diff --git a/pkg/skoop/cmd/app.go b/pkg/skoop/cmd/app.go
index 6c15ddab..0aa79eb6 100644
--- a/pkg/skoop/cmd/app.go
+++ b/pkg/skoop/cmd/app.go
@@ -70,7 +70,6 @@ func NewSkoopCmd() *cobra.Command {
 					}
 					return nil
 				}
-
 			} else {
 				fmt.Printf("Packet path:\n%+v\n", packetPath.Paths())
 			}
diff --git a/pkg/skoop/context/task.go b/pkg/skoop/context/task.go
index 18fe35c5..297fcf43 100644
--- a/pkg/skoop/context/task.go
+++ b/pkg/skoop/context/task.go
@@ -2,6 +2,9 @@ package context
 
 import (
 	"fmt"
+	"net"
+
+	"golang.org/x/exp/slices"
 
 	"github.com/alibaba/kubeskoop/pkg/skoop/model"
 
@@ -27,6 +30,28 @@ func (tc *TaskConfig) BindFlags(fs *pflag.FlagSet) {
 }
 
 func (tc *TaskConfig) Validate() error {
+	if tc.Source == "" || tc.Destination.Address == "" {
+		return fmt.Errorf("source or destination address cannot be empty")
+	}
+
+	if tc.Destination.Port <= 0 || tc.Destination.Port > 65535 {
+		return fmt.Errorf("a valid destination port should be provided")
+	}
+
+	ip := net.ParseIP(tc.Source)
+	if ip == nil || ip.To4() == nil {
+		return fmt.Errorf("source address should be a valid IPv4 address")
+	}
+
+	ip = net.ParseIP(tc.Destination.Address)
+	if ip == nil || ip.To4() == nil {
+		return fmt.Errorf("destination address should be a valid IPv4 address")
+	}
+
+	if !slices.Contains([]string{"tcp", "udp"}, tc.Protocol) {
+		return fmt.Errorf("protocol should be tcp,udp")
+	}
+
 	return nil
 }
 
diff --git a/pkg/skoop/context/ui.go b/pkg/skoop/context/ui.go
index 26ca79cf..6749b7ad 100644
--- a/pkg/skoop/context/ui.go
+++ b/pkg/skoop/context/ui.go
@@ -1,7 +1,11 @@
 package context
 
 import (
+	"fmt"
+	"strings"
+
 	"github.com/spf13/pflag"
+	"golang.org/x/exp/slices"
 )
 
 type UIConfig struct {
@@ -12,6 +16,10 @@ type UIConfig struct {
 	HTTPPort    uint
 }
 
+var (
+	supportedFormat = []string{"d2", "svg", "json"}
+)
+
 func (c *UIConfig) BindFlags(fs *pflag.FlagSet) {
 	fs.StringVarP(&c.Format, "format", "", "", "Output format of diagnose result, support d2/svg/json. If not set, only print simple path info on console.")
 	fs.StringVarP(&c.Output, "output", "", "", "Output file name, default is output.d2/svg/json in current work directory.")
@@ -20,6 +28,9 @@ func (c *UIConfig) BindFlags(fs *pflag.FlagSet) {
 }
 
 func (c *UIConfig) Validate() error {
+	if c.Format != "" && !slices.Contains(supportedFormat, c.Format) {
+		return fmt.Errorf("unsupported output format %q, should be %s", c.Format, strings.Join(supportedFormat, ","))
+	}
 	return nil
 }
 
diff --git a/pkg/skoop/plugin/flannel.go b/pkg/skoop/plugin/flannel.go
index 8ac88785..27224e1c 100644
--- a/pkg/skoop/plugin/flannel.go
+++ b/pkg/skoop/plugin/flannel.go
@@ -6,6 +6,8 @@ import (
 	"net"
 	"strings"
 
+	"golang.org/x/exp/slices"
+
 	"github.com/spf13/pflag"
 	"k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -32,6 +34,10 @@ type FlannelConfig struct {
 	Interface   string
 }
 
+var (
+	supportedFlannelBackendType = []string{"host-gw", "vxlan", "alloc"}
+)
+
 func (f *FlannelConfig) BindFlags(fs *pflag.FlagSet) {
 	fs.StringVarP(&f.BackendType, "flannel-backend-type", "", "",
 		"Backend type for flannel plugin, support host-gw,vxlan,alloc. If not set, it will auto detect from flannel config.")
@@ -46,6 +52,10 @@ func (f *FlannelConfig) BindFlags(fs *pflag.FlagSet) {
 }
 
 func (f *FlannelConfig) Validate() error {
+	if f.BackendType != "" && !slices.Contains(supportedFlannelBackendType, f.BackendType) {
+		return fmt.Errorf("unsupported flannel backed type %q, should be %s",
+			f.BackendType, strings.Join(supportedFlannelBackendType, ","))
+	}
 	return nil
 }