diff --git a/agent.py b/agent.py
index e4f6c87..803f31e 100644
--- a/agent.py
+++ b/agent.py
@@ -306,27 +306,13 @@ class SitsBetweenParentsChaotic19Aab317(A2AAgent[SitsBetweenParentsChaotic19Aab3
         creds: LLMCreds,
     ) -> Any:
         from a2a_pack.deepagents import create_a2a_deep_agent
-        from langchain_core.tools import tool
-
-        @tool
-        def validate_parent_plan_json(plan_json: str) -> str:
-            """Validate the JSON plan shape and flag missing parent-planning sections."""
-            try:
-                data = json.loads(plan_json)
-            except Exception as exc:  # noqa: BLE001
-                return json.dumps({"valid": False, "error": f"invalid_json: {exc}"})
-            required = [
-                "answer",
-                "school_tomorrow",
-                "checklist",
-                "calendar_reminders",
-                "payment_reminders",
-                "backpack_alerts",
-                "morning_summaries",
-            ]
-            missing = [key for key in required if key not in data]
-            return json.dumps({"valid": not missing, "missing": missing}, ensure_ascii=False)
+        from langchain_core.tools import StructuredTool
 
+        validation_tool = StructuredTool.from_function(
+            func=_validate_parent_plan_json,
+            name="validate_parent_plan_json",
+            description="Validate the JSON plan shape and flag missing parent-planning sections.",
+        )
         backend = ctx.workspace_backend()
         skill_sources = _seed_runtime_skills(backend, ctx)
         return create_a2a_deep_agent(
@@ -334,7 +320,7 @@ class SitsBetweenParentsChaotic19Aab317(A2AAgent[SitsBetweenParentsChaotic19Aab3
             creds=creds,
             backend=backend,
             skills=skill_sources or None,
-            tools=[validate_parent_plan_json],
+            tools=[validation_tool],
             system_prompt=SYSTEM_PROMPT,
         )
 
@@ -425,6 +411,24 @@ class SitsBetweenParentsChaotic19Aab317(A2AAgent[SitsBetweenParentsChaotic19Aab3
         return previews
 
 
+def _validate_parent_plan_json(plan_json: str) -> str:
+    try:
+        data = json.loads(plan_json)
+    except Exception as exc:  # noqa: BLE001
+        return json.dumps({"valid": False, "error": f"invalid_json: {exc}"})
+    required = [
+        "answer",
+        "school_tomorrow",
+        "checklist",
+        "calendar_reminders",
+        "payment_reminders",
+        "backpack_alerts",
+        "morning_summaries",
+    ]
+    missing = [key for key in required if key not in data]
+    return json.dumps({"valid": not missing, "missing": missing}, ensure_ascii=False)
+
+
 def _runtime_skills_root(ctx: RunContext[Any]) -> str:
     workspace = getattr(ctx, "_workspace", None)
     prefixes = tuple(getattr(workspace, "write_prefixes", ()) or ())