fix(mcp): strip scheme default port from get_request_base_url netloc

litellm/proxy/_experimental/mcp_server/oauth_utils.py

@@ -129,7 +129,7 @@ def get_request_base_url(request: Request) -> str:
         if x_forwarded_port and ":" not in netloc:
             netloc = f"{netloc}:{x_forwarded_port}"
 
-    return urlunparse((scheme, netloc, parsed.path, "", "", ""))
+    return urlunparse((scheme, _strip_default_port(scheme, netloc), parsed.path, "", "", ""))
 
 
 def validate_loopback_redirect_uri(redirect_uri: str) -> None:

tests/test_litellm/proxy/_experimental/mcp_server/test_discoverable_endpoints.py

@@ -1848,6 +1848,41 @@ async def test_token_endpoint_respects_x_forwarded_host():
             None,
             "https://external.com",
         ),
+        (
+            "http://localhost:4000/",
+            "https",
+            "proxy.example.com",
+            "443",
+            "https://proxy.example.com",
+        ),
+        (
+            "http://localhost:4000/",
+            "http",
+            "proxy.example.com",
+            "80",
+            "http://proxy.example.com",
+        ),
+        (
+            "http://internal.local/",
+            "https",
+            None,
+            "443",
+            "https://internal.local",
+        ),
+        (
+            "http://localhost:4000/",
+            "https",
+            "proxy.example.com",
+            "8443",
+            "https://proxy.example.com:8443",
+        ),
+        (
+            "http://localhost:4000/",
+            "https",
+            "proxy.example.com:443",
+            None,
+            "https://proxy.example.com",
+        ),
     ],
 )
 def test_get_request_base_url_comprehensive(