diff --git a/conf/db/upgrade/V5.5.6__schema.sql b/conf/db/upgrade/V5.5.6__schema.sql
index 69eee484a0..4b92ec28fb 100644
--- a/conf/db/upgrade/V5.5.6__schema.sql
+++ b/conf/db/upgrade/V5.5.6__schema.sql
@@ -6,3 +6,11 @@ ALTER TABLE `GuestVmScriptExecutedRecordDetailVO`
 
 CALL ADD_COLUMN('PciDeviceVO', 'vmPciDeviceAddress', 'varchar(32)', 1, NULL);
 CALL ADD_COLUMN('MdevDeviceVO', 'mdevDeviceAddress', 'varchar(32)', 1, NULL);
+
+-- Add index for modelId field to support duplicate checking
+-- Use CREATE_INDEX procedure (defined in beforeMigrate.sql) for idempotent operation
+CALL CREATE_INDEX('ModelVO', 'idx_modelId', 'modelId');
+
+-- Upgrade existing data: set modelId to uuid if modelId is NULL
+-- This UPDATE is idempotent: WHERE clause ensures only NULL values are updated
+UPDATE ModelVO SET modelId = uuid WHERE modelId IS NULL;
diff --git a/sdk/src/main/java/org/zstack/sdk/AddModelAction.java b/sdk/src/main/java/org/zstack/sdk/AddModelAction.java
index d05730e861..993a073b9c 100644
--- a/sdk/src/main/java/org/zstack/sdk/AddModelAction.java
+++ b/sdk/src/main/java/org/zstack/sdk/AddModelAction.java
@@ -67,6 +67,9 @@ public Result throwExceptionIfError() {
     @Param(required = false, maxLength = 512, nonempty = false, nullElements = false, emptyString = true, noTrim = false)
     public java.lang.String gpuConstraintDescription;
 
+    @Param(required = false, maxLength = 255, nonempty = false, nullElements = false, emptyString = true, noTrim = false)
+    public java.lang.String modelId;
+
     @Param(required = false)
     public java.lang.String resourceUuid;
 
diff --git a/sdk/src/main/java/org/zstack/sdk/UpdateModelAction.java b/sdk/src/main/java/org/zstack/sdk/UpdateModelAction.java
index 108cfa2e38..d8a6de859d 100644
--- a/sdk/src/main/java/org/zstack/sdk/UpdateModelAction.java
+++ b/sdk/src/main/java/org/zstack/sdk/UpdateModelAction.java
@@ -52,6 +52,9 @@ public Result throwExceptionIfError() {
     @Param(required = false, maxLength = 512, nonempty = false, nullElements = false, emptyString = true, noTrim = false)
     public java.lang.String gpuConstraintDescription;
 
+    @Param(required = false, maxLength = 255, nonempty = false, nullElements = false, emptyString = true, noTrim = false)
+    public java.lang.String modelId;
+
     @Param(required = false)
     public java.util.List systemTags;