diff --git a/backend/tests/test_knowledge_management_extension.py b/backend/tests/test_knowledge_management_extension.py
index 7d6c5d61ec..c5b53ee330 100644
--- a/backend/tests/test_knowledge_management_extension.py
+++ b/backend/tests/test_knowledge_management_extension.py
@@ -229,6 +229,29 @@ async def test_router_upload_is_bounded_and_errors_are_sanitized(api, monkeypatc
         assert len(calls) == 1
 
 
+@pytest.mark.parametrize(
+    "content_type",
+    [
+        "Application/Octet-Stream; charset=binary",
+        "application/octet-stream ; charset=binary",
+        "APPLICATION/OCTET-STREAM",
+    ],
+    ids=["mixed-case-with-parameter", "space-before-parameter", "uppercase"],
+)
+@pytest.mark.asyncio
+async def test_router_upload_accepts_normalized_media_type(api, content_type):
+    app, _, calls, _ = api
+    async with httpx.AsyncClient(transport=httpx.ASGITransport(app=app), base_url="http://test") as client:
+        response = await client.post(
+            API_BASE + "/files?filename=guide.txt",
+            content=b"knowledge",
+            headers={"content-type": content_type},
+        )
+
+    assert response.status_code == 202
+    assert calls[-1].url.path.endswith("/file")
+
+
 @pytest.mark.asyncio
 async def test_router_fails_closed_without_host_resolver(api):
     from deerflow_extension_api.auth import EXTENSION_PRINCIPAL_RESOLVER_KEY
diff --git a/examples/deerflow-extension-knowledge-management/deerflow_extension_knowledge_management/router.py b/examples/deerflow-extension-knowledge-management/deerflow_extension_knowledge_management/router.py
index dc3105d2df..6a0d14874f 100644
--- a/examples/deerflow-extension-knowledge-management/deerflow_extension_knowledge_management/router.py
+++ b/examples/deerflow-extension-knowledge-management/deerflow_extension_knowledge_management/router.py
@@ -74,7 +74,8 @@ def build_router(provider: ManagementProvider) -> APIRouter:
 
     @router.post(prefix + "/files", status_code=202)
     async def upload(request: Request, connection: str, base: str, filename: str, context: ManagementContext = Depends(_context)):
-        if request.headers.get("content-type", "").split(";", 1)[0] != "application/octet-stream":
+        media_type = request.headers.get("content-type", "").split(";", 1)[0].strip().lower()
+        if media_type != "application/octet-stream":
             raise HTTPException(415, "Use application/octet-stream")
         try:
             options = ProcessingOptions.model_validate_json(request.headers.get("x-processing-options", "{}"))