diff --git a/web/app/components/workflow/nodes/knowledge-base/default.ts b/web/app/components/workflow/nodes/knowledge-base/default.ts
index 94caf73253..29d37c66d2 100644
--- a/web/app/components/workflow/nodes/knowledge-base/default.ts
+++ b/web/app/components/workflow/nodes/knowledge-base/default.ts
@@ -18,10 +18,16 @@ const nodeDefault: NodeDefault<KnowledgeBaseNodeType> = {
       score_threshold: 0.5,
     },
   },
-  checkValid() {
+  checkValid(payload) {
+    const { chunk_structure } = payload
+    let errorMessage = ''
+
+    if (!chunk_structure)
+      errorMessage = 'Chunk structure is required.'
+
     return {
-      isValid: true,
-      errorMessage: '',
+      isValid: !errorMessage,
+      errorMessage,
     }
   },
 }
diff --git a/web/app/components/workflow/nodes/tool/components/input-var-list.tsx b/web/app/components/workflow/nodes/tool/components/input-var-list.tsx
index 1a609c58f5..7f310051e2 100644
--- a/web/app/components/workflow/nodes/tool/components/input-var-list.tsx
+++ b/web/app/components/workflow/nodes/tool/components/input-var-list.tsx
@@ -172,7 +172,7 @@ const InputVarList: FC<Props> = ({
 
           return (
             <div key={variable} className='space-y-1'>
-              <div className='flex h-[18px] items-center space-x-2'>
+              <div className='flex items-center space-x-2 leading-[18px]'>
                 <span className='code-sm-semibold text-text-secondary'>{label[language] || label.en_US}</span>
                 <span className='system-xs-regular text-text-tertiary'>{paramType(type)}</span>
                 {required && <span className='system-xs-regular text-util-colors-orange-dark-orange-dark-600'>Required</span>}