diff --git a/src/acp-agent.ts b/src/acp-agent.ts
index b6abf63b..0ce9837d 100644
--- a/src/acp-agent.ts
+++ b/src/acp-agent.ts
@@ -7992,6 +7992,10 @@ export class ClaudeAcpAgent {
     };
 
     const replayMessage = async (message: SessionMessage): Promise<void> => {
+      // A long history is sent in order, but with event-loop turns in between,
+      // so other sessions and incoming requests are not starved meanwhile.
+      const pause = messageLoopYielder.maybeYield();
+      if (pause) await pause;
       if (pending?.stopped || isReplayHiddenMetaMessage(message)) {
         return;
       }