diff --git a/example/cmd/root_test.go b/example/cmd/root_test.go
index 8942a6d30..a94f42b5d 100644
--- a/example/cmd/root_test.go
+++ b/example/cmd/root_test.go
@@ -128,5 +128,11 @@ func TestRoot(t *testing.T) {
 			Expect(carapace.ActionStyledValuesDescribed(
 				"--array", "multiflag", style.Blue,
 			).NoSpace('.').Tag("flags"))
+
+		s.Run("--toggle=").
+			Expect(carapace.ActionStyledValues(
+				"false", style.Red,
+				"true", style.Green,
+			).Prefix("--toggle="))
 	})
 }
diff --git a/traverse.go b/traverse.go
index faaa1387b..beb9970e3 100644
--- a/traverse.go
+++ b/traverse.go
@@ -6,6 +6,7 @@ import (
 	"github.com/rsteube/carapace/internal/common"
 	"github.com/rsteube/carapace/internal/config"
 	"github.com/rsteube/carapace/internal/pflagfork"
+	"github.com/rsteube/carapace/pkg/style"
 	"github.com/spf13/cobra"
 )
 
@@ -161,7 +162,13 @@ loop:
 			LOG.Printf("completing optional flag argument for arg %#v\n", context.CallbackValue)
 			prefix, optarg := f.Split(context.CallbackValue)
 			context.CallbackValue = optarg
-			return storage.getFlag(c, f.Name).Prefix(prefix), context
+
+			switch f.Value.Type() {
+			case "bool":
+				return ActionValues("true", "false").StyleF(style.ForKeyword).Prefix(prefix), context
+			default:
+				return storage.getFlag(c, f.Name).Prefix(prefix), context
+			}
 		}
 		LOG.Printf("completing flags for arg %#v\n", context.CallbackValue)
 		return actionFlags(c), context