diff --git a/client/src/components/Chat/Input/Files/AttachFileMenu.tsx b/client/src/components/Chat/Input/Files/AttachFileMenu.tsx
index 181d219c08..0b10e6c712 100644
--- a/client/src/components/Chat/Input/Files/AttachFileMenu.tsx
+++ b/client/src/components/Chat/Input/Files/AttachFileMenu.tsx
@@ -1,4 +1,4 @@
-import React, { useRef, useState, useMemo } from 'react';
+import React, { useRef, useState, useMemo, useCallback } from 'react';
 import { useRecoilState } from 'recoil';
 import * as Ariakit from '@ariakit/react';
 import {
@@ -19,6 +19,7 @@ import {
   Providers,
   EToolResources,
   EModelEndpoint,
+  isPermissiveMimeConfig,
   defaultAgentCapabilities,
   bedrockDocumentExtensions,
   isDocumentSupportedProvider,
@@ -110,27 +111,35 @@ const AttachFileMenu = ({
     ephemeralAgent,
   );
 
-  const handleUploadClick = (fileType?: FileUploadType) => {
-    if (!inputRef.current) {
-      return;
-    }
-    inputRef.current.value = '';
-    if (fileType === 'image') {
-      inputRef.current.accept = 'image/*,.heif,.heic';
-    } else if (fileType === 'document') {
-      inputRef.current.accept = '.pdf,application/pdf';
-    } else if (fileType === 'image_document') {
-      inputRef.current.accept = 'image/*,.heif,.heic,.pdf,application/pdf';
-    } else if (fileType === 'image_document_extended') {
-      inputRef.current.accept = `image/*,.heif,.heic,${bedrockDocumentExtensions}`;
-    } else if (fileType === 'image_document_video_audio') {
-      inputRef.current.accept = 'image/*,.heif,.heic,.pdf,application/pdf,video/*,audio/*';
-    } else {
+  const handleUploadClick = useCallback(
+    (fileType?: FileUploadType) => {
+      if (!inputRef.current) {
+        return;
+      }
+      inputRef.current.value = '';
+      if (
+        fileType !== undefined &&
+        isPermissiveMimeConfig(endpointFileConfig?.supportedMimeTypes)
+      ) {
+        inputRef.current.accept = '';
+      } else if (fileType === 'image') {
+        inputRef.current.accept = 'image/*,.heif,.heic';
+      } else if (fileType === 'document') {
+        inputRef.current.accept = '.pdf,application/pdf';
+      } else if (fileType === 'image_document') {
+        inputRef.current.accept = 'image/*,.heif,.heic,.pdf,application/pdf';
+      } else if (fileType === 'image_document_extended') {
+        inputRef.current.accept = `image/*,.heif,.heic,${bedrockDocumentExtensions}`;
+      } else if (fileType === 'image_document_video_audio') {
+        inputRef.current.accept = 'image/*,.heif,.heic,.pdf,application/pdf,video/*,audio/*';
+      } else {
+        inputRef.current.accept = '';
+      }
+      inputRef.current.click();
       inputRef.current.accept = '';
-    }
-    inputRef.current.click();
-    inputRef.current.accept = '';
-  };
+    },
+    [endpointFileConfig?.supportedMimeTypes],
+  );
 
   const dropdownItems = useMemo(() => {
     const createMenuItems = (onAction: (fileType?: FileUploadType) => void) => {
@@ -247,6 +256,7 @@ const AttachFileMenu = ({
     endpointType,
     capabilities,
     useResponsesApi,
+    handleUploadClick,
     setToolResource,
     setEphemeralAgent,
     sharePointEnabled,
diff --git a/packages/data-provider/src/file-config.spec.ts b/packages/data-provider/src/file-config.spec.ts
index 96f48621cc..ee894712ff 100644
--- a/packages/data-provider/src/file-config.spec.ts
+++ b/packages/data-provider/src/file-config.spec.ts
@@ -1,6 +1,8 @@
 import type { FileConfig } from './types/files';
 import {
   fileConfig as baseFileConfig,
+  isPermissiveMimeConfig,
+  convertStringsToRegex,
   documentParserMimeTypes,
   getEndpointFileConfig,
   applicationMimeTypes,
@@ -1246,3 +1248,62 @@ describe('getEndpointFileConfig', () => {
     });
   });
 });
+
+describe('isPermissiveMimeConfig', () => {
+  it('returns true for wildcard .* pattern', () => {
+    expect(isPermissiveMimeConfig([/.*/])).toBe(true);
+  });
+
+  it('returns true for .+ pattern', () => {
+    expect(isPermissiveMimeConfig([/.+/])).toBe(true);
+  });
+
+  it('returns true for anchored ^.*$ pattern', () => {
+    expect(isPermissiveMimeConfig([/^.*$/])).toBe(true);
+  });
+
+  it('returns true for anchored ^.+$ pattern', () => {
+    expect(isPermissiveMimeConfig([/^.+$/])).toBe(true);
+  });
+
+  it('returns true when at least one pattern is permissive', () => {
+    expect(isPermissiveMimeConfig([/^image\/.*$/, /.*/])).toBe(true);
+  });
+
+  it('returns false for image-only patterns', () => {
+    expect(isPermissiveMimeConfig([/^image\/(jpeg|png)$/])).toBe(false);
+  });
+
+  it('returns false for category patterns', () => {
+    expect(isPermissiveMimeConfig([/^image\/.*$/, /^text\/.*$/])).toBe(false);
+  });
+
+  it('returns false for specific MIME type patterns', () => {
+    expect(isPermissiveMimeConfig([/^application\/pdf$/])).toBe(false);
+  });
+
+  it('returns false for broad application category pattern', () => {
+    expect(isPermissiveMimeConfig([/^application\/.*$/])).toBe(false);
+  });
+
+  it('returns false for multi-category pattern', () => {
+    expect(isPermissiveMimeConfig([/^(application|text)\/.*$/])).toBe(false);
+  });
+
+  it('returns false for default supportedMimeTypes', () => {
+    expect(isPermissiveMimeConfig(supportedMimeTypes)).toBe(false);
+  });
+
+  it('returns false for undefined', () => {
+    expect(isPermissiveMimeConfig(undefined)).toBe(false);
+  });
+
+  it('returns false for empty array', () => {
+    expect(isPermissiveMimeConfig([])).toBe(false);
+  });
+
+  it('returns true for regex produced by convertStringsToRegex with .*', () => {
+    const converted = convertStringsToRegex(['.*']);
+    expect(isPermissiveMimeConfig(converted)).toBe(true);
+  });
+});
diff --git a/packages/data-provider/src/file-config.ts b/packages/data-provider/src/file-config.ts
index 7ec184755d..a93daf79e2 100644
--- a/packages/data-provider/src/file-config.ts
+++ b/packages/data-provider/src/file-config.ts
@@ -497,6 +497,14 @@ export const convertStringsToRegex = (patterns: string[]): RegExp[] =>
     return acc;
   }, []);
 
+/** Detects whether the given MIME type patterns accept all file types (e.g., `.*` or `.+`). */
+export const isPermissiveMimeConfig = (types?: RegExp[]): boolean => {
+  if (!types || types.length === 0) {
+    return false;
+  }
+  return types.some((regex) => regex.test('x-librechat/x-probe'));
+};
+
 /**
  * Gets the appropriate endpoint file configuration with standardized lookup logic.
  *