diff --git a/internal/aggregate/metrics.go b/internal/aggregate/metrics.go
index 11b8e83..917fc1c 100644
--- a/internal/aggregate/metrics.go
+++ b/internal/aggregate/metrics.go
@@ -9,7 +9,7 @@ import (
 	"notashelf.dev/watchdog/internal/config"
 )
 
-var prometheusLabelPattern = regexp.MustCompile(`^[a-zA-Z0-9_/:-]*$`)
+var prometheusLabelPattern = regexp.MustCompile(`^[a-zA-Z0-9_/:.-]*$`)
 
 // Records analytics events as Prometheus metrics
 type MetricsAggregator struct {
diff --git a/internal/aggregate/metrics_test.go b/internal/aggregate/metrics_test.go
index c067198..3f964b5 100644
--- a/internal/aggregate/metrics_test.go
+++ b/internal/aggregate/metrics_test.go
@@ -22,7 +22,7 @@ func TestMetricsAggregator_RecordPageview(t *testing.T) {
 		},
 	}
 
-	agg := NewMetricsAggregator(registry, cfg)
+	agg := NewMetricsAggregator(registry, NewCustomEventRegistry(100), cfg)
 
 	// Record pageview with all dimensions
 	agg.RecordPageview("/home", "US", "desktop", "google.com")
@@ -51,7 +51,7 @@ func TestMetricsAggregator_RecordPageview_MinimalDimensions(t *testing.T) {
 		},
 	}
 
-	agg := NewMetricsAggregator(registry, cfg)
+	agg := NewMetricsAggregator(registry, NewCustomEventRegistry(100), cfg)
 
 	// Record pageview with only path
 	agg.RecordPageview("/home", "", "", "")
@@ -78,7 +78,7 @@ func TestMetricsAggregator_PathOverflow(t *testing.T) {
 		},
 	}
 
-	agg := NewMetricsAggregator(registry, cfg)
+	agg := NewMetricsAggregator(registry, NewCustomEventRegistry(100), cfg)
 
 	// Add two paths successfully
 	registry.Add("/path1")
@@ -114,7 +114,7 @@ func TestMetricsAggregator_RecordCustomEvent(t *testing.T) {
 		},
 	}
 
-	agg := NewMetricsAggregator(registry, cfg)
+	agg := NewMetricsAggregator(registry, NewCustomEventRegistry(100), cfg)
 
 	// Record custom event
 	agg.RecordCustomEvent("signup")
@@ -141,7 +141,7 @@ func TestMetricsAggregator_RecordCustomEvent_MultipleEvents(t *testing.T) {
 		},
 	}
 
-	agg := NewMetricsAggregator(registry, cfg)
+	agg := NewMetricsAggregator(registry, NewCustomEventRegistry(100), cfg)
 
 	// Record multiple events
 	agg.RecordCustomEvent("signup")
@@ -170,7 +170,7 @@ func TestMetricsAggregator_MustRegister(t *testing.T) {
 	}
 
 	promRegistry := prometheus.NewRegistry()
-	agg := NewMetricsAggregator(registry, cfg)
+	agg := NewMetricsAggregator(registry, NewCustomEventRegistry(100), cfg)
 
 	// Register metrics
 	agg.MustRegister(promRegistry)
diff --git a/internal/api/handler.go b/internal/api/handler.go
index f02ac95..4265d38 100644
--- a/internal/api/handler.go
+++ b/internal/api/handler.go
@@ -74,8 +74,8 @@ func (h *IngestionHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	// Apply sampling
-	if h.cfg.Site.Sampling < 1.0 {
+	// Apply sampling (0.0 or 1.0 = no sampling, < 1.0 = sample)
+	if h.cfg.Site.Sampling > 0.0 && h.cfg.Site.Sampling < 1.0 {
 		if h.rng.Float64() > h.cfg.Site.Sampling {
 			// Sampled out, return success but don't track
 			w.WriteHeader(http.StatusNoContent)
diff --git a/internal/api/handler_test.go b/internal/api/handler_test.go
index 227c23d..af50bfe 100644
--- a/internal/api/handler_test.go
+++ b/internal/api/handler_test.go
@@ -38,7 +38,7 @@ func TestIngestionHandler_Pageview(t *testing.T) {
 	pathNorm := normalize.NewPathNormalizer(cfg.Site.Path)
 	pathRegistry := aggregate.NewPathRegistry(cfg.Limits.MaxPaths)
 	refRegistry := normalize.NewReferrerRegistry(cfg.Limits.MaxSources)
-	metricsAgg := aggregate.NewMetricsAggregator(pathRegistry, cfg)
+	metricsAgg := aggregate.NewMetricsAggregator(pathRegistry, aggregate.NewCustomEventRegistry(100), cfg)
 
 	handler := NewIngestionHandler(cfg, pathNorm, pathRegistry, refRegistry, metricsAgg)
 
@@ -80,7 +80,7 @@ func TestIngestionHandler_CustomEvent(t *testing.T) {
 	pathNorm := normalize.NewPathNormalizer(cfg.Site.Path)
 	pathRegistry := aggregate.NewPathRegistry(cfg.Limits.MaxPaths)
 	refRegistry := normalize.NewReferrerRegistry(cfg.Limits.MaxSources)
-	metricsAgg := aggregate.NewMetricsAggregator(pathRegistry, cfg)
+	metricsAgg := aggregate.NewMetricsAggregator(pathRegistry, aggregate.NewCustomEventRegistry(100), cfg)
 
 	handler := NewIngestionHandler(cfg, pathNorm, pathRegistry, refRegistry, metricsAgg)
 
@@ -114,7 +114,7 @@ func TestIngestionHandler_WrongDomain(t *testing.T) {
 	pathNorm := normalize.NewPathNormalizer(cfg.Site.Path)
 	pathRegistry := aggregate.NewPathRegistry(cfg.Limits.MaxPaths)
 	refRegistry := normalize.NewReferrerRegistry(cfg.Limits.MaxSources)
-	metricsAgg := aggregate.NewMetricsAggregator(pathRegistry, cfg)
+	metricsAgg := aggregate.NewMetricsAggregator(pathRegistry, aggregate.NewCustomEventRegistry(100), cfg)
 
 	handler := NewIngestionHandler(cfg, pathNorm, pathRegistry, refRegistry, metricsAgg)
 
@@ -144,7 +144,7 @@ func TestIngestionHandler_MethodNotAllowed(t *testing.T) {
 	pathNorm := normalize.NewPathNormalizer(cfg.Site.Path)
 	pathRegistry := aggregate.NewPathRegistry(cfg.Limits.MaxPaths)
 	refRegistry := normalize.NewReferrerRegistry(cfg.Limits.MaxSources)
-	metricsAgg := aggregate.NewMetricsAggregator(pathRegistry, cfg)
+	metricsAgg := aggregate.NewMetricsAggregator(pathRegistry, aggregate.NewCustomEventRegistry(100), cfg)
 
 	handler := NewIngestionHandler(cfg, pathNorm, pathRegistry, refRegistry, metricsAgg)
 
@@ -171,7 +171,7 @@ func TestIngestionHandler_InvalidJSON(t *testing.T) {
 	pathNorm := normalize.NewPathNormalizer(cfg.Site.Path)
 	pathRegistry := aggregate.NewPathRegistry(cfg.Limits.MaxPaths)
 	refRegistry := normalize.NewReferrerRegistry(cfg.Limits.MaxSources)
-	metricsAgg := aggregate.NewMetricsAggregator(pathRegistry, cfg)
+	metricsAgg := aggregate.NewMetricsAggregator(pathRegistry, aggregate.NewCustomEventRegistry(100), cfg)
 
 	handler := NewIngestionHandler(cfg, pathNorm, pathRegistry, refRegistry, metricsAgg)
 
@@ -206,7 +206,7 @@ func TestIngestionHandler_DeviceClassification(t *testing.T) {
 	pathNorm := normalize.NewPathNormalizer(cfg.Site.Path)
 	pathRegistry := aggregate.NewPathRegistry(cfg.Limits.MaxPaths)
 	refRegistry := normalize.NewReferrerRegistry(cfg.Limits.MaxSources)
-	metricsAgg := aggregate.NewMetricsAggregator(pathRegistry, cfg)
+	metricsAgg := aggregate.NewMetricsAggregator(pathRegistry, aggregate.NewCustomEventRegistry(100), cfg)
 
 	handler := NewIngestionHandler(cfg, pathNorm, pathRegistry, refRegistry, metricsAgg)
 
diff --git a/internal/normalize/path_test.go b/internal/normalize/path_test.go
index b96c5ce..2ffc8a4 100644
--- a/internal/normalize/path_test.go
+++ b/internal/normalize/path_test.go
@@ -121,7 +121,7 @@ func TestNormalizePath(t *testing.T) {
 			name:  "very long path",
 			cfg:   config.PathConfig{},
 			input: "/" + strings.Repeat("a", 2050),
-			want:  "/" + strings.Repeat("a", 2050),
+			want:  "/", // reject overly long paths
 		},
 		{
 			name:  "dot segments only",
diff --git a/testdata/config.valid.yaml b/testdata/config.valid.yaml
index b9a5f28..b3b362c 100644
--- a/testdata/config.valid.yaml
+++ b/testdata/config.valid.yaml
@@ -5,7 +5,7 @@ site:
     pageviews: true
     country: true
     device: true
-    referrer: classify
+    referrer: domain
   custom_events:
     - signup
     - purchase