diff --git a/lib/providers/tasks_provider.dart b/lib/providers/tasks_provider.dart
index 0fd7c123..9f6c36a9 100644
--- a/lib/providers/tasks_provider.dart
+++ b/lib/providers/tasks_provider.dart
@@ -556,22 +556,56 @@ class TasksController {
     required String status,
   }) async {
     if (status == 'completed') {
-      // fetch current metadata to validate
+      // fetch current metadata to validate several required fields
       try {
         final row = await _client
             .from('tasks')
-            .select('request_type, request_category')
+            // include all columns that must be non-null/empty before completing
+            .select(
+              'request_type, request_category, requested_by, noted_by, received_by, action_taken',
+            )
             .eq('id', taskId)
             .maybeSingle();
-        final rt = row is Map ? row['request_type'] : null;
-        final rc = row is Map ? row['request_category'] : null;
-        if (rt == null || rc == null) {
+        if (row is! Map<String, dynamic>) {
+          throw Exception('Task not found');
+        }
+
+        final rt = row['request_type'];
+        final rc = row['request_category'];
+        final requested = row['requested_by'];
+        final noted = row['noted_by'];
+        final received = row['received_by'];
+        final action = row['action_taken'];
+
+        final missing = <String>[];
+        if (rt == null || (rt is String && rt.trim().isEmpty)) {
+          missing.add('request type');
+        }
+        if (rc == null || (rc is String && rc.trim().isEmpty)) {
+          missing.add('request category');
+        }
+        if (requested == null ||
+            (requested is String && requested.trim().isEmpty)) {
+          missing.add('requested by');
+        }
+        if (noted == null || (noted is String && noted.trim().isEmpty)) {
+          missing.add('noted by');
+        }
+        if (received == null ||
+            (received is String && received.trim().isEmpty)) {
+          missing.add('received by');
+        }
+        if (action == null || (action is String && action.trim().isEmpty)) {
+          missing.add('action taken');
+        }
+
+        if (missing.isNotEmpty) {
           throw Exception(
-            'Request type and category must be set before completing a task.',
+            'The following fields must be set before completing a task: ${missing.join(', ')}.',
           );
         }
       } catch (e) {
-        // rethrow so callers can handle
+        // rethrow so callers can handle (UI will display message)
         rethrow;
       }
     }
diff --git a/lib/screens/tasks/task_detail_screen.dart b/lib/screens/tasks/task_detail_screen.dart
index f7154cc7..9c81d7a3 100644
--- a/lib/screens/tasks/task_detail_screen.dart
+++ b/lib/screens/tasks/task_detail_screen.dart
@@ -2731,9 +2731,16 @@ class _TaskDetailScreenState extends ConsumerState<TaskDetailScreen>
         // Update DB only — Supabase realtime stream will emit the
         // updated task list, so explicit invalidation here causes a
         // visible loading/refresh and is unnecessary.
-        await ref
-            .read(tasksControllerProvider)
-            .updateTaskStatus(taskId: task.id, status: value);
+        try {
+          await ref
+              .read(tasksControllerProvider)
+              .updateTaskStatus(taskId: task.id, status: value);
+        } catch (e) {
+          // surface validation or other errors to user
+          if (mounted) {
+            showErrorSnackBar(context, e.toString());
+          }
+        }
       },
       itemBuilder: (context) => _statusOptions
           .map(
diff --git a/test/tasks_provider_test.dart b/test/tasks_provider_test.dart
index de8e0ac4..c9eb41f7 100644
--- a/test/tasks_provider_test.dart
+++ b/test/tasks_provider_test.dart
@@ -90,8 +90,8 @@ void main() {
       // note: controller expects SupabaseClient; using dynamic bypass.
     });
 
-    test('cannot complete a task without request details', () async {
-      // insert a task with no metadata
+    test('cannot complete a task without required metadata', () async {
+      // insert a task with no metadata at all
       final row = {'id': 'tsk-1', 'status': 'queued'};
       fake.tables['tasks']!.add(row);
 
@@ -101,6 +101,43 @@ void main() {
       );
     });
 
+    test('cannot complete when signatories or action taken missing', () async {
+      // insert a task that has the basic request metadata but nothing else
+      final row = {
+        'id': 'tsk-3',
+        'status': 'queued',
+        'request_type': 'Repair',
+        'request_category': 'Hardware',
+      };
+      fake.tables['tasks']!.add(row);
+
+      // still missing signatories/actionTaken
+      expect(
+        () => controller.updateTaskStatus(taskId: 'tsk-3', status: 'completed'),
+        throwsA(isA<Exception>()),
+      );
+
+      // add signatories but actionTaken still missing
+      await controller.updateTask(
+        taskId: 'tsk-3',
+        requestedBy: 'Alice',
+        notedBy: 'Bob',
+        receivedBy: 'Carol',
+      );
+      expect(
+        () => controller.updateTaskStatus(taskId: 'tsk-3', status: 'completed'),
+        throwsA(isA<Exception>()),
+      );
+
+      // add action taken (empty JSON string)
+      await controller.updateTask(taskId: 'tsk-3', actionTaken: '{}');
+      await controller.updateTaskStatus(taskId: 'tsk-3', status: 'completed');
+      expect(
+        fake.tables['tasks']!.firstWhere((t) => t['id'] == 'tsk-3')['status'],
+        'completed',
+      );
+    });
+
     test('completing after adding metadata succeeds', () async {
       // insert a task
       final row = {'id': 'tsk-2', 'status': 'queued'};