diff --git a/tracing/impl/stackdriver_tracer.go b/tracing/impl/stackdriver_tracer.go
index c705ba48469f5d1e4b868d737e78c6b51b15f448..56cc579e0c9dbcda7e9d95ad05b911e670d124f6 100644
--- a/tracing/impl/stackdriver_tracer.go
+++ b/tracing/impl/stackdriver_tracer.go
@@ -154,32 +154,51 @@ func (span *adapterSpan) SetOperationName(operationName string) opentracing.Span
 	return span
 }
 
-func castToAttribute(key string, value interface{}) []trace.Attribute {
-	switch v := reflect.ValueOf(value); v.Kind() {
-	case reflect.Bool:
-		return []trace.Attribute{trace.BoolAttribute(key, v.Bool())}
-	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
-		return []trace.Attribute{trace.Int64Attribute(key, v.Int())}
-	case reflect.Float32, reflect.Float64:
-		return []trace.Attribute{trace.Float64Attribute(key, v.Float())}
-	case reflect.String:
-		chunks := chunkString(v.String(), 256)
-		attrs := []trace.Attribute{}
-		for i, chunk := range chunks {
-			var k string
-			if i == 0 {
-				k = key
-			} else {
-				k = key + "." + strconv.Itoa(i)
-			}
-			attrs = append(attrs, trace.StringAttribute(k, chunk))
-		}
-		return attrs
+func castToAttribute(key string, value any) []trace.Attribute {
+	switch v := value.(type) {
+	case bool:
+		return []trace.Attribute{trace.BoolAttribute(key, v)}
+	case int, int8, int16, int32, int64:
+		return []trace.Attribute{trace.Int64Attribute(key, reflect.ValueOf(v).Int())}
+	case uint, uint8, uint16, uint32, uint64:
+		return []trace.Attribute{trace.Int64Attribute(key, int64(reflect.ValueOf(v).Uint()))}
+	case float32, float64:
+		return []trace.Attribute{trace.Float64Attribute(key, reflect.ValueOf(v).Float())}
+	case string:
+		return newStringAttribute(key, v)
+	case fmt.Stringer:
+		return newStringAttribute(key, v.String())
 	default:
-		return []trace.Attribute{trace.StringAttribute(key, fmt.Sprintf("castToAttribute not implemented for type %+v", v.Kind()))}
+		return []trace.Attribute{
+			trace.StringAttribute(key, fmt.Sprint(value)),
+			trace.StringAttribute(key+".error", fmt.Sprintf("unknown type: %T", value)),
+		}
 	}
 }
 
+// stackdriver limits attribute values to 256 bytes
+const stringChunkSize = 256
+
+func newStringAttribute(key, value string) []trace.Attribute {
+	var attrs []trace.Attribute
+
+	for i, chunk := range chunkString(value, stringChunkSize) {
+		k := key
+		if i != 0 {
+			k = key + "." + strconv.Itoa(i)
+		}
+		attrs = append(attrs, trace.StringAttribute(k, chunk))
+	}
+
+	if len(attrs) > 1 {
+		attrs = append(attrs,
+			trace.StringAttribute(key+".error",
+				fmt.Sprintf("string is exceeding the maximum attribute length of %d; it has been chunked", stringChunkSize)))
+	}
+
+	return attrs
+}
+
 // stackdriver limits attribute values to 256 bytes
 // we use runes here, hopefully that's close enough
 // values get truncated silently, so we can set $key to the full value
diff --git a/tracing/impl/stackdriver_tracer_test.go b/tracing/impl/stackdriver_tracer_test.go
index 6cb9dc31ada7f8fab28bddb9de7ffcf2cf04882a..66fff0835f059570bbfeace6559a17fcb7a4aec9 100644
--- a/tracing/impl/stackdriver_tracer_test.go
+++ b/tracing/impl/stackdriver_tracer_test.go
@@ -4,6 +4,7 @@ package impl
 
 import (
 	"fmt"
+	"net/url"
 	"reflect"
 	"strings"
 	"testing"
@@ -20,6 +21,8 @@ import (
 type unsupportedType struct{}
 
 func TestOcSpanAdapterCastToAttribute(t *testing.T) {
+	const errChunked = "string is exceeding the maximum attribute length of 256; it has been chunked"
+
 	tests := []struct {
 		name  string
 		key   string
@@ -87,6 +90,7 @@ func TestOcSpanAdapterCastToAttribute(t *testing.T) {
 			want: []trace.Attribute{
 				trace.StringAttribute("foo", strings.Repeat("a", 256)),
 				trace.StringAttribute("foo.1", strings.Repeat("a", 1)),
+				trace.StringAttribute("foo.error", errChunked),
 			},
 		},
 		{
@@ -96,6 +100,7 @@ func TestOcSpanAdapterCastToAttribute(t *testing.T) {
 			want: []trace.Attribute{
 				trace.StringAttribute("foo", strings.Repeat("a", 256)),
 				trace.StringAttribute("foo.1", strings.Repeat("a", 255)),
+				trace.StringAttribute("foo.error", errChunked),
 			},
 		},
 		{
@@ -105,6 +110,7 @@ func TestOcSpanAdapterCastToAttribute(t *testing.T) {
 			want: []trace.Attribute{
 				trace.StringAttribute("foo", strings.Repeat("a", 256)),
 				trace.StringAttribute("foo.1", strings.Repeat("a", 256)),
+				trace.StringAttribute("foo.error", errChunked),
 			},
 		},
 		{
@@ -115,6 +121,7 @@ func TestOcSpanAdapterCastToAttribute(t *testing.T) {
 				trace.StringAttribute("foo", strings.Repeat("a", 256)),
 				trace.StringAttribute("foo.1", strings.Repeat("a", 256)),
 				trace.StringAttribute("foo.2", strings.Repeat("a", 1)),
+				trace.StringAttribute("foo.error", errChunked),
 			},
 		},
 		{
@@ -122,7 +129,19 @@ func TestOcSpanAdapterCastToAttribute(t *testing.T) {
 			key:   "foo",
 			value: unsupportedType{},
 			want: []trace.Attribute{
-				trace.StringAttribute("foo", "castToAttribute not implemented for type struct"),
+				trace.StringAttribute("foo", "{}"),
+				trace.StringAttribute("foo.error", "unknown type: impl.unsupportedType"),
+			},
+		},
+		{
+			name: "net.url type",
+			key:  "foo",
+			value: func() *url.URL {
+				u, _ := url.Parse("https://example.com")
+				return u
+			}(),
+			want: []trace.Attribute{
+				trace.StringAttribute("foo", "https://example.com"),
 			},
 		},
 	}