diff --git a/apps/ai-game-creator-shell/src-tauri/src/tests/project.rs b/apps/ai-game-creator-shell/src-tauri/src/tests/project.rs
index 52ad3d47d..839132da7 100644
--- a/apps/ai-game-creator-shell/src-tauri/src/tests/project.rs
+++ b/apps/ai-game-creator-shell/src-tauri/src/tests/project.rs
@@ -2031,8 +2031,8 @@ fn register_local_asset_keeps_explicit_category_when_kind_is_unchanged() {
     let registered = register_local_asset_at(
         &root,
         "ui/UI 设计 1.json",
-        "UI",
-        "application/json",
+        shared_contracts::game_creation_app::GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND,
+        shared_contracts::game_creation_app::GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE,
         "ui-workflow",
         source(),
     )
@@ -2053,8 +2053,8 @@ fn register_local_asset_keeps_explicit_category_when_kind_is_unchanged() {
     register_local_asset_at(
         &root,
         "ui/UI 设计 1.json",
-        "UI",
-        "application/json",
+        shared_contracts::game_creation_app::GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND,
+        shared_contracts::game_creation_app::GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE,
         "ui-workflow",
         source(),
     )
@@ -2063,7 +2063,10 @@ fn register_local_asset_keeps_explicit_category_when_kind_is_unchanged() {
     let manifest: Value =
         serde_json::from_str(&fs::read_to_string(root.join(".agent/manifest.json")).unwrap())
             .expect("manifest json");
-    assert_eq!(manifest["assets"][0]["kind"], "UI");
+    assert_eq!(
+        manifest["assets"][0]["kind"],
+        shared_contracts::game_creation_app::GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND
+    );
     assert_eq!(manifest["assets"][0]["category"], "audio");
     assert_eq!(manifest["assets"][0]["tags"], serde_json::json!(["界面"]));
 
@@ -2074,7 +2077,7 @@ fn register_local_asset_keeps_explicit_category_when_kind_is_unchanged() {
 ///
 /// 这里的字面量与写入侧逐字一致：UI 设计资产是
 /// `ui_editor/resource_bridge.rs` / `workflow.rs` / `persistence.rs` 的
-/// `register_local_asset_at(root, path, "UI", "application/json", ...)`，
+/// `register_local_asset_at` 使用 UI 文档 kind/media 常量，
 /// 字体是 `commands.rs` 字体上传的 `register_local_asset_entry(root, path, "font", ...)`。
 /// 只要别名表漏掉它们，真机资产就会永远停在「待归类」且读时自愈也救不回来。
 #[test]
@@ -2099,8 +2102,8 @@ fn register_local_asset_derives_category_from_real_write_side_kinds() {
     register_local_asset_at(
         &root,
         "ui/UI 设计 1.json",
-        "UI",
-        "application/json",
+        shared_contracts::game_creation_app::GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND,
+        shared_contracts::game_creation_app::GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE,
         "ui-workflow",
         source(),
     )
@@ -2133,7 +2136,11 @@ fn register_local_asset_derives_category_from_real_write_side_kinds() {
     assert_eq!(
         categories,
         vec![
-            ("UI".to_string(), "ui-interaction".to_string()),
+            (
+                shared_contracts::game_creation_app::GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND
+                    .to_string(),
+                "ui-interaction".to_string(),
+            ),
             ("font".to_string(), "document".to_string()),
         ]
     );
diff --git a/apps/ai-game-creator-shell/src-tauri/src/ui_editor/persistence.rs b/apps/ai-game-creator-shell/src-tauri/src/ui_editor/persistence.rs
index 7755cdbd3..f9f1a018a 100644
--- a/apps/ai-game-creator-shell/src-tauri/src/ui_editor/persistence.rs
+++ b/apps/ai-game-creator-shell/src-tauri/src/ui_editor/persistence.rs
@@ -19,8 +19,10 @@ use std::time::{SystemTime, UNIX_EPOCH};
 use typed_floats::tf32::StrictlyPositiveFinite;
 
 const UI_DESIGN_STATE_SCHEMA_VERSION: &str = "game-creator-ui-design-state.v1";
-pub(crate) const UI_DESIGN_DOC_ASSET_KIND: &str = "ui-design-doc";
-pub(crate) const UI_DESIGN_DOC_MEDIA_TYPE: &str = "application/json";
+pub(crate) use shared_contracts::game_creation_app::{
+    GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND as UI_DESIGN_DOC_ASSET_KIND,
+    GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE as UI_DESIGN_DOC_MEDIA_TYPE,
+};
 const UI_DESIGN_STATE_MAX_BYTES: usize = 2 * 1024 * 1024;
 const UI_DESIGN_CODE_MAX_BYTES: usize = UI_DESIGN_STATE_MAX_BYTES * 8;
 const UI_DESIGN_STATE_MAX_IMAGES: usize = 4;
diff --git a/apps/ai-game-creator-shell/src/features/project-workspace/ResourceReferenceInput.tsx b/apps/ai-game-creator-shell/src/features/project-workspace/ResourceReferenceInput.tsx
index 1971660b5..591cc3830 100644
--- a/apps/ai-game-creator-shell/src/features/project-workspace/ResourceReferenceInput.tsx
+++ b/apps/ai-game-creator-shell/src/features/project-workspace/ResourceReferenceInput.tsx
@@ -53,6 +53,7 @@ import { createPortal, flushSync } from 'react-dom';
 import { PlatformResourceFilterBar } from '../../../../../packages/shared/src/components/PlatformResourceFilterBar';
 import { PlatformSegmentedTabs } from '../../../../../packages/shared/src/components/PlatformSegmentedTabs';
 import {
+  GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE,
   type GameCreationAppAssetManifestEntry,
   gameCreationAppAssetTags,
   type GameIterationVersion,
@@ -1253,7 +1254,10 @@ function ResourcePickerThumbnail({
   if (mediaType.startsWith('image/')) {
     return <Loader2 size={18} className="animate-spin" aria-hidden="true" />;
   }
-  if (kind === 'ui' || mediaType === 'application/json') {
+  if (
+    kind === 'ui' ||
+    mediaType === GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE
+  ) {
     return <FileText size={18} aria-hidden="true" />;
   }
   return <ImageIcon size={18} aria-hidden="true" />;
diff --git a/apps/ai-game-creator-shell/src/features/ui-editor/uiDesignResourceBridge.ts b/apps/ai-game-creator-shell/src/features/ui-editor/uiDesignResourceBridge.ts
index 232ca97bf..c42ca8c58 100644
--- a/apps/ai-game-creator-shell/src/features/ui-editor/uiDesignResourceBridge.ts
+++ b/apps/ai-game-creator-shell/src/features/ui-editor/uiDesignResourceBridge.ts
@@ -2,6 +2,10 @@ import type {
   GameCreationAppAssetManifestEntry,
   GameCreationAppManifest,
 } from '../../../../../packages/shared/src/contracts/gameCreationApp';
+import {
+  GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND,
+  GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE,
+} from '../../../../../packages/shared/src/contracts/gameCreationApp';
 
 export type UiDesignResourceBridgeResult = {
   asset: GameCreationAppAssetManifestEntry;
@@ -48,8 +52,8 @@ export function findLinkedUiDesignResource(
     manifest.assets
       .filter(
         (asset) =>
-          asset.kind === 'ui-design-doc' &&
-          asset.mediaType === 'application/json' &&
+          asset.kind === GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND &&
+          asset.mediaType === GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE &&
           asset.source.referenceResourceIds?.some((reference) =>
             referenceIds.has(reference),
           ),
diff --git a/apps/ai-game-creator-shell/src/view/project-development/index.tsx b/apps/ai-game-creator-shell/src/view/project-development/index.tsx
index 7ab94d191..7619517cd 100644
--- a/apps/ai-game-creator-shell/src/view/project-development/index.tsx
+++ b/apps/ai-game-creator-shell/src/view/project-development/index.tsx
@@ -73,6 +73,10 @@ import type {
   GameIterationVersion,
   ProjectResourceCanvasLayoutMode,
 } from '../../../../../packages/shared/src/contracts/gameCreationApp';
+import {
+  GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND,
+  GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE,
+} from '../../../../../packages/shared/src/contracts/gameCreationApp';
 import { ImageCanvasCharacterAnimationPanelView } from '../../../../../src/components/image-editor/ImageCanvasCharacterAnimationPanelView';
 import type {
   CanvasLayer,
@@ -5040,8 +5044,8 @@ export default function ProjectDevelopmentView({
         if (canvasOpenEpochRef.current !== openEpoch) return;
         if (
           result.manifest.projectId !== manifest.projectId ||
-          result.asset.kind !== 'ui-design-doc' ||
-          result.asset.mediaType !== 'application/json'
+          result.asset.kind !== GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND ||
+          result.asset.mediaType !== GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE
         ) {
           throw new Error('UI 编辑资源结果与当前项目不一致');
         }
@@ -5112,8 +5116,8 @@ export default function ProjectDevelopmentView({
     if (uiEditorRoute) return;
     const completed = manifest.assets.find(
       (asset) =>
-        asset.kind === 'ui-design-doc' &&
-        asset.mediaType === 'application/json' &&
+        asset.kind === GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND &&
+        asset.mediaType === GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE &&
         asset.source.generationKind === 'ui-workflow.completed',
     );
     if (
@@ -6812,7 +6816,7 @@ export default function ProjectDevelopmentView({
     [manifest, selectedResource],
   );
   const selectedResourceOpensUiEditor =
-    selectedResource?.subtype === 'ui-design-doc' ||
+    selectedResource?.subtype === GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND ||
     selectedResource?.subtype === 'ui-prototype';
 
   const selectedToolbarStyle = selectedResourceLayer
diff --git a/apps/ai-game-creator-shell/tests/appSurface/project-development.suite.ts b/apps/ai-game-creator-shell/tests/appSurface/project-development.suite.ts
index 51da64e3c..8642f30d3 100644
--- a/apps/ai-game-creator-shell/tests/appSurface/project-development.suite.ts
+++ b/apps/ai-game-creator-shell/tests/appSurface/project-development.suite.ts
@@ -4,6 +4,10 @@ import type {
   ProjectResourceCanvasLayout,
   ProjectResourceCanvasPosition,
 } from '../../../../packages/shared/src/contracts/gameCreationApp';
+import {
+  GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND,
+  GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE,
+} from '../../../../packages/shared/src/contracts/gameCreationApp';
 import { RESOURCE_REFERENCE_INSERT_EVENT } from '../../src/features/project-workspace/resourceReferences';
 import { RESOURCE_BOOK_OVERVIEW_STACK_LIMIT } from '../../src/view/project-development/resourceBookLayout';
 import {
@@ -5908,8 +5912,8 @@ export function registerProjectWorkbenchFoundationTests() {
     manifest.assets = [
       {
         id: 'ui-design-resource',
-        kind: 'ui-design-doc',
-        mediaType: 'application/json',
+        kind: GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND,
+        mediaType: GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE,
         localPath: 'assets/ui-design.json',
         source: { kind: 'generated' },
       },
diff --git a/apps/ai-game-creator-shell/tests/assetKindCanonicalMapping.test.ts b/apps/ai-game-creator-shell/tests/assetKindCanonicalMapping.test.ts
index bb076aa9c..1e9dd4fff 100644
--- a/apps/ai-game-creator-shell/tests/assetKindCanonicalMapping.test.ts
+++ b/apps/ai-game-creator-shell/tests/assetKindCanonicalMapping.test.ts
@@ -10,6 +10,7 @@ import {
   canonicalGameCreationAppAssetKind,
   GAME_CREATION_APP_ASSET_CATEGORY_BY_KIND,
   GAME_CREATION_APP_CANONICAL_ASSET_KINDS,
+  GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND,
   type GameCreationAppAssetCategory,
   gameCreationAppAssetCategory,
   gameCreationAppAssetCategoryForKind,
@@ -222,8 +223,8 @@ describe('真机出现的 kind 归类口径', () => {
     // UI 文档与字体 kind，两者都必须落进明确栏目。
     { kind: 'UI', canonical: 'ui-design', category: 'ui-interaction' },
     {
-      kind: 'ui-design-doc',
-      canonical: 'ui-design-doc',
+      kind: GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND,
+      canonical: GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND,
       category: 'ui-interaction',
     },
     { kind: 'font', canonical: 'document', category: 'document' },
@@ -286,9 +287,11 @@ describe('写侧 kind 字面量 → 分类的端到端口径', () => {
     for (const file of UI_EDITOR_WRITE_SITES) {
       expect(readFileSync(file, 'utf8')).toContain('UI_DESIGN_DOC_ASSET_KIND');
     }
-    expect(gameCreationAppAssetCategoryForKind('ui-design-doc')).toBe(
-      'ui-interaction',
-    );
+    expect(
+      gameCreationAppAssetCategoryForKind(
+        GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND,
+      ),
+    ).toBe('ui-interaction');
   });
 
   test('UI 编辑器写点写出的每个 kind 都落明确栏目', () => {
diff --git a/apps/ai-game-creator-shell/tests/uiDesignResourceBridge.test.ts b/apps/ai-game-creator-shell/tests/uiDesignResourceBridge.test.ts
index a7bf8eaa0..18b2a235d 100644
--- a/apps/ai-game-creator-shell/tests/uiDesignResourceBridge.test.ts
+++ b/apps/ai-game-creator-shell/tests/uiDesignResourceBridge.test.ts
@@ -4,6 +4,10 @@ import type {
   GameCreationAppAssetManifestEntry,
   GameCreationAppManifest,
 } from '../../../packages/shared/src/contracts/gameCreationApp';
+import {
+  GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND,
+  GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE,
+} from '../../../packages/shared/src/contracts/gameCreationApp';
 import {
   ensureUiDesignResourceForPrototype,
   findLinkedUiDesignResource,
@@ -37,8 +41,8 @@ describe('ui design resource bridge', () => {
     const manifest = manifestWithPrototype();
     manifest.assets.push({
       id: 'unrelated-ui',
-      kind: 'UI',
-      mediaType: 'application/json',
+      kind: GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND,
+      mediaType: GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE,
       localPath: 'ui/unrelated.json',
       source: { kind: 'generated', referenceResourceIds: ['other'] },
       imageSequenceFrames: null,
@@ -47,8 +51,8 @@ describe('ui design resource bridge', () => {
     expect(findLinkedUiDesignResource(manifest, 'prototype-asset')).toBeNull();
     manifest.assets.push({
       id: 'linked-ui',
-      kind: 'UI',
-      mediaType: 'application/json',
+      kind: GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND,
+      mediaType: GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE,
       localPath: 'ui/linked.json',
       source: { kind: 'generated', referenceResourceIds: ['prototype-asset'] },
       imageSequenceFrames: null,
@@ -64,8 +68,8 @@ describe('ui design resource bridge', () => {
     manifest.assets[0]!.source.resourceId = 'canvas-resource-1';
     manifest.assets.push({
       id: 'workflow-ui',
-      kind: 'UI',
-      mediaType: 'application/json',
+      kind: GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND,
+      mediaType: GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE,
       localPath: 'ui/workflow.json',
       source: {
         kind: 'generated',
@@ -85,8 +89,8 @@ describe('ui design resource bridge', () => {
     manifest.assets.push(
       {
         id: 'bridge-ui',
-        kind: 'UI',
-        mediaType: 'application/json',
+        kind: GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND,
+        mediaType: GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE,
         localPath: 'ui/UI 设计 1.json',
         source: {
           kind: 'generated',
@@ -97,8 +101,8 @@ describe('ui design resource bridge', () => {
       },
       {
         id: 'completed-ui',
-        kind: 'UI',
-        mediaType: 'application/json',
+        kind: GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND,
+        mediaType: GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE,
         localPath: 'ui/ui-workflow-page.json',
         source: {
           kind: 'generated',
@@ -118,8 +122,8 @@ describe('ui design resource bridge', () => {
     const manifest = manifestWithPrototype();
     const linked = {
       id: 'linked-ui',
-      kind: 'UI',
-      mediaType: 'application/json',
+      kind: GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND,
+      mediaType: GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE,
       localPath: 'ui/linked.json',
       source: {
         kind: 'generated' as const,
@@ -146,8 +150,8 @@ describe('ui design resource bridge', () => {
     const result = {
       asset: {
         id: 'new-ui',
-        kind: 'UI',
-        mediaType: 'application/json',
+        kind: GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND,
+        mediaType: GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE,
         localPath: 'ui/UI 设计 1.json',
         source: {
           kind: 'generated' as const,
diff --git a/packages/shared/src/contracts/gameCreationApp.ts b/packages/shared/src/contracts/gameCreationApp.ts
index 6b9a6abfb..65370e4be 100644
--- a/packages/shared/src/contracts/gameCreationApp.ts
+++ b/packages/shared/src/contracts/gameCreationApp.ts
@@ -549,7 +549,7 @@ const GAME_CREATION_APP_LEGACY_ASSET_KINDS: Record<
 export function canonicalGameCreationAppAssetKind(
   value: string,
 ): GameCreationAppCanonicalAssetKind {
-  /** kind 词汇大小写不敏感；UI Editor 文档写入侧统一使用 `ui-design-doc`。 */
+  /** kind 词汇大小写不敏感；UI Editor 文档写入侧使用 UI 文档常量。 */
   const normalized = value.trim().toLowerCase();
   /**
    * `kind` 是外部输入，可能正好是 `Object.prototype` 上的键（`constructor` / `__proto__` /
@@ -596,7 +596,7 @@ export const GAME_CREATION_APP_ASSET_CATEGORY_BY_KIND: Record<
   'icon-spritesheet': 'ui-interaction',
   'icon-spec': 'ui-interaction',
   'ui-design': 'ui-interaction',
-  'ui-design-doc': 'ui-interaction',
+  [GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND]: 'ui-interaction',
   'publication-material': 'unclassified',
   spec: 'document',
   video: 'unclassified',
diff --git a/server-rs/crates/shared-contracts/src/game_creation_app.rs b/server-rs/crates/shared-contracts/src/game_creation_app.rs
index 6d9fb6ddd..605f72cf6 100644
--- a/server-rs/crates/shared-contracts/src/game_creation_app.rs
+++ b/server-rs/crates/shared-contracts/src/game_creation_app.rs
@@ -5,6 +5,8 @@ pub const GAME_CREATION_APP_MANIFEST_SCHEMA_VERSION: &str = "game-creation-app.m
 pub const GAME_CREATION_AGENT_RUN_SCHEMA_VERSION: &str = "game-creator-agent-run.v1";
 pub const GAME_CREATION_AGENT_RUN_MAX_PASSES: u8 = 3;
 pub const GAME_CREATION_AGENT_TOOL_CALL_MAX: u16 = 128;
+pub const GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND: &str = "ui-design-doc";
+pub const GAME_CREATION_APP_UI_DESIGN_DOC_MEDIA_TYPE: &str = "application/json";
 
 #[derive(Clone, Copy, Debug, Deserialize, Eq, PartialEq, Serialize)]
 #[serde(rename_all = "snake_case")]
@@ -574,7 +576,7 @@ pub const GAME_CREATION_APP_CANONICAL_ASSET_KINDS: [&str; 17] = [
     "icon-spritesheet",
     "icon-spec",
     "ui-design",
-    "ui-design-doc",
+    GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND,
     "publication-material",
     "spec",
     "video",
@@ -652,7 +654,10 @@ pub const GAME_CREATION_APP_ASSET_CATEGORY_BY_KIND: [(&str, GameCreationAppAsset
     ),
     ("icon-spec", GameCreationAppAssetCategory::UiInteraction),
     ("ui-design", GameCreationAppAssetCategory::UiInteraction),
-    ("ui-design-doc", GameCreationAppAssetCategory::UiInteraction),
+    (
+        GAME_CREATION_APP_UI_DESIGN_DOC_ASSET_KIND,
+        GameCreationAppAssetCategory::UiInteraction,
+    ),
     (
         "publication-material",
         GameCreationAppAssetCategory::Unclassified,