diff --git a/src/services/n8n-validation.ts b/src/services/n8n-validation.ts
index 1163419..efe1be6 100644
--- a/src/services/n8n-validation.ts
+++ b/src/services/n8n-validation.ts
@@ -193,17 +193,18 @@ export function cleanWorkflowForUpdate(workflow: Workflow): Partial<Workflow> {
       }
     }
 
-    // Only include settings if it has properties after filtering
-    // n8n API rejects empty settings objects
+    // n8n API requires settings to be present but rejects empty settings objects.
+    // If no valid properties remain after filtering, include minimal default settings.
     if (Object.keys(filteredSettings).length > 0) {
       cleanedWorkflow.settings = filteredSettings;
     } else {
-      delete cleanedWorkflow.settings;
+      // Provide minimal valid settings (executionOrder is always accepted)
+      cleanedWorkflow.settings = { executionOrder: 'v0' as const };
     }
   } else {
-    // No settings provided - remove the property entirely
-    // n8n API rejects empty settings objects
-    delete cleanedWorkflow.settings;
+    // No settings provided - include minimal default settings
+    // n8n API requires settings in workflow updates
+    cleanedWorkflow.settings = { executionOrder: 'v0' as const };
   }
 
   return cleanedWorkflow;
diff --git a/tests/unit/services/n8n-validation.test.ts b/tests/unit/services/n8n-validation.test.ts
index 3e7c7f9..55ce5b9 100644
--- a/tests/unit/services/n8n-validation.test.ts
+++ b/tests/unit/services/n8n-validation.test.ts
@@ -383,7 +383,7 @@ describe('n8n-validation', () => {
         expect(cleaned.name).toBe('Test Workflow');
       });
 
-      it('should omit settings property when no settings provided (Issue #431)', () => {
+      it('should provide minimal default settings when no settings provided (Issue #431)', () => {
         const workflow = {
           name: 'Test Workflow',
           nodes: [],
@@ -391,7 +391,8 @@ describe('n8n-validation', () => {
         } as any;
 
         const cleaned = cleanWorkflowForUpdate(workflow);
-        expect(cleaned).not.toHaveProperty('settings');
+        // n8n API requires settings to be present, so we provide minimal defaults
+        expect(cleaned.settings).toEqual({ executionOrder: 'v0' });
       });
 
       it('should filter settings to safe properties to prevent API errors (Issue #248 - final fix)', () => {
@@ -483,10 +484,11 @@ describe('n8n-validation', () => {
         } as any;
 
         const cleaned = cleanWorkflowForUpdate(workflow);
-        expect(cleaned).not.toHaveProperty('settings');
+        // n8n API requires settings, so we provide minimal defaults
+        expect(cleaned.settings).toEqual({ executionOrder: 'v0' });
       });
 
-      it('should omit settings when only non-whitelisted properties exist (Issue #431)', () => {
+      it('should provide minimal settings when only non-whitelisted properties exist (Issue #431)', () => {
         const workflow = {
           name: 'Test Workflow',
           nodes: [],
@@ -499,9 +501,10 @@ describe('n8n-validation', () => {
         } as any;
 
         const cleaned = cleanWorkflowForUpdate(workflow);
-        // All properties were filtered out, so settings should not exist
-        // to avoid "must NOT have additional properties" API error
-        expect(cleaned).not.toHaveProperty('settings');
+        // All properties were filtered out, but n8n API requires settings
+        // so we provide minimal defaults to avoid both "additional properties"
+        // and "required property" API errors
+        expect(cleaned.settings).toEqual({ executionOrder: 'v0' });
       });
 
       it('should preserve whitelisted settings when mixed with non-whitelisted (Issue #431)', () => {
@@ -1403,7 +1406,8 @@ describe('n8n-validation', () => {
       expect(forUpdate).not.toHaveProperty('active');
       expect(forUpdate).not.toHaveProperty('tags');
       expect(forUpdate).not.toHaveProperty('meta');
-      expect(forUpdate).not.toHaveProperty('settings'); // Settings omitted when not present (Issue #431)
+      // n8n API requires settings in updates, so minimal defaults are provided (Issue #431)
+      expect(forUpdate.settings).toEqual({ executionOrder: 'v0' });
       expect(validateWorkflowStructure(forUpdate)).toEqual([]);
     });
   });