diff --git a/packages/data-provider/src/file-config.spec.ts b/packages/data-provider/src/file-config.spec.ts
index 018b4dbfcf..0ab9f23a3e 100644
--- a/packages/data-provider/src/file-config.spec.ts
+++ b/packages/data-provider/src/file-config.spec.ts
@@ -1,15 +1,52 @@
 import type { FileConfig } from './types/files';
 import {
   fileConfig as baseFileConfig,
+  documentParserMimeTypes,
   getEndpointFileConfig,
-  mergeFileConfig,
   applicationMimeTypes,
   defaultOCRMimeTypes,
-  documentParserMimeTypes,
   supportedMimeTypes,
+  mergeFileConfig,
+  inferMimeType,
+  textMimeTypes,
 } from './file-config';
 import { EModelEndpoint } from './schemas';
 
+describe('inferMimeType', () => {
+  it('should normalize text/x-python-script to text/x-python', () => {
+    expect(inferMimeType('test.py', 'text/x-python-script')).toBe('text/x-python');
+  });
+
+  it('should return a type that matches textMimeTypes after normalization', () => {
+    const normalized = inferMimeType('test.py', 'text/x-python-script');
+    expect(textMimeTypes.test(normalized)).toBe(true);
+  });
+
+  it('should pass through standard browser types unchanged', () => {
+    expect(inferMimeType('test.py', 'text/x-python')).toBe('text/x-python');
+    expect(inferMimeType('doc.pdf', 'application/pdf')).toBe('application/pdf');
+  });
+
+  it('should infer from extension when browser type is empty', () => {
+    expect(inferMimeType('test.py', '')).toBe('text/x-python');
+    expect(inferMimeType('code.js', '')).toBe('text/javascript');
+    expect(inferMimeType('photo.heic', '')).toBe('image/heic');
+  });
+
+  it('should return empty string for unknown extension with no browser type', () => {
+    expect(inferMimeType('file.xyz', '')).toBe('');
+  });
+
+  it('should produce a type accepted by checkType after normalizing text/x-python-script', () => {
+    const normalized = inferMimeType('test.py', 'text/x-python-script');
+    expect(baseFileConfig.checkType(normalized)).toBe(true);
+  });
+
+  it('should reject raw text/x-python-script without normalization', () => {
+    expect(baseFileConfig.checkType('text/x-python-script')).toBe(false);
+  });
+});
+
 describe('applicationMimeTypes', () => {
   const odfTypes = [
     'application/vnd.oasis.opendocument.text',
diff --git a/packages/data-provider/src/file-config.ts b/packages/data-provider/src/file-config.ts
index 033c868a80..67b4197958 100644
--- a/packages/data-provider/src/file-config.ts
+++ b/packages/data-provider/src/file-config.ts
@@ -357,15 +357,21 @@ export const imageTypeMapping: { [key: string]: string } = {
   heif: 'image/heif',
 };
 
+/** Normalizes non-standard MIME types that browsers may report to their canonical forms */
+export const mimeTypeAliases: Readonly<Record<string, string>> = {
+  'text/x-python-script': 'text/x-python',
+};
+
 /**
- * Infers the MIME type from a file's extension when the browser doesn't recognize it
- * @param fileName - The name of the file including extension
- * @param currentType - The current MIME type reported by the browser (may be empty)
- * @returns The inferred MIME type if browser didn't provide one, otherwise the original type
+ * Infers the MIME type from a file's extension when the browser doesn't recognize it,
+ * and normalizes known non-standard MIME type aliases to their canonical forms.
+ * @param fileName - The file name including its extension
+ * @param currentType - The MIME type reported by the browser (may be empty string)
+ * @returns The normalized or inferred MIME type; empty string if unresolvable
  */
 export function inferMimeType(fileName: string, currentType: string): string {
   if (currentType) {
-    return currentType;
+    return mimeTypeAliases[currentType] ?? currentType;
   }
 
   const extension = fileName.split('.').pop()?.toLowerCase() ?? '';