diff --git a/workspace-server/src/__tests__/features/feature-config.test.ts b/workspace-server/src/__tests__/features/feature-config.test.ts
index b4fe478f..54e96bbc 100644
--- a/workspace-server/src/__tests__/features/feature-config.test.ts
+++ b/workspace-server/src/__tests__/features/feature-config.test.ts
@@ -32,16 +32,22 @@ describe('feature-config', () => {
     expect(duplicates).toEqual([]);
   });
 
-  it('should have slides.write, sheets.write, tasks.read, and tasks.write defaulted to OFF', () => {
+  it('should have slides.write, tasks.read, and tasks.write defaulted to OFF', () => {
     const offByDefault = FEATURE_GROUPS.filter((fg) => !fg.defaultEnabled).map(
       featureGroupKey,
     );
     expect(offByDefault).toContain('slides.write');
-    expect(offByDefault).toContain('sheets.write');
     expect(offByDefault).toContain('tasks.read');
     expect(offByDefault).toContain('tasks.write');
   });
 
+  it('should have sheets.write defaulted to ON', () => {
+    const onByDefault = FEATURE_GROUPS.filter((fg) => fg.defaultEnabled).map(
+      featureGroupKey,
+    );
+    expect(onByDefault).toContain('sheets.write');
+  });
+
   it('should have all default-ON services with at least one tool', () => {
     const defaultOnWithNoTools = FEATURE_GROUPS.filter(
       (fg) => fg.defaultEnabled && fg.tools.length === 0,
diff --git a/workspace-server/src/__tests__/features/feature-resolver.test.ts b/workspace-server/src/__tests__/features/feature-resolver.test.ts
index fa473f3c..2b755037 100644
--- a/workspace-server/src/__tests__/features/feature-resolver.test.ts
+++ b/workspace-server/src/__tests__/features/feature-resolver.test.ts
@@ -244,10 +244,14 @@ describe('resolveFeatures', () => {
       expect(requiredScopes).toContain(fullUrl('userinfo.profile'));
     });
 
-    it('should still include readonly scopes for default-OFF write groups (slides, sheets)', () => {
+    it('should still include readonly scopes for default-OFF write groups (slides)', () => {
       const { requiredScopes } = resolveFeatures();
       expect(requiredScopes).toContain(fullUrl('presentations.readonly'));
-      expect(requiredScopes).toContain(fullUrl('spreadsheets.readonly'));
+    });
+
+    it('should request the write scope for default-ON sheets.write', () => {
+      const { requiredScopes } = resolveFeatures();
+      expect(requiredScopes).toContain(fullUrl('spreadsheets'));
     });
   });
 });
diff --git a/workspace-server/src/__tests__/services/SheetsService.test.ts b/workspace-server/src/__tests__/services/SheetsService.test.ts
index 50c1ff4d..6422ff2e 100644
--- a/workspace-server/src/__tests__/services/SheetsService.test.ts
+++ b/workspace-server/src/__tests__/services/SheetsService.test.ts
@@ -38,6 +38,7 @@ describe('SheetsService', () => {
     mockSheetsAPI = {
       spreadsheets: {
         get: jest.fn(),
+        batchUpdate: jest.fn(),
         values: {
           get: jest.fn(),
         },
@@ -370,4 +371,74 @@ describe('SheetsService', () => {
       expect(response.error).toBe('Metadata Error');
     });
   });
+
+  describe('batchUpdate', () => {
+    it('should apply formatting requests via spreadsheets.batchUpdate', async () => {
+      mockSheetsAPI.spreadsheets.batchUpdate.mockResolvedValue({
+        data: {
+          spreadsheetId: 'test-id',
+          replies: [{}],
+        },
+      });
+
+      const requests = JSON.stringify([
+        {
+          repeatCell: {
+            range: { sheetId: 0, startRowIndex: 0, endRowIndex: 1 },
+            cell: { userEnteredFormat: { textFormat: { bold: true } } },
+            fields: 'userEnteredFormat.textFormat.bold',
+          },
+        },
+      ]);
+
+      const result = await sheetsService.batchUpdate({
+        spreadsheetId: 'test-id',
+        requests,
+      });
+      const response = JSON.parse(result.content[0].text);
+
+      expect(mockSheetsAPI.spreadsheets.batchUpdate).toHaveBeenCalledWith({
+        spreadsheetId: 'test-id',
+        requestBody: { requests: JSON.parse(requests) },
+      });
+      expect(response.spreadsheetId).toBe('test-id');
+      expect(response.repliesCount).toBe(1);
+    });
+
+    it('should return an error when requests is not valid JSON', async () => {
+      const result = await sheetsService.batchUpdate({
+        spreadsheetId: 'test-id',
+        requests: 'not json',
+      });
+      const response = JSON.parse(result.content[0].text);
+
+      expect(response.error).toContain('must be a valid JSON array');
+      expect(mockSheetsAPI.spreadsheets.batchUpdate).not.toHaveBeenCalled();
+    });
+
+    it('should return an error when requests is not a JSON array', async () => {
+      const result = await sheetsService.batchUpdate({
+        spreadsheetId: 'test-id',
+        requests: '{"repeatCell":{}}',
+      });
+      const response = JSON.parse(result.content[0].text);
+
+      expect(response.error).toContain('must be a JSON array');
+      expect(mockSheetsAPI.spreadsheets.batchUpdate).not.toHaveBeenCalled();
+    });
+
+    it('should handle API errors gracefully', async () => {
+      mockSheetsAPI.spreadsheets.batchUpdate.mockRejectedValue(
+        new Error('BatchUpdate Error'),
+      );
+
+      const result = await sheetsService.batchUpdate({
+        spreadsheetId: 'error-id',
+        requests: '[]',
+      });
+      const response = JSON.parse(result.content[0].text);
+
+      expect(response.error).toBe('BatchUpdate Error');
+    });
+  });
 });
diff --git a/workspace-server/src/features/feature-config.ts b/workspace-server/src/features/feature-config.ts
index dc9eef53..e0bca194 100644
--- a/workspace-server/src/features/feature-config.ts
+++ b/workspace-server/src/features/feature-config.ts
@@ -242,8 +242,8 @@ export const FEATURE_GROUPS: readonly FeatureGroup[] = [
     service: 'sheets',
     group: 'write',
     scopes: scopes('spreadsheets'),
-    tools: [],
-    defaultEnabled: false,
+    tools: ['sheets.batchUpdate'],
+    defaultEnabled: true,
   },
 
   // Time (no scopes needed)
diff --git a/workspace-server/src/index.ts b/workspace-server/src/index.ts
index e7a8077b..9ba8faf5 100644
--- a/workspace-server/src/index.ts
+++ b/workspace-server/src/index.ts
@@ -940,6 +940,23 @@ async function main() {
     sheetsService.getMetadata,
   );
 
+  registerTool(
+    'sheets.batchUpdate',
+    {
+      description:
+        'Applies one or more batchUpdate requests to a Google Sheets spreadsheet. This is the general-purpose write operation for everything beyond cell values: cell/text formatting (bold, colors, number formats, borders), column widths, wrapping, frozen rows, conditional formatting, merges, and sheet properties. Use sheets.getMetadata first to obtain the numeric sheetId that most requests target.',
+      inputSchema: {
+        spreadsheetId: z.string().describe('The ID or URL of the spreadsheet.'),
+        requests: z
+          .string()
+          .describe(
+            'A JSON string containing an array of Request objects conforming to the Google Sheets batchUpdate schema (https://developers.google.com/workspace/sheets/api/reference/rest/v4/spreadsheets/request#Request). Example (bold A1 on sheetId 0): \'[{"repeatCell":{"range":{"sheetId":0,"startRowIndex":0,"endRowIndex":1,"startColumnIndex":0,"endColumnIndex":1},"cell":{"userEnteredFormat":{"textFormat":{"bold":true}}},"fields":"userEnteredFormat.textFormat.bold"}}]\'.',
+          ),
+      },
+    },
+    sheetsService.batchUpdate,
+  );
+
   registerTool(
     'drive.search',
     {
diff --git a/workspace-server/src/services/SheetsService.ts b/workspace-server/src/services/SheetsService.ts
index 636f03ca..51cf8610 100644
--- a/workspace-server/src/services/SheetsService.ts
+++ b/workspace-server/src/services/SheetsService.ts
@@ -246,4 +246,66 @@ export class SheetsService {
       };
     }
   };
+
+  public batchUpdate = async ({
+    spreadsheetId,
+    requests,
+  }: {
+    spreadsheetId: string;
+    requests: string;
+  }) => {
+    logToFile(
+      `[SheetsService] Starting batchUpdate for spreadsheet: ${spreadsheetId}`,
+    );
+    try {
+      const id = extractDocId(spreadsheetId) || spreadsheetId;
+
+      let parsedRequests: sheets_v4.Schema$Request[];
+      try {
+        parsedRequests = JSON.parse(requests);
+      } catch (parseError) {
+        const message =
+          parseError instanceof Error ? parseError.message : String(parseError);
+        throw new Error(`"requests" must be a valid JSON array: ${message}`);
+      }
+      if (!Array.isArray(parsedRequests)) {
+        throw new Error('"requests" must be a JSON array of Request objects.');
+      }
+
+      const sheets = await this.getSheetsClient();
+      const response = await sheets.spreadsheets.batchUpdate({
+        spreadsheetId: id,
+        requestBody: { requests: parsedRequests },
+      });
+
+      logToFile(
+        `[SheetsService] Finished batchUpdate for spreadsheet: ${id} (${parsedRequests.length} request(s))`,
+      );
+      return {
+        content: [
+          {
+            type: 'text' as const,
+            text: JSON.stringify({
+              spreadsheetId: response.data.spreadsheetId,
+              repliesCount: response.data.replies?.length ?? 0,
+            }),
+          },
+        ],
+      };
+    } catch (error) {
+      const errorMessage =
+        error instanceof Error ? error.message : String(error);
+      logToFile(
+        `[SheetsService] Error during sheets.batchUpdate: ${errorMessage}`,
+      );
+      return {
+        content: [
+          {
+            type: 'text' as const,
+            text: JSON.stringify({ error: errorMessage }),
+          },
+        ],
+      };
+    }
+  };
 }