diff --git a/package-lock.json b/package-lock.json
index 272a3ddd49..9f1b9cc620 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -24371,6 +24371,17 @@
         "undici-types": "~5.26.4"
       }
     },
+    "node_modules/@types/node-fetch": {
+      "version": "2.6.13",
+      "resolved": "https://registry.npmjs.org/@types/node-fetch/-/node-fetch-2.6.13.tgz",
+      "integrity": "sha512-QGpRVpzSaUs30JBSGPjOg4Uveu384erbHBoT1zeONvyCfwQxIkUshLAOqN/k9EjGviPRmWTTe6aH2qySWKTVSw==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@types/node": "*",
+        "form-data": "^4.0.4"
+      }
+    },
     "node_modules/@types/passport": {
       "version": "1.0.17",
       "resolved": "https://registry.npmjs.org/@types/passport/-/passport-1.0.17.tgz",
@@ -45745,6 +45756,7 @@
         "@types/jsonwebtoken": "^9.0.0",
         "@types/multer": "^1.4.13",
         "@types/node": "^20.3.0",
+        "@types/node-fetch": "^2.6.13",
         "@types/react": "^18.2.18",
         "@types/winston": "^2.4.4",
         "jest": "^29.5.0",
diff --git a/packages/api/package.json b/packages/api/package.json
index 6e5f16f054..a29a3c637e 100644
--- a/packages/api/package.json
+++ b/packages/api/package.json
@@ -60,6 +60,7 @@
     "@types/jsonwebtoken": "^9.0.0",
     "@types/multer": "^1.4.13",
     "@types/node": "^20.3.0",
+    "@types/node-fetch": "^2.6.13",
     "@types/react": "^18.2.18",
     "@types/winston": "^2.4.4",
     "jest": "^29.5.0",
diff --git a/packages/api/src/files/context.ts b/packages/api/src/files/context.ts
index 24418ce49d..1da6c387ce 100644
--- a/packages/api/src/files/context.ts
+++ b/packages/api/src/files/context.ts
@@ -1,8 +1,7 @@
 import { logger } from '@librechat/data-schemas';
 import { FileSources, mergeFileConfig } from 'librechat-data-provider';
-import type { fileConfigSchema } from 'librechat-data-provider';
 import type { IMongoFile } from '@librechat/data-schemas';
-import type { z } from 'zod';
+import type { ServerRequest } from '~/types';
 import { processTextWithTokenLimit } from '~/utils/text';
 
 /**
@@ -20,10 +19,7 @@ export async function extractFileContext({
   tokenCountFn,
 }: {
   attachments: IMongoFile[];
-  req?: {
-    body?: { fileTokenLimit?: number };
-    config?: { fileConfig?: z.infer<typeof fileConfigSchema> };
-  };
+  req?: ServerRequest;
   tokenCountFn: (text: string) => number;
 }): Promise<string | undefined> {
   if (!attachments || attachments.length === 0) {
diff --git a/packages/api/src/files/encode/audio.ts b/packages/api/src/files/encode/audio.ts
index d411e61640..85b90ce0f8 100644
--- a/packages/api/src/files/encode/audio.ts
+++ b/packages/api/src/files/encode/audio.ts
@@ -1,10 +1,9 @@
 import { Providers } from '@librechat/agents';
 import { isDocumentSupportedProvider } from 'librechat-data-provider';
 import type { IMongoFile } from '@librechat/data-schemas';
-import type { Request } from 'express';
-import type { StrategyFunctions, AudioResult } from '~/types/files';
+import type { ServerRequest, StrategyFunctions, AudioResult } from '~/types';
+import { getFileStream, getConfiguredFileSizeLimit } from './utils';
 import { validateAudio } from '~/files/validation';
-import { getFileStream } from './utils';
 
 /**
  * Encodes and formats audio files for different providers
@@ -15,7 +14,7 @@ import { getFileStream } from './utils';
  * @returns Promise that resolves to audio and file metadata
  */
 export async function encodeAndFormatAudios(
-  req: Request,
+  req: ServerRequest,
   files: IMongoFile[],
   provider: Providers,
   getStrategyFunctions: (source: string) => StrategyFunctions,
@@ -53,7 +52,16 @@ export async function encodeAndFormatAudios(
     }
 
     const audioBuffer = Buffer.from(content, 'base64');
-    const validation = await validateAudio(audioBuffer, audioBuffer.length, provider);
+
+    /** Extract configured file size limit from fileConfig for this endpoint */
+    const configuredFileSizeLimit = getConfiguredFileSizeLimit(req, provider);
+
+    const validation = await validateAudio(
+      audioBuffer,
+      audioBuffer.length,
+      provider,
+      configuredFileSizeLimit,
+    );
 
     if (!validation.isValid) {
       throw new Error(`Audio validation failed: ${validation.error}`);
diff --git a/packages/api/src/files/encode/document.spec.ts b/packages/api/src/files/encode/document.spec.ts
new file mode 100644
index 0000000000..ac1573f3e3
--- /dev/null
+++ b/packages/api/src/files/encode/document.spec.ts
@@ -0,0 +1,529 @@
+import { Providers } from '@librechat/agents';
+import { mbToBytes } from 'librechat-data-provider';
+import type { AppConfig, IMongoFile } from '@librechat/data-schemas';
+import type { ServerRequest } from '~/types';
+import { encodeAndFormatDocuments } from './document';
+
+/** Mock the validation module */
+jest.mock('~/files/validation', () => ({
+  validatePdf: jest.fn(),
+}));
+
+/** Mock the utils module */
+jest.mock('./utils', () => ({
+  getFileStream: jest.fn(),
+  getConfiguredFileSizeLimit: jest.fn(),
+}));
+
+import { validatePdf } from '~/files/validation';
+import { getFileStream, getConfiguredFileSizeLimit } from './utils';
+import { Types } from 'mongoose';
+
+const mockedValidatePdf = validatePdf as jest.MockedFunction<typeof validatePdf>;
+const mockedGetFileStream = getFileStream as jest.MockedFunction<typeof getFileStream>;
+const mockedGetConfiguredFileSizeLimit = getConfiguredFileSizeLimit as jest.MockedFunction<
+  typeof getConfiguredFileSizeLimit
+>;
+
+describe('encodeAndFormatDocuments - fileConfig integration', () => {
+  const mockStrategyFunctions = jest.fn();
+
+  beforeEach(() => {
+    jest.clearAllMocks();
+    /** Default mock implementation for getConfiguredFileSizeLimit */
+    mockedGetConfiguredFileSizeLimit.mockImplementation((req, provider) => {
+      if (!req.config?.fileConfig) {
+        return undefined;
+      }
+      const fileConfig = req.config.fileConfig;
+      const endpoints = fileConfig.endpoints;
+      if (endpoints?.[provider]) {
+        const limit = endpoints[provider].fileSizeLimit;
+        return limit !== undefined ? mbToBytes(limit) : undefined;
+      }
+      if (endpoints?.default) {
+        const limit = endpoints.default.fileSizeLimit;
+        return limit !== undefined ? mbToBytes(limit) : undefined;
+      }
+      return undefined;
+    });
+  });
+
+  /** Helper to create a mock request with file config */
+  const createMockRequest = (fileSizeLimit?: number): Partial<AppConfig> => ({
+    config:
+      fileSizeLimit !== undefined
+        ? {
+            fileConfig: {
+              endpoints: {
+                [Providers.OPENAI]: {
+                  fileSizeLimit,
+                },
+              },
+            },
+          }
+        : undefined,
+  });
+
+  /** Helper to create a mock PDF file */
+  const createMockFile = (sizeInMB: number): IMongoFile =>
+    ({
+      _id: new Types.ObjectId(),
+      user: new Types.ObjectId(),
+      file_id: new Types.ObjectId().toString(),
+      filename: 'test.pdf',
+      type: 'application/pdf',
+      bytes: Math.floor(sizeInMB * 1024 * 1024),
+      object: 'file',
+      usage: 0,
+      source: 'test',
+      filepath: '/test/path.pdf',
+      createdAt: new Date(),
+      updatedAt: new Date(),
+    }) as unknown as IMongoFile;
+
+  describe('Configuration extraction and validation', () => {
+    it('should pass configured file size limit to validatePdf for OpenAI', async () => {
+      const configuredLimit = mbToBytes(15);
+      const req = createMockRequest(15) as ServerRequest;
+      const file = createMockFile(10);
+
+      const mockContent = Buffer.from('test-pdf-content').toString('base64');
+      mockedGetFileStream.mockResolvedValue({
+        file,
+        content: mockContent,
+        metadata: file,
+      });
+
+      mockedValidatePdf.mockResolvedValue({ isValid: true });
+
+      await encodeAndFormatDocuments(
+        req,
+        [file],
+        { provider: Providers.OPENAI },
+        mockStrategyFunctions,
+      );
+
+      expect(mockedValidatePdf).toHaveBeenCalledWith(
+        expect.any(Buffer),
+        expect.any(Number),
+        Providers.OPENAI,
+        configuredLimit,
+      );
+    });
+
+    it('should pass undefined when no fileConfig is provided', async () => {
+      const req = {} as ServerRequest;
+      const file = createMockFile(10);
+
+      const mockContent = Buffer.from('test-pdf-content').toString('base64');
+      mockedGetFileStream.mockResolvedValue({
+        file,
+        content: mockContent,
+        metadata: file,
+      });
+
+      mockedValidatePdf.mockResolvedValue({ isValid: true });
+
+      await encodeAndFormatDocuments(
+        req,
+        [file],
+        { provider: Providers.OPENAI },
+        mockStrategyFunctions,
+      );
+
+      expect(mockedValidatePdf).toHaveBeenCalledWith(
+        expect.any(Buffer),
+        expect.any(Number),
+        Providers.OPENAI,
+        undefined,
+      );
+    });
+
+    it('should pass undefined when fileConfig.endpoints is not defined', async () => {
+      const req = {
+        config: {
+          fileConfig: {},
+        },
+      } as ServerRequest;
+      const file = createMockFile(10);
+
+      const mockContent = Buffer.from('test-pdf-content').toString('base64');
+      mockedGetFileStream.mockResolvedValue({
+        file,
+        content: mockContent,
+        metadata: file,
+      });
+
+      mockedValidatePdf.mockResolvedValue({ isValid: true });
+
+      await encodeAndFormatDocuments(
+        req,
+        [file],
+        { provider: Providers.OPENAI },
+        mockStrategyFunctions,
+      );
+
+      /** When fileConfig has no endpoints, getConfiguredFileSizeLimit returns undefined */
+      expect(mockedValidatePdf).toHaveBeenCalledWith(
+        expect.any(Buffer),
+        expect.any(Number),
+        Providers.OPENAI,
+        undefined,
+      );
+    });
+
+    it('should use endpoint-specific config for Anthropic', async () => {
+      const configuredLimit = mbToBytes(20);
+      const req = {
+        config: {
+          fileConfig: {
+            endpoints: {
+              [Providers.ANTHROPIC]: {
+                fileSizeLimit: 20,
+              },
+            },
+          },
+        },
+      } as unknown as ServerRequest;
+      const file = createMockFile(15);
+
+      const mockContent = Buffer.from('test-pdf-content').toString('base64');
+      mockedGetFileStream.mockResolvedValue({
+        file,
+        content: mockContent,
+        metadata: file,
+      });
+
+      mockedValidatePdf.mockResolvedValue({ isValid: true });
+
+      await encodeAndFormatDocuments(
+        req,
+        [file],
+        { provider: Providers.ANTHROPIC },
+        mockStrategyFunctions,
+      );
+
+      expect(mockedValidatePdf).toHaveBeenCalledWith(
+        expect.any(Buffer),
+        expect.any(Number),
+        Providers.ANTHROPIC,
+        configuredLimit,
+      );
+    });
+
+    it('should use endpoint-specific config for Google', async () => {
+      const configuredLimit = mbToBytes(25);
+      const req = {
+        config: {
+          fileConfig: {
+            endpoints: {
+              [Providers.GOOGLE]: {
+                fileSizeLimit: 25,
+              },
+            },
+          },
+        },
+      } as unknown as ServerRequest;
+      const file = createMockFile(18);
+
+      const mockContent = Buffer.from('test-pdf-content').toString('base64');
+      mockedGetFileStream.mockResolvedValue({
+        file,
+        content: mockContent,
+        metadata: file,
+      });
+
+      mockedValidatePdf.mockResolvedValue({ isValid: true });
+
+      await encodeAndFormatDocuments(
+        req,
+        [file],
+        { provider: Providers.GOOGLE },
+        mockStrategyFunctions,
+      );
+
+      expect(mockedValidatePdf).toHaveBeenCalledWith(
+        expect.any(Buffer),
+        expect.any(Number),
+        Providers.GOOGLE,
+        configuredLimit,
+      );
+    });
+
+    it('should pass undefined when provider-specific config not found and no default', async () => {
+      const req = {
+        config: {
+          fileConfig: {
+            endpoints: {
+              /** Only configure a different provider, not OpenAI */
+              [Providers.ANTHROPIC]: {
+                fileSizeLimit: 25,
+              },
+            },
+          },
+        },
+      } as unknown as ServerRequest;
+      const file = createMockFile(20);
+
+      const mockContent = Buffer.from('test-pdf-content').toString('base64');
+      mockedGetFileStream.mockResolvedValue({
+        file,
+        content: mockContent,
+        metadata: file,
+      });
+
+      mockedValidatePdf.mockResolvedValue({ isValid: true });
+
+      await encodeAndFormatDocuments(
+        req,
+        [file],
+        { provider: Providers.OPENAI },
+        mockStrategyFunctions,
+      );
+
+      /** When provider-specific config not found and no default, returns undefined */
+      expect(mockedValidatePdf).toHaveBeenCalledWith(
+        expect.any(Buffer),
+        expect.any(Number),
+        Providers.OPENAI,
+        undefined,
+      );
+    });
+  });
+
+  describe('Validation failure handling', () => {
+    it('should throw error when validation fails', async () => {
+      const req = createMockRequest(10) as ServerRequest;
+      const file = createMockFile(12);
+
+      const mockContent = Buffer.from('test-pdf-content').toString('base64');
+      mockedGetFileStream.mockResolvedValue({
+        file,
+        content: mockContent,
+        metadata: file,
+      });
+
+      mockedValidatePdf.mockResolvedValue({
+        isValid: false,
+        error: 'PDF file size (12MB) exceeds the 10MB limit',
+      });
+
+      await expect(
+        encodeAndFormatDocuments(
+          req,
+          [file],
+          { provider: Providers.OPENAI },
+          mockStrategyFunctions,
+        ),
+      ).rejects.toThrow('PDF validation failed: PDF file size (12MB) exceeds the 10MB limit');
+    });
+
+    it('should not call validatePdf for non-PDF files', async () => {
+      const req = createMockRequest(10) as ServerRequest;
+      const file: IMongoFile = {
+        ...createMockFile(5),
+        type: 'image/jpeg',
+        filename: 'test.jpg',
+      };
+
+      const mockContent = Buffer.from('test-image-content').toString('base64');
+      mockedGetFileStream.mockResolvedValue({
+        file,
+        content: mockContent,
+        metadata: file,
+      });
+
+      await encodeAndFormatDocuments(
+        req,
+        [file],
+        { provider: Providers.OPENAI },
+        mockStrategyFunctions,
+      );
+
+      expect(mockedValidatePdf).not.toHaveBeenCalled();
+    });
+  });
+
+  describe('Bug reproduction scenarios', () => {
+    it('should respect user-configured lower limit (stricter than provider)', async () => {
+      /**
+       * Scenario: User sets openAI.fileSizeLimit = 5MB (stricter than 10MB provider limit)
+       * Uploads 7MB PDF
+       * Expected: Validation called with 5MB limit
+       */
+      const req = createMockRequest(5) as ServerRequest;
+      const file = createMockFile(7);
+
+      const mockContent = Buffer.from('test-pdf-content').toString('base64');
+      mockedGetFileStream.mockResolvedValue({
+        file,
+        content: mockContent,
+        metadata: file,
+      });
+
+      mockedValidatePdf.mockResolvedValue({
+        isValid: false,
+        error: 'PDF file size (7MB) exceeds the 5MB limit',
+      });
+
+      await expect(
+        encodeAndFormatDocuments(
+          req,
+          [file],
+          { provider: Providers.OPENAI },
+          mockStrategyFunctions,
+        ),
+      ).rejects.toThrow('PDF validation failed');
+
+      expect(mockedValidatePdf).toHaveBeenCalledWith(
+        expect.any(Buffer),
+        expect.any(Number),
+        Providers.OPENAI,
+        mbToBytes(5),
+      );
+    });
+
+    it('should respect user-configured higher limit (allows API changes)', async () => {
+      /**
+       * Scenario: User sets openAI.fileSizeLimit = 50MB (higher than 10MB provider default)
+       * Uploads 15MB PDF
+       * Expected: Validation called with 50MB limit, allowing files between 10-50MB
+       * This allows users to take advantage of API limit increases
+       */
+      const req = createMockRequest(50) as ServerRequest;
+      const file = createMockFile(15);
+
+      const mockContent = Buffer.from('test-pdf-content').toString('base64');
+      mockedGetFileStream.mockResolvedValue({
+        file,
+        content: mockContent,
+        metadata: file,
+      });
+
+      mockedValidatePdf.mockResolvedValue({ isValid: true });
+
+      await encodeAndFormatDocuments(
+        req,
+        [file],
+        { provider: Providers.OPENAI },
+        mockStrategyFunctions,
+      );
+
+      expect(mockedValidatePdf).toHaveBeenCalledWith(
+        expect.any(Buffer),
+        expect.any(Number),
+        Providers.OPENAI,
+        mbToBytes(50),
+      );
+    });
+
+    it('should handle multiple files with different sizes', async () => {
+      const req = createMockRequest(10) as ServerRequest;
+      const file1 = createMockFile(5);
+      const file2 = createMockFile(8);
+
+      const mockContent1 = Buffer.from('pdf-content-1').toString('base64');
+      const mockContent2 = Buffer.from('pdf-content-2').toString('base64');
+
+      mockedGetFileStream
+        .mockResolvedValueOnce({
+          file: file1,
+          content: mockContent1,
+          metadata: file1,
+        })
+        .mockResolvedValueOnce({
+          file: file2,
+          content: mockContent2,
+          metadata: file2,
+        });
+
+      mockedValidatePdf.mockResolvedValue({ isValid: true });
+
+      await encodeAndFormatDocuments(
+        req,
+        [file1, file2],
+        { provider: Providers.OPENAI },
+        mockStrategyFunctions,
+      );
+
+      expect(mockedValidatePdf).toHaveBeenCalledTimes(2);
+      expect(mockedValidatePdf).toHaveBeenNthCalledWith(
+        1,
+        expect.any(Buffer),
+        expect.any(Number),
+        Providers.OPENAI,
+        mbToBytes(10),
+      );
+      expect(mockedValidatePdf).toHaveBeenNthCalledWith(
+        2,
+        expect.any(Buffer),
+        expect.any(Number),
+        Providers.OPENAI,
+        mbToBytes(10),
+      );
+    });
+  });
+
+  describe('Document formatting after validation', () => {
+    it('should format Anthropic document with valid PDF', async () => {
+      const req = createMockRequest(30) as ServerRequest;
+      const file = createMockFile(20);
+
+      const mockContent = Buffer.from('test-pdf-content').toString('base64');
+      mockedGetFileStream.mockResolvedValue({
+        file,
+        content: mockContent,
+        metadata: file,
+      });
+
+      mockedValidatePdf.mockResolvedValue({ isValid: true });
+
+      const result = await encodeAndFormatDocuments(
+        req,
+        [file],
+        { provider: Providers.ANTHROPIC },
+        mockStrategyFunctions,
+      );
+
+      expect(result.documents).toHaveLength(1);
+      expect(result.documents[0]).toMatchObject({
+        type: 'document',
+        source: {
+          type: 'base64',
+          media_type: 'application/pdf',
+          data: mockContent,
+        },
+        citations: { enabled: true },
+      });
+    });
+
+    it('should format OpenAI document with responses API', async () => {
+      const req = createMockRequest(15) as ServerRequest;
+      const file = createMockFile(10);
+
+      const mockContent = Buffer.from('test-pdf-content').toString('base64');
+      mockedGetFileStream.mockResolvedValue({
+        file,
+        content: mockContent,
+        metadata: file,
+      });
+
+      mockedValidatePdf.mockResolvedValue({ isValid: true });
+
+      const result = await encodeAndFormatDocuments(
+        req,
+        [file],
+        { provider: Providers.OPENAI, useResponsesApi: true },
+        mockStrategyFunctions,
+      );
+
+      expect(result.documents).toHaveLength(1);
+      expect(result.documents[0]).toMatchObject({
+        type: 'input_file',
+        filename: 'test.pdf',
+        file_data: `data:application/pdf;base64,${mockContent}`,
+      });
+    });
+  });
+});
diff --git a/packages/api/src/files/encode/document.ts b/packages/api/src/files/encode/document.ts
index 338a4ddea6..dbe829b09f 100644
--- a/packages/api/src/files/encode/document.ts
+++ b/packages/api/src/files/encode/document.ts
@@ -1,10 +1,14 @@
 import { Providers } from '@librechat/agents';
 import { isOpenAILikeProvider, isDocumentSupportedProvider } from 'librechat-data-provider';
 import type { IMongoFile } from '@librechat/data-schemas';
-import type { Request } from 'express';
-import type { StrategyFunctions, DocumentResult, AnthropicDocumentBlock } from '~/types/files';
+import type {
+  AnthropicDocumentBlock,
+  StrategyFunctions,
+  DocumentResult,
+  ServerRequest,
+} from '~/types';
+import { getFileStream, getConfiguredFileSizeLimit } from './utils';
 import { validatePdf } from '~/files/validation';
-import { getFileStream } from './utils';
 
 /**
  * Processes and encodes document files for various providers
@@ -15,7 +19,7 @@ import { getFileStream } from './utils';
  * @returns Promise that resolves to documents and file metadata
  */
 export async function encodeAndFormatDocuments(
-  req: Request,
+  req: ServerRequest,
   files: IMongoFile[],
   { provider, useResponsesApi }: { provider: Providers; useResponsesApi?: boolean },
   getStrategyFunctions: (source: string) => StrategyFunctions,
@@ -62,7 +66,16 @@ export async function encodeAndFormatDocuments(
 
     if (file.type === 'application/pdf' && isDocumentSupportedProvider(provider)) {
       const pdfBuffer = Buffer.from(content, 'base64');
-      const validation = await validatePdf(pdfBuffer, pdfBuffer.length, provider);
+
+      /** Extract configured file size limit from fileConfig for this endpoint */
+      const configuredFileSizeLimit = getConfiguredFileSizeLimit(req, provider);
+
+      const validation = await validatePdf(
+        pdfBuffer,
+        pdfBuffer.length,
+        provider,
+        configuredFileSizeLimit,
+      );
 
       if (!validation.isValid) {
         throw new Error(`PDF validation failed: ${validation.error}`);
diff --git a/packages/api/src/files/encode/utils.ts b/packages/api/src/files/encode/utils.ts
index 3664e074c9..4f77703836 100644
--- a/packages/api/src/files/encode/utils.ts
+++ b/packages/api/src/files/encode/utils.ts
@@ -1,8 +1,26 @@
 import getStream from 'get-stream';
-import { FileSources } from 'librechat-data-provider';
+import { Providers } from '@librechat/agents';
+import { FileSources, mergeFileConfig } from 'librechat-data-provider';
 import type { IMongoFile } from '@librechat/data-schemas';
-import type { Request } from 'express';
-import type { StrategyFunctions, ProcessedFile } from '~/types/files';
+import type { ServerRequest, StrategyFunctions, ProcessedFile } from '~/types';
+
+/**
+ * Extracts the configured file size limit for a specific provider from fileConfig
+ * @param req - The server request object containing config
+ * @param provider - The provider to get the limit for
+ * @returns The configured file size limit in bytes, or undefined if not configured
+ */
+export const getConfiguredFileSizeLimit = (
+  req: ServerRequest,
+  provider: Providers,
+): number | undefined => {
+  if (!req.config?.fileConfig) {
+    return undefined;
+  }
+  const fileConfig = mergeFileConfig(req.config.fileConfig);
+  const endpointConfig = fileConfig.endpoints[provider] ?? fileConfig.endpoints.default;
+  return endpointConfig?.fileSizeLimit;
+};
 
 /**
  * Processes a file by downloading and encoding it to base64
@@ -13,7 +31,7 @@ import type { StrategyFunctions, ProcessedFile } from '~/types/files';
  * @returns Processed file with content and metadata, or null if filepath missing
  */
 export async function getFileStream(
-  req: Request,
+  req: ServerRequest,
   file: IMongoFile,
   encodingMethods: Record<string, StrategyFunctions>,
   getStrategyFunctions: (source: string) => StrategyFunctions,
diff --git a/packages/api/src/files/encode/video.ts b/packages/api/src/files/encode/video.ts
index 10fd4c691f..34e25c2296 100644
--- a/packages/api/src/files/encode/video.ts
+++ b/packages/api/src/files/encode/video.ts
@@ -1,10 +1,9 @@
 import { Providers } from '@librechat/agents';
 import { isDocumentSupportedProvider } from 'librechat-data-provider';
 import type { IMongoFile } from '@librechat/data-schemas';
-import type { Request } from 'express';
-import type { StrategyFunctions, VideoResult } from '~/types/files';
+import type { ServerRequest, StrategyFunctions, VideoResult } from '~/types';
+import { getFileStream, getConfiguredFileSizeLimit } from './utils';
 import { validateVideo } from '~/files/validation';
-import { getFileStream } from './utils';
 
 /**
  * Encodes and formats video files for different providers
@@ -15,7 +14,7 @@ import { getFileStream } from './utils';
  * @returns Promise that resolves to videos and file metadata
  */
 export async function encodeAndFormatVideos(
-  req: Request,
+  req: ServerRequest,
   files: IMongoFile[],
   provider: Providers,
   getStrategyFunctions: (source: string) => StrategyFunctions,
@@ -53,7 +52,16 @@ export async function encodeAndFormatVideos(
     }
 
     const videoBuffer = Buffer.from(content, 'base64');
-    const validation = await validateVideo(videoBuffer, videoBuffer.length, provider);
+
+    /** Extract configured file size limit from fileConfig for this endpoint */
+    const configuredFileSizeLimit = getConfiguredFileSizeLimit(req, provider);
+
+    const validation = await validateVideo(
+      videoBuffer,
+      videoBuffer.length,
+      provider,
+      configuredFileSizeLimit,
+    );
 
     if (!validation.isValid) {
       throw new Error(`Video validation failed: ${validation.error}`);
diff --git a/packages/api/src/files/text.ts b/packages/api/src/files/text.ts
index 06e781bb5f..e560f266a3 100644
--- a/packages/api/src/files/text.ts
+++ b/packages/api/src/files/text.ts
@@ -3,7 +3,7 @@ import FormData from 'form-data';
 import { createReadStream } from 'fs';
 import { logger } from '@librechat/data-schemas';
 import { FileSources } from 'librechat-data-provider';
-import type { Request as ServerRequest } from 'express';
+import type { ServerRequest } from '~/types';
 import { logAxiosError, readFileAsString } from '~/utils';
 import { generateShortLivedToken } from '~/crypto/jwt';
 
@@ -20,9 +20,7 @@ export async function parseText({
   file,
   file_id,
 }: {
-  req: Pick<ServerRequest, 'user'> & {
-    user?: { id: string };
-  };
+  req: ServerRequest;
   file: Express.Multer.File;
   file_id: string;
 }): Promise<{ text: string; bytes: number; source: string }> {
diff --git a/packages/api/src/files/validation.spec.ts b/packages/api/src/files/validation.spec.ts
new file mode 100644
index 0000000000..384f499f43
--- /dev/null
+++ b/packages/api/src/files/validation.spec.ts
@@ -0,0 +1,558 @@
+import { Providers } from '@librechat/agents';
+import { mbToBytes } from 'librechat-data-provider';
+import { validatePdf, validateVideo, validateAudio } from './validation';
+
+describe('PDF Validation with fileConfig.endpoints.*.fileSizeLimit', () => {
+  /** Helper to create a PDF buffer with valid header */
+  const createMockPdfBuffer = (sizeInMB: number): Buffer => {
+    const bytes = Math.floor(sizeInMB * 1024 * 1024);
+    const buffer = Buffer.alloc(bytes);
+    buffer.write('%PDF-1.4\n', 0);
+    return buffer;
+  };
+
+  describe('validatePdf - OpenAI provider', () => {
+    const provider = Providers.OPENAI;
+
+    it('should accept PDF within provider limit when no config provided', async () => {
+      const pdfBuffer = createMockPdfBuffer(8);
+      const result = await validatePdf(pdfBuffer, pdfBuffer.length, provider);
+
+      expect(result.isValid).toBe(true);
+      expect(result.error).toBeUndefined();
+    });
+
+    it('should reject PDF exceeding provider limit when no config provided', async () => {
+      const pdfBuffer = createMockPdfBuffer(12);
+      const result = await validatePdf(pdfBuffer, pdfBuffer.length, provider);
+
+      expect(result.isValid).toBe(false);
+      expect(result.error).toContain('12MB');
+      expect(result.error).toContain('10MB');
+    });
+
+    it('should use configured limit when it is lower than provider limit', async () => {
+      const configuredLimit = 5 * 1024 * 1024; // 5MB
+      const pdfBuffer = createMockPdfBuffer(7); // Between configured and provider limit
+      const result = await validatePdf(pdfBuffer, pdfBuffer.length, provider, configuredLimit);
+
+      expect(result.isValid).toBe(false);
+      expect(result.error).toContain('7MB');
+      expect(result.error).toContain('5MB');
+    });
+
+    it('should allow configured limit higher than provider default', async () => {
+      const configuredLimit = 50 * 1024 * 1024; // 50MB (higher than 10MB provider default)
+      const pdfBuffer = createMockPdfBuffer(12); // Between provider default and configured limit
+      const result = await validatePdf(pdfBuffer, pdfBuffer.length, provider, configuredLimit);
+
+      expect(result.isValid).toBe(true);
+      expect(result.error).toBeUndefined();
+    });
+
+    it('should accept PDF within both configured and provider limits', async () => {
+      const configuredLimit = 50 * 1024 * 1024; // 50MB
+      const pdfBuffer = createMockPdfBuffer(8);
+      const result = await validatePdf(pdfBuffer, pdfBuffer.length, provider, configuredLimit);
+
+      expect(result.isValid).toBe(true);
+      expect(result.error).toBeUndefined();
+    });
+
+    it('should accept PDF within lower configured limit', async () => {
+      const configuredLimit = 5 * 1024 * 1024; // 5MB
+      const pdfBuffer = createMockPdfBuffer(4);
+      const result = await validatePdf(pdfBuffer, pdfBuffer.length, provider, configuredLimit);
+
+      expect(result.isValid).toBe(true);
+      expect(result.error).toBeUndefined();
+    });
+
+    it('should handle exact limit size correctly', async () => {
+      const configuredLimit = 10 * 1024 * 1024; // Exactly 10MB
+      const pdfBuffer = Buffer.alloc(10 * 1024 * 1024);
+      pdfBuffer.write('%PDF-1.4\n', 0);
+      const result = await validatePdf(pdfBuffer, pdfBuffer.length, provider, configuredLimit);
+
+      expect(result.isValid).toBe(true);
+    });
+  });
+
+  describe('validatePdf - Anthropic provider', () => {
+    const provider = Providers.ANTHROPIC;
+
+    it('should accept PDF within provider limit when no config provided', async () => {
+      const pdfBuffer = createMockPdfBuffer(20);
+      const result = await validatePdf(pdfBuffer, pdfBuffer.length, provider);
+
+      expect(result.isValid).toBe(true);
+      expect(result.error).toBeUndefined();
+    });
+
+    it('should reject PDF exceeding provider limit when no config provided', async () => {
+      const pdfBuffer = createMockPdfBuffer(35);
+      const result = await validatePdf(pdfBuffer, pdfBuffer.length, provider);
+
+      expect(result.isValid).toBe(false);
+      expect(result.error).toContain('35MB');
+      expect(result.error).toContain('32MB');
+    });
+
+    it('should use configured limit when it is lower than provider limit', async () => {
+      const configuredLimit = mbToBytes(15); // 15MB
+      const pdfBuffer = createMockPdfBuffer(20); // Between configured and provider limit
+      const result = await validatePdf(pdfBuffer, pdfBuffer.length, provider, configuredLimit);
+
+      expect(result.isValid).toBe(false);
+      expect(result.error).toContain('20MB');
+      expect(result.error).toContain('15MB');
+    });
+
+    it('should allow configured limit higher than provider default', async () => {
+      const configuredLimit = mbToBytes(50); // 50MB (higher than 32MB provider default)
+      const pdfBuffer = createMockPdfBuffer(35); // Between provider default and configured limit
+      const result = await validatePdf(pdfBuffer, pdfBuffer.length, provider, configuredLimit);
+
+      expect(result.isValid).toBe(true);
+      expect(result.error).toBeUndefined();
+    });
+
+    it('should reject encrypted PDFs regardless of size', async () => {
+      const pdfBuffer = Buffer.alloc(1024);
+      pdfBuffer.write('%PDF-1.4\n', 0);
+      pdfBuffer.write('/Encrypt ', 100);
+      const result = await validatePdf(pdfBuffer, pdfBuffer.length, provider);
+
+      expect(result.isValid).toBe(false);
+      expect(result.error).toContain('encrypted');
+    });
+
+    it('should reject PDFs with invalid header', async () => {
+      const pdfBuffer = Buffer.alloc(1024);
+      pdfBuffer.write('INVALID', 0);
+      const result = await validatePdf(pdfBuffer, pdfBuffer.length, provider);
+
+      expect(result.isValid).toBe(false);
+      expect(result.error).toContain('PDF header');
+    });
+
+    it('should reject PDFs that are too small', async () => {
+      const pdfBuffer = Buffer.alloc(3);
+      const result = await validatePdf(pdfBuffer, pdfBuffer.length, provider);
+
+      expect(result.isValid).toBe(false);
+      expect(result.error).toContain('too small');
+    });
+  });
+
+  describe('validatePdf - Google provider', () => {
+    const provider = Providers.GOOGLE;
+
+    it('should accept PDF within provider limit when no config provided', async () => {
+      const pdfBuffer = createMockPdfBuffer(15);
+      const result = await validatePdf(pdfBuffer, pdfBuffer.length, provider);
+
+      expect(result.isValid).toBe(true);
+      expect(result.error).toBeUndefined();
+    });
+
+    it('should reject PDF exceeding provider limit when no config provided', async () => {
+      const pdfBuffer = createMockPdfBuffer(25);
+      const result = await validatePdf(pdfBuffer, pdfBuffer.length, provider);
+
+      expect(result.isValid).toBe(false);
+      expect(result.error).toContain('25MB');
+      expect(result.error).toContain('20MB');
+    });
+
+    it('should use configured limit when it is lower than provider limit', async () => {
+      const configuredLimit = 10 * 1024 * 1024; // 10MB
+      const pdfBuffer = createMockPdfBuffer(15); // Between configured and provider limit
+      const result = await validatePdf(pdfBuffer, pdfBuffer.length, provider, configuredLimit);
+
+      expect(result.isValid).toBe(false);
+      expect(result.error).toContain('15MB');
+      expect(result.error).toContain('10MB');
+    });
+
+    it('should allow configured limit higher than provider default', async () => {
+      const configuredLimit = 50 * 1024 * 1024; // 50MB (higher than 20MB provider default)
+      const pdfBuffer = createMockPdfBuffer(25); // Between provider default and configured limit
+      const result = await validatePdf(pdfBuffer, pdfBuffer.length, provider, configuredLimit);
+
+      expect(result.isValid).toBe(true);
+      expect(result.error).toBeUndefined();
+    });
+  });
+
+  describe('validatePdf - VertexAI provider', () => {
+    const provider = Providers.VERTEXAI;
+
+    it('should accept PDF within provider limit', async () => {
+      const pdfBuffer = createMockPdfBuffer(15);
+      const result = await validatePdf(pdfBuffer, pdfBuffer.length, provider);
+
+      expect(result.isValid).toBe(true);
+    });
+
+    it('should respect configured limit', async () => {
+      const configuredLimit = 10 * 1024 * 1024;
+      const pdfBuffer = createMockPdfBuffer(15);
+      const result = await validatePdf(pdfBuffer, pdfBuffer.length, provider, configuredLimit);
+
+      expect(result.isValid).toBe(false);
+      expect(result.error).toContain('10MB');
+    });
+  });
+
+  describe('validatePdf - Azure OpenAI provider', () => {
+    const provider = Providers.AZURE;
+
+    it('should accept PDF within OpenAI-like provider limit', async () => {
+      const pdfBuffer = createMockPdfBuffer(8);
+      const result = await validatePdf(pdfBuffer, pdfBuffer.length, provider);
+
+      expect(result.isValid).toBe(true);
+    });
+
+    it('should respect configured limit for Azure', async () => {
+      const configuredLimit = 5 * 1024 * 1024;
+      const pdfBuffer = createMockPdfBuffer(7);
+      const result = await validatePdf(pdfBuffer, pdfBuffer.length, provider, configuredLimit);
+
+      expect(result.isValid).toBe(false);
+    });
+  });
+
+  describe('validatePdf - Unsupported providers', () => {
+    it('should return valid for providers without specific validation', async () => {
+      const pdfBuffer = createMockPdfBuffer(100); // Very large file
+      const provider = 'unsupported' as Providers;
+      const result = await validatePdf(pdfBuffer, pdfBuffer.length, provider);
+
+      expect(result.isValid).toBe(true);
+    });
+  });
+
+  describe('Edge cases', () => {
+    it('should handle zero-configured limit', async () => {
+      const configuredLimit = 0;
+      const pdfBuffer = createMockPdfBuffer(1);
+      const result = await validatePdf(
+        pdfBuffer,
+        pdfBuffer.length,
+        Providers.OPENAI,
+        configuredLimit,
+      );
+
+      expect(result.isValid).toBe(false);
+      expect(result.error).toContain('0MB');
+    });
+
+    it('should handle very small PDF files', async () => {
+      const pdfBuffer = Buffer.alloc(100);
+      pdfBuffer.write('%PDF-1.4\n', 0);
+      const result = await validatePdf(
+        pdfBuffer,
+        pdfBuffer.length,
+        Providers.OPENAI,
+        10 * 1024 * 1024,
+      );
+
+      expect(result.isValid).toBe(true);
+    });
+
+    it('should handle configured limit equal to provider limit', async () => {
+      const configuredLimit = 10 * 1024 * 1024; // Same as OpenAI provider limit
+      const pdfBuffer = createMockPdfBuffer(12);
+      const result = await validatePdf(
+        pdfBuffer,
+        pdfBuffer.length,
+        Providers.OPENAI,
+        configuredLimit,
+      );
+
+      expect(result.isValid).toBe(false);
+      expect(result.error).toContain('10MB');
+    });
+
+    it('should use provider limit when configured limit is undefined', async () => {
+      const pdfBuffer = createMockPdfBuffer(12);
+      const result = await validatePdf(pdfBuffer, pdfBuffer.length, Providers.OPENAI, undefined);
+
+      expect(result.isValid).toBe(false);
+      expect(result.error).toContain('10MB');
+    });
+  });
+
+  describe('Bug reproduction - Original issue', () => {
+    it('should reproduce the original bug scenario from issue description', async () => {
+      /**
+       * Original bug: User configures openAI.fileSizeLimit = 50MB in librechat.yaml
+       * Uploads a 15MB PDF to OpenAI endpoint
+       * Expected: Should be accepted (within 50MB config)
+       * Actual (before fix): Rejected with "exceeds 10MB limit"
+       */
+      const configuredLimit = mbToBytes(50); // User configured 50MB
+      const pdfBuffer = createMockPdfBuffer(15); // User uploads 15MB file
+
+      const result = await validatePdf(
+        pdfBuffer,
+        pdfBuffer.length,
+        Providers.OPENAI,
+        configuredLimit,
+      );
+
+      /**
+       * After fix: Should be accepted because configured limit (50MB) overrides
+       * provider default (10MB), allowing for API changes
+       */
+      expect(result.isValid).toBe(true);
+      expect(result.error).toBeUndefined();
+    });
+
+    it('should allow user to set stricter limits than provider', async () => {
+      /**
+       * Use case: User wants to enforce stricter limits than provider allows
+       * User configures openAI.fileSizeLimit = 5MB
+       * Uploads a 7MB PDF to OpenAI endpoint
+       * Expected: Should be rejected (exceeds 5MB configured limit)
+       */
+      const configuredLimit = mbToBytes(5); // User configured 5MB
+      const pdfBuffer = createMockPdfBuffer(7); // User uploads 7MB file
+
+      const result = await validatePdf(
+        pdfBuffer,
+        pdfBuffer.length,
+        Providers.OPENAI,
+        configuredLimit,
+      );
+
+      expect(result.isValid).toBe(false);
+      expect(result.error).toContain('7MB');
+      expect(result.error).toContain('5MB');
+    });
+
+    it('should allow upload within stricter user-configured limit', async () => {
+      /**
+       * User configures openAI.fileSizeLimit = 5MB
+       * Uploads a 4MB PDF
+       * Expected: Should be accepted
+       */
+      const configuredLimit = mbToBytes(5);
+      const pdfBuffer = createMockPdfBuffer(4);
+
+      const result = await validatePdf(
+        pdfBuffer,
+        pdfBuffer.length,
+        Providers.OPENAI,
+        configuredLimit,
+      );
+
+      expect(result.isValid).toBe(true);
+      expect(result.error).toBeUndefined();
+    });
+  });
+
+  describe('Video and Audio Validation with fileConfig', () => {
+    /** Helper to create a mock video/audio buffer */
+    const createMockMediaBuffer = (sizeInMB: number): Buffer => {
+      const bytes = Math.floor(sizeInMB * 1024 * 1024);
+      return Buffer.alloc(bytes);
+    };
+
+    describe('validateVideo - Google provider', () => {
+      const provider = Providers.GOOGLE;
+
+      it('should accept video within provider limit when no config provided', async () => {
+        const videoBuffer = createMockMediaBuffer(15);
+        const result = await validateVideo(videoBuffer, videoBuffer.length, provider);
+
+        expect(result.isValid).toBe(true);
+        expect(result.error).toBeUndefined();
+      });
+
+      it('should reject video exceeding provider limit when no config provided', async () => {
+        const videoBuffer = createMockMediaBuffer(25);
+        const result = await validateVideo(videoBuffer, videoBuffer.length, provider);
+
+        expect(result.isValid).toBe(false);
+        expect(result.error).toContain('25MB');
+        expect(result.error).toContain('20MB');
+      });
+
+      it('should use configured limit when it is lower than provider limit', async () => {
+        const configuredLimit = mbToBytes(10); // 10MB
+        const videoBuffer = createMockMediaBuffer(15); // Between configured and provider limit
+        const result = await validateVideo(
+          videoBuffer,
+          videoBuffer.length,
+          provider,
+          configuredLimit,
+        );
+
+        expect(result.isValid).toBe(false);
+        expect(result.error).toContain('15MB');
+        expect(result.error).toContain('10MB');
+      });
+
+      it('should allow configured limit higher than provider default', async () => {
+        const configuredLimit = mbToBytes(50); // 50MB (higher than 20MB provider default)
+        const videoBuffer = createMockMediaBuffer(25); // Between provider default and configured limit
+        const result = await validateVideo(
+          videoBuffer,
+          videoBuffer.length,
+          provider,
+          configuredLimit,
+        );
+
+        expect(result.isValid).toBe(true);
+        expect(result.error).toBeUndefined();
+      });
+
+      it('should accept video within lower configured limit', async () => {
+        const configuredLimit = mbToBytes(8);
+        const videoBuffer = createMockMediaBuffer(7);
+        const result = await validateVideo(
+          videoBuffer,
+          videoBuffer.length,
+          provider,
+          configuredLimit,
+        );
+
+        expect(result.isValid).toBe(true);
+        expect(result.error).toBeUndefined();
+      });
+
+      it('should reject videos that are too small', async () => {
+        const videoBuffer = Buffer.alloc(5);
+        const result = await validateVideo(videoBuffer, videoBuffer.length, provider);
+
+        expect(result.isValid).toBe(false);
+        expect(result.error).toContain('too small');
+      });
+    });
+
+    describe('validateAudio - Google provider', () => {
+      const provider = Providers.GOOGLE;
+
+      it('should accept audio within provider limit when no config provided', async () => {
+        const audioBuffer = createMockMediaBuffer(15);
+        const result = await validateAudio(audioBuffer, audioBuffer.length, provider);
+
+        expect(result.isValid).toBe(true);
+        expect(result.error).toBeUndefined();
+      });
+
+      it('should reject audio exceeding provider limit when no config provided', async () => {
+        const audioBuffer = createMockMediaBuffer(25);
+        const result = await validateAudio(audioBuffer, audioBuffer.length, provider);
+
+        expect(result.isValid).toBe(false);
+        expect(result.error).toContain('25MB');
+        expect(result.error).toContain('20MB');
+      });
+
+      it('should use configured limit when it is lower than provider limit', async () => {
+        const configuredLimit = mbToBytes(10); // 10MB
+        const audioBuffer = createMockMediaBuffer(15); // Between configured and provider limit
+        const result = await validateAudio(
+          audioBuffer,
+          audioBuffer.length,
+          provider,
+          configuredLimit,
+        );
+
+        expect(result.isValid).toBe(false);
+        expect(result.error).toContain('15MB');
+        expect(result.error).toContain('10MB');
+      });
+
+      it('should allow configured limit higher than provider default', async () => {
+        const configuredLimit = mbToBytes(50); // 50MB (higher than 20MB provider default)
+        const audioBuffer = createMockMediaBuffer(25); // Between provider default and configured limit
+        const result = await validateAudio(
+          audioBuffer,
+          audioBuffer.length,
+          provider,
+          configuredLimit,
+        );
+
+        expect(result.isValid).toBe(true);
+        expect(result.error).toBeUndefined();
+      });
+
+      it('should accept audio within lower configured limit', async () => {
+        const configuredLimit = mbToBytes(8);
+        const audioBuffer = createMockMediaBuffer(7);
+        const result = await validateAudio(
+          audioBuffer,
+          audioBuffer.length,
+          provider,
+          configuredLimit,
+        );
+
+        expect(result.isValid).toBe(true);
+        expect(result.error).toBeUndefined();
+      });
+
+      it('should reject audio files that are too small', async () => {
+        const audioBuffer = Buffer.alloc(5);
+        const result = await validateAudio(audioBuffer, audioBuffer.length, provider);
+
+        expect(result.isValid).toBe(false);
+        expect(result.error).toContain('too small');
+      });
+    });
+
+    describe('validateVideo and validateAudio - VertexAI provider', () => {
+      const provider = Providers.VERTEXAI;
+
+      it('should respect configured video limit for VertexAI', async () => {
+        const configuredLimit = mbToBytes(10);
+        const videoBuffer = createMockMediaBuffer(15);
+        const result = await validateVideo(
+          videoBuffer,
+          videoBuffer.length,
+          provider,
+          configuredLimit,
+        );
+
+        expect(result.isValid).toBe(false);
+        expect(result.error).toContain('10MB');
+      });
+
+      it('should respect configured audio limit for VertexAI', async () => {
+        const configuredLimit = mbToBytes(10);
+        const audioBuffer = createMockMediaBuffer(15);
+        const result = await validateAudio(
+          audioBuffer,
+          audioBuffer.length,
+          provider,
+          configuredLimit,
+        );
+
+        expect(result.isValid).toBe(false);
+        expect(result.error).toContain('10MB');
+      });
+    });
+
+    describe('validateVideo and validateAudio - Unsupported providers', () => {
+      it('should return valid for video from unsupported provider', async () => {
+        const videoBuffer = createMockMediaBuffer(100);
+        const provider = Providers.OPENAI;
+        const result = await validateVideo(videoBuffer, videoBuffer.length, provider);
+
+        expect(result.isValid).toBe(true);
+      });
+
+      it('should return valid for audio from unsupported provider', async () => {
+        const audioBuffer = createMockMediaBuffer(100);
+        const provider = Providers.OPENAI;
+        const result = await validateAudio(audioBuffer, audioBuffer.length, provider);
+
+        expect(result.isValid).toBe(true);
+      });
+    });
+  });
+});
diff --git a/packages/api/src/files/validation.ts b/packages/api/src/files/validation.ts
index a8394fd8f6..7c1eccd8ed 100644
--- a/packages/api/src/files/validation.ts
+++ b/packages/api/src/files/validation.ts
@@ -20,17 +20,18 @@ export async function validatePdf(
   pdfBuffer: Buffer,
   fileSize: number,
   provider: Providers,
+  configuredFileSizeLimit?: number,
 ): Promise<PDFValidationResult> {
   if (provider === Providers.ANTHROPIC) {
-    return validateAnthropicPdf(pdfBuffer, fileSize);
+    return validateAnthropicPdf(pdfBuffer, fileSize, configuredFileSizeLimit);
   }
 
   if (isOpenAILikeProvider(provider)) {
-    return validateOpenAIPdf(fileSize);
+    return validateOpenAIPdf(fileSize, configuredFileSizeLimit);
   }
 
   if (provider === Providers.GOOGLE || provider === Providers.VERTEXAI) {
-    return validateGooglePdf(fileSize);
+    return validateGooglePdf(fileSize, configuredFileSizeLimit);
   }
 
   return { isValid: true };
@@ -40,17 +41,23 @@ export async function validatePdf(
  * Validates if a PDF meets Anthropic's requirements
  * @param pdfBuffer - The PDF file as a buffer
  * @param fileSize - The file size in bytes
+ * @param configuredFileSizeLimit - Optional configured file size limit from fileConfig (in bytes)
  * @returns Promise that resolves to validation result
  */
 async function validateAnthropicPdf(
   pdfBuffer: Buffer,
   fileSize: number,
+  configuredFileSizeLimit?: number,
 ): Promise<PDFValidationResult> {
   try {
-    if (fileSize > mbToBytes(32)) {
+    const providerLimit = mbToBytes(32);
+    const effectiveLimit = configuredFileSizeLimit ?? providerLimit;
+
+    if (fileSize > effectiveLimit) {
+      const limitMB = Math.round(effectiveLimit / (1024 * 1024));
       return {
         isValid: false,
-        error: `PDF file size (${Math.round(fileSize / (1024 * 1024))}MB) exceeds Anthropic's 32MB limit`,
+        error: `PDF file size (${Math.round(fileSize / (1024 * 1024))}MB) exceeds the ${limitMB}MB limit`,
       };
     }
 
@@ -101,22 +108,48 @@ async function validateAnthropicPdf(
   }
 }
 
-async function validateOpenAIPdf(fileSize: number): Promise<PDFValidationResult> {
-  if (fileSize > 10 * 1024 * 1024) {
+/**
+ * Validates if a PDF meets OpenAI's requirements
+ * @param fileSize - The file size in bytes
+ * @param configuredFileSizeLimit - Optional configured file size limit from fileConfig (in bytes)
+ * @returns Promise that resolves to validation result
+ */
+async function validateOpenAIPdf(
+  fileSize: number,
+  configuredFileSizeLimit?: number,
+): Promise<PDFValidationResult> {
+  const providerLimit = mbToBytes(10);
+  const effectiveLimit = configuredFileSizeLimit ?? providerLimit;
+
+  if (fileSize > effectiveLimit) {
+    const limitMB = Math.round(effectiveLimit / (1024 * 1024));
     return {
       isValid: false,
-      error: "PDF file size exceeds OpenAI's 10MB limit",
+      error: `PDF file size (${Math.round(fileSize / (1024 * 1024))}MB) exceeds the ${limitMB}MB limit`,
     };
   }
 
   return { isValid: true };
 }
 
-async function validateGooglePdf(fileSize: number): Promise<PDFValidationResult> {
-  if (fileSize > 20 * 1024 * 1024) {
+/**
+ * Validates if a PDF meets Google's requirements
+ * @param fileSize - The file size in bytes
+ * @param configuredFileSizeLimit - Optional configured file size limit from fileConfig (in bytes)
+ * @returns Promise that resolves to validation result
+ */
+async function validateGooglePdf(
+  fileSize: number,
+  configuredFileSizeLimit?: number,
+): Promise<PDFValidationResult> {
+  const providerLimit = mbToBytes(20);
+  const effectiveLimit = configuredFileSizeLimit ?? providerLimit;
+
+  if (fileSize > effectiveLimit) {
+    const limitMB = Math.round(effectiveLimit / (1024 * 1024));
     return {
       isValid: false,
-      error: "PDF file size exceeds Google's 20MB limit",
+      error: `PDF file size (${Math.round(fileSize / (1024 * 1024))}MB) exceeds the ${limitMB}MB limit`,
     };
   }
 
@@ -128,18 +161,24 @@ async function validateGooglePdf(fileSize: number): Promise<PDFValidationResult>
  * @param videoBuffer - The video file as a buffer
  * @param fileSize - The file size in bytes
  * @param provider - The provider to validate for
+ * @param configuredFileSizeLimit - Optional configured file size limit from fileConfig (in bytes)
  * @returns Promise that resolves to validation result
  */
 export async function validateVideo(
   videoBuffer: Buffer,
   fileSize: number,
   provider: Providers,
+  configuredFileSizeLimit?: number,
 ): Promise<VideoValidationResult> {
   if (provider === Providers.GOOGLE || provider === Providers.VERTEXAI) {
-    if (fileSize > 20 * 1024 * 1024) {
+    const providerLimit = mbToBytes(20);
+    const effectiveLimit = configuredFileSizeLimit ?? providerLimit;
+
+    if (fileSize > effectiveLimit) {
+      const limitMB = Math.round(effectiveLimit / (1024 * 1024));
       return {
         isValid: false,
-        error: `Video file size (${Math.round(fileSize / (1024 * 1024))}MB) exceeds Google's 20MB limit`,
+        error: `Video file size (${Math.round(fileSize / (1024 * 1024))}MB) exceeds the ${limitMB}MB limit`,
       };
     }
   }
@@ -159,18 +198,24 @@ export async function validateVideo(
  * @param audioBuffer - The audio file as a buffer
  * @param fileSize - The file size in bytes
  * @param provider - The provider to validate for
+ * @param configuredFileSizeLimit - Optional configured file size limit from fileConfig (in bytes)
  * @returns Promise that resolves to validation result
  */
 export async function validateAudio(
   audioBuffer: Buffer,
   fileSize: number,
   provider: Providers,
+  configuredFileSizeLimit?: number,
 ): Promise<AudioValidationResult> {
   if (provider === Providers.GOOGLE || provider === Providers.VERTEXAI) {
-    if (fileSize > 20 * 1024 * 1024) {
+    const providerLimit = mbToBytes(20);
+    const effectiveLimit = configuredFileSizeLimit ?? providerLimit;
+
+    if (fileSize > effectiveLimit) {
+      const limitMB = Math.round(effectiveLimit / (1024 * 1024));
       return {
         isValid: false,
-        error: `Audio file size (${Math.round(fileSize / (1024 * 1024))}MB) exceeds Google's 20MB limit`,
+        error: `Audio file size (${Math.round(fileSize / (1024 * 1024))}MB) exceeds the ${limitMB}MB limit`,
       };
     }
   }
diff --git a/packages/api/src/types/files.ts b/packages/api/src/types/files.ts
index 5b25f0b3e9..06a9381ddf 100644
--- a/packages/api/src/types/files.ts
+++ b/packages/api/src/types/files.ts
@@ -1,7 +1,6 @@
 import type { IMongoFile } from '@librechat/data-schemas';
 import type { ServerRequest } from './http';
 import type { Readable } from 'stream';
-import type { Request } from 'express';
 export interface STTService {
   getInstance(): Promise<STTService>;
   getProviderSchema(req: ServerRequest): Promise<[string, object]>;
@@ -131,5 +130,5 @@ export interface ProcessedFile {
 }
 
 export interface StrategyFunctions {
-  getDownloadStream: (req: Request, filepath: string) => Promise<Readable>;
+  getDownloadStream: (req: ServerRequest, filepath: string) => Promise<Readable>;
 }
diff --git a/packages/api/src/types/http.ts b/packages/api/src/types/http.ts
index f57e4674f9..513ece3774 100644
--- a/packages/api/src/types/http.ts
+++ b/packages/api/src/types/http.ts
@@ -7,11 +7,12 @@ import type { IUser, AppConfig } from '@librechat/data-schemas';
  */
 export type RequestBody = {
   messageId?: string;
+  fileTokenLimit?: number;
   conversationId?: string;
   parentMessageId?: string;
 };
 
-export type ServerRequest = Request & {
+export type ServerRequest = Request<unknown, unknown, RequestBody> & {
   user?: IUser;
   config?: AppConfig;
 };
diff --git a/packages/data-provider/src/file-config.ts b/packages/data-provider/src/file-config.ts
index 3ad24da67a..327ce52490 100644
--- a/packages/data-provider/src/file-config.ts
+++ b/packages/data-provider/src/file-config.ts
@@ -317,6 +317,8 @@ export const fileConfigSchema = z.object({
     .optional(),
 });
 
+export type TFileConfig = z.infer<typeof fileConfigSchema>;
+
 /** Helper function to safely convert string patterns to RegExp objects */
 export const convertStringsToRegex = (patterns: string[]): RegExp[] =>
   patterns.reduce((acc: RegExp[], pattern) => {
diff --git a/packages/data-schemas/src/types/app.ts b/packages/data-schemas/src/types/app.ts
index 1078cb3f92..324aa151e4 100644
--- a/packages/data-schemas/src/types/app.ts
+++ b/packages/data-schemas/src/types/app.ts
@@ -1,6 +1,7 @@
 import type {
   TEndpoint,
   FileSources,
+  TFileConfig,
   TAzureConfig,
   TCustomConfig,
   TMemoryConfig,
@@ -82,7 +83,7 @@ export interface AppConfig {
   /** MCP server configuration */
   mcpConfig?: TCustomConfig['mcpServers'] | null;
   /** File configuration */
-  fileConfig?: TCustomConfig['fileConfig'];
+  fileConfig?: TFileConfig;
   /** Secure image links configuration */
   secureImageLinks?: TCustomConfig['secureImageLinks'];
   /** Processed model specifications */