diff --git a/admin/slices/bridle/stores/bridle.ts b/admin/slices/bridle/stores/bridle.ts
index 71da2859..9d1a2ecc 100644
--- a/admin/slices/bridle/stores/bridle.ts
+++ b/admin/slices/bridle/stores/bridle.ts
@@ -730,7 +730,7 @@ export const useBridleStore = defineStore('bridle', {
       for (const file of list) {
         const mimeType = resolveMimeType(file)
         const problem = !isAllowedMimeType(mimeType)
-          ? `${file.name} is not a supported file type. Try an image, a PDF, or a text file.`
+          ? `${file.name} is not a supported file type. Try an image, a PDF, an Office document, or a text file.`
           : this._rejectReason(file, pendingBytes)
 
         if (problem) {
diff --git a/admin/slices/bridle/utils/attachment.ts b/admin/slices/bridle/utils/attachment.ts
index 8e26d7c4..360a34e8 100644
--- a/admin/slices/bridle/utils/attachment.ts
+++ b/admin/slices/bridle/utils/attachment.ts
@@ -26,7 +26,16 @@ export const TEXT_MIME_TYPES = [
   'application/json',
 ] as const
 
-export const BINARY_MIME_TYPES = ['application/pdf'] as const
+export const BINARY_MIME_TYPES = [
+  'application/pdf',
+  'application/msword',
+  'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
+  'application/vnd.ms-excel',
+  'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
+  'application/vnd.ms-excel.sheet.macroEnabled.12',
+  'application/vnd.ms-powerpoint',
+  'application/vnd.openxmlformats-officedocument.presentationml.presentation',
+] as const
 
 export const ALLOWED_MIME_TYPES: readonly string[] = [
   ...IMAGE_MIME_TYPES,
@@ -45,6 +54,13 @@ export const FILE_PICKER_ACCEPT = [
   '.csv',
   '.txt',
   '.json',
+  '.doc',
+  '.docx',
+  '.xls',
+  '.xlsx',
+  '.xlsm',
+  '.ppt',
+  '.pptx',
 ].join(',')
 
 /** Same extension fallback the server uses when `file.type` is blank. */
@@ -60,6 +76,15 @@ export const MIME_BY_EXTENSION: Readonly<Record<string, string>> = {
   '.markdown': 'text/markdown',
   '.csv': 'text/csv',
   '.json': 'application/json',
+  '.doc': 'application/msword',
+  '.docx':
+    'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
+  '.xls': 'application/vnd.ms-excel',
+  '.xlsx': 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
+  '.xlsm': 'application/vnd.ms-excel.sheet.macroEnabled.12',
+  '.ppt': 'application/vnd.ms-powerpoint',
+  '.pptx':
+    'application/vnd.openxmlformats-officedocument.presentationml.presentation',
 }
 
 export enum BridleAttachmentKinds {
diff --git a/api/src/slices/bridle/domain/attachment.constants.ts b/api/src/slices/bridle/domain/attachment.constants.ts
index d4da466e..1c77783e 100644
--- a/api/src/slices/bridle/domain/attachment.constants.ts
+++ b/api/src/slices/bridle/domain/attachment.constants.ts
@@ -44,8 +44,19 @@ export const TEXT_MIME_TYPES = [
   'application/json',
 ] as const;
 
-/** Accepted but not readable by the agent: delivered as a named reference. */
-export const BINARY_MIME_TYPES = ['application/pdf'] as const;
+/** Accepted but not readable by the agent: delivered as a named reference.
+ *  Office formats are zip/OLE containers — extracting their text is a
+ *  separate feature; until then they travel like PDFs, name and bytes only. */
+export const BINARY_MIME_TYPES = [
+  'application/pdf',
+  'application/msword',
+  'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
+  'application/vnd.ms-excel',
+  'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
+  'application/vnd.ms-excel.sheet.macroEnabled.12',
+  'application/vnd.ms-powerpoint',
+  'application/vnd.openxmlformats-officedocument.presentationml.presentation',
+] as const;
 
 export const ALLOWED_MIME_TYPES: readonly string[] = [
   ...IMAGE_MIME_TYPES,
@@ -68,6 +79,15 @@ export const EXTENSION_BY_MIME: Readonly<Record<string, string>> = {
   'text/markdown': '.md',
   'text/csv': '.csv',
   'application/json': '.json',
+  'application/msword': '.doc',
+  'application/vnd.openxmlformats-officedocument.wordprocessingml.document':
+    '.docx',
+  'application/vnd.ms-excel': '.xls',
+  'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet': '.xlsx',
+  'application/vnd.ms-excel.sheet.macroEnabled.12': '.xlsm',
+  'application/vnd.ms-powerpoint': '.ppt',
+  'application/vnd.openxmlformats-officedocument.presentationml.presentation':
+    '.pptx',
 };
 
 /** Fallback when a file arrives with no usable MIME type but a known extension. */
@@ -83,4 +103,13 @@ export const MIME_BY_EXTENSION: Readonly<Record<string, string>> = {
   '.markdown': 'text/markdown',
   '.csv': 'text/csv',
   '.json': 'application/json',
+  '.doc': 'application/msword',
+  '.docx':
+    'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
+  '.xls': 'application/vnd.ms-excel',
+  '.xlsx': 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
+  '.xlsm': 'application/vnd.ms-excel.sheet.macroEnabled.12',
+  '.ppt': 'application/vnd.ms-powerpoint',
+  '.pptx':
+    'application/vnd.openxmlformats-officedocument.presentationml.presentation',
 };
diff --git a/api/src/slices/bridle/domain/attachment.service.spec.ts b/api/src/slices/bridle/domain/attachment.service.spec.ts
index c4ecaca5..8095220e 100644
--- a/api/src/slices/bridle/domain/attachment.service.spec.ts
+++ b/api/src/slices/bridle/domain/attachment.service.spec.ts
@@ -83,6 +83,47 @@ describe('BridleAttachmentService — upload validation', () => {
     expect(result.readableByAgent).toBe(false);
   });
 
+  it('accepts Office documents as binary references', async () => {
+    const { service } = makeService();
+    const cases = [
+      ['macros.xlsm', 'application/vnd.ms-excel.sheet.macroEnabled.12'],
+      [
+        'sheet.xlsx',
+        'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
+      ],
+      [
+        'letter.docx',
+        'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
+      ],
+      ['deck.ppt', 'application/vnd.ms-powerpoint'],
+    ] as const;
+
+    for (const [name, mimeType] of cases) {
+      const result = await service.upload({
+        agentId: AGENT,
+        name,
+        mimeType,
+        body: Buffer.from('PK'),
+      });
+      expect(result.kind).toBe(BridleAttachmentKinds.Binary);
+      expect(result.readableByAgent).toBe(false);
+      expect(result.mimeType).toBe(mimeType);
+    }
+  });
+
+  it('resolves an Office file by extension when the browser reports a blank type', async () => {
+    const { service } = makeService();
+    const result = await service.upload({
+      agentId: AGENT,
+      name: 'quarterly.xlsm',
+      mimeType: '',
+      body: Buffer.from('PK'),
+    });
+
+    expect(result.mimeType).toBe('application/vnd.ms-excel.sheet.macroEnabled.12');
+    expect(result.kind).toBe(BridleAttachmentKinds.Binary);
+  });
+
   it('rejects a zero-byte file', async () => {
     const { service } = makeService();
     await expect(
diff --git a/app/i18n.sync.json b/app/i18n.sync.json
index ddc87d3f..99c6e10c 100644
--- a/app/i18n.sync.json
+++ b/app/i18n.sync.json
@@ -61,7 +61,7 @@
       "chat.error_empty": "0b50d48fcbac",
       "chat.error_size": "5dd5c28ddbbd",
       "chat.error_total": "2a28704f7f5c",
-      "chat.error_type": "b5e7f88b3582",
+      "chat.error_type": "8c3cacb2300a",
       "chat.input_hint": "8a8c17c82d18",
       "chat.placeholder": "57ef13894e3b",
       "chat.send": "f6f4688ff23d",
diff --git a/app/slices/bridle/domain/attachment.constants.ts b/app/slices/bridle/domain/attachment.constants.ts
index 7ef028a6..bd537b33 100644
--- a/app/slices/bridle/domain/attachment.constants.ts
+++ b/app/slices/bridle/domain/attachment.constants.ts
@@ -26,7 +26,16 @@ export const TEXT_MIME_TYPES = [
   'application/json',
 ] as const;
 
-export const BINARY_MIME_TYPES = ['application/pdf'] as const;
+export const BINARY_MIME_TYPES = [
+  'application/pdf',
+  'application/msword',
+  'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
+  'application/vnd.ms-excel',
+  'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
+  'application/vnd.ms-excel.sheet.macroEnabled.12',
+  'application/vnd.ms-powerpoint',
+  'application/vnd.openxmlformats-officedocument.presentationml.presentation',
+] as const;
 
 export const ALLOWED_MIME_TYPES: readonly string[] = [
   ...IMAGE_MIME_TYPES,
@@ -43,6 +52,13 @@ export const FILE_PICKER_ACCEPT = [
   '.csv',
   '.txt',
   '.json',
+  '.doc',
+  '.docx',
+  '.xls',
+  '.xlsx',
+  '.xlsm',
+  '.ppt',
+  '.pptx',
 ].join(',');
 
 /** Same extension fallback the server uses when `file.type` is blank. */
@@ -58,6 +74,15 @@ export const MIME_BY_EXTENSION: Readonly<Record<string, string>> = {
   '.markdown': 'text/markdown',
   '.csv': 'text/csv',
   '.json': 'application/json',
+  '.doc': 'application/msword',
+  '.docx':
+    'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
+  '.xls': 'application/vnd.ms-excel',
+  '.xlsx': 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
+  '.xlsm': 'application/vnd.ms-excel.sheet.macroEnabled.12',
+  '.ppt': 'application/vnd.ms-powerpoint',
+  '.pptx':
+    'application/vnd.openxmlformats-officedocument.presentationml.presentation',
 };
 
 /** Human-readable byte size for chips and error copy. */
diff --git a/app/slices/bridle/i18n/locales/en.json b/app/slices/bridle/i18n/locales/en.json
index 7d434df2..bbb86681 100644
--- a/app/slices/bridle/i18n/locales/en.json
+++ b/app/slices/bridle/i18n/locales/en.json
@@ -21,7 +21,7 @@
     "attachment_failed": "Couldn't upload {name}",
     "attachment_unavailable": "This file is no longer available",
     "attachment_not_readable": "The agent sees the name, not the contents",
-    "error_type": "{name} isn't a supported file type. Try an image, a PDF, or a text file.",
+    "error_type": "{name} isn't a supported file type. Try an image, a PDF, an Office document, or a text file.",
     "error_size": "{name} is larger than {limit}",
     "error_total": "Those files add up to more than {limit} in one message",
     "error_empty": "{name} is empty"
diff --git a/app/slices/bridle/i18n/locales/ru.json b/app/slices/bridle/i18n/locales/ru.json
index 2cc6b259..0313d10b 100644
--- a/app/slices/bridle/i18n/locales/ru.json
+++ b/app/slices/bridle/i18n/locales/ru.json
@@ -21,7 +21,7 @@
     "attachment_failed": "Не удалось загрузить {name}",
     "attachment_unavailable": "Этот файл больше недоступен",
     "attachment_not_readable": "Агент видит имя файла, но не содержимое",
-    "error_type": "{name} — неподдерживаемый тип файла. Попробуйте изображение, PDF или текстовый файл.",
+    "error_type": "{name} — неподдерживаемый тип файла. Попробуйте изображение, PDF, документ Office или текстовый файл.",
     "error_size": "{name} больше, чем {limit}",
     "error_total": "Суммарный размер файлов в одном сообщении превышает {limit}",
     "error_empty": "{name} пуст"