Remove the redundant DefaultOutputName report definition field

internal/app/app_test.go

@@ -358,6 +358,7 @@ func TestGenerateReportIncludesRecentChangesFromPriorSnapshot(t *testing.T) {
 	}
 	_, err = store.SaveMetadata(context.Background(), state.BuildMetadata(priorResolved, priorBriefing, state.ArtifactPaths{
 		Briefing:       priorBriefingPath,
+		Metadata:       priorPaths.Metadata,
 		DataPackage:    priorPaths.DataPackage,
 		Preflight:      priorPaths.Preflight,
 		RenderedReport: priorPaths.RenderedReport,
@@ -472,6 +473,7 @@ func TestTomorrowReportCanCompareAgainstPriorDailySnapshot(t *testing.T) {
 	}
 	_, err = store.SaveMetadata(context.Background(), state.BuildMetadata(priorResolved, priorBriefing, state.ArtifactPaths{
 		Briefing:       priorBriefingPath,
+		Metadata:       priorPaths.Metadata,
 		DataPackage:    priorPaths.DataPackage,
 		Preflight:      priorPaths.Preflight,
 		RenderedReport: priorPaths.RenderedReport,
@@ -538,6 +540,7 @@ func TestGenerateThreeDayReportWritesReportAndRecentChanges(t *testing.T) {
 	}
 	_, err = store.SaveMetadata(context.Background(), state.BuildMetadata(priorResolved, priorBriefing, state.ArtifactPaths{
 		Briefing:       priorBriefingPath,
+		Metadata:       priorPaths.Metadata,
 		DataPackage:    priorPaths.DataPackage,
 		Preflight:      priorPaths.Preflight,
 		RenderedReport: priorPaths.RenderedReport,
@@ -613,6 +616,7 @@ func TestGenerateWeekendReportWritesReportAndRecentChanges(t *testing.T) {
 	}
 	_, err = store.SaveMetadata(context.Background(), state.BuildMetadata(priorResolved, priorBriefing, state.ArtifactPaths{
 		Briefing:       priorBriefingPath,
+		Metadata:       priorPaths.Metadata,
 		DataPackage:    priorPaths.DataPackage,
 		Preflight:      priorPaths.Preflight,
 		RenderedReport: priorPaths.RenderedReport,

internal/report/definition.go

@@ -38,7 +38,6 @@ type Definition struct {
 	Name               string
 	PromptID           string
 	ComparisonStrategy ComparisonStrategy
-	DefaultOutputName  string
 	ArtifactGroup      string
 	BatchOutputName    string
 	Generated          bool

internal/report/registry.go

@@ -13,7 +13,6 @@ func DefaultRegistry() Registry {
 			Name:               "Daily Report",
 			PromptID:           "weather.daily_report",
 			ComparisonStrategy: CompareSameValidDate,
-			DefaultOutputName:  "daily.md",
 			ArtifactGroup:      "daily",
 			BatchOutputName:    "daily.md",
 			Generated:          true,
@@ -26,7 +25,6 @@ func DefaultRegistry() Registry {
 			Name:               "Tomorrow Planning Brief",
 			PromptID:           "weather.daily_report",
 			ComparisonStrategy: CompareSameValidDate,
-			DefaultOutputName:  "tomorrow.md",
 			ArtifactGroup:      "daily",
 			BatchOutputName:    "tomorrow.md",
 			Generated:          true,
@@ -39,7 +37,6 @@ func DefaultRegistry() Registry {
 			Name:               "3-Day Outlook",
 			PromptID:           "weather.three_day_outlook",
 			ComparisonStrategy: CompareSameValidDate,
-			DefaultOutputName:  "three_day.md",
 			ArtifactGroup:      "three-day",
 			BatchOutputName:    "three-day.md",
 			Generated:          true,
@@ -52,7 +49,6 @@ func DefaultRegistry() Registry {
 			Name:               "Weekend Outlook",
 			PromptID:           "weather.weekend_outlook",
 			ComparisonStrategy: CompareWeekendWindow,
-			DefaultOutputName:  "weekend.md",
 			ArtifactGroup:      "weekend",
 			BatchOutputName:    "weekend.md",
 			Generated:          true,
@@ -65,7 +61,6 @@ func DefaultRegistry() Registry {
 			Name:               "Storm Report",
 			PromptID:           "weather.storm_report",
 			ComparisonStrategy: CompareExplicitWindow,
-			DefaultOutputName:  "storm.md",
 			ArtifactGroup:      "storm",
 			BatchOutputName:    "storm.md",
 			Generated:          true,

internal/state/filesystem.go

@@ -154,14 +154,13 @@ func (s *FilesystemStore) SaveMetadata(_ context.Context, metadata Metadata) (st
 	if metadata.PreflightPath == "" {
 		return "", fmt.Errorf("metadata preflight path is required")
 	}
-	path := metadataPathFromStored(metadata)
+	if metadata.MetadataPath == "" {
-	if path == "" {
+		return "", fmt.Errorf("metadata path is required")
-		return "", fmt.Errorf("metadata path cannot be resolved")
 	}
-	if err := fileutil.WriteJSONAtomic(path, metadata); err != nil {
+	if err := fileutil.WriteJSONAtomic(metadata.MetadataPath, metadata); err != nil {
 		return "", err
 	}
-	return path, nil
+	return metadata.MetadataPath, nil
 }
 
 func (s *FilesystemStore) FindPriorSnapshot(_ context.Context, resolved report.Resolved) (*PriorSnapshot, error) {
@@ -366,14 +365,6 @@ func readJSON(path string, target any) error {
 	return nil
 }
 
-func metadataPathFromStored(metadata Metadata) string {
-	if metadata.BriefingPath == "" {
-		return ""
-	}
-	filename := metadata.RunID + ".metadata.json"
-	return filepath.Join(filepath.Dir(metadata.BriefingPath), filename)
-}
-
 func sameValidDate(metadata Metadata, resolved report.Resolved) bool {
 	return metadata.ValidPeriod.Start.Format("2006-01-02") == resolved.ValidPeriod.Start.Format("2006-01-02")
 }

internal/state/filesystem_test.go

@@ -122,6 +122,43 @@ func TestSaveArtifactsAndMetadataRoundTrip(t *testing.T) {
 	if decoded.RenderedReportPath != renderedReportPath {
 		t.Fatalf("RenderedReportPath = %q, want %q", decoded.RenderedReportPath, renderedReportPath)
 	}
+	if strings.Contains(string(data), "MetadataPath") || strings.Contains(string(data), "metadataPath") {
+		t.Fatalf("metadata JSON includes runtime-only MetadataPath:\n%s", string(data))
+	}
+}
+
+func TestSaveMetadataUsesExplicitMetadataPath(t *testing.T) {
+	store := newTestStore(t)
+	resolved := resolveDailyAt(t, "2026-05-29T05:00:00-05:00")
+	briefingPackage := stateBriefingPackage(resolved)
+	paths, err := store.Paths(resolved)
+	if err != nil {
+		t.Fatalf("Paths() error = %v", err)
+	}
+	otherDir := filepath.Join(t.TempDir(), "other-artifacts")
+	otherBriefingPath := filepath.Join(otherDir, resolved.Metadata().RunID+".briefing.json")
+	derivedMetadataPath := filepath.Join(otherDir, resolved.Metadata().RunID+".metadata.json")
+
+	metadata := BuildMetadata(resolved, briefingPackage, ArtifactPaths{
+		Briefing:       otherBriefingPath,
+		Metadata:       paths.Metadata,
+		DataPackage:    paths.DataPackage,
+		Preflight:      paths.Preflight,
+		RenderedReport: paths.RenderedReport,
+	})
+	metadataPath, err := store.SaveMetadata(context.Background(), metadata)
+	if err != nil {
+		t.Fatalf("SaveMetadata() error = %v", err)
+	}
+	if metadataPath != paths.Metadata {
+		t.Fatalf("SaveMetadata() path = %q, want explicit metadata path %q", metadataPath, paths.Metadata)
+	}
+	if _, err := os.Stat(paths.Metadata); err != nil {
+		t.Fatalf("expected explicit metadata path %q: %v", paths.Metadata, err)
+	}
+	if _, err := os.Stat(derivedMetadataPath); !os.IsNotExist(err) {
+		t.Fatalf("derived metadata path stat error = %v, want not exist", err)
+	}
 }
 
 func TestFindPriorSnapshot(t *testing.T) {

internal/state/metadata.go

@@ -14,6 +14,7 @@ const MetadataSchemaVersion = "weatherreporter.metadata.v1"
 type Metadata struct {
 	SchemaVersion      string                    `json:"schemaVersion"`
 	RunID              string                    `json:"runId"`
+	MetadataPath       string                    `json:"-"`
 	ReportID           report.ID                 `json:"reportId"`
 	Variant            string                    `json:"variant,omitempty"`
 	PromptID           string                    `json:"promptId"`
@@ -35,6 +36,7 @@ func BuildMetadata(resolved report.Resolved, briefingPackage briefing.Package, p
 	return Metadata{
 		SchemaVersion:      MetadataSchemaVersion,
 		RunID:              metadata.RunID,
+		MetadataPath:       paths.Metadata,
 		ReportID:           metadata.ReportID,
 		Variant:            briefingPackage.Metadata.Variant,
 		PromptID:           metadata.PromptID,