Complete comparison failure summaries

internal/app/comparison.go

@@ -90,6 +90,11 @@ func CompareDetailed(ctx context.Context, req ComparisonRequest) (*ComparisonRes
 		return nil, fmt.Errorf("build comparison identity: %w", err)
 	}
 	result := initialComparisonResult(req, resolved, comparisonID, now.UTC())
+	defer func() {
+		if result.FinishedAt.IsZero() {
+			finalizeComparisonResult(result, clock)
+		}
+	}()
 
 	outputName, err := resolved.OutputName()
 	if err != nil {
@@ -99,11 +104,11 @@ func CompareDetailed(ctx context.Context, req ComparisonRequest) (*ComparisonRes
 	if err != nil {
 		return result, err
 	}
-	initialPlan, err := comparison.PlanDestination(req.WorkingDir, outputDirectory, req.Replace)
+	result.OutputDirectory = outputDirectory
+	_, err = comparison.PlanDestination(req.WorkingDir, outputDirectory, req.Replace)
 	if err != nil {
 		return result, fmt.Errorf("preflight comparison destination: %w", err)
 	}
-	result.OutputDirectory = initialPlan.Target
 
 	debugWriter, err := promptdebug.NewPromptDebugWriter(req.LLMDebugDir)
 	if err != nil {
@@ -129,7 +134,7 @@ func CompareDetailed(ctx context.Context, req ComparisonRequest) (*ComparisonRes
 	executed := executeComparisonProfiles(ctx, comparisonExecutionRequest{
 		Prepared: prepared, Inspection: inspection, ComparisonID: comparisonID, DebugWriter: debugWriter, Executor: req.Executor,
 	})
-	result.FinishedAt = clock.Now().UTC()
+	finalizeComparisonResult(result, clock)
 	copyComparisonOutcomes(result, executed.Outcomes, false)
 	if executed.Canceled {
 		return result, fmt.Errorf("comparison execution: %w", ctx.Err())
@@ -160,6 +165,17 @@ func CompareDetailed(ctx context.Context, req ComparisonRequest) (*ComparisonRes
 	return result, nil
 }
 
+func finalizeComparisonResult(result *ComparisonResult, clock timeutil.Clock) {
+	finishedAt := clock.Now().UTC()
+	if finishedAt.IsZero() {
+		finishedAt = time.Unix(0, 1).UTC()
+	}
+	if finishedAt.Before(result.StartedAt) {
+		finishedAt = result.StartedAt
+	}
+	result.FinishedAt = finishedAt
+}
+
 func initialComparisonResult(req ComparisonRequest, resolved report.Resolved, comparisonID string, startedAt time.Time) *ComparisonResult {
 	metadata := resolved.Metadata()
 	return &ComparisonResult{