diff --git a/src/agents/pi-embedded-runner/run/attempt.ts b/src/agents/pi-embedded-runner/run/attempt.ts
index d750bbc4f74..01ab6984ba2 100644
--- a/src/agents/pi-embedded-runner/run/attempt.ts
+++ b/src/agents/pi-embedded-runner/run/attempt.ts
@@ -1144,9 +1144,11 @@ export async function runEmbeddedAttempt(
         throw new Error("Embedded agent session missing");
       }
       const activeSession = session;
-      const baseConvertToLlm = activeSession.agent.convertToLlm.bind(activeSession.agent);
-      activeSession.agent.convertToLlm = async (messages) =>
-        await baseConvertToLlm(normalizeAssistantReplayContent(messages));
+      if (typeof activeSession.agent.convertToLlm === "function") {
+        const baseConvertToLlm = activeSession.agent.convertToLlm.bind(activeSession.agent);
+        activeSession.agent.convertToLlm = async (messages) =>
+          await baseConvertToLlm(normalizeAssistantReplayContent(messages));
+      }
       let prePromptMessageCount = activeSession.messages.length;
       abortSessionForYield = () => {
         yieldAbortSettled = Promise.resolve(activeSession.abort());