diff --git a/ui/litellm-dashboard/src/components/playground/chat_ui/ChatUI.test.tsx b/ui/litellm-dashboard/src/components/playground/chat_ui/ChatUI.test.tsx
index d992ff0ecb4..8d64d727189 100644
--- a/ui/litellm-dashboard/src/components/playground/chat_ui/ChatUI.test.tsx
+++ b/ui/litellm-dashboard/src/components/playground/chat_ui/ChatUI.test.tsx
@@ -19,7 +19,7 @@ vi.mock("../networking", () => ({
 
 // Mock scrollIntoView which is not available in jsdom
 beforeEach(() => {
-  Element.prototype.scrollIntoView = () => {};
+  Element.prototype.scrollIntoView = () => { };
 });
 
 describe("ChatUI", () => {
@@ -270,4 +270,43 @@ describe("ChatUI", () => {
       expect(mcpSelect).not.toHaveClass("ant-select-disabled");
     });
   });
+
+  it("should show Fill button and populate customProxyBaseUrl when proxySettings.LITELLM_UI_API_DOC_BASE_URL is provided", async () => {
+    const testProxyUrl = "http://localhost:5000";
+
+    render(
+      <ChatUI
+        accessToken="1234567890"
+        token="1234567890"
+        userRole="user"
+        userID="1234567890"
+        disabledPersonalKeyCreation={false}
+        proxySettings={{
+          LITELLM_UI_API_DOC_BASE_URL: testProxyUrl,
+        }}
+      />,
+    );
+
+    await waitFor(() => {
+      expect(screen.getByText("Test Key")).toBeInTheDocument();
+    });
+
+    const fillButton = screen.getByText("Fill");
+    expect(fillButton).toBeInTheDocument();
+
+    act(() => {
+      fireEvent.click(fillButton);
+    });
+
+    await waitFor(() => {
+      expect(sessionStorage.getItem("customProxyBaseUrl")).toBe(testProxyUrl);
+    });
+
+    await waitFor(() => {
+      expect(screen.queryByText("Fill")).toBeNull();
+    });
+
+    const customProxyInput = screen.getByPlaceholderText("Optional: Enter custom proxy URL (e.g., http://localhost:5000)");
+    expect(customProxyInput).toHaveValue(testProxyUrl);
+  });
 });
diff --git a/ui/litellm-dashboard/src/components/playground/chat_ui/ChatUI.tsx b/ui/litellm-dashboard/src/components/playground/chat_ui/ChatUI.tsx
index cbdffe46819..a3bdaccd805 100644
--- a/ui/litellm-dashboard/src/components/playground/chat_ui/ChatUI.tsx
+++ b/ui/litellm-dashboard/src/components/playground/chat_ui/ChatUI.tsx
@@ -10,6 +10,7 @@ import {
   FilePdfOutlined,
   InfoCircleOutlined,
   KeyOutlined,
+  LinkOutlined,
   LoadingOutlined,
   PictureOutlined,
   RobotOutlined,
@@ -1172,9 +1173,23 @@ const ChatUI: React.FC<ChatUIProps> = ({
 
               <div>
                 <div className="flex items-center justify-between mb-2">
-                  <Text className="font-medium text-gray-700 flex items-center">
+                  <Text className="font-medium block text-gray-700 flex items-center">
                     <SettingOutlined className="mr-2" /> Custom Proxy Base URL
                   </Text>
+                  {proxySettings?.LITELLM_UI_API_DOC_BASE_URL && !customProxyBaseUrl && (
+                    <Button
+                      type="link"
+                      size="small"
+                      icon={<LinkOutlined />}
+                      onClick={() => {
+                        setCustomProxyBaseUrl(proxySettings.LITELLM_UI_API_DOC_BASE_URL || "");
+                        sessionStorage.setItem("customProxyBaseUrl", proxySettings.LITELLM_UI_API_DOC_BASE_URL || "");
+                      }}
+                      className="text-gray-500 hover:text-gray-700"
+                    >
+                      Fill
+                    </Button>
+                  )}
                   {customProxyBaseUrl && (
                     <Button
                       type="link"
@@ -1219,7 +1234,7 @@ const ChatUI: React.FC<ChatUIProps> = ({
                     try {
                       sessionStorage.removeItem("selectedModel");
                       sessionStorage.removeItem("selectedAgent");
-                    } catch {}
+                    } catch { }
                   }}
                   className="mb-4"
                 />
@@ -1575,7 +1590,7 @@ const ChatUI: React.FC<ChatUIProps> = ({
                     enabled={codeInterpreter.enabled}
                     onEnabledChange={codeInterpreter.setEnabled}
                     selectedContainerId={null}
-                    onContainerChange={() => {}}
+                    onContainerChange={() => { }}
                     selectedModel={selectedModel || ""}
                   />
                 </div>
@@ -2071,11 +2086,10 @@ const ChatUI: React.FC<ChatUIProps> = ({
                         }
                       >
                         <button
-                          className={`p-1.5 rounded-md transition-colors ${
-                            codeInterpreter.enabled
-                              ? "bg-blue-100 text-blue-600"
-                              : "text-gray-400 hover:text-gray-600 hover:bg-gray-100"
-                          }`}
+                          className={`p-1.5 rounded-md transition-colors ${codeInterpreter.enabled
+                            ? "bg-blue-100 text-blue-600"
+                            : "text-gray-400 hover:text-gray-600 hover:bg-gray-100"
+                            }`}
                           onClick={() => {
                             codeInterpreter.toggle();
                             if (!codeInterpreter.enabled) {
@@ -2096,9 +2110,9 @@ const ChatUI: React.FC<ChatUIProps> = ({
                     onKeyDown={handleKeyDown}
                     placeholder={
                       endpointType === EndpointType.CHAT ||
-                      endpointType === EndpointType.EMBEDDINGS ||
-                      endpointType === EndpointType.RESPONSES ||
-                      endpointType === EndpointType.ANTHROPIC_MESSAGES
+                        endpointType === EndpointType.EMBEDDINGS ||
+                        endpointType === EndpointType.RESPONSES ||
+                        endpointType === EndpointType.ANTHROPIC_MESSAGES
                         ? "Type your message... (Shift+Enter for new line)"
                         : endpointType === EndpointType.A2A_AGENTS
                           ? "Send a message to the A2A agent..."