🆔 fix: Atomic File Dedupe, Bedrock Tokens Fix, and Allowed MIME Types (#11675)

* feat: Add support for Apache Parquet MIME types

- Introduced 'application/x-parquet' to the full MIME types list and code interpreter MIME types list.
- Updated application MIME types regex to include 'x-parquet' and 'vnd.apache.parquet'.
- Added mapping for '.parquet' files to 'application/x-parquet' in code type mapping, enhancing file format support.

* feat: Implement atomic file claiming for code execution outputs

- Added a new `claimCodeFile` function to atomically claim a file_id for code execution outputs, preventing duplicates by using a compound key of filename and conversationId.
- Updated `processCodeOutput` to utilize the new claiming mechanism, ensuring that concurrent calls for the same filename converge on a single record.
- Refactored related tests to validate the new atomic claiming behavior and its impact on file usage tracking and versioning.

* fix: Update image file handling to use cache-busting filepath

- Modified the `processCodeOutput` function to generate a cache-busting filepath for updated image files, improving browser caching behavior.
- Adjusted related tests to reflect the change from versioned filenames to cache-busted filepaths, ensuring accurate validation of image updates.

* fix: Update step handler to prevent undefined content for non-tool call types

- Modified the condition in useStepHandler to ensure that undefined content is only assigned for specific content types, enhancing the robustness of content handling.

* fix: Update bedrockOutputParser to handle maxTokens for adaptive models

- Modified the bedrockOutputParser logic to ensure that maxTokens is not set for adaptive models when neither maxTokens nor maxOutputTokens are provided, improving the handling of adaptive thinking configurations.
- Updated related tests to reflect these changes, ensuring accurate validation of the output for adaptive models.

* chore: Update @librechat/agents to version 3.1.38 in package.json and package-lock.json

* fix: Enhance file claiming and error handling in code processing

- Updated the `processCodeOutput` function to use a consistent file ID for claiming files, preventing duplicates and improving concurrency handling.
- Refactored the `createFileMethods` to include error handling for failed file claims, ensuring robust behavior when claiming files for conversations.
- These changes enhance the reliability of file management in the application.

* fix: Update adaptive thinking test for Opus 4.6 model

- Modified the test for configuring adaptive thinking to reflect that no default maxTokens should be set for the Opus 4.6 model.
- Updated assertions to ensure that maxTokens is undefined, aligning with the expected behavior for adaptive models.

Author: danny-avila

api/package.json

@@ -44,7 +44,7 @@
     "@google/genai": "^1.19.0",
     "@keyv/redis": "^4.3.3",
     "@langchain/core": "^0.3.80",
-    "@librechat/agents": "^3.1.37",
+    "@librechat/agents": "^3.1.38",
     "@librechat/api": "*",
     "@librechat/data-schemas": "*",
     "@microsoft/microsoft-graph-client": "^3.0.7",

api/server/services/Files/Code/process.js

@@ -18,9 +18,9 @@ const {
   getEndpointFileConfig,
 } = require('librechat-data-provider');
 const { filterFilesByAgentAccess } = require('~/server/services/Files/permissions');
+const { createFile, getFiles, updateFile, claimCodeFile } = require('~/models');
 const { getStrategyFunctions } = require('~/server/services/Files/strategies');
 const { convertImage } = require('~/server/services/Files/images/convert');
-const { createFile, getFiles, updateFile } = require('~/models');
 const { determineFileType } = require('~/server/utils');
 
 /**
@@ -56,50 +56,6 @@ const createDownloadFallback = ({
   };
 };
 
-/**
- * Find an existing code-generated file by filename in the conversation.
- * Used to update existing files instead of creating duplicates.
- *
- * ## Deduplication Strategy
- *
- * Files are deduplicated by `(conversationId, filename)` - NOT including `messageId`.
- * This is an intentional design decision to handle iterative code development patterns:
- *
- * **Rationale:**
- * - When users iteratively refine code (e.g., "regenerate that chart with red bars"),
- *   the same logical file (e.g., "chart.png") is produced multiple times
- * - Without deduplication, each iteration would create a new file, leading to storage bloat
- * - The latest version is what matters for re-upload to the code environment
- *
- * **Implications:**
- * - Different messages producing files with the same name will update the same file record
- * - The `messageId` field tracks which message last updated the file
- * - The `usage` counter tracks how many times the file has been generated
- *
- * **Future Considerations:**
- * - If file versioning is needed, consider adding a `versions` array or separate version collection
- * - The current approach prioritizes storage efficiency over history preservation
- *
- * @param {string} filename - The filename to search for.
- * @param {string} conversationId - The conversation ID.
- * @returns {Promise<MongoFile | null>} The existing file or null.
- */
-const findExistingCodeFile = async (filename, conversationId) => {
-  if (!filename || !conversationId) {
-    return null;
-  }
-  const files = await getFiles(
-    {
-      filename,
-      conversationId,
-      context: FileContext.execute_code,
-    },
-    { createdAt: -1 },
-    { text: 0 },
-  );
-  return files?.[0] ?? null;
-};
-
 /**
  * Process code execution output files - downloads and saves both images and non-image files.
  * All files are saved to local storage with fileIdentifier metadata for code env re-upload.
@@ -170,12 +126,19 @@ const processCodeOutput = async ({
     const fileIdentifier = `${session_id}/${id}`;
 
     /**
-     * Check for existing file with same filename in this conversation.
-     * If found, we'll update it instead of creating a duplicate.
+     * Atomically claim a file_id for this (filename, conversationId, context) tuple.
+     * Uses $setOnInsert so concurrent calls for the same filename converge on
+     * a single record instead of creating duplicates (TOCTOU race fix).
      */
-    const existingFile = await findExistingCodeFile(name, conversationId);
-    const file_id = existingFile?.file_id ?? v4();
-    const isUpdate = !!existingFile;
+    const newFileId = v4();
+    const claimed = await claimCodeFile({
+      filename: name,
+      conversationId,
+      file_id: newFileId,
+      user: req.user.id,
+    });
+    const file_id = claimed.file_id;
+    const isUpdate = file_id !== newFileId;
 
     if (isUpdate) {
       logger.debug(
@@ -184,27 +147,29 @@ const processCodeOutput = async ({
     }
 
     if (isImage) {
+      const usage = isUpdate ? (claimed.usage ?? 0) + 1 : 1;
       const _file = await convertImage(req, buffer, 'high', `${file_id}${fileExt}`);
+      const filepath = usage > 1 ? `${_file.filepath}?v=${Date.now()}` : _file.filepath;
       const file = {
         ..._file,
+        filepath,
         file_id,
         messageId,
-        usage: isUpdate ? (existingFile.usage ?? 0) + 1 : 1,
+        usage,
         filename: name,
         conversationId,
         user: req.user.id,
         type: `image/${appConfig.imageOutputType}`,
-        createdAt: isUpdate ? existingFile.createdAt : formattedDate,
+        createdAt: isUpdate ? claimed.createdAt : formattedDate,
         updatedAt: formattedDate,
         source: appConfig.fileStrategy,
         context: FileContext.execute_code,
         metadata: { fileIdentifier },
       };
-      createFile(file, true);
+      await createFile(file, true);
       return Object.assign(file, { messageId, toolCallId });
     }
 
-    // For non-image files, save to configured storage strategy
     const { saveBuffer } = getStrategyFunctions(appConfig.fileStrategy);
     if (!saveBuffer) {
       logger.warn(
@@ -221,7 +186,6 @@ const processCodeOutput = async ({
       });
     }
 
-    // Determine MIME type from buffer or extension
     const detectedType = await determineFileType(buffer, true);
     const mimeType = detectedType?.mime || inferMimeType(name, '') || 'application/octet-stream';
 
@@ -258,11 +222,11 @@ const processCodeOutput = async ({
       metadata: { fileIdentifier },
       source: appConfig.fileStrategy,
       context: FileContext.execute_code,
-      usage: isUpdate ? (existingFile.usage ?? 0) + 1 : 1,
-      createdAt: isUpdate ? existingFile.createdAt : formattedDate,
+      usage: isUpdate ? (claimed.usage ?? 0) + 1 : 1,
+      createdAt: isUpdate ? claimed.createdAt : formattedDate,
     };
 
-    createFile(file, true);
+    await createFile(file, true);
     return Object.assign(file, { messageId, toolCallId });
   } catch (error) {
     logAxiosError({

api/server/services/Files/Code/process.spec.js

@@ -61,10 +61,12 @@ jest.mock('@librechat/api', () => ({
 }));
 
 // Mock models
+const mockClaimCodeFile = jest.fn();
 jest.mock('~/models', () => ({
-  createFile: jest.fn(),
+  createFile: jest.fn().mockResolvedValue({}),
   getFiles: jest.fn(),
   updateFile: jest.fn(),
+  claimCodeFile: (...args) => mockClaimCodeFile(...args),
 }));
 
 // Mock permissions (must be before process.js import)
@@ -119,7 +121,11 @@ describe('Code Process', () => {
 
   beforeEach(() => {
     jest.clearAllMocks();
-    // Default mock implementations
+    // Default mock: atomic claim returns a new file record (no existing file)
+    mockClaimCodeFile.mockResolvedValue({
+      file_id: 'mock-uuid-1234',
+      user: 'user-123',
+    });
     getFiles.mockResolvedValue(null);
     createFile.mockResolvedValue({});
     getStrategyFunctions.mockReturnValue({
@@ -128,67 +134,46 @@ describe('Code Process', () => {
     determineFileType.mockResolvedValue({ mime: 'text/plain' });
   });
 
-  describe('findExistingCodeFile (via processCodeOutput)', () => {
-    it('should find existing file by filename and conversationId', async () => {
-      const existingFile = {
+  describe('atomic file claim (via processCodeOutput)', () => {
+    it('should reuse file_id from existing record via atomic claim', async () => {
+      mockClaimCodeFile.mockResolvedValue({
         file_id: 'existing-file-id',
         filename: 'test-file.txt',
         usage: 2,
         createdAt: '2024-01-01T00:00:00.000Z',
-      };
-      getFiles.mockResolvedValue([existingFile]);
+      });
 
       const smallBuffer = Buffer.alloc(100);
       axios.mockResolvedValue({ data: smallBuffer });
 
       const result = await processCodeOutput(baseParams);
 
-      // Verify getFiles was called with correct deduplication query
-      expect(getFiles).toHaveBeenCalledWith(
-        {
-          filename: 'test-file.txt',
-          conversationId: 'conv-123',
-          context: FileContext.execute_code,
-        },
-        { createdAt: -1 },
-        { text: 0 },
-      );
+      expect(mockClaimCodeFile).toHaveBeenCalledWith({
+        filename: 'test-file.txt',
+        conversationId: 'conv-123',
+        file_id: 'mock-uuid-1234',
+        user: 'user-123',
+      });
 
-      // Verify the existing file_id was reused
       expect(result.file_id).toBe('existing-file-id');
-      // Verify usage was incremented
       expect(result.usage).toBe(3);
-      // Verify original createdAt was preserved
       expect(result.createdAt).toBe('2024-01-01T00:00:00.000Z');
     });
 
     it('should create new file when no existing file found', async () => {
-      getFiles.mockResolvedValue(null);
+      mockClaimCodeFile.mockResolvedValue({
+        file_id: 'mock-uuid-1234',
+        user: 'user-123',
+      });
 
       const smallBuffer = Buffer.alloc(100);
       axios.mockResolvedValue({ data: smallBuffer });
 
       const result = await processCodeOutput(baseParams);
 
-      // Should use the mocked uuid
       expect(result.file_id).toBe('mock-uuid-1234');
-      // Should have usage of 1 for new file
       expect(result.usage).toBe(1);
     });
-
-    it('should return null for invalid inputs (empty filename)', async () => {
-      const smallBuffer = Buffer.alloc(100);
-      axios.mockResolvedValue({ data: smallBuffer });
-
-      // The function handles this internally - with empty name
-      // findExistingCodeFile returns null early for empty filename (guard clause)
-      const result = await processCodeOutput({ ...baseParams, name: '' });
-
-      // getFiles should NOT be called due to early return in findExistingCodeFile
-      expect(getFiles).not.toHaveBeenCalled();
-      // A new file_id should be generated since no existing file was found
-      expect(result.file_id).toBe('mock-uuid-1234');
-    });
   });
 
   describe('processCodeOutput', () => {
@@ -203,7 +188,6 @@ describe('Code Process', () => {
           bytes: 400,
         };
         convertImage.mockResolvedValue(convertedFile);
-        getFiles.mockResolvedValue(null);
 
         const result = await processCodeOutput(imageParams);
 
@@ -218,23 +202,29 @@ describe('Code Process', () => {
         expect(result.filename).toBe('chart.png');
       });
 
-      it('should update existing image file and increment usage', async () => {
+      it('should update existing image file with cache-busted filepath', async () => {
         const imageParams = { ...baseParams, name: 'chart.png' };
-        const existingFile = {
+        mockClaimCodeFile.mockResolvedValue({
           file_id: 'existing-img-id',
           usage: 1,
           createdAt: '2024-01-01T00:00:00.000Z',
-        };
-        getFiles.mockResolvedValue([existingFile]);
+        });
 
         const imageBuffer = Buffer.alloc(500);
         axios.mockResolvedValue({ data: imageBuffer });
-        convertImage.mockResolvedValue({ filepath: '/uploads/img.webp' });
+        convertImage.mockResolvedValue({ filepath: '/images/user-123/existing-img-id.webp' });
 
         const result = await processCodeOutput(imageParams);
 
+        expect(convertImage).toHaveBeenCalledWith(
+          mockReq,
+          imageBuffer,
+          'high',
+          'existing-img-id.png',
+        );
         expect(result.file_id).toBe('existing-img-id');
         expect(result.usage).toBe(2);
+        expect(result.filepath).toMatch(/^\/images\/user-123\/existing-img-id\.webp\?v=\d+$/);
         expect(logger.debug).toHaveBeenCalledWith(
           expect.stringContaining('Updating existing file'),
         );
@@ -335,7 +325,6 @@ describe('Code Process', () => {
 
     describe('usage counter increment', () => {
       it('should set usage to 1 for new files', async () => {
-        getFiles.mockResolvedValue(null);
         const smallBuffer = Buffer.alloc(100);
         axios.mockResolvedValue({ data: smallBuffer });
 
@@ -345,8 +334,11 @@ describe('Code Process', () => {
       });
 
       it('should increment usage for existing files', async () => {
-        const existingFile = { file_id: 'existing-id', usage: 5, createdAt: '2024-01-01' };
-        getFiles.mockResolvedValue([existingFile]);
+        mockClaimCodeFile.mockResolvedValue({
+          file_id: 'existing-id',
+          usage: 5,
+          createdAt: '2024-01-01',
+        });
         const smallBuffer = Buffer.alloc(100);
         axios.mockResolvedValue({ data: smallBuffer });
 
@@ -356,14 +348,15 @@ describe('Code Process', () => {
       });
 
       it('should handle existing file with undefined usage', async () => {
-        const existingFile = { file_id: 'existing-id', createdAt: '2024-01-01' };
-        getFiles.mockResolvedValue([existingFile]);
+        mockClaimCodeFile.mockResolvedValue({
+          file_id: 'existing-id',
+          createdAt: '2024-01-01',
+        });
         const smallBuffer = Buffer.alloc(100);
         axios.mockResolvedValue({ data: smallBuffer });
 
         const result = await processCodeOutput(baseParams);
 
-        // (undefined ?? 0) + 1 = 1
         expect(result.usage).toBe(1);
       });
     });

client/src/hooks/SSE/useStepHandler.ts

@@ -111,7 +111,7 @@ export default function useStepHandler({
     const updatedContent = [...(message.content || [])] as Array<
       Partial<TMessageContentParts> | undefined
     >;
-    if (!updatedContent[index]) {
+    if (!updatedContent[index] && contentType !== ContentTypes.TOOL_CALL) {
       updatedContent[index] = { type: contentPart.type as AllContentTypes };
     }
 

package-lock.json

@@ -87,7 +87,7 @@
     "@google/genai": "^1.19.0",
     "@keyv/redis": "^4.3.3",
     "@langchain/core": "^0.3.80",
-    "@librechat/agents": "^3.1.37",
+    "@librechat/agents": "^3.1.38",
     "@librechat/data-schemas": "*",
     "@modelcontextprotocol/sdk": "^1.26.0",
     "@smithy/node-http-handler": "^4.4.5",