Improve handling of alerts when no active alerts are present

docs/integrations/weatherapi.md

@@ -28,9 +28,14 @@ Every response used by the adapter must be JSON with a top-level `data` field:
 }
 ```
 
-`data: null` is treated as a missing source. Missing optional sources follow the
+For most sources, `data: null` is treated as a missing source. Missing optional
-configured missing-source policy. Missing hourly forecast data fails bundle
+sources follow the configured missing-source policy. Missing hourly forecast
-fetching because hourly periods are required for report generation.
+data fails bundle fetching because hourly periods are required for report
+generation.
+
+`/alerts/active` is the exception: a successful response with `data: null`
+means the endpoint was checked and there are no current active alerts. The
+adapter records a non-missing alerts source and an empty alert run.
 
 Malformed JSON envelopes, non-2xx statuses, and response read failures include
 endpoint context in returned errors. Decode errors include source context when
@@ -92,9 +97,14 @@ Policy behavior:
 - `warn`: omit the source data, add a warning, and continue
 - `none`: omit the source data and continue without a warning
 
+For `/alerts/active`, an HTTP error or missing `data` field still fails or
+follows the relevant error path, but explicit `data: null` is not a
+missing-source condition.
+
 ## Source Identity
 
-For non-null source payloads, the adapter records:
+For source payloads accepted into the bundle, including the explicit `null`
+alerts payload, the adapter records:
 
 - source name
 - endpoint path

docs/internal/weather-data.md

@@ -53,8 +53,9 @@ contract used by this project.
 
 The adapter records source name, endpoint, query, fetch time, source timestamps
 when available, SHA-256 hash over compact raw `data` JSON, missing status, and
-source warnings. `app.FetchAndSaveBundle` can write bundle JSON atomically for
+source warnings. Successful `data: null` responses from `/alerts/active`
-inspection.
+represent a checked empty active-alert list, not a missing source.
+`app.FetchAndSaveBundle` can write bundle JSON atomically for inspection.
 
 ## Skip And Resume Behavior
 
@@ -69,6 +70,8 @@ data is required and cannot be skipped.
   endpoint context.
 - Missing hourly data or hourly forecasts with no periods fail bundle fetch.
 - Optional and stub sources follow missing-source policy.
+- Explicit `data: null` from `/alerts/active` produces an empty, non-missing
+  alert run.
 
 ## Tests
 

internal/adapters/weatherapi/client.go

@@ -202,13 +202,18 @@ func (b *bundleBuilder) fetchNarrative(ctx context.Context) error {
 }
 
 func (b *bundleBuilder) fetchAlerts(ctx context.Context) error {
-	raw, source, err := b.client.fetch(ctx, "alerts", "/alerts/active", queryOptions{})
+	raw, source, err := b.client.fetch(ctx, "alerts", "/alerts/active", queryOptions{allowNull: true})
 	if err != nil {
 		return err
 	}
 	if raw == nil {
 		return b.handleMissing(&source, "active alerts data is missing", false)
 	}
+	if isJSONNull(raw) {
+		b.bundle.Alerts = &forecast.AlertRun{Raw: append(json.RawMessage(nil), raw...)}
+		b.addSource(source)
+		return nil
+	}
 	var alerts forecast.AlertRun
 	if err := decodeSource(raw, &alerts); err != nil {
 		return b.handleMalformed(&source, err, false)
@@ -301,6 +306,7 @@ func (c *Client) policyFor(source string) config.MissingSourcePolicy {
 type queryOptions struct {
 	precision bool
 	timezone  bool
+	allowNull bool
 }
 
 type envelope struct {
@@ -339,7 +345,7 @@ func (c *Client) fetch(ctx context.Context, sourceName string, endpoint string,
 		Query:     queryMap(reqURL.Query()),
 		FetchedAt: c.now(),
 	}
-	if len(env.Data) == 0 || bytes.Equal(bytes.TrimSpace(env.Data), []byte("null")) {
+	if len(env.Data) == 0 || (isJSONNull(env.Data) && !opts.allowNull) {
 		source.Missing = true
 		return nil, source, nil
 	}
@@ -351,6 +357,10 @@ func (c *Client) fetch(ctx context.Context, sourceName string, endpoint string,
 	return env.Data, source, nil
 }
 
+func isJSONNull(raw json.RawMessage) bool {
+	return bytes.Equal(bytes.TrimSpace(raw), []byte("null"))
+}
+
 func (c *Client) endpointURL(endpoint string, opts queryOptions) *url.URL {
 	reqURL := *c.baseURL
 	reqURL.Path = path.Join(c.baseURL.Path, endpoint)

internal/adapters/weatherapi/client_test.go

@@ -125,6 +125,36 @@ func TestRequiredHourlyForecast(t *testing.T) {
 	}
 }
 
+func TestNullAlertsMeansNoActiveAlerts(t *testing.T) {
+	server := fixtureServer(t, map[string]handlerOverride{
+		"/alerts/active": {status: http.StatusOK, body: `{"data": null}`},
+	}, nil)
+	client := newTestClient(t, server.URL+"/", nil)
+
+	bundle, err := client.FetchBundle(context.Background())
+	if err != nil {
+		t.Fatalf("FetchBundle() error = %v", err)
+	}
+	if bundle.Alerts == nil {
+		t.Fatal("Alerts = nil, want checked empty alert run")
+	}
+	if len(bundle.Alerts.Alerts) != 0 {
+		t.Fatalf("Alerts length = %d, want no active alerts", len(bundle.Alerts.Alerts))
+	}
+	source := sourceByName(t, bundle.Sources, "alerts")
+	if source.Missing {
+		t.Fatalf("alerts source Missing = true, want false")
+	}
+	if source.DataSHA256 == "" {
+		t.Fatal("alerts DataSHA256 is empty, want hash for explicit null payload")
+	}
+	for _, warning := range bundle.Warnings {
+		if warning.Source == "alerts" {
+			t.Fatalf("warnings = %#v, want no alerts warning", bundle.Warnings)
+		}
+	}
+}
+
 func TestMissingSourcePolicyWarnNoneError(t *testing.T) {
 	tests := []struct {
 		name       string

internal/briefing/daily.go

@@ -81,6 +81,7 @@ func BuildDaily(ctx BuildContext, summary *forecast.DailySummary) (Package, erro
 			ForecastSummaryDate: summary.Date,
 		},
 	}
+	setRelevantAlertCount(&pkg.Metadata, len(summary.AlertOverlaps))
 	if ctx.Resolved.Definition.ID == report.DailyTomorrow {
 		pkg.Daily.Planning = buildTomorrowPlanning(summary)
 	}

internal/briefing/daily_test.go

@@ -85,7 +85,11 @@ func TestDailyBriefingQuietWeather(t *testing.T) {
 		Hourly: &forecast.ForecastRun{Periods: []forecast.ForecastPeriod{
 			quietHour("2026-05-29T09:00:00-05:00", "2026-05-29T10:00:00-05:00", 72),
 		}},
-		Sources: []forecast.Source{{Name: "hourly", FetchedAt: time.Now()}},
+		Alerts: &forecast.AlertRun{},
+		Sources: []forecast.Source{
+			{Name: "hourly", FetchedAt: time.Now()},
+			{Name: "alerts", Endpoint: "/alerts/active", FetchedAt: time.Now()},
+		},
 	}
 	summary, err := forecast.BuildDailySummary(bundle, resolved.ValidPeriod.Start, location, defaultDayparts())
 	if err != nil {
@@ -101,6 +105,19 @@ func TestDailyBriefingQuietWeather(t *testing.T) {
 	if len(pkg.Daily.RelevantAlerts) != 0 {
 		t.Fatalf("RelevantAlerts length = %d, want 0", len(pkg.Daily.RelevantAlerts))
 	}
+	if pkg.Metadata.Alerts == nil {
+		t.Fatal("Metadata.Alerts = nil, want checked no-active-alerts status")
+	}
+	if !pkg.Metadata.Alerts.Checked || pkg.Metadata.Alerts.ActiveCount != 0 || pkg.Metadata.Alerts.RelevantCount != 0 || pkg.Metadata.Alerts.Missing {
+		t.Fatalf("Metadata.Alerts = %#v, want checked no-active-alerts status", pkg.Metadata.Alerts)
+	}
+	data, err := json.Marshal(pkg.Metadata)
+	if err != nil {
+		t.Fatalf("marshal metadata: %v", err)
+	}
+	if strings.Contains(string(data), `"missing"`) {
+		t.Fatalf("metadata includes missing for checked empty alerts:\n%s", string(data))
+	}
 }
 
 func TestDailyBriefingAlertExclusion(t *testing.T) {

internal/briefing/package.go

@@ -35,6 +35,7 @@ type Metadata struct {
 	SourceLocation   string                   `json:"sourceLocation,omitempty"`
 	Sources          []SourceMetadata         `json:"sources,omitempty"`
 	SourceWarnings   []forecast.SourceWarning `json:"sourceWarnings,omitempty"`
+	Alerts           *AlertStatus             `json:"alerts,omitempty"`
 }
 
 type SourceMetadata struct {
@@ -48,6 +49,13 @@ type SourceMetadata struct {
 	Warnings   []forecast.SourceWarning `json:"warnings,omitempty"`
 }
 
+type AlertStatus struct {
+	Checked       bool `json:"checked"`
+	ActiveCount   int  `json:"activeCount"`
+	RelevantCount int  `json:"relevantCount"`
+	Missing       bool `json:"missing,omitempty"`
+}
+
 type BuildContext struct {
 	Resolved report.Resolved
 	Bundle   *forecast.Bundle
@@ -72,6 +80,7 @@ func BuildMetadata(ctx BuildContext) Metadata {
 		SourceLocation:   sourceLocation,
 		Sources:          sourceMetadata(ctx.Bundle),
 		SourceWarnings:   sourceWarnings(ctx.Bundle),
+		Alerts:           alertStatus(ctx.Bundle),
 	}
 }
 
@@ -124,6 +133,37 @@ func sourceWarnings(bundle *forecast.Bundle) []forecast.SourceWarning {
 	return bundle.Warnings
 }
 
+func alertStatus(bundle *forecast.Bundle) *AlertStatus {
+	if bundle == nil {
+		return nil
+	}
+	status := &AlertStatus{}
+	if bundle.Alerts != nil {
+		status.Checked = true
+		status.ActiveCount = len(bundle.Alerts.Alerts)
+	}
+	for _, source := range bundle.Sources {
+		if source.Name == "alerts" && source.Missing {
+			status.Missing = true
+			break
+		}
+	}
+	if !status.Checked && !status.Missing {
+		return nil
+	}
+	return status
+}
+
+func setRelevantAlertCount(metadata *Metadata, count int) {
+	if metadata.Alerts == nil {
+		if count == 0 {
+			return
+		}
+		metadata.Alerts = &AlertStatus{}
+	}
+	metadata.Alerts.RelevantCount = count
+}
+
 func variantForReport(id report.ID) string {
 	switch id {
 	case report.DailyToday:

internal/briefing/storm.go

@@ -56,10 +56,12 @@ func BuildStorm(ctx BuildContext) (Package, error) {
 		Discussion:          buildDiscussion(ctx.Bundle.Discussion),
 		WeatherStory:        buildWeatherStory(ctx.Bundle),
 	}
-	return Package{
+	pkg := Package{
 		Metadata: BuildMetadata(ctx),
 		Storm:    storm,
-	}, nil
+	}
+	setRelevantAlertCount(&pkg.Metadata, len(alerts))
+	return pkg, nil
 }
 
 func stormHeadlines(alerts []forecast.AlertOverlap) []string {

internal/briefing/three_day.go

@@ -49,6 +49,7 @@ func BuildThreeDay(ctx BuildContext, summaries []forecast.DailySummary) (Package
 		pkg.ThreeDay.Days = append(pkg.ThreeDay.Days, day)
 	}
 	pkg.ThreeDay.RelevantAlerts = collectOutlookAlerts(pkg.ThreeDay.Days)
+	setRelevantAlertCount(&pkg.Metadata, len(pkg.ThreeDay.RelevantAlerts))
 	return pkg, nil
 }
 

internal/briefing/weekend.go

@@ -42,6 +42,7 @@ func BuildWeekend(ctx BuildContext, summaries []forecast.DailySummary) (Package,
 		pkg.Weekend.Days = append(pkg.Weekend.Days, buildOutlookDay(summary))
 	}
 	pkg.Weekend.RelevantAlerts = collectOutlookAlerts(pkg.Weekend.Days)
+	setRelevantAlertCount(&pkg.Metadata, len(pkg.Weekend.RelevantAlerts))
 	pkg.Weekend.Planning = buildWeekendPlanning(pkg.Weekend.Days, pkg.Weekend.Discussion, ctx.Bundle)
 	return pkg, nil
 }