diff --git a/apps/ai-game-creator-shell/src-tauri/src/agent/runtime_actions/action_execution.rs b/apps/ai-game-creator-shell/src-tauri/src/agent/runtime_actions/action_execution.rs
index ad7117320..653595170 100644
--- a/apps/ai-game-creator-shell/src-tauri/src/agent/runtime_actions/action_execution.rs
+++ b/apps/ai-game-creator-shell/src-tauri/src/agent/runtime_actions/action_execution.rs
@@ -154,13 +154,15 @@ pub(crate) async fn execute_game_creator_agent_runtime_tool_action_with_pending_
         }
         "canvas.asset_import" => observe_agent_runtime_asset_import(root, &action.input).await,
         "ui-design-doc.from-images" => {
-            observe_agent_runtime_ui_design_doc_from_images(root, &action.input)
+            observe_agent_runtime_ui_design_doc_from_images(root, &action.input).await
         }
         "ui-design-doc.run-workflow" => {
             observe_agent_runtime_ui_design_doc_run_workflow(root, agent_id, run_id, &action.input)
                 .await
         }
-        "ui-design-doc.into-js" => observe_agent_runtime_ui_design_doc_into_js(root, &action.input),
+        "ui-design-doc.into-js" => {
+            observe_agent_runtime_ui_design_doc_into_js(root, &action.input).await
+        }
         "project.index" => observe_agent_runtime_project_snapshot_with_lock(
             root,
             agent_id,
diff --git a/apps/ai-game-creator-shell/src-tauri/src/agent/runtime_tools/ui_design_doc.rs b/apps/ai-game-creator-shell/src-tauri/src/agent/runtime_tools/ui_design_doc.rs
index ca9a24160..4017acbc9 100644
--- a/apps/ai-game-creator-shell/src-tauri/src/agent/runtime_tools/ui_design_doc.rs
+++ b/apps/ai-game-creator-shell/src-tauri/src/agent/runtime_tools/ui_design_doc.rs
@@ -28,7 +28,7 @@ struct DesignDocArguments {
     design_doc_asset_id: String,
 }
 
-pub(in crate::agent) fn observe_agent_runtime_ui_design_doc_from_images(
+pub(in crate::agent) async fn observe_agent_runtime_ui_design_doc_from_images(
     root: &Path,
     input: &Value,
 ) -> AgentRuntimeToolObservation {
@@ -44,11 +44,25 @@ pub(in crate::agent) fn observe_agent_runtime_ui_design_doc_from_images(
     let revision_before = read_game_creator_agent_runtime_project_revision(root)
         .ok()
         .map(|snapshot| snapshot.revision);
-    match create_ui_design_doc_from_images(CreateUiDesignDocFromImagesInput {
-        project_path: root.to_string_lossy().into_owned(),
-        expected_project_id,
-        images: arguments.images,
-    }) {
+    // 新建文档要逐张解码设计图并写 manifest：整段阻塞 IO 交给 blocking 线程池，
+    // 别把 async 执行器（同一个 runtime 还要继续跑其它动作）占住。
+    let project_path = root.to_string_lossy().into_owned();
+    let images = arguments.images;
+    let created = match tokio::task::spawn_blocking(move || {
+        create_ui_design_doc_from_images(CreateUiDesignDocFromImagesInput {
+            project_path,
+            expected_project_id,
+            images,
+        })
+    })
+    .await
+    {
+        Ok(created) => created,
+        Err(_) => {
+            return error_observation(root, tool, "后台创建 UI 设计文档任务未完成".to_string())
+        }
+    };
+    match created {
         Ok(created) => {
             if revision_before.is_none_or(|before| created.committed_project_revision > before) {
                 emit_game_creator_manifest_invalidated(root, tool);
@@ -135,7 +149,7 @@ pub(in crate::agent) async fn observe_agent_runtime_ui_design_doc_run_workflow(
     }
 }
 
-pub(in crate::agent) fn observe_agent_runtime_ui_design_doc_into_js(
+pub(in crate::agent) async fn observe_agent_runtime_ui_design_doc_into_js(
     root: &Path,
     input: &Value,
 ) -> AgentRuntimeToolObservation {
@@ -148,11 +162,24 @@ pub(in crate::agent) fn observe_agent_runtime_ui_design_doc_into_js(
         Ok(project_id) => project_id,
         Err(error) => return rejected(root, tool, error),
     };
-    match generate_ui_design_code_at(GenerateUiDesignCodeInput {
-        project_path: root.to_string_lossy().into_owned(),
-        expected_project_id,
-        asset_id: arguments.design_doc_asset_id,
-    }) {
+    // 生成代码要读整份文档、算 SHA-256 再落盘，同样是阻塞 IO，放到 blocking 线程池。
+    let project_path = root.to_string_lossy().into_owned();
+    let asset_id = arguments.design_doc_asset_id;
+    let generated = match tokio::task::spawn_blocking(move || {
+        generate_ui_design_code_at(GenerateUiDesignCodeInput {
+            project_path,
+            expected_project_id,
+            asset_id,
+        })
+    })
+    .await
+    {
+        Ok(generated) => generated,
+        Err(_) => {
+            return error_observation(root, tool, "后台生成 UI 设计代码任务未完成".to_string())
+        }
+    };
+    match generated {
         Ok(result) => AgentRuntimeToolObservation {
             tool: tool.to_string(),
             status: "ok".to_string(),
@@ -190,13 +217,14 @@ mod tests {
     use super::*;
     use serde_json::json;
 
-    #[test]
-    fn from_images_rejects_unknown_fields_and_accepts_reference_pairs() {
+    #[tokio::test]
+    async fn from_images_rejects_unknown_fields_and_accepts_reference_pairs() {
         let root = Path::new(".");
         let rejected = observe_agent_runtime_ui_design_doc_from_images(
             root,
             &json!({ "images": [{ "assetId": "a", "path": null }], "extra": 1 }),
-        );
+        )
+        .await;
         assert_eq!(rejected.status, "rejected");
         assert!(rejected.summary.contains("extra"), "{}", rejected.summary);
 
@@ -204,21 +232,23 @@ mod tests {
         let invalid_project = observe_agent_runtime_ui_design_doc_from_images(
             root,
             &json!({ "images": [{ "assetId": "a", "path": null }] }),
-        );
+        )
+        .await;
         assert_eq!(invalid_project.status, "rejected");
         assert!(!invalid_project.summary.contains("输入无效"));
     }
 
-    #[test]
-    fn design_doc_asset_id_must_be_a_string() {
-        // run-workflow 与 into-js 共用同一份入参解析，这里解析一次、同步调用一次。
+    #[tokio::test]
+    async fn design_doc_asset_id_must_be_a_string() {
+        // run-workflow 与 into-js 共用同一份入参解析，这里解析一次、各调用一次。
         assert!(
             serde_json::from_value::<DesignDocArguments>(json!({ "designDocAssetId": 1 })).is_err()
         );
         let observation = observe_agent_runtime_ui_design_doc_into_js(
             Path::new("."),
             &json!({ "designDocAssetId": 1 }),
-        );
+        )
+        .await;
         assert_eq!(observation.status, "rejected");
         assert!(
             observation.summary.contains("输入无效"),