From f95fa55cceacbac154ef7be9f52ef27ed65d2431 Mon Sep 17 00:00:00 2001
From: Danny Avila <danny@librechat.ai>
Date: Wed, 27 May 2026 22:00:53 -0700
Subject: [PATCH] =?UTF-8?q?=F0=9F=93=8E=20fix:=20Preserve=20Gemini=20PDF?=
 =?UTF-8?q?=20Media=20Blocks=20(#13357)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../api/src/files/encode/document.spec.ts     | 32 +++++++++++++++++++
 packages/api/src/files/encode/document.ts     | 31 ++++++++++++------
 2 files changed, 53 insertions(+), 10 deletions(-)

diff --git a/packages/api/src/files/encode/document.spec.ts b/packages/api/src/files/encode/document.spec.ts
index f285d47d5d..846b61eb88 100644
--- a/packages/api/src/files/encode/document.spec.ts
+++ b/packages/api/src/files/encode/document.spec.ts
@@ -749,6 +749,38 @@ describe('encodeAndFormatDocuments - fileConfig integration', () => {
         file_data: `data:application/pdf;base64,${mockContent}`,
       });
     });
+
+    it.each([Providers.GOOGLE, Providers.VERTEXAI] as const)(
+      'should format %s PDF as media block when responses API is enabled',
+      async (provider) => {
+        const req = createMockRequest(15, provider) 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, useResponsesApi: true },
+          mockStrategyFunctions,
+        );
+
+        expect(result.documents).toHaveLength(1);
+        expect(result.documents[0]).toMatchObject({
+          type: 'media',
+          mimeType: 'application/pdf',
+          data: mockContent,
+        });
+        expect(result.documents[0]).not.toHaveProperty('type', 'input_file');
+      },
+    );
   });
 
   describe('Generic document encoding path', () => {
diff --git a/packages/api/src/files/encode/document.ts b/packages/api/src/files/encode/document.ts
index f04ad43ef2..9f595fee1e 100644
--- a/packages/api/src/files/encode/document.ts
+++ b/packages/api/src/files/encode/document.ts
@@ -55,6 +55,14 @@ function formatDocumentBlock(
     return document;
   }
 
+  if (provider === Providers.GOOGLE || provider === Providers.VERTEXAI) {
+    return {
+      type: 'media',
+      mimeType,
+      data: content,
+    };
+  }
+
   const resolvedFilename = filename ?? 'document';
 
   if (useResponsesApi) {
@@ -65,14 +73,6 @@ function formatDocumentBlock(
     };
   }
 
-  if (provider === Providers.GOOGLE || provider === Providers.VERTEXAI) {
-    return {
-      type: 'media',
-      mimeType,
-      data: content,
-    };
-  }
-
   if (isOpenAILikeProvider(provider) && provider !== Providers.AZURE) {
     return {
       type: 'file',
@@ -86,6 +86,18 @@ function formatDocumentBlock(
   return null;
 }
 
+function getBase64DecodedByteCount(content: string): number {
+  let paddingChars = 0;
+
+  if (content.endsWith('==')) {
+    paddingChars = 2;
+  } else if (content.endsWith('=')) {
+    paddingChars = 1;
+  }
+
+  return Math.floor((content.length * 3) / 4) - paddingChars;
+}
+
 /**
  * Encodes and formats document files for various providers.
  *
@@ -208,8 +220,7 @@ export async function encodeAndFormatDocuments(
         result.files.push(metadata);
       }
     } else if (isDocSupported && !isBedrock) {
-      const paddingChars = content.endsWith('==') ? 2 : content.endsWith('=') ? 1 : 0;
-      const decodedByteCount = Math.floor((content.length * 3) / 4) - paddingChars;
+      const decodedByteCount = getBase64DecodedByteCount(content);
       if (configuredFileSizeLimit && decodedByteCount > configuredFileSizeLimit) {
         throw new Error(
           `File size (~${(decodedByteCount / 1024 / 1024).toFixed(1)}MB) exceeds the configured limit for ${provider}`,