diff --git a/gadget-drone/src/services/agent.ts b/gadget-drone/src/services/agent.ts
index 5a42217..06372e0 100644
--- a/gadget-drone/src/services/agent.ts
+++ b/gadget-drone/src/services/agent.ts
@@ -673,10 +673,16 @@ class AgentService extends GadgetService {
     const provider = workOrder.turn.provider as IAiProvider | undefined;
 
     // Build session block matching the format used in gadget-code's buildSystemPrompt
+    const sessionCreated = session?.createdAt
+      ? (session.createdAt instanceof Date
+        ? session.createdAt.toISOString()
+        : String(session.createdAt))
+      : "unknown";
+
     const sessionBlock = [
       `Session ID: ${session?._id ?? "unknown"}`,
       `Session Name: ${session?.name ?? "unknown"}`,
-      `Session Created: ${session?.createdAt?.toISOString() ?? "unknown"}`,
+      `Session Created: ${sessionCreated}`,
       `AI Provider: ${provider?.name ?? "unknown"}`,
       `AI API: ${provider?.apiType ?? "unknown"}`,
       `Model: ${workOrder.turn.llm}`,