diff --git a/apps/ai-game-creator-shell/src-tauri/src/agent/tool/create_or_derive_resource/error.rs b/apps/ai-game-creator-shell/src-tauri/src/agent/tool/create_or_derive_resource/error.rs
index a6e529e74..9b2597b51 100644
--- a/apps/ai-game-creator-shell/src-tauri/src/agent/tool/create_or_derive_resource/error.rs
+++ b/apps/ai-game-creator-shell/src-tauri/src/agent/tool/create_or_derive_resource/error.rs
@@ -5,13 +5,9 @@
 use crate::agent::direct_tool_bridge::DirectResourceGenerationKind;
 use crate::agent::tool::error::{
     ProjectManifestRejection, ProjectPermissionRejection, ResourceCompletionRejection,
-    ToolArgumentsRejection, ToolFailure,
+    ToolArgumentsRejection, ToolFailure, UNREGISTERED_SOURCE_HINT,
 };
 
-/// `sourceLocalAssetId` 不在当前项目 manifest 时的完整指引：模型要知道下一步做什么，
-/// 只报「不属于已登记资源」会让它原地重试。
-const UNREGISTERED_SOURCE_HINT: &str = "先调用 agc_list_registered_assets 选择已有 localAssetId；若目标图片只在项目里，先用 agc_list_project_files 确认它 assetImportable=true，再用 agc_import_account_assets.localPaths 登记后重试。";
-
 /// `agc_create_or_derive_resource` 的每一种失败各占一个变体；文案写在这里，捕获处只调
 /// `to_user_msg`。
 #[derive(serde::Serialize, Debug)]
diff --git a/apps/ai-game-creator-shell/src-tauri/src/agent/tool/error.rs b/apps/ai-game-creator-shell/src-tauri/src/agent/tool/error.rs
index d3c1b4f8e..ca8e95977 100644
--- a/apps/ai-game-creator-shell/src-tauri/src/agent/tool/error.rs
+++ b/apps/ai-game-creator-shell/src-tauri/src/agent/tool/error.rs
@@ -6,6 +6,12 @@
 
 use serde_json::Value;
 
+/// `sourceLocalAssetId` 不在当前项目 manifest 时的完整指引：模型要知道下一步做什么，
+/// 只报「不属于已登记资源」会让它原地重试。
+///
+/// 生成/派生与抠图都会命中这个 case，指引只在这里写一份。
+pub(crate) const UNREGISTERED_SOURCE_HINT: &str = "先调用 agc_list_registered_assets 选择已有 localAssetId；若目标图片只在项目里，先用 agc_list_project_files 确认它 assetImportable=true，再用 agc_import_account_assets.localPaths 登记后重试。";
+
 /// 工具失败对用户（以及转述给用户的模型）说的那一句话。
 pub(crate) trait ToolFailure: serde::Serialize {
     fn to_user_msg(&self) -> String;
diff --git a/apps/ai-game-creator-shell/src-tauri/src/agent/tool/remove_background/error.rs b/apps/ai-game-creator-shell/src-tauri/src/agent/tool/remove_background/error.rs
index d70da55a2..a04887152 100644
--- a/apps/ai-game-creator-shell/src-tauri/src/agent/tool/remove_background/error.rs
+++ b/apps/ai-game-creator-shell/src-tauri/src/agent/tool/remove_background/error.rs
@@ -4,7 +4,7 @@
 
 use crate::agent::tool::error::{
     ProjectManifestRejection, ProjectPermissionRejection, ResourceCompletionRejection,
-    ToolArgumentsRejection, ToolFailure,
+    ToolArgumentsRejection, ToolFailure, UNREGISTERED_SOURCE_HINT,
 };
 
 /// `agc_remove_background` 的每一种失败各占一个变体；文案写在这里，捕获处只调
@@ -71,9 +71,7 @@ impl ToolFailure for RemoveBackgroundError {
             Self::PermissionDenied(rejection) => rejection.to_user_msg(),
             Self::Manifest(rejection) => rejection.to_user_msg(),
             Self::Completion(rejection) => rejection.to_user_msg(),
-            Self::SourceLocalAssetIdEmpty => {
-                "抠图失败：sourceLocalAssetId 不能为空。".to_string()
-            }
+            Self::SourceLocalAssetIdEmpty => "抠图失败：sourceLocalAssetId 不能为空。".to_string(),
             Self::SourceLocalAssetIdTooLong {
                 got_chars,
                 max_chars,
@@ -83,39 +81,41 @@ impl ToolFailure for RemoveBackgroundError {
             Self::SourceLocalAssetIdHasControlCharacters => {
                 "抠图失败：sourceLocalAssetId 含有控制字符。".to_string()
             }
-            Self::SourceLocalAssetIdNotText { got } => format!(
-                "抠图失败：sourceLocalAssetId 必须是字符串，当前是「{got}」。"
-            ),
+            Self::SourceLocalAssetIdNotText { got } => {
+                format!("抠图失败：sourceLocalAssetId 必须是字符串，当前是「{got}」。")
+            }
             Self::AssetNameEmpty => "抠图失败：assetName 不能为空。".to_string(),
             Self::AssetNameTooLong {
                 got_chars,
                 max_chars,
             } => format!("抠图失败：assetName 有 {got_chars} 个字符，超过上限 {max_chars}。"),
-            Self::AssetNameHasControlCharacters => {
-                "抠图失败：assetName 含有控制字符。".to_string()
-            }
+            Self::AssetNameHasControlCharacters => "抠图失败：assetName 含有控制字符。".to_string(),
             Self::AssetNameNotText { got } => {
                 format!("抠图失败：assetName 必须是字符串，当前是「{got}」。")
             }
-            Self::BackgroundModeNotText { got } => format!(
-                "抠图失败：backgroundMode 必须是 complex 或 flat，当前是「{got}」。"
-            ),
+            Self::BackgroundModeNotText { got } => {
+                format!("抠图失败：backgroundMode 必须是 complex 或 flat，当前是「{got}」。")
+            }
             Self::BackgroundModeUnsupported { got } => {
                 format!("抠图失败：backgroundMode「{got}」不受支持，只能是 complex 或 flat。")
             }
-            Self::ScreenColorNotText { got } => format!(
-                "抠图失败：screenColor 必须是 auto 或 #RRGGBB，当前是「{got}」。"
-            ),
-            Self::ScreenColorMalformed { got } => format!(
-                "抠图失败：screenColor「{got}」不是受支持的取值，必须是 auto 或 #RRGGBB。"
-            ),
+            Self::ScreenColorNotText { got } => {
+                format!("抠图失败：screenColor 必须是 auto 或 #RRGGBB，当前是「{got}」。")
+            }
+            Self::ScreenColorMalformed { got } => {
+                format!("抠图失败：screenColor「{got}」不是受支持的取值，必须是 auto 或 #RRGGBB。")
+            }
             Self::ScreenColorRequiresFlatMode => {
                 "抠图失败：complex 模式不能传 screenColor。".to_string()
             }
-            Self::SourceAssetNotRegistered => "抠图失败：sourceLocalAssetId 不是当前项目已登记资源。先调用 agc_list_registered_assets 选择已有 localAssetId；若目标图片只在项目里，先用 agc_list_project_files 确认它 assetImportable=true，再用 agc_import_account_assets.localPaths 登记后重试。".to_string(),
-            Self::SourceNotImage { media_type } => format!(
-                "抠图失败：抠图工具只接受当前项目已登记的图片资源，该资源是 {media_type}。"
-            ),
+            Self::SourceAssetNotRegistered => {
+                format!(
+                    "抠图失败：sourceLocalAssetId 不是当前项目已登记资源。{UNREGISTERED_SOURCE_HINT}"
+                )
+            }
+            Self::SourceNotImage { media_type } => {
+                format!("抠图失败：抠图工具只接受当前项目已登记的图片资源，该资源是 {media_type}。")
+            }
             Self::CredentialsUnavailable { cause } => {
                 format!("抠图失败：无法取得平台凭据，未发起抠图：{cause}")
             }