diff --git a/client-sdks/stainless/openapi.yml b/client-sdks/stainless/openapi.yml
index 51607d92d..7b19b14d3 100644
--- a/client-sdks/stainless/openapi.yml
+++ b/client-sdks/stainless/openapi.yml
@@ -4157,6 +4157,16 @@ components:
             type: array
           - type: 'null'
           nullable: true
+        reasoning_content:
+          anyOf:
+          - type: string
+          - type: 'null'
+          nullable: true
+        reasoning:
+          anyOf:
+          - type: string
+          - type: 'null'
+          nullable: true
       title: OpenAIAssistantMessageParam
       type: object
     OpenAIChatCompletionContentPartImageParam:
@@ -4224,6 +4234,11 @@ components:
             title: OpenAIChatCompletionToolCallFunction
           - type: 'null'
           title: OpenAIChatCompletionToolCallFunction
+        extra_content:
+          anyOf:
+          - additionalProperties: true
+            type: object
+          - type: 'null'
       type: object
       title: OpenAIChatCompletionToolCall
       description: Tool call specification for OpenAI-compatible chat completion responses.
@@ -4886,6 +4901,11 @@ components:
           - type: string
           - type: 'null'
           nullable: true
+        reasoning:
+          anyOf:
+          - type: string
+          - type: 'null'
+          nullable: true
       title: OpenAIChoiceDelta
       type: object
     OpenAIChunkChoice:
@@ -11753,6 +11773,14 @@ components:
               $ref: '#/components/schemas/OpenAIChatCompletionToolCall'
             type: array
           - type: 'null'
+        reasoning_content:
+          anyOf:
+          - type: string
+          - type: 'null'
+        reasoning:
+          anyOf:
+          - type: string
+          - type: 'null'
       type: object
       title: OpenAIAssistantMessageParam
       description: A message containing the model's (assistant) response in an OpenAI-compatible chat completion request.
@@ -11782,6 +11810,14 @@ components:
               $ref: '#/components/schemas/OpenAIChatCompletionToolCall'
             type: array
           - type: 'null'
+        reasoning_content:
+          anyOf:
+          - type: string
+          - type: 'null'
+        reasoning:
+          anyOf:
+          - type: string
+          - type: 'null'
       type: object
       title: OpenAIAssistantMessageParam
       description: A message containing the model's (assistant) response in an OpenAI-compatible chat completion request.
diff --git a/docs/static/deprecated-llama-stack-spec.yaml b/docs/static/deprecated-llama-stack-spec.yaml
index 2d0ce6e08..6b13c699e 100644
--- a/docs/static/deprecated-llama-stack-spec.yaml
+++ b/docs/static/deprecated-llama-stack-spec.yaml
@@ -1151,6 +1151,16 @@ components:
             type: array
           - type: 'null'
           nullable: true
+        reasoning_content:
+          anyOf:
+          - type: string
+          - type: 'null'
+          nullable: true
+        reasoning:
+          anyOf:
+          - type: string
+          - type: 'null'
+          nullable: true
       title: OpenAIAssistantMessageParam
       type: object
     OpenAIChatCompletionContentPartImageParam:
@@ -1218,6 +1228,11 @@ components:
             title: OpenAIChatCompletionToolCallFunction
           - type: 'null'
           title: OpenAIChatCompletionToolCallFunction
+        extra_content:
+          anyOf:
+          - additionalProperties: true
+            type: object
+          - type: 'null'
       type: object
       title: OpenAIChatCompletionToolCall
       description: Tool call specification for OpenAI-compatible chat completion responses.
@@ -1880,6 +1895,11 @@ components:
           - type: string
           - type: 'null'
           nullable: true
+        reasoning:
+          anyOf:
+          - type: string
+          - type: 'null'
+          nullable: true
       title: OpenAIChoiceDelta
       type: object
     OpenAIChunkChoice:
@@ -8747,6 +8767,14 @@ components:
               $ref: '#/components/schemas/OpenAIChatCompletionToolCall'
             type: array
           - type: 'null'
+        reasoning_content:
+          anyOf:
+          - type: string
+          - type: 'null'
+        reasoning:
+          anyOf:
+          - type: string
+          - type: 'null'
       type: object
       title: OpenAIAssistantMessageParam
       description: A message containing the model's (assistant) response in an OpenAI-compatible chat completion request.
@@ -8776,6 +8804,14 @@ components:
               $ref: '#/components/schemas/OpenAIChatCompletionToolCall'
             type: array
           - type: 'null'
+        reasoning_content:
+          anyOf:
+          - type: string
+          - type: 'null'
+        reasoning:
+          anyOf:
+          - type: string
+          - type: 'null'
       type: object
       title: OpenAIAssistantMessageParam
       description: A message containing the model's (assistant) response in an OpenAI-compatible chat completion request.
diff --git a/docs/static/experimental-llama-stack-spec.yaml b/docs/static/experimental-llama-stack-spec.yaml
index 4d5a43693..b6fff643b 100644
--- a/docs/static/experimental-llama-stack-spec.yaml
+++ b/docs/static/experimental-llama-stack-spec.yaml
@@ -859,6 +859,16 @@ components:
             type: array
           - type: 'null'
           nullable: true
+        reasoning_content:
+          anyOf:
+          - type: string
+          - type: 'null'
+          nullable: true
+        reasoning:
+          anyOf:
+          - type: string
+          - type: 'null'
+          nullable: true
       title: OpenAIAssistantMessageParam
       type: object
     OpenAIChatCompletionContentPartImageParam:
@@ -926,6 +936,11 @@ components:
             title: OpenAIChatCompletionToolCallFunction
           - type: 'null'
           title: OpenAIChatCompletionToolCallFunction
+        extra_content:
+          anyOf:
+          - additionalProperties: true
+            type: object
+          - type: 'null'
       type: object
       title: OpenAIChatCompletionToolCall
       description: Tool call specification for OpenAI-compatible chat completion responses.
@@ -1588,6 +1603,11 @@ components:
           - type: string
           - type: 'null'
           nullable: true
+        reasoning:
+          anyOf:
+          - type: string
+          - type: 'null'
+          nullable: true
       title: OpenAIChoiceDelta
       type: object
     OpenAIChunkChoice:
@@ -7582,6 +7602,14 @@ components:
               $ref: '#/components/schemas/OpenAIChatCompletionToolCall'
             type: array
           - type: 'null'
+        reasoning_content:
+          anyOf:
+          - type: string
+          - type: 'null'
+        reasoning:
+          anyOf:
+          - type: string
+          - type: 'null'
       type: object
       title: OpenAIAssistantMessageParam
       description: A message containing the model's (assistant) response in an OpenAI-compatible chat completion request.
@@ -7611,6 +7639,14 @@ components:
               $ref: '#/components/schemas/OpenAIChatCompletionToolCall'
             type: array
           - type: 'null'
+        reasoning_content:
+          anyOf:
+          - type: string
+          - type: 'null'
+        reasoning:
+          anyOf:
+          - type: string
+          - type: 'null'
       type: object
       title: OpenAIAssistantMessageParam
       description: A message containing the model's (assistant) response in an OpenAI-compatible chat completion request.
diff --git a/docs/static/llama-stack-spec.yaml b/docs/static/llama-stack-spec.yaml
index a593fef85..b79285b41 100644
--- a/docs/static/llama-stack-spec.yaml
+++ b/docs/static/llama-stack-spec.yaml
@@ -2962,6 +2962,16 @@ components:
             type: array
           - type: 'null'
           nullable: true
+        reasoning_content:
+          anyOf:
+          - type: string
+          - type: 'null'
+          nullable: true
+        reasoning:
+          anyOf:
+          - type: string
+          - type: 'null'
+          nullable: true
       title: OpenAIAssistantMessageParam
       type: object
     OpenAIChatCompletionContentPartImageParam:
@@ -3029,6 +3039,11 @@ components:
             title: OpenAIChatCompletionToolCallFunction
           - type: 'null'
           title: OpenAIChatCompletionToolCallFunction
+        extra_content:
+          anyOf:
+          - additionalProperties: true
+            type: object
+          - type: 'null'
       type: object
       title: OpenAIChatCompletionToolCall
       description: Tool call specification for OpenAI-compatible chat completion responses.
@@ -3691,6 +3706,11 @@ components:
           - type: string
           - type: 'null'
           nullable: true
+        reasoning:
+          anyOf:
+          - type: string
+          - type: 'null'
+          nullable: true
       title: OpenAIChoiceDelta
       type: object
     OpenAIChunkChoice:
@@ -10189,6 +10209,14 @@ components:
               $ref: '#/components/schemas/OpenAIChatCompletionToolCall'
             type: array
           - type: 'null'
+        reasoning_content:
+          anyOf:
+          - type: string
+          - type: 'null'
+        reasoning:
+          anyOf:
+          - type: string
+          - type: 'null'
       type: object
       title: OpenAIAssistantMessageParam
       description: A message containing the model's (assistant) response in an OpenAI-compatible chat completion request.
@@ -10218,6 +10246,14 @@ components:
               $ref: '#/components/schemas/OpenAIChatCompletionToolCall'
             type: array
           - type: 'null'
+        reasoning_content:
+          anyOf:
+          - type: string
+          - type: 'null'
+        reasoning:
+          anyOf:
+          - type: string
+          - type: 'null'
       type: object
       title: OpenAIAssistantMessageParam
       description: A message containing the model's (assistant) response in an OpenAI-compatible chat completion request.
diff --git a/docs/static/stainless-llama-stack-spec.yaml b/docs/static/stainless-llama-stack-spec.yaml
index 51607d92d..7b19b14d3 100644
--- a/docs/static/stainless-llama-stack-spec.yaml
+++ b/docs/static/stainless-llama-stack-spec.yaml
@@ -4157,6 +4157,16 @@ components:
             type: array
           - type: 'null'
           nullable: true
+        reasoning_content:
+          anyOf:
+          - type: string
+          - type: 'null'
+          nullable: true
+        reasoning:
+          anyOf:
+          - type: string
+          - type: 'null'
+          nullable: true
       title: OpenAIAssistantMessageParam
       type: object
     OpenAIChatCompletionContentPartImageParam:
@@ -4224,6 +4234,11 @@ components:
             title: OpenAIChatCompletionToolCallFunction
           - type: 'null'
           title: OpenAIChatCompletionToolCallFunction
+        extra_content:
+          anyOf:
+          - additionalProperties: true
+            type: object
+          - type: 'null'
       type: object
       title: OpenAIChatCompletionToolCall
       description: Tool call specification for OpenAI-compatible chat completion responses.
@@ -4886,6 +4901,11 @@ components:
           - type: string
           - type: 'null'
           nullable: true
+        reasoning:
+          anyOf:
+          - type: string
+          - type: 'null'
+          nullable: true
       title: OpenAIChoiceDelta
       type: object
     OpenAIChunkChoice:
@@ -11753,6 +11773,14 @@ components:
               $ref: '#/components/schemas/OpenAIChatCompletionToolCall'
             type: array
           - type: 'null'
+        reasoning_content:
+          anyOf:
+          - type: string
+          - type: 'null'
+        reasoning:
+          anyOf:
+          - type: string
+          - type: 'null'
       type: object
       title: OpenAIAssistantMessageParam
       description: A message containing the model's (assistant) response in an OpenAI-compatible chat completion request.
@@ -11782,6 +11810,14 @@ components:
               $ref: '#/components/schemas/OpenAIChatCompletionToolCall'
             type: array
           - type: 'null'
+        reasoning_content:
+          anyOf:
+          - type: string
+          - type: 'null'
+        reasoning:
+          anyOf:
+          - type: string
+          - type: 'null'
       type: object
       title: OpenAIAssistantMessageParam
       description: A message containing the model's (assistant) response in an OpenAI-compatible chat completion request.
diff --git a/src/llama_stack_api/inference.py b/src/llama_stack_api/inference.py
index 4a169486a..4613fb226 100644
--- a/src/llama_stack_api/inference.py
+++ b/src/llama_stack_api/inference.py
@@ -438,6 +438,7 @@ class OpenAIChatCompletionToolCall(BaseModel):
     id: str | None = None
     type: Literal["function"] = "function"
     function: OpenAIChatCompletionToolCallFunction | None = None
+    extra_content: dict[str, Any] | None = None
 
 
 @json_schema_type
@@ -448,12 +449,16 @@ class OpenAIAssistantMessageParam(BaseModel):
     :param content: The content of the model's response
     :param name: (Optional) The name of the assistant message participant.
     :param tool_calls: List of tool calls. Each tool call is an OpenAIChatCompletionToolCall object.
+    :param reasoning_content: (Optional) The reasoning content from the model (for vLLM ≤ v0.8.4)
+    :param reasoning: (Optional) The reasoning content from the model (for vLLM ≥ v0.9.x)
     """
 
     role: Literal["assistant"] = "assistant"
     content: OpenAIChatCompletionTextOnlyMessageContent | None = None
     name: str | None = None
     tool_calls: list[OpenAIChatCompletionToolCall] | None = None
+    reasoning_content: str | None = None
+    reasoning: str | None = None
 
 
 @json_schema_type
@@ -605,7 +610,8 @@ class OpenAIChoiceDelta(BaseModel):
     :param refusal: (Optional) The refusal of the delta
     :param role: (Optional) The role of the delta
     :param tool_calls: (Optional) The tool calls of the delta
-    :param reasoning_content: (Optional) The reasoning content from the model (non-standard, for o1/o3 models)
+    :param reasoning_content: (Optional) The reasoning content from the model (for vLLM ≤ v0.8.4)
+    :param reasoning: (Optional) The reasoning content from the model (for vLLM ≥ v0.9.x)
     """
 
     content: str | None = None
@@ -613,6 +619,7 @@ class OpenAIChoiceDelta(BaseModel):
     role: str | None = None
     tool_calls: list[OpenAIChatCompletionToolCall] | None = None
     reasoning_content: str | None = None
+    reasoning: str | None = None
 
 
 @json_schema_type