diff --git a/app/auth.py b/app/auth.py
index d6b2ec39..0e39c95b 100644
--- a/app/auth.py
+++ b/app/auth.py
@@ -83,11 +83,14 @@ def require_login(func):
         if not request.session.get("user"):
             request.session["redirect_after_login"] = str(request.url)
             return RedirectResponse(url="/login", status_code=status.HTTP_302_FOUND)
-        # Check if the wrapped function is a coroutine function
+        # Pass request as a keyword argument so that endpoints whose first
+        # parameter is a path variable (e.g. pipeline_id) are not accidentally
+        # bound to the request object when FastAPI supplies all arguments as
+        # keyword arguments.
         if inspect.iscoroutinefunction(func):
-            return await func(request, *args, **kwargs)
+            return await func(*args, request=request, **kwargs)
         else:
-            return func(request, *args, **kwargs)
+            return func(*args, request=request, **kwargs)
 
     return wrapper
 
diff --git a/tests/test_auth.py b/tests/test_auth.py
index c16fe318..ccb2dd7c 100644
--- a/tests/test_auth.py
+++ b/tests/test_auth.py
@@ -1,5 +1,6 @@
 """Tests for app/auth.py module."""
 
+import asyncio
 import hashlib
 from unittest.mock import AsyncMock, MagicMock, patch
 
@@ -168,13 +169,54 @@ class TestRequireLogin:
             mock_request.session = {"user": {"id": "test"}}
 
             # Call the decorated sync function
-            import asyncio
-
             result = asyncio.run(sync_endpoint(request=mock_request, param="test_value"))
 
             assert result["message"] == "sync"
             assert result["param"] == "test_value"
 
+    @pytest.mark.asyncio
+    async def test_path_param_before_request_async(self):
+        """Regression: endpoints with a path param before request must not get
+        'multiple values for argument' when AUTH_ENABLED=True.
+
+        FastAPI passes all resolved parameters as keyword arguments to the
+        wrapper.  The wrapper must forward ``request`` as a keyword argument
+        too, otherwise the positional ``request`` object would bind to the
+        first parameter (e.g. ``pipeline_id``) while FastAPI simultaneously
+        supplies ``pipeline_id`` as a keyword argument → TypeError.
+        """
+        with patch("app.auth.AUTH_ENABLED", True):
+            from app.auth import require_login
+
+            @require_login
+            async def endpoint_with_path_param(pipeline_id: int, request: Request, extra: str = ""):
+                return {"pipeline_id": pipeline_id, "extra": extra}
+
+            mock_request = MagicMock(spec=Request)
+            mock_request.session = {"user": {"id": "test"}}
+
+            # Simulate how FastAPI calls the wrapper: all args as keyword args.
+            result = await endpoint_with_path_param(request=mock_request, pipeline_id=42, extra="hello")
+
+            assert result["pipeline_id"] == 42
+            assert result["extra"] == "hello"
+
+    def test_path_param_before_request_sync(self):
+        """Regression: same as above but for synchronous endpoint functions."""
+        with patch("app.auth.AUTH_ENABLED", True):
+            from app.auth import require_login
+
+            @require_login
+            def sync_endpoint_with_path_param(item_id: int, request: Request):
+                return {"item_id": item_id}
+
+            mock_request = MagicMock(spec=Request)
+            mock_request.session = {"user": {"id": "test"}}
+
+            result = asyncio.run(sync_endpoint_with_path_param(request=mock_request, item_id=7))
+
+            assert result["item_id"] == 7
+
 
 @pytest.mark.integration
 class TestWhoamiEndpoint: