diff --git a/client/src/Providers/DragDropContext.tsx b/client/src/Providers/DragDropContext.tsx
index 35827c7e96..e5a2177f2d 100644
--- a/client/src/Providers/DragDropContext.tsx
+++ b/client/src/Providers/DragDropContext.tsx
@@ -1,7 +1,8 @@
 import React, { createContext, useContext, useMemo } from 'react';
-import { getEndpointField } from 'librechat-data-provider';
+import { getEndpointField, isAgentsEndpoint } from 'librechat-data-provider';
 import type { EModelEndpoint } from 'librechat-data-provider';
-import { useGetEndpointsQuery } from '~/data-provider';
+import { useGetEndpointsQuery, useGetAgentByIdQuery } from '~/data-provider';
+import { useAgentsMapContext } from './AgentsMapContext';
 import { useChatContext } from './ChatContext';
 
 interface DragDropContextValue {
@@ -9,6 +10,7 @@ interface DragDropContextValue {
   agentId: string | null | undefined;
   endpoint: string | null | undefined;
   endpointType?: EModelEndpoint | undefined;
+  useResponsesApi?: boolean;
 }
 
 const DragDropContext = createContext<DragDropContextValue | undefined>(undefined);
@@ -16,6 +18,7 @@ const DragDropContext = createContext<DragDropContextValue | undefined>(undefine
 export function DragDropProvider({ children }: { children: React.ReactNode }) {
   const { conversation } = useChatContext();
   const { data: endpointsConfig } = useGetEndpointsQuery();
+  const agentsMap = useAgentsMapContext();
 
   const endpointType = useMemo(() => {
     return (
@@ -24,6 +27,34 @@ export function DragDropProvider({ children }: { children: React.ReactNode }) {
     );
   }, [conversation?.endpoint, endpointsConfig]);
 
+  const needsAgentFetch = useMemo(() => {
+    const isAgents = isAgentsEndpoint(conversation?.endpoint);
+    if (!isAgents || !conversation?.agent_id) {
+      return false;
+    }
+    const agent = agentsMap?.[conversation.agent_id];
+    return !agent?.model_parameters;
+  }, [conversation?.endpoint, conversation?.agent_id, agentsMap]);
+
+  const { data: agentData } = useGetAgentByIdQuery(conversation?.agent_id, {
+    enabled: needsAgentFetch,
+  });
+
+  const useResponsesApi = useMemo(() => {
+    const isAgents = isAgentsEndpoint(conversation?.endpoint);
+    if (!isAgents || !conversation?.agent_id || conversation?.useResponsesApi) {
+      return conversation?.useResponsesApi;
+    }
+    const agent = agentData || agentsMap?.[conversation.agent_id];
+    return agent?.model_parameters?.useResponsesApi;
+  }, [
+    conversation?.endpoint,
+    conversation?.agent_id,
+    conversation?.useResponsesApi,
+    agentData,
+    agentsMap,
+  ]);
+
   /** Context value only created when conversation fields change */
   const contextValue = useMemo<DragDropContextValue>(
     () => ({
@@ -31,8 +62,15 @@ export function DragDropProvider({ children }: { children: React.ReactNode }) {
       agentId: conversation?.agent_id,
       endpoint: conversation?.endpoint,
       endpointType: endpointType,
+      useResponsesApi: useResponsesApi,
     }),
-    [conversation?.conversationId, conversation?.agent_id, conversation?.endpoint, endpointType],
+    [
+      conversation?.conversationId,
+      conversation?.agent_id,
+      conversation?.endpoint,
+      useResponsesApi,
+      endpointType,
+    ],
   );
 
   return <DragDropContext.Provider value={contextValue}>{children}</DragDropContext.Provider>;
diff --git a/client/src/components/Chat/Input/Files/AttachFileChat.tsx b/client/src/components/Chat/Input/Files/AttachFileChat.tsx
index 90ac3145bf..37b3584d3e 100644
--- a/client/src/components/Chat/Input/Files/AttachFileChat.tsx
+++ b/client/src/components/Chat/Input/Files/AttachFileChat.tsx
@@ -10,7 +10,8 @@ import {
   getEndpointFileConfig,
 } from 'librechat-data-provider';
 import type { TConversation } from 'librechat-data-provider';
-import { useGetFileConfig, useGetEndpointsQuery } from '~/data-provider';
+import { useGetFileConfig, useGetEndpointsQuery, useGetAgentByIdQuery } from '~/data-provider';
+import { useAgentsMapContext } from '~/Providers';
 import AttachFileMenu from './AttachFileMenu';
 import AttachFile from './AttachFile';
 
@@ -26,6 +27,28 @@ function AttachFileChat({
   const isAgents = useMemo(() => isAgentsEndpoint(endpoint), [endpoint]);
   const isAssistants = useMemo(() => isAssistantsEndpoint(endpoint), [endpoint]);
 
+  const agentsMap = useAgentsMapContext();
+
+  const needsAgentFetch = useMemo(() => {
+    if (!isAgents || !conversation?.agent_id) {
+      return false;
+    }
+    const agent = agentsMap?.[conversation.agent_id];
+    return !agent?.model_parameters;
+  }, [isAgents, conversation?.agent_id, agentsMap]);
+
+  const { data: agentData } = useGetAgentByIdQuery(conversation?.agent_id, {
+    enabled: needsAgentFetch,
+  });
+
+  const useResponsesApi = useMemo(() => {
+    if (!isAgents || !conversation?.agent_id || conversation?.useResponsesApi) {
+      return conversation?.useResponsesApi;
+    }
+    const agent = agentData || agentsMap?.[conversation.agent_id];
+    return agent?.model_parameters?.useResponsesApi;
+  }, [isAgents, conversation?.agent_id, conversation?.useResponsesApi, agentData, agentsMap]);
+
   const { data: fileConfig = null } = useGetFileConfig({
     select: (data) => mergeFileConfig(data),
   });
@@ -68,6 +91,7 @@ function AttachFileChat({
         conversationId={conversationId}
         agentId={conversation?.agent_id}
         endpointFileConfig={endpointFileConfig}
+        useResponsesApi={useResponsesApi}
       />
     );
   }
diff --git a/client/src/components/Chat/Input/Files/AttachFileMenu.tsx b/client/src/components/Chat/Input/Files/AttachFileMenu.tsx
index 6e57759e16..4a85c78374 100644
--- a/client/src/components/Chat/Input/Files/AttachFileMenu.tsx
+++ b/client/src/components/Chat/Input/Files/AttachFileMenu.tsx
@@ -46,6 +46,7 @@ interface AttachFileMenuProps {
   conversationId: string;
   endpointType?: EModelEndpoint;
   endpointFileConfig?: EndpointFileConfig;
+  useResponsesApi?: boolean;
 }
 
 const AttachFileMenu = ({
@@ -55,6 +56,7 @@ const AttachFileMenu = ({
   endpointType,
   conversationId,
   endpointFileConfig,
+  useResponsesApi,
 }: AttachFileMenuProps) => {
   const localize = useLocalize();
   const isUploadDisabled = disabled ?? false;
@@ -117,9 +119,13 @@ const AttachFileMenu = ({
         currentProvider = Providers.OPENROUTER;
       }
 
+      const isAzureWithResponsesApi =
+        currentProvider === EModelEndpoint.azureOpenAI && useResponsesApi;
+
       if (
         isDocumentSupportedProvider(endpointType) ||
-        isDocumentSupportedProvider(currentProvider)
+        isDocumentSupportedProvider(currentProvider) ||
+        isAzureWithResponsesApi
       ) {
         items.push({
           label: localize('com_ui_upload_provider'),
@@ -211,6 +217,7 @@ const AttachFileMenu = ({
     provider,
     endpointType,
     capabilities,
+    useResponsesApi,
     setToolResource,
     setEphemeralAgent,
     sharePointEnabled,
diff --git a/client/src/components/Chat/Input/Files/DragDropModal.tsx b/client/src/components/Chat/Input/Files/DragDropModal.tsx
index 65647a2f22..a59a7e3e9d 100644
--- a/client/src/components/Chat/Input/Files/DragDropModal.tsx
+++ b/client/src/components/Chat/Input/Files/DragDropModal.tsx
@@ -47,7 +47,7 @@ const DragDropModal = ({ onOptionSelect, setShowModal, files, isVisible }: DragD
    * Use definition for agents endpoint for ephemeral agents
    * */
   const capabilities = useAgentCapabilities(agentsConfig?.capabilities ?? defaultAgentCapabilities);
-  const { conversationId, agentId, endpoint, endpointType } = useDragDropContext();
+  const { conversationId, agentId, endpoint, endpointType, useResponsesApi } = useDragDropContext();
   const ephemeralAgent = useRecoilValue(ephemeralAgentByConvoId(conversationId ?? ''));
   const { fileSearchAllowedByAgent, codeAllowedByAgent, provider } = useAgentToolPermissions(
     agentId,
@@ -66,8 +66,15 @@ const DragDropModal = ({ onOptionSelect, setShowModal, files, isVisible }: DragD
     /** Helper to get inferred MIME type for a file */
     const getFileType = (file: File) => inferMimeType(file.name, file.type);
 
+    const isAzureWithResponsesApi =
+      currentProvider === EModelEndpoint.azureOpenAI && useResponsesApi;
+
     // Check if provider supports document upload
-    if (isDocumentSupportedProvider(endpointType) || isDocumentSupportedProvider(currentProvider)) {
+    if (
+      isDocumentSupportedProvider(endpointType) ||
+      isDocumentSupportedProvider(currentProvider) ||
+      isAzureWithResponsesApi
+    ) {
       const supportsImageDocVideoAudio =
         currentProvider === EModelEndpoint.google || currentProvider === Providers.OPENROUTER;
       const validFileTypes = supportsImageDocVideoAudio
@@ -130,6 +137,7 @@ const DragDropModal = ({ onOptionSelect, setShowModal, files, isVisible }: DragD
     endpoint,
     endpointType,
     capabilities,
+    useResponsesApi,
     codeAllowedByAgent,
     fileSearchAllowedByAgent,
   ]);
diff --git a/client/src/components/Chat/Input/Files/__tests__/AttachFileMenu.spec.tsx b/client/src/components/Chat/Input/Files/__tests__/AttachFileMenu.spec.tsx
index a9b7139737..d3f0fb65bc 100644
--- a/client/src/components/Chat/Input/Files/__tests__/AttachFileMenu.spec.tsx
+++ b/client/src/components/Chat/Input/Files/__tests__/AttachFileMenu.spec.tsx
@@ -278,7 +278,6 @@ describe('AttachFileMenu', () => {
       { name: 'OpenAI', endpoint: EModelEndpoint.openAI },
       { name: 'Anthropic', endpoint: EModelEndpoint.anthropic },
       { name: 'Google', endpoint: EModelEndpoint.google },
-      { name: 'Azure OpenAI', endpoint: EModelEndpoint.azureOpenAI },
       { name: 'Custom', endpoint: EModelEndpoint.custom },
     ];
 
@@ -301,6 +300,45 @@ describe('AttachFileMenu', () => {
         expect(screen.getByText('Upload to Provider')).toBeInTheDocument();
       });
     });
+
+    it('should show Upload to Provider for Azure OpenAI with useResponsesApi', () => {
+      mockUseAgentToolPermissions.mockReturnValue({
+        fileSearchAllowedByAgent: false,
+        codeAllowedByAgent: false,
+        provider: EModelEndpoint.azureOpenAI,
+      });
+
+      renderAttachFileMenu({
+        endpoint: EModelEndpoint.azureOpenAI,
+        endpointType: EModelEndpoint.azureOpenAI,
+        useResponsesApi: true,
+      });
+
+      const button = screen.getByRole('button', { name: /attach file options/i });
+      fireEvent.click(button);
+
+      expect(screen.getByText('Upload to Provider')).toBeInTheDocument();
+    });
+
+    it('should NOT show Upload to Provider for Azure OpenAI without useResponsesApi', () => {
+      mockUseAgentToolPermissions.mockReturnValue({
+        fileSearchAllowedByAgent: false,
+        codeAllowedByAgent: false,
+        provider: EModelEndpoint.azureOpenAI,
+      });
+
+      renderAttachFileMenu({
+        endpoint: EModelEndpoint.azureOpenAI,
+        endpointType: EModelEndpoint.azureOpenAI,
+        useResponsesApi: false,
+      });
+
+      const button = screen.getByRole('button', { name: /attach file options/i });
+      fireEvent.click(button);
+
+      expect(screen.queryByText('Upload to Provider')).not.toBeInTheDocument();
+      expect(screen.getByText('Upload Image')).toBeInTheDocument();
+    });
   });
 
   describe('Agent Capabilities', () => {
diff --git a/client/src/components/Chat/Input/Files/__tests__/DragDropModal.spec.tsx b/client/src/components/Chat/Input/Files/__tests__/DragDropModal.spec.tsx
index 44e632fa12..6def1f3d10 100644
--- a/client/src/components/Chat/Input/Files/__tests__/DragDropModal.spec.tsx
+++ b/client/src/components/Chat/Input/Files/__tests__/DragDropModal.spec.tsx
@@ -63,7 +63,6 @@ describe('DragDropModal - Provider Detection', () => {
       { name: 'OpenAI', value: EModelEndpoint.openAI },
       { name: 'Anthropic', value: EModelEndpoint.anthropic },
       { name: 'Google', value: EModelEndpoint.google },
-      { name: 'Azure OpenAI', value: EModelEndpoint.azureOpenAI },
       { name: 'Custom', value: EModelEndpoint.custom },
     ];
 
@@ -72,6 +71,10 @@ describe('DragDropModal - Provider Detection', () => {
         expect(isDocumentSupportedProvider(value)).toBe(true);
       });
     });
+
+    it('should NOT recognize Azure OpenAI as supported (requires useResponsesApi)', () => {
+      expect(isDocumentSupportedProvider(EModelEndpoint.azureOpenAI)).toBe(false);
+    });
   });
 
   describe('real-world scenarios', () => {
diff --git a/packages/api/src/mcp/oauth/handler.ts b/packages/api/src/mcp/oauth/handler.ts
index 0ae9a29292..c07918c591 100644
--- a/packages/api/src/mcp/oauth/handler.ts
+++ b/packages/api/src/mcp/oauth/handler.ts
@@ -970,8 +970,8 @@ export class MCPOAuthHandler {
       });
 
       const headers: HeadersInit = {
-        'Content-Type': 'application/x-www-form-urlencoded',
         Accept: 'application/json',
+        'Content-Type': 'application/x-www-form-urlencoded',
         ...oauthHeaders,
       };
 
diff --git a/packages/data-provider/src/schemas.ts b/packages/data-provider/src/schemas.ts
index 7dabc549db..0266ee5109 100644
--- a/packages/data-provider/src/schemas.ts
+++ b/packages/data-provider/src/schemas.ts
@@ -49,7 +49,8 @@ export const documentSupportedProviders = new Set<string>([
   EModelEndpoint.anthropic,
   EModelEndpoint.openAI,
   EModelEndpoint.custom,
-  EModelEndpoint.azureOpenAI,
+  // handled in AttachFileMenu and DragDropModal since azureOpenAI only supports documents with Use Responses API set to true
+  // EModelEndpoint.azureOpenAI,
   EModelEndpoint.google,
   Providers.VERTEXAI,
   Providers.MISTRALAI,
diff --git a/packages/data-provider/src/types/assistants.ts b/packages/data-provider/src/types/assistants.ts
index 185df5fa9f..9e1deb20c1 100644
--- a/packages/data-provider/src/types/assistants.ts
+++ b/packages/data-provider/src/types/assistants.ts
@@ -166,6 +166,7 @@ export type AgentModelParameters = {
   top_p: AgentParameterValue;
   frequency_penalty: AgentParameterValue;
   presence_penalty: AgentParameterValue;
+  useResponsesApi?: boolean;
 };
 
 export interface AgentBaseResource {