diff --git a/src/scripts/app.ts b/src/scripts/app.ts
index 1acc90778..7c1749982 100644
--- a/src/scripts/app.ts
+++ b/src/scripts/app.ts
@@ -70,10 +70,8 @@ import type { ComfyExtension, MissingNodeType } from '@/types/comfy'
 import { type ExtensionManager } from '@/types/extensionTypes'
 import type { NodeExecutionId } from '@/types/nodeIdentification'
 import { graphToPrompt } from '@/utils/executionUtil'
-import {
-  createMissingNodeTypeFromError,
-  type MissingNodeTypeExtraInfo
-} from '@/utils/missingNodeUtil'
+import type { MissingNodeTypeExtraInfo } from '@/workbench/extensions/manager/types/missingNodeErrorTypes'
+import { createMissingNodeTypeFromError } from '@/workbench/extensions/manager/utils/missingNodeErrorUtil'
 import { anyItemOverlapsRect } from '@/utils/mathUtil'
 import { collectAllNodes, forEachNode } from '@/utils/graphTraversalUtil'
 import {
diff --git a/src/workbench/extensions/manager/types/missingNodeErrorTypes.ts b/src/workbench/extensions/manager/types/missingNodeErrorTypes.ts
new file mode 100644
index 000000000..8af9b21d2
--- /dev/null
+++ b/src/workbench/extensions/manager/types/missingNodeErrorTypes.ts
@@ -0,0 +1,9 @@
+/**
+ * Extra info returned by the backend for missing_node_type errors
+ * from the /prompt endpoint validation.
+ */
+export interface MissingNodeTypeExtraInfo {
+  class_type?: string | null
+  node_title?: string | null
+  node_id?: string
+}
diff --git a/src/utils/missingNodeUtil.test.ts b/src/workbench/extensions/manager/utils/missingNodeErrorUtil.test.ts
similarity index 98%
rename from src/utils/missingNodeUtil.test.ts
rename to src/workbench/extensions/manager/utils/missingNodeErrorUtil.test.ts
index a2966551a..0200fa20e 100644
--- a/src/utils/missingNodeUtil.test.ts
+++ b/src/workbench/extensions/manager/utils/missingNodeErrorUtil.test.ts
@@ -3,7 +3,7 @@ import { describe, expect, it } from 'vitest'
 import {
   buildMissingNodeHint,
   createMissingNodeTypeFromError
-} from './missingNodeUtil'
+} from './missingNodeErrorUtil'
 
 describe('buildMissingNodeHint', () => {
   it('returns hint with title and node ID when both available', () => {
diff --git a/src/utils/missingNodeUtil.ts b/src/workbench/extensions/manager/utils/missingNodeErrorUtil.ts
similarity index 84%
rename from src/utils/missingNodeUtil.ts
rename to src/workbench/extensions/manager/utils/missingNodeErrorUtil.ts
index fcaae1416..34f84f88d 100644
--- a/src/utils/missingNodeUtil.ts
+++ b/src/workbench/extensions/manager/utils/missingNodeErrorUtil.ts
@@ -1,13 +1,6 @@
 import type { MissingNodeType } from '@/types/comfy'
 
-/**
- * Extra info returned by the backend for missing_node_type errors
- */
-export interface MissingNodeTypeExtraInfo {
-  class_type?: string | null
-  node_title?: string | null
-  node_id?: string
-}
+import type { MissingNodeTypeExtraInfo } from '../types/missingNodeErrorTypes'
 
 /**
  * Builds a hint string from missing node metadata.