diff --git a/agent/store/xun/assistant.go b/agent/store/xun/assistant.go
index 5369e140..af1fdc4b 100644
--- a/agent/store/xun/assistant.go
+++ b/agent/store/xun/assistant.go
@@ -319,25 +319,20 @@ func (store *Xun) GetAssistants(filter types.AssistantFilter, locale ...string)
 	if len(filter.Tags) > 0 {
 		qb.Where(func(qb query.Query) {
 			for i, tag := range filter.Tags {
-				// For each tag, we need to match it as part of a JSON array
-				// This will match both single tag arrays ["tag1"] and multi-tag arrays ["tag1","tag2"]
 				pattern := fmt.Sprintf("%%\"%s\"%%", tag)
-				if i == 0 {
-					qb.Where("tags", "like", pattern)
-				} else {
-					qb.OrWhere("tags", "like", pattern)
-				}
+				store.whereJsonLike(qb, "tags", pattern, i > 0)
 			}
 		})
 	}
 
 	// Apply keyword filter if provided
 	if filter.Keywords != "" {
+		kw := fmt.Sprintf("%%%s%%", filter.Keywords)
 		qb.Where(func(qb query.Query) {
-			qb.Where("name", "like", fmt.Sprintf("%%%s%%", filter.Keywords)).
-				OrWhere("description", "like", fmt.Sprintf("%%%s%%", filter.Keywords)).
-				OrWhere("capabilities", "like", fmt.Sprintf("%%%s%%", filter.Keywords)).
-				OrWhere("locales", "like", fmt.Sprintf("%%%s%%", filter.Keywords))
+			qb.Where("name", "like", kw).
+				OrWhere("description", "like", kw).
+				OrWhere("capabilities", "like", kw)
+			store.whereJsonLike(qb, "locales", kw, true)
 		})
 	}
 
@@ -714,20 +709,17 @@ func (store *Xun) DeleteAssistants(filter types.AssistantFilter) (int64, error)
 		qb.Where(func(qb query.Query) {
 			for i, tag := range filter.Tags {
 				pattern := fmt.Sprintf("%%\"%s\"%%", tag)
-				if i == 0 {
-					qb.Where("tags", "like", pattern)
-				} else {
-					qb.OrWhere("tags", "like", pattern)
-				}
+				store.whereJsonLike(qb, "tags", pattern, i > 0)
 			}
 		})
 	}
 
 	// Apply keyword filter if provided
 	if filter.Keywords != "" {
+		kw := fmt.Sprintf("%%%s%%", filter.Keywords)
 		qb.Where(func(qb query.Query) {
-			qb.Where("name", "like", fmt.Sprintf("%%%s%%", filter.Keywords)).
-				OrWhere("description", "like", fmt.Sprintf("%%%s%%", filter.Keywords))
+			qb.Where("name", "like", kw).
+				OrWhere("description", "like", kw)
 		})
 	}
 
diff --git a/agent/store/xun/xun.go b/agent/store/xun/xun.go
index 181249b6..46d54230 100644
--- a/agent/store/xun/xun.go
+++ b/agent/store/xun/xun.go
@@ -198,6 +198,35 @@ func (store *Xun) getDriver() string {
 	return "mysql"
 }
 
+// jsonLikeExpr returns a dialect-specific SQL expression for LIKE on a JSON column.
+// PostgreSQL requires casting json/jsonb to text before applying LIKE.
+func (store *Xun) jsonLikeExpr(column string) string {
+	switch store.getDriver() {
+	case "postgres":
+		return fmt.Sprintf(`"%s"::text LIKE ?`, column)
+	default:
+		return column + " LIKE ?"
+	}
+}
+
+// whereJsonLike applies a LIKE condition on a JSON column with proper dialect handling.
+func (store *Xun) whereJsonLike(qb query.Query, column, pattern string, or bool) {
+	if store.getDriver() == "postgres" {
+		expr := fmt.Sprintf(`"%s"::text LIKE ?`, column)
+		if or {
+			qb.OrWhereRaw(expr, pattern)
+		} else {
+			qb.WhereRaw(expr, pattern)
+		}
+	} else {
+		if or {
+			qb.OrWhere(column, "like", pattern)
+		} else {
+			qb.Where(column, "like", pattern)
+		}
+	}
+}
+
 // GenerateAssistantID generates a random-looking 6-digit ID
 func (store *Xun) GenerateAssistantID() (string, error) {
 	maxAttempts := 10 // Maximum number of attempts to generate a unique ID
diff --git a/agent/store/xun/xun_internal_test.go b/agent/store/xun/xun_internal_test.go
index fc64199f..5f437d7b 100644
--- a/agent/store/xun/xun_internal_test.go
+++ b/agent/store/xun/xun_internal_test.go
@@ -81,6 +81,32 @@ func TestSandboxRawSQLAllDialects(t *testing.T) {
 	assert.Contains(t, isNull, "=")
 }
 
+func TestJsonLikeExpr(t *testing.T) {
+	test.Prepare(t, config.Conf)
+	defer test.Clean()
+
+	store, err := NewXun(typeSetting("default"))
+	assert.NoError(t, err)
+	xunStore := store.(*Xun)
+
+	expr := xunStore.jsonLikeExpr("tags")
+	assert.Contains(t, expr, "LIKE ?")
+
+	driver := xunStore.getDriver()
+	switch driver {
+	case "postgres":
+		assert.Contains(t, expr, `"tags"::text`)
+	default:
+		assert.Equal(t, "tags LIKE ?", expr)
+	}
+}
+
+func TestJsonLikeExprFallback(t *testing.T) {
+	store := &Xun{}
+	expr := store.jsonLikeExpr("tags")
+	assert.Equal(t, "tags LIKE ?", expr)
+}
+
 func TestToDBTime(t *testing.T) {
 	assert.Equal(t, int64(0), toDBTime(0))
 	assert.Equal(t, int64(1234567890), toDBTime(1234567890))