fix(mcp): bind inherited preview credentials to the saved origin

litellm/proxy/_experimental/mcp_server/rest_endpoints.py

@@ -1255,7 +1255,18 @@ if MCP_AVAILABLE:
             MCPRequestHandler,
         )
 
-        request: Final = _inherit_credentials_from_existing_server(new_mcp_server_request)
+        saved_server: Final = (
+            global_mcp_server_manager.get_mcp_server_by_id(new_mcp_server_request.server_id)
+            if new_mcp_server_request.server_id
+            else None
+        )
+        saved_origin: Final = _redact_mcp_resource_url(saved_server.url) if saved_server else None
+        may_inherit: Final = new_mcp_server_request.auth_type not in _STAGED_AUTH_VALUE_AUTH_TYPES or (
+            saved_origin is not None and saved_origin == _redact_mcp_resource_url(new_mcp_server_request.url)
+        )
+        request: Final = (
+            _inherit_credentials_from_existing_server(new_mcp_server_request) if may_inherit else new_mcp_server_request
+        )
         mcp_auth_header: Final = (
             request.credentials.get("auth_value")
             if request.auth_type in _STAGED_AUTH_VALUE_AUTH_TYPES and isinstance(request.credentials, dict)

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

@@ -128,7 +128,7 @@ class TestExecuteWithMcpClient:
         payload: Final = NewMCPServerRequest(
             server_id=saved.server_id,
             server_name="edited",
-            url="https://edited.example/mcp",
+            url="https://stored.example/corrected-mcp",
             transport=MCPTransport.sse,
             auth_type=auth_type,
             credentials={"auth_value": auth_value} if auth_value is not None else None,
@@ -146,13 +146,48 @@ class TestExecuteWithMcpClient:
             oauth2_headers=staged.oauth2_headers,
         )
         assert result == {
-            "url": "https://edited.example/mcp",
+            "url": "https://stored.example/corrected-mcp",
             "transport": MCPTransport.sse,
             "headers": {"X-Preview": "edited", **expected_auth},
         }
         assert manager.get_mcp_server_by_id(saved.server_id) is saved
         assert saved.url == "https://stored.example/mcp"
 
+    @pytest.mark.parametrize(
+        "url", ("https://other.example/mcp", "http://stored.example/mcp", "https://stored.example:8443/mcp")
+    )
+    @pytest.mark.parametrize("explicit_credential", (None, "preview:explicit"))
+    def test_static_preview_does_not_inherit_credentials_across_origins(
+        self, monkeypatch: pytest.MonkeyPatch, url: str, explicit_credential: str | None
+    ) -> None:
+        from starlette.datastructures import Headers
+
+        from litellm.proxy._experimental.mcp_server.mcp_server_manager import MCPServerManager
+        from litellm.proxy.management_endpoints import mcp_management_endpoints
+
+        saved: Final = MCPServer(
+            server_id="saved-preview-server",
+            name="saved",
+            url="https://stored.example/mcp",
+            transport=MCPTransport.http,
+            auth_type=MCPAuth.basic,
+            authentication_token="preview:stored",
+        )
+        manager: Final = MCPServerManager()
+        manager.registry = {saved.server_id: saved}
+        monkeypatch.setattr(rest_endpoints, "global_mcp_server_manager", manager)
+        monkeypatch.setattr(mcp_management_endpoints, "global_mcp_server_manager", manager)
+        payload: Final = NewMCPServerRequest(
+            server_id=saved.server_id,
+            url=url,
+            transport=MCPTransport.http,
+            auth_type=MCPAuth.basic,
+            credentials={"auth_value": explicit_credential} if explicit_credential else None,
+        )
+        staged: Final = rest_endpoints._stage_server_test(payload, Headers())
+        assert staged.mcp_auth_header == explicit_credential
+        assert staged.request.credentials == payload.credentials
+
     @pytest.mark.asyncio
     async def test_redacts_stack_trace(self, monkeypatch):
         async def fake_create_client(*args, **kwargs):

ui/litellm-dashboard/src/app/(dashboard)/mcp-servers/_components/editToolPreview.test.ts

@@ -14,10 +14,10 @@ describe("getEditToolPreview", () => {
   });
 
   it("previews URL changes with the existing server credential left for server-side inheritance", () => {
-    expect(getEditToolPreview({ ...saved, url: "https://correct.example/mcp" }, saved)).toEqual({
+    expect(getEditToolPreview({ ...saved, url: "https://example.com/corrected-mcp" }, saved)).toEqual({
       kind: "preview",
       config: {
-        url: "https://correct.example/mcp",
+        url: "https://example.com/corrected-mcp",
         transport: "http",
         auth_type: "basic",
         static_headers: { "X-Tenant": "original" },
@@ -26,6 +26,24 @@ describe("getEditToolPreview", () => {
     });
   });
 
+  it.each(["https://other.example/mcp", "http://example.com/mcp", "https://example.com:8443/mcp"])(
+    "requires explicit credentials for a changed origin: %s",
+    (url) => {
+      expect(getEditToolPreview({ ...saved, url, static_headers: [] }, saved)).toEqual({
+        kind: "incomplete",
+        message: expect.stringContaining("origin changed"),
+      });
+      const explicit = { ...saved, url, static_headers: [], credentials: { auth_value: "new:secret" } };
+      expect(getEditToolPreview(explicit, saved).kind).toBe("preview");
+    },
+  );
+
+  it("does not automatically send saved static headers to a new origin", () => {
+    expect(getEditToolPreview({ ...saved, url: "https://other.example/mcp", auth_type: "none" }, saved).kind).toBe(
+      "incomplete",
+    );
+  });
+
   it("uses edited static headers and only the static auth value", () => {
     expect(
       getEditToolPreview(

ui/litellm-dashboard/src/app/(dashboard)/mcp-servers/_components/editToolPreview.ts

@@ -21,7 +21,7 @@ const connectionConfig = (values: Readonly<Record<string, unknown>>) => {
 
 type EditToolPreview =
   | { readonly kind: "saved" }
-  | { readonly kind: "incomplete" }
+  | { readonly kind: "incomplete"; readonly message?: string }
   | { readonly kind: "preview"; readonly config: ReturnType<typeof connectionConfig> };
 
 export const getEditToolPreview = (
@@ -49,5 +49,19 @@ export const getEditToolPreview = (
   if (!validUrl || missingNewCredential || incompleteHeaders) {
     return { kind: "incomplete" };
   }
+  const savedConfig = connectionConfig(initialValues);
+  const changedOrigin =
+    !URL.canParse(savedConfig.url) || new URL(config.url).origin !== new URL(savedConfig.url).origin;
+  const reusesHeader = Object.entries(config.static_headers).some(
+    ([key, value]) => savedConfig.static_headers[key] === value,
+  );
+  const needsSavedCredential = AUTH_TYPES_REQUIRING_AUTH_VALUE.includes(config.auth_type) && !config.credentials;
+  if (changedOrigin && (needsSavedCredential || reusesHeader)) {
+    return {
+      kind: "incomplete",
+      message:
+        "The server origin changed. Enter credentials and replace or remove saved static headers to preview tools.",
+    };
+  }
   return { kind: "preview", config };
 };

ui/litellm-dashboard/src/app/(dashboard)/mcp-servers/_components/mcp_server_edit.tsx

@@ -454,19 +454,22 @@ const MCPServerEdit: React.FC<MCPServerEditProps> = ({
   const toolPreviewKey = JSON.stringify(toolPreview);
 
   useEffect(() => {
-    let active = true;
+    const controller = new AbortController();
     setTools([]);
     setToolsError(null);
     setIsLoadingTools(false);
     if (!accessToken || !mcpServer.server_id) return;
     if (toolPreview.kind === "incomplete") {
-      setToolsError("Complete the URL, authentication, and header settings to load tools.");
+      setToolsError(toolPreview.message ?? "Complete the URL, authentication, and header settings to load tools.");
       return;
     }
     setIsLoadingTools(true);
-    const timer = setTimeout(() => fetchTools(() => active), toolPreview.kind === "preview" ? 500 : 0);
+    const timer = setTimeout(
+      () => fetchTools(() => !controller.signal.aborted),
+      toolPreview.kind === "preview" ? 500 : 0,
+    );
     return () => {
-      active = false;
+      controller.abort();
       clearTimeout(timer);
     };
     // eslint-disable-next-line react-hooks/exhaustive-deps