diff --git a/web/app/components/app/configuration/config-var/config-modal/__tests__/index-logic.spec.tsx b/web/app/components/app/configuration/config-var/config-modal/__tests__/index-logic.spec.tsx
index 603d5991704..16f22f59f78 100644
--- a/web/app/components/app/configuration/config-var/config-modal/__tests__/index-logic.spec.tsx
+++ b/web/app/components/app/configuration/config-var/config-modal/__tests__/index-logic.spec.tsx
@@ -176,4 +176,26 @@ describe('ConfigModal logic', () => {
 
     expect(latestFormProps?.modelId).toBe('model-1')
   })
+
+  it('should pass object json_schema to the editor as JSON text', () => {
+    const jsonSchema = {
+      type: 'object',
+      properties: {
+        id: { type: 'string' },
+        name: { type: 'string' },
+      },
+      required: ['id', 'name'],
+    }
+
+    renderConfigModal(
+      createPayload({
+        type: InputVarType.jsonObject,
+        label: 'dsmworksheet',
+        variable: 'dsmworksheet',
+        json_schema: jsonSchema as InputVar['json_schema'],
+      }),
+    )
+
+    expect(latestFormProps?.jsonSchemaStr).toBe(JSON.stringify(jsonSchema, null, 2))
+  })
 })
diff --git a/web/app/components/workflow/nodes/_base/components/editor/code-editor/__tests__/index.spec.tsx b/web/app/components/workflow/nodes/_base/components/editor/code-editor/__tests__/index.spec.tsx
new file mode 100644
index 00000000000..41083443e2e
--- /dev/null
+++ b/web/app/components/workflow/nodes/_base/components/editor/code-editor/__tests__/index.spec.tsx
@@ -0,0 +1,26 @@
+import { render, screen } from '@testing-library/react'
+import { CodeLanguage } from '@/app/components/workflow/nodes/code/types'
+import CodeEditor from '..'
+
+vi.mock('@/hooks/use-theme', () => ({
+  default: () => ({ theme: 'light' }),
+}))
+
+const jsonObjectSchema = {
+  type: 'object',
+  properties: {
+    id: { type: 'string' },
+    name: { type: 'string' },
+  },
+  required: ['id', 'name'],
+}
+
+describe('CodeEditor', () => {
+  it('serializes object JSON values so Monaco receives text instead of a buffer factory', () => {
+    render(<CodeEditor language={CodeLanguage.json} value={jsonObjectSchema} noWrapper />)
+
+    expect(screen.getByTestId('monaco-editor')).toHaveValue(
+      JSON.stringify(jsonObjectSchema, null, 2),
+    )
+  })
+})
diff --git a/web/app/components/workflow/nodes/_base/components/editor/code-editor/__tests__/utils.spec.ts b/web/app/components/workflow/nodes/_base/components/editor/code-editor/__tests__/utils.spec.ts
new file mode 100644
index 00000000000..747dd1a40ab
--- /dev/null
+++ b/web/app/components/workflow/nodes/_base/components/editor/code-editor/__tests__/utils.spec.ts
@@ -0,0 +1,16 @@
+import { serializeCodeEditorValue } from '../utils'
+
+describe('serializeCodeEditorValue', () => {
+  it('turns object values into JSON text so Monaco does not treat them as a buffer factory', () => {
+    const schema = {
+      type: 'object',
+      properties: { id: { type: 'string' } },
+    }
+
+    expect(serializeCodeEditorValue(schema)).toBe(JSON.stringify(schema, null, 2))
+    expect(serializeCodeEditorValue(schema, true)).toBe(JSON.stringify(schema, null, 2))
+    expect(serializeCodeEditorValue('{"type":"object"}')).toBe('{"type":"object"}')
+    expect(serializeCodeEditorValue(undefined)).toBe('')
+    expect(serializeCodeEditorValue(null as never)).toBe('')
+  })
+})
diff --git a/web/app/components/workflow/nodes/_base/components/editor/code-editor/index.tsx b/web/app/components/workflow/nodes/_base/components/editor/code-editor/index.tsx
index 2fb7fe4ae58..893cf6d1e29 100644
--- a/web/app/components/workflow/nodes/_base/components/editor/code-editor/index.tsx
+++ b/web/app/components/workflow/nodes/_base/components/editor/code-editor/index.tsx
@@ -11,6 +11,7 @@ import useTheme from '@/hooks/use-theme'
 import { Theme } from '@/types/app'
 import { basePath } from '@/utils/var'
 import Base from '../base'
+import { serializeCodeEditorValue } from './utils'
 import './style.css'
 
 // load file from local instead of cdn https://github.com/suren-atoyan/monaco-react/issues/482
@@ -117,14 +118,7 @@ const CodeEditor: FC<Props> = ({
     setIsMounted(true)
   }
 
-  const outPutValue = (() => {
-    if (!isJSONStringifyBeauty) return value as string
-    try {
-      return JSON.stringify(value as object, null, 2)
-    } catch {
-      return value as string
-    }
-  })()
+  const outPutValue = serializeCodeEditorValue(value, isJSONStringifyBeauty)
 
   const theme = useMemo(() => {
     if (appTheme === Theme.light) return 'light'
diff --git a/web/app/components/workflow/nodes/_base/components/editor/code-editor/utils.ts b/web/app/components/workflow/nodes/_base/components/editor/code-editor/utils.ts
new file mode 100644
index 00000000000..6d5ae777931
--- /dev/null
+++ b/web/app/components/workflow/nodes/_base/components/editor/code-editor/utils.ts
@@ -0,0 +1,21 @@
+export const serializeCodeEditorValue = (
+  value?: string | object,
+  isJSONStringifyBeauty?: boolean,
+): string => {
+  if (value == null) return ''
+
+  if (!isJSONStringifyBeauty) {
+    if (typeof value === 'string') return value
+    try {
+      return JSON.stringify(value, null, 2)
+    } catch {
+      return ''
+    }
+  }
+
+  try {
+    return JSON.stringify(value, null, 2)
+  } catch {
+    return typeof value === 'string' ? value : ''
+  }
+}