ResponsesAPIResponse(BaseLiteLLMOpenAIResponseObject):
             | ResponseFunctionToolCall
             | ResponseFunctionWebSearch
             | CustomToolCallOutputItem
+            | ResponseReasoningItem
             | OutputToolSearchCall
         ]
     )
diff --git a/tests/unit/responses/litellm_completion_transformation/test_litellm_completion_responses.py b/tests/unit/responses/litellm_completion_transformation/test_litellm_completion_responses.py
index f34ca7d0ff8..66f677afe57 100644
--- a/tests/unit/responses/litellm_completion_transformation/test_litellm_completion_responses.py
+++ b/tests/unit/responses/litellm_completion_transformation/test_litellm_completion_responses.py
@@ -307,9 +307,10 @@ class TestLiteLLMCompletionResponsesConfig:
         if hasattr(reasoning_item, "id") and reasoning_item.id:
             assert reasoning_item.id.startswith("rs_"), f"Expected ID to start with 'rs_', got: {reasoning_item.id}"
         assert reasoning_item.status == "completed"
-        assert reasoning_item.role == "assistant"
+        assert reasoning_item.summary == []
+        assert not hasattr(reasoning_item, "role")
         assert len(reasoning_item.content) == 1
-        assert reasoning_item.content[0].type == "output_text"
+        assert reasoning_item.content[0].type == "reasoning_text"
         assert "step by step" in reasoning_item.content[0].text
         assert "42" in reasoning_item.content[0].text
 
@@ -319,6 +320,76 @@ class TestLiteLLMCompletionResponsesConfig:
         message_item = message_items[0]
         assert message_item.content[0].text == "The answer is 42."
 
+    def test_reasoning_output_items_validate_against_openai_sdk(self):
+        """Bridged reasoning items must carry a summary array and reasoning_text
+        content parts so ResponseReasoningItem accepts them (issue #45552)."""
+        from openai.types.responses import ResponseReasoningItem
+
+        chat_completion_response = ModelResponse(
+            id="test-response-id",
+            created=1234567890,
+            model="test-model",
+            object="chat.completion",
+            choices=[
+                Choices(
+                    finish_reason="stop",
+                    index=0,
+                    message=Message(
+                        content="The answer is 42.",
+                        role="assistant",
+                        reasoning_content="Thinking about the question.",
+                    ),
+                )
+            ],
+        )
+
+        responses_api_response = LiteLLMCompletionResponsesConfig.transform_chat_completion_response_to_responses_api_response(
+            request_input="What is the meaning of life?",
+            responses_api_request={},
+            chat_completion_response=chat_completion_response,
+        )
+
+        reasoning_items = [
+            item for item in responses_api_response.output if item.type == "reasoning"
+        ]
+        assert len(reasoning_items) == 1
+
+        dumped = reasoning_items[0].model_dump(mode="json")
+        assert dumped["summary"] == []
+        assert dumped["content"][0]["type"] == "reasoning_text"
+        assert "role" not in dumped
+        assert "phase" not in dumped
+
+        validated = ResponseReasoningItem.model_validate(dumped)
+        assert validated.summary == []
+
+    def test_reasoning_output_item_without_text_still_validates(self):
+        """Encrypted-only reasoning (empty content) must still carry summary: [] and
+        validate against the SDK (issue #45552, display: omitted case)."""
+        from openai.types.responses import ResponseReasoningItem
+
+        message = Message(role="assistant", content="apple")
+        message.thinking_blocks = [
+            {"type": "thinking", "thinking": "", "signature": "sig"}
+        ]
+        choice = Choices(index=0, finish_reason="stop", message=message)
+
+        items = LiteLLMCompletionResponsesConfig._extract_reasoning_output_items(
+            chat_completion_response=ModelResponse(
+                id="test-response-id",
+                created=1234567890,
+                model="test-model",
+                object="chat.completion",
+            ),
+            choices=[choice],
+        )
+
+        assert len(items) == 1
+        dumped = items[0].model_dump(mode="json")
+        assert dumped["summary"] == []
+        assert dumped["content"] == []
+        ResponseReasoningItem.model_validate(dumped)
+
     def test_transform_chat_completion_response_without_reasoning_content(self):
         """Test that transformation works normally when no reasoning content is present"""
         # Setup
diff --git a/ui/litellm-dashboard/src/lib/http/schema.d.ts b/ui/litellm-dashboard/src/lib/http/schema.d.ts
index 2b174a1141a..ad1688acf59 100644
--- a/ui/litellm-dashboard/src/lib/http/schema.d.ts
+++ b/ui/litellm-dashboard/src/lib/http/schema.d.ts
@@ -44279,7 +44279,7 @@ export interface components {
             /** Output */
             output: (components["schemas"]["ResponseOutputMessage"] | components["schemas"]["ResponseFileSearchToolCall"] | components["schemas"]["ResponseFunctionToolCall"] | components["schemas"]["ResponseFunctionToolCallOutputItem"] | components["schemas"]["ResponseFunctionWebSearch"] | components["schemas"]["ResponseComputerToolCall"] | components["schemas"]["ResponseComputerToolCallOutputItem"] | components["schemas"]["ResponseReasoningItem"] | components["schemas"]["ResponseToolSearchCall"] | components["schemas"]["ResponseToolSearchOutputItem"] | components["schemas"]["ResponseCompactionItem"] | components["schemas"]["ImageGenerationCall"] | components["schemas"]["ResponseCodeInterpreterToolCall"] | components["schemas"]["LocalShellCall"] | components["schemas"]["LocalShellCallOutput"] | components["schemas"]["ResponseFunctionShellToolCall"] | components["schemas"]["ResponseFunctionShellToolCallOutput"] | components["schemas"]["ResponseApplyPatchToolCall"] | components["schemas"]["ResponseApplyPatchToolCallOutput"] | components["schemas"]["McpCall"] | components["schemas"]["McpListTools"] | components["schemas"]["McpApprovalRequest"] | components["schemas"]["McpApprovalResponse"] | components["schemas"]["ResponseCustomToolCall"] | components["schemas"]["ResponseCustomToolCallOutputItem"] | {
                 [key: string]: unknown;
-            })[] | (components["schemas"]["GenericResponseOutputItem"] | components["schemas"]["OutputCodeInterpreterCall"] | components["schemas"]["OutputFunctionToolCall"] | components["schemas"]["OutputImageGenerationCall"] | components["schemas"]["ResponseFunctionToolCall"] | components["schemas"]["ResponseFunctionWebSearch"] | components["schemas"]["CustomToolCallOutputItem"] | components["schemas"]["OutputToolSearchCall"])[];
+            })[] | (components["schemas"]["GenericResponseOutputItem"] | components["schemas"]["OutputCodeInterpreterCall"] | components["schemas"]["OutputFunctionToolCall"] | components["schemas"]["OutputImageGenerationCall"] | components["schemas"]["ResponseFunctionToolCall"] | components["schemas"]["ResponseFunctionWebSearch"] | components["schemas"]["CustomToolCallOutputItem"] | components["schemas"]["ResponseReasoningItem"] | components["schemas"]["OutputToolSearchCall"])[];
             /** Parallel Tool Calls */
             parallel_tool_calls?: boolean | null;
             /** Previous Response Id */