fix(azure): strip litellm format field from file and image content parts

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

litellm/litellm_core_utils/prompt_templates/factory.py

@@ -1067,6 +1067,13 @@ def _azure_tool_call_invoke_helper(
 def _azure_image_url_helper(content: ChatCompletionImageObject):
     if isinstance(content["image_url"], str):
         content["image_url"] = {"url": content["image_url"]}
+    elif isinstance(content["image_url"], dict):
+        content["image_url"].pop("format", None)
+
+
+def _azure_file_helper(content: ChatCompletionFileObject) -> None:
+    if isinstance(content.get("file"), dict):
+        content["file"].pop("format", None)
 
 
 def convert_to_azure_openai_messages(
@@ -1082,6 +1089,8 @@ def convert_to_azure_openai_messages(
             for content in m.get("content", []):
                 if isinstance(content, dict) and content.get("type") == "image_url":
                     _azure_image_url_helper(content)
+                elif isinstance(content, dict) and content.get("type") == "file":
+                    _azure_file_helper(content)
     return messages
 
 

tests/test_litellm/litellm_core_utils/prompt_templates/test_litellm_core_utils_prompt_templates_factory.py

@@ -297,6 +297,37 @@ def test_convert_to_azure_openai_messages():
     assert content == expected_content
 
 
+def test_convert_to_azure_openai_messages_strips_litellm_format_from_file_and_image():
+    """Managed file ids write file.format = MIME type, which Azure rejects"""
+
+    from litellm.litellm_core_utils.prompt_templates.factory import (
+        convert_to_azure_openai_messages,
+    )
+    from litellm.types.llms.openai import AllMessageValues
+
+    input: list[AllMessageValues] = [
+        {
+            "role": "user",
+            "content": [
+                {
+                    "type": "file",
+                    "file": {"file_id": "assistant-xyz", "format": "application/pdf"},
+                },
+                {
+                    "type": "image_url",
+                    "image_url": {"url": "https://x/y.png", "format": "image/png"},
+                },
+            ],
+        }
+    ]
+
+    output = convert_to_azure_openai_messages(input)
+
+    content = output[0].get("content")
+    assert content[0]["file"] == {"file_id": "assistant-xyz"}
+    assert content[1]["image_url"] == {"url": "https://x/y.png"}
+
+
 def test_bedrock_validate_format_image_or_video():
     """Test the _validate_format method for images, videos, and documents"""
 

tests/test_litellm/llms/azure/chat/test_azure_chat_gpt_transformation.py

@@ -307,3 +307,38 @@ class TestAzureToolSchemaCombinatorFlattening:
         )
         assert "tools" not in request
         assert request["temperature"] == 0.2
+
+
+def test_transform_request_strips_litellm_format_from_managed_file_id():
+    """update_messages_with_model_file_ids writes file.format = MIME type, which Azure rejects"""
+    import base64
+
+    from litellm.litellm_core_utils.prompt_templates.common_utils import (
+        update_messages_with_model_file_ids,
+    )
+
+    managed_file_id: Final = base64.b64encode(
+        b"litellm_proxy:application/pdf;unified_id,abc123;llm_output_file_id,assistant-xyz;target_model_names,azure-gpt"
+    ).decode()
+    messages = [
+        {
+            "role": "user",
+            "content": [
+                {"type": "text", "text": "Summarize this file"},
+                {"type": "file", "file": {"file_id": managed_file_id}},
+            ],
+        }
+    ]
+    messages = update_messages_with_model_file_ids(messages, None, {})
+
+    request = AzureOpenAIConfig().transform_request(
+        model="gpt-5.4",
+        messages=messages,
+        optional_params={},
+        litellm_params={},
+        headers={},
+    )
+
+    file_part = request["messages"][0]["content"][1]["file"]
+    assert "format" not in file_part
+    assert file_part["file_id"] == "assistant-xyz"