diff --git a/k8s/apis/ai/v1/model_webhook.go b/k8s/apis/ai/v1/model_webhook.go
index 9adb85543..f792ffa82 100644
--- a/k8s/apis/ai/v1/model_webhook.go
+++ b/k8s/apis/ai/v1/model_webhook.go
@@ -155,7 +155,8 @@ func (r *Model) validateCreateModel() error {
 			pack := extractModelValidationPack(models, p)
 			ret, err := configutils.CheckValidationPack(r.ObjectMeta.Name, readModelValiationTarget(r, p), p.ValidationType, pack)
 			if err != nil {
-				return err
+				allErrs = append(allErrs, field.Forbidden(&field.Path{}, strings.ReplaceAll(p.Message, "%s", "Validation encountered an unexpected error.")))
+				return apierrors.NewInvalid(schema.GroupKind{Group: "ai.symphony", Kind: "Model"}, r.Name, allErrs)
 			}
 			if ret != "" {
 				allErrs = append(allErrs, field.Forbidden(&field.Path{}, strings.ReplaceAll(p.Message, "%s", ret)))
@@ -188,7 +189,8 @@ func (r *Model) validateUpdateModel() error {
 			pack := extractModelValidationPack(models, p)
 			ret, err := configutils.CheckValidationPack(r.ObjectMeta.Name, readModelValiationTarget(r, p), p.ValidationType, pack)
 			if err != nil {
-				return err
+				allErrs = append(allErrs, field.Forbidden(&field.Path{}, strings.ReplaceAll(p.Message, "%s", "Validation encountered an unexpected error.")))
+				return apierrors.NewInvalid(schema.GroupKind{Group: "ai.symphony", Kind: "Model"}, r.Name, allErrs)
 			}
 			if ret != "" {
 				allErrs = append(allErrs, field.Forbidden(&field.Path{}, strings.ReplaceAll(p.Message, "%s", ret)))
diff --git a/k8s/apis/ai/v1/skill_webhook.go b/k8s/apis/ai/v1/skill_webhook.go
index dcd791ef3..1ed40a258 100644
--- a/k8s/apis/ai/v1/skill_webhook.go
+++ b/k8s/apis/ai/v1/skill_webhook.go
@@ -12,6 +12,7 @@ import (
 	"gopls-workspace/apis/metrics/v1"
 	"time"
 
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/runtime"
 	ctrl "sigs.k8s.io/controller-runtime"
 	"sigs.k8s.io/controller-runtime/pkg/client"
@@ -126,7 +127,7 @@ func (r *Skill) validateCreateSkill() error {
 	var skills SkillList
 	mySkillClient.List(context.Background(), &skills, client.InNamespace(r.Namespace), client.MatchingFields{".spec.displayName": r.Spec.DisplayName})
 	if len(skills.Items) != 0 {
-		return fmt.Errorf("skill display name '%s' is already taken", r.Spec.DisplayName)
+		return apierrors.NewBadRequest(fmt.Sprintf("skill display name '%s' is already taken", r.Spec.DisplayName))
 	}
 	return nil
 }
@@ -135,10 +136,10 @@ func (r *Skill) validateUpdateSkill() error {
 	var skills SkillList
 	err := mySkillClient.List(context.Background(), &skills, client.InNamespace(r.Namespace), client.MatchingFields{".spec.displayName": r.Spec.DisplayName})
 	if err != nil {
-		return err
+		return apierrors.NewInternalError(err)
 	}
 	if !(len(skills.Items) == 0 || len(skills.Items) == 1 && skills.Items[0].ObjectMeta.Name == r.ObjectMeta.Name) {
-		return fmt.Errorf("skill display name '%s' is already taken", r.Spec.DisplayName)
+		return apierrors.NewBadRequest(fmt.Sprintf("skill display name '%s' is already taken", r.Spec.DisplayName))
 	}
 	return nil
 }
diff --git a/k8s/apis/fabric/v1/device_webhook.go b/k8s/apis/fabric/v1/device_webhook.go
index b884e2bd4..b85fbdb58 100644
--- a/k8s/apis/fabric/v1/device_webhook.go
+++ b/k8s/apis/fabric/v1/device_webhook.go
@@ -12,6 +12,7 @@ import (
 	"gopls-workspace/apis/metrics/v1"
 	"time"
 
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/runtime"
 	ctrl "sigs.k8s.io/controller-runtime"
 	"sigs.k8s.io/controller-runtime/pkg/client"
@@ -126,7 +127,7 @@ func (r *Device) validateCreateDevice() error {
 	var devices DeviceList
 	myDeviceClient.List(context.Background(), &devices, client.InNamespace(r.Namespace), client.MatchingFields{".spec.displayName": r.Spec.DisplayName})
 	if len(devices.Items) != 0 {
-		return fmt.Errorf("device display name '%s' is already taken", r.Spec.DisplayName)
+		return apierrors.NewBadRequest(fmt.Sprintf("device display name '%s' is already taken", r.Spec.DisplayName))
 	}
 	return nil
 }
@@ -135,10 +136,10 @@ func (r *Device) validateUpdateDevice() error {
 	var devices DeviceList
 	err := myDeviceClient.List(context.Background(), &devices, client.InNamespace(r.Namespace), client.MatchingFields{".spec.displayName": r.Spec.DisplayName})
 	if err != nil {
-		return err
+		return apierrors.NewInternalError(err)
 	}
 	if !(len(devices.Items) == 0 || len(devices.Items) == 1 && devices.Items[0].ObjectMeta.Name == r.ObjectMeta.Name) {
-		return fmt.Errorf("device display name '%s' is already taken", r.Spec.DisplayName)
+		return apierrors.NewBadRequest(fmt.Sprintf("device display name '%s' is already taken", r.Spec.DisplayName))
 	}
 	return nil
 }
diff --git a/k8s/apis/federation/v1/catalog_webhook.go b/k8s/apis/federation/v1/catalog_webhook.go
index 80e379d2e..f6b7a996a 100644
--- a/k8s/apis/federation/v1/catalog_webhook.go
+++ b/k8s/apis/federation/v1/catalog_webhook.go
@@ -9,11 +9,12 @@ package v1
 import (
 	"context"
 	"encoding/json"
+	"fmt"
 	"gopls-workspace/apis/metrics/v1"
 	"time"
 
 	"github.com/eclipse-symphony/symphony/api/pkg/apis/v1alpha1/utils"
-	"github.com/eclipse-symphony/symphony/coa/pkg/apis/v1alpha2"
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/runtime"
 	ctrl "sigs.k8s.io/controller-runtime"
 	"sigs.k8s.io/controller-runtime/pkg/client"
@@ -130,7 +131,7 @@ func (r *Catalog) checkSchema() error {
 			err := myCatalogClient.List(context.Background(), &catalogs, client.InNamespace(r.ObjectMeta.Namespace), client.MatchingFields{".metadata.name": schemaName})
 			if err != nil || len(catalogs.Items) == 0 {
 				cataloglog.Error(err, "Could not find the required schema.", "name", schemaName)
-				return v1alpha2.NewCOAError(err, "schema not found", v1alpha2.NotFound)
+				return apierrors.NewBadRequest(fmt.Sprintf("Could not find the required schema, %s.", schemaName))
 			}
 
 			jData, _ := json.Marshal(catalogs.Items[0].Spec.Properties)
@@ -138,7 +139,7 @@ func (r *Catalog) checkSchema() error {
 			err = json.Unmarshal(jData, &properties)
 			if err != nil {
 				cataloglog.Error(err, "Invalid schema.", "name", schemaName)
-				return v1alpha2.NewCOAError(err, "invalid schema", v1alpha2.ValidateFailed)
+				return apierrors.NewBadRequest(fmt.Sprintf("Invalid schema, %s.", schemaName))
 			}
 			if spec, ok := properties["spec"]; ok {
 				var schemaObj utils.Schema
@@ -146,23 +147,23 @@ func (r *Catalog) checkSchema() error {
 				err := json.Unmarshal(jData, &schemaObj)
 				if err != nil {
 					cataloglog.Error(err, "Invalid schema.", "name", schemaName)
-					return v1alpha2.NewCOAError(err, "invalid schema", v1alpha2.ValidateFailed)
+					return apierrors.NewBadRequest(fmt.Sprintf("Invalid schema, %s.", schemaName))
 				}
 				jData, _ = json.Marshal(r.Spec.Properties)
 				var properties map[string]interface{}
 				err = json.Unmarshal(jData, &properties)
 				if err != nil {
 					cataloglog.Error(err, "Validating failed.")
-					return v1alpha2.NewCOAError(err, "invalid properties", v1alpha2.ValidateFailed)
+					return apierrors.NewBadRequest("Invalid properties of the catalog.")
 				}
 				result, err := schemaObj.CheckProperties(properties, nil)
 				if err != nil {
 					cataloglog.Error(err, "Validating failed.")
-					return v1alpha2.NewCOAError(err, "invalid properties", v1alpha2.ValidateFailed)
+					return apierrors.NewBadRequest("Validate failed for the catalog.")
 				}
 				if !result.Valid {
 					cataloglog.Error(err, "Validating failed.")
-					return v1alpha2.NewCOAError(err, "invalid properties", v1alpha2.ValidateFailed)
+					return apierrors.NewBadRequest("This is not a valid catalog according to the schema.")
 				}
 			}
 			cataloglog.Info("Validation finished.", "name", r.Name)
diff --git a/k8s/apis/solution/v1/solution_webhook.go b/k8s/apis/solution/v1/solution_webhook.go
index 8700a0a4c..4c81fcf44 100644
--- a/k8s/apis/solution/v1/solution_webhook.go
+++ b/k8s/apis/solution/v1/solution_webhook.go
@@ -10,6 +10,7 @@ import (
 	"context"
 	"fmt"
 
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/runtime"
 	ctrl "sigs.k8s.io/controller-runtime"
 	"sigs.k8s.io/controller-runtime/pkg/client"
@@ -78,7 +79,7 @@ func (r *Solution) validateCreateSolution() error {
 	var solutions SolutionList
 	mySolutionClient.List(context.Background(), &solutions, client.InNamespace(r.Namespace), client.MatchingFields{".spec.displayName": r.Spec.DisplayName})
 	if len(solutions.Items) != 0 {
-		return fmt.Errorf("solution display name '%s' is already taken", r.Spec.DisplayName)
+		return apierrors.NewBadRequest(fmt.Sprintf("solution display name '%s' is already taken", r.Spec.DisplayName))
 	}
 	return nil
 }
@@ -87,10 +88,10 @@ func (r *Solution) validateUpdateSolution() error {
 	var solutions SolutionList
 	err := mySolutionClient.List(context.Background(), &solutions, client.InNamespace(r.Namespace), client.MatchingFields{".spec.displayName": r.Spec.DisplayName})
 	if err != nil {
-		return err
+		return apierrors.NewInternalError(err)
 	}
 	if !(len(solutions.Items) == 0 || len(solutions.Items) == 1 && solutions.Items[0].ObjectMeta.Name == r.ObjectMeta.Name) {
-		return fmt.Errorf("solution display name '%s' is already taken", r.Spec.DisplayName)
+		return apierrors.NewBadRequest(fmt.Sprintf("solution display name '%s' is already taken", r.Spec.DisplayName))
 	}
 	return nil
 }