fix(aci): Preserve metric resolution automatic on edit

static/app/views/detectors/components/forms/metric/metricFormData.tsx

@@ -399,6 +399,14 @@ function processDetectorConditions(
     conditionType = mainCondition.type;
   }
 
+  // Determine resolution strategy: automatic if OK threshold matches warning or critical
+  const resolutionValue = okCondition?.comparison ?? undefined;
+  const computedResolutionStrategy: 'automatic' | 'manual' =
+    defined(resolutionValue) &&
+    ![mainCondition?.comparison, highCondition?.comparison].includes(resolutionValue)
+      ? 'manual'
+      : 'automatic';
+
   return {
     initialPriorityLevel,
     conditionValue:
@@ -410,8 +418,7 @@ function processDetectorConditions(
       typeof highCondition?.comparison === 'number'
         ? highCondition.comparison.toString()
         : '',
-    resolutionStrategy:
-      typeof okCondition?.comparison === 'number' ? 'manual' : 'automatic',
+    resolutionStrategy: computedResolutionStrategy,
     resolutionValue:
       typeof okCondition?.comparison === 'number'
         ? okCondition.comparison.toString()

static/app/views/detectors/edit.spec.tsx

@@ -19,6 +19,11 @@ import {
 
 import OrganizationStore from 'sentry/stores/organizationStore';
 import ProjectsStore from 'sentry/stores/projectsStore';
+import {
+  DataConditionGroupLogicType,
+  DataConditionType,
+  DetectorPriorityLevel,
+} from 'sentry/types/workflowEngine/dataConditions';
 import {Dataset, EventTypes} from 'sentry/views/alerts/rules/metric/types';
 import {SnubaQueryType} from 'sentry/views/detectors/components/forms/metric/metricFormData';
 import DetectorEdit from 'sentry/views/detectors/edit';
@@ -379,6 +384,54 @@ describe('DetectorEdit', () => {
       expect(screen.getByRole('option', {name: 'Last 7 days'})).toBeInTheDocument();
     });
 
+    it('sets resolution method to Automatic when OK equals critical threshold', async () => {
+      const detectorWithOkEqualsHigh = MetricDetectorFixture({
+        conditionGroup: {
+          id: 'cg2',
+          logicType: DataConditionGroupLogicType.ANY,
+          conditions: [
+            {
+              id: 'c-main',
+              type: DataConditionType.GREATER,
+              comparison: 5,
+              conditionResult: DetectorPriorityLevel.MEDIUM,
+            },
+            {
+              id: 'c-high',
+              type: DataConditionType.GREATER,
+              comparison: 10,
+              conditionResult: DetectorPriorityLevel.HIGH,
+            },
+            {
+              id: 'c-ok',
+              type: DataConditionType.LESS,
+              comparison: 10, // equals high threshold
+              conditionResult: DetectorPriorityLevel.OK,
+            },
+          ],
+        },
+        dataSources: [SnubaQueryDataSourceFixture()],
+      });
+
+      MockApiClient.addMockResponse({
+        url: `/organizations/${organization.slug}/detectors/${detectorWithOkEqualsHigh.id}/`,
+        body: detectorWithOkEqualsHigh,
+      });
+
+      render(<DetectorEdit />, {organization, initialRouterConfig});
+
+      expect(
+        await screen.findByRole('link', {name: detectorWithOkEqualsHigh.name})
+      ).toBeInTheDocument();
+
+      expect(screen.getByRole('radio', {name: 'Automatic'})).toBeChecked();
+
+      // Switching to Manual should reveal prefilled resolution input with the current OK value
+      await userEvent.click(screen.getByRole('radio', {name: 'Manual'}));
+      const resolutionInput = await screen.findByLabelText('Resolution threshold');
+      expect(resolutionInput).toHaveValue(10);
+    });
+
     it('includes comparisonDelta in events-stats request when using percent change detection', async () => {
       MockApiClient.addMockResponse({
         url: `/organizations/${organization.slug}/detectors/${mockDetector.id}/`,