diff --git a/railpack-plan.json b/railpack-plan.json
index 2a789a7..16a8f40 100644
--- a/railpack-plan.json
+++ b/railpack-plan.json
@@ -1,7 +1,15 @@
 {
   "packages": {
     "node": "20",
-    "pnpm": "9",
-    "yarn": "1"
+    "pnpm": "9"
+  },
+  "steps": {
+    "install": {
+      "commands": [
+        "corepack enable",
+        "corepack prepare yarn@1 --activate",
+        "..."
+      ]
+    }
   }
 }