diff --git a/frontend/src/core/hooks/tools/shared/useToolOperation.ts b/frontend/src/core/hooks/tools/shared/useToolOperation.ts
index 4ef803efb5..4804032d0d 100644
--- a/frontend/src/core/hooks/tools/shared/useToolOperation.ts
+++ b/frontend/src/core/hooks/tools/shared/useToolOperation.ts
@@ -8,6 +8,7 @@ import { useToolResources } from '@app/hooks/tools/shared/useToolResources';
 import { extractErrorMessage } from '@app/utils/toolErrorHandler';
 import { StirlingFile, extractFiles, FileId, StirlingFileStub, createStirlingFile } from '@app/types/fileContext';
 import { FILE_EVENTS } from '@app/services/errorUtils';
+import { getFilenameWithoutExtension } from '@app/utils/fileUtils';
 import { ResponseHandler } from '@app/utils/toolResponseProcessor';
 import { createChildStub, generateProcessedFileMetadata } from '@app/contexts/file/fileActions';
 import { ToolOperation } from '@app/types/file';
@@ -305,12 +306,12 @@ export const useToolOperation = <TParams>(
             // Try to map outputs back to inputs by filename (before extension)
             const inputBaseNames = new Map<string, FileId>();
             for (const f of validFiles) {
-              const base = (f.name || '').replace(/\.[^.]+$/, '').toLowerCase();
+              const base = getFilenameWithoutExtension(f.name || '');
               inputBaseNames.set(base, f.fileId);
             }
             const mappedSuccess: FileId[] = [];
             for (const out of processedFiles) {
-              const base = (out.name || '').replace(/\.[^.]+$/, '').toLowerCase();
+              const base = getFilenameWithoutExtension(out.name || '');
               const id = inputBaseNames.get(base);
               if (id) mappedSuccess.push(id);
             }
diff --git a/frontend/src/core/utils/fileUtils.ts b/frontend/src/core/utils/fileUtils.ts
index 0f14714019..4061884b55 100644
--- a/frontend/src/core/utils/fileUtils.ts
+++ b/frontend/src/core/utils/fileUtils.ts
@@ -52,6 +52,29 @@ export function detectFileExtension(filename: string): string {
   return extension;
 }
 
+/**
+ * Removes the file extension from a filename
+ * @param filename - The filename to process
+ * @param options - Options for processing
+ * @param options.preserveCase - If true, preserves original case. If false (default), converts to lowercase
+ * @returns Filename without extension
+ * @example
+ * getFilenameWithoutExtension('document.pdf') // 'document'
+ * getFilenameWithoutExtension('my.file.name.txt') // 'my.file.name'
+ * getFilenameWithoutExtension('REPORT.PDF', { preserveCase: true }) // 'REPORT'
+ */
+export function getFilenameWithoutExtension(
+  filename: string,
+  options: { preserveCase?: boolean } = {}
+): string {
+  if (!filename || typeof filename !== 'string') return '';
+
+  const { preserveCase = false } = options;
+  const withoutExtension = filename.replace(/\.[^.]+$/, '');
+
+  return preserveCase ? withoutExtension : withoutExtension.toLowerCase();
+}
+
 /**
  * Checks if a file is a PDF based on extension and MIME type
  * @param file - File or file-like object with name and type properties