fix(billing-cost-management-mcp-server): surface EBS attachment_state on COH get_recommendation (#4966)

Author: Anshul00S

src/billing-cost-management-mcp-server/awslabs/billing_cost_management_mcp_server/tools/cost_optimization_hub_helpers.py

@@ -270,6 +270,13 @@ async def get_recommendation(
                 'recommendedResourceDetails'
             )
 
+        # An EBS volume's attachmentState ("Attached"/"Unattached") tells an idle volume from an
+        # unattached one under action type Delete, so surface it at the top level.
+        current_details = recommendation.get('currentResourceDetails') or {}
+        ebs_config = (current_details.get('ebsVolume') or {}).get('configuration') or {}
+        if ebs_config.get('attachmentState') is not None:
+            formatted_response['attachment_state'] = ebs_config['attachmentState']
+
         if 'tags' in recommendation:
             formatted_response['tags'] = recommendation.get('tags')
 

src/billing-cost-management-mcp-server/awslabs/billing_cost_management_mcp_server/tools/cost_optimization_hub_tools.py

@@ -603,7 +603,10 @@ def _validate_order_by(
 
 Cost Optimization Hub provides recommendations across multiple AWS services, including:
 - EC2 instances (right-sizing, Graviton migration)
-- EBS volumes (unused volumes, IOPS optimization)
+- EBS volumes (Delete covers both idle attached volumes and unattached ones: a
+  recommended_resource_summary starting "Detach volume from instance" marks an attached
+  volume, and get_recommendation returns attachment_state "Attached" or "Unattached" as of
+  last_refresh_timestamp), IOPS/type optimization
 - RDS instances (right-sizing, engine optimization)
 - Lambda functions (memory size optimization)
 - SP/RI

src/billing-cost-management-mcp-server/tests/tools/test_cost_optimization_hub_helpers.py

@@ -364,6 +364,63 @@ async def test_includes_current_and_recommended_resource_details(
         rec = result['data']
         assert rec['current_resource_details'] == current_details
         assert rec['recommended_resource_details'] == recommended_details
+        # Not an EBS volume, so there is no attachment state to surface.
+        assert 'attachment_state' not in rec
+
+    @pytest.mark.parametrize(
+        'action_type, state',
+        [('Delete', 'Unattached'), ('Rightsize', 'Attached'), ('Upgrade', 'Attached')],
+    )
+    async def test_surfaces_ebs_attachment_state(
+        self, mock_context, mock_coh_client, action_type, state
+    ):
+        """Test get_recommendation surfaces an EBS volume's attachmentState on any action type."""
+        current_details = {
+            'ebsVolume': {
+                'configuration': {
+                    'storage': {'type': 'gp3', 'sizeInGb': 100.0},
+                    'attachmentState': state,
+                }
+            }
+        }
+        mock_coh_client.get_recommendation.return_value = {
+            'recommendationId': 'rec-ebs',
+            'resourceId': 'vol-0123456789abcdef0',
+            'currentResourceType': 'EbsVolume',
+            'actionType': action_type,
+            'currentResourceDetails': current_details,
+        }
+
+        result = await get_recommendation(mock_context, mock_coh_client, 'rec-ebs')
+
+        rec = result['data']
+        assert rec['attachment_state'] == state
+        # The nested details are passed through unchanged.
+        assert rec['current_resource_details'] == current_details
+
+    @pytest.mark.parametrize(
+        'current_details',
+        [
+            {'ebsVolume': {'configuration': {'storage': {'type': 'gp2'}}}},
+            {'ebsVolume': {}},
+            {'ebsVolume': {'configuration': None}},
+            {'ebsVolume': None},
+        ],
+    )
+    async def test_no_attachment_state_when_absent(
+        self, mock_context, mock_coh_client, current_details
+    ):
+        """Test get_recommendation omits attachment_state when the API returns none."""
+        mock_coh_client.get_recommendation.return_value = {
+            'recommendationId': 'rec-ebs',
+            'currentResourceType': 'EbsVolume',
+            'currentResourceDetails': current_details,
+        }
+
+        result = await get_recommendation(mock_context, mock_coh_client, 'rec-ebs')
+
+        assert result['status'] == 'success'
+        assert 'attachment_state' not in result['data']
 
 
 def _account_groups(count):