diff --git a/src/auto-reply/reply.ts b/src/auto-reply/reply.ts
index e7f95bb0d..9f481978d 100644
--- a/src/auto-reply/reply.ts
+++ b/src/auto-reply/reply.ts
@@ -722,7 +722,9 @@ export async function getReplyFromConfig(
     resolvedThinkLevel = await modelState.resolveDefaultThinkingLevel();
   }
   const sessionIdFinal = sessionId ?? crypto.randomUUID();
-  const sessionFile = resolveSessionFilePath(sessionIdFinal, sessionEntry);
+  const sessionFile = resolveSessionFilePath(sessionIdFinal, sessionEntry, {
+    topicId: ctx.MessageThreadId,
+  });
   const queueBodyBase = transcribedText
     ? [threadStarterNote, baseBodyFinal, `Transcript:\n${transcribedText}`]
         .filter(Boolean)
diff --git a/src/config/sessions.ts b/src/config/sessions.ts
index 27b100937..5ddf95534 100644
--- a/src/config/sessions.ts
+++ b/src/config/sessions.ts
@@ -178,8 +178,10 @@ export const DEFAULT_IDLE_MINUTES = 60;
 export function resolveSessionTranscriptPath(
   sessionId: string,
   agentId?: string,
+  topicId?: number,
 ): string {
-  return path.join(resolveAgentSessionsDir(agentId), `${sessionId}.jsonl`);
+  const fileName = topicId !== undefined ? `${sessionId}-topic-${topicId}.jsonl` : `${sessionId}.jsonl`;
+  return path.join(resolveAgentSessionsDir(agentId), fileName);
 }
 
 export function resolveSessionFilePath(