diff --git a/.memory/worklog.json b/.memory/worklog.json
index ee2d4ec..7623ffb 100644
--- a/.memory/worklog.json
+++ b/.memory/worklog.json
@@ -1853,6 +1853,13 @@
       "message": "auto-save 2026-05-20 22:48 (~2)",
       "hash": "a3d0c97",
       "files_changed": 2
+    },
+    {
+      "ts": "2026-05-20T22:54:10+08:00",
+      "type": "commit",
+      "message": "auto-save 2026-05-20 22:54 (~3)",
+      "hash": "7697754",
+      "files_changed": 3
     }
   ]
 }
diff --git a/src/lib/packGenerator.ts b/src/lib/packGenerator.ts
index cdede29..6591c3a 100644
--- a/src/lib/packGenerator.ts
+++ b/src/lib/packGenerator.ts
@@ -389,24 +389,38 @@ export async function generateAssetPack(opts: {
     };
   }
 
-  while (remainingTemplates.length > 0) {
-    const readyTemplates = remainingTemplates
-      .filter(template => !template.anchorTemplateId || generatedTemplateIds.has(template.anchorTemplateId))
-      .slice(0, PACK_ASSET_CONCURRENCY);
-    if (!readyTemplates.length) {
+  const inFlight = new Set<Promise<void>>();
+  function takeReadyTemplate(): AssetTemplate | undefined {
+    const index = remainingTemplates.findIndex(template => !template.anchorTemplateId || generatedTemplateIds.has(template.anchorTemplateId));
+    if (index === -1) return undefined;
+    const [template] = remainingTemplates.splice(index, 1);
+    return template;
+  }
+
+  function scheduleReadyTemplates() {
+    while (inFlight.size < PACK_ASSET_CONCURRENCY) {
+      const template = takeReadyTemplate();
+      if (!template) return;
+      const task = (async () => {
+        const asset = await createAsset(template);
+        assets.push(asset);
+        generatedTemplateIds.add(template.id);
+        await opts.onProgress?.(pack);
+      })();
+      inFlight.add(task);
+      task.then(
+        () => inFlight.delete(task),
+        () => inFlight.delete(task),
+      );
+    }
+  }
+
+  while (remainingTemplates.length > 0 || inFlight.size > 0) {
+    scheduleReadyTemplates();
+    if (inFlight.size === 0) {
       throw new Error(`template anchor cycle or missing root: ${remainingTemplates.map(template => template.id).join(', ')}`);
     }
-
-    for (const template of readyTemplates) {
-      remainingTemplates.splice(remainingTemplates.indexOf(template), 1);
-    }
-
-    await Promise.all(readyTemplates.map(async template => {
-      const asset = await createAsset(template);
-      assets.push(asset);
-      generatedTemplateIds.add(template.id);
-      await opts.onProgress?.(pack);
-    }));
+    await Promise.race(inFlight);
   }
 
   const templateOrder = new Map(templates.map((template, index) => [template.id, index]));