fix: preserve post-stream error payloads (#67991)

* fix(reply): preserve post-stream error payloads

* fix: preserve post-stream error payloads (#67991)

src/auto-reply/reply/agent-runner-payloads.test.ts

@@ -210,6 +210,32 @@ describe("buildReplyPayloads media filter integration", () => {
     expect(replyPayloads).toHaveLength(0);
   });
 
+  it("preserves post-stream error payloads when block pipeline streamed successfully", async () => {
+    const pipeline: Parameters<typeof buildReplyPayloads>[0]["blockReplyPipeline"] = {
+      didStream: () => true,
+      isAborted: () => false,
+      hasSentPayload: () => false,
+      enqueue: () => {},
+      flush: async () => {},
+      stop: () => {},
+      hasBuffered: () => false,
+    };
+
+    const { replyPayloads } = await buildReplyPayloads({
+      ...baseParams,
+      blockStreamingEnabled: true,
+      blockReplyPipeline: pipeline,
+      replyToMode: "all",
+      payloads: [{ text: "Agent couldn't generate a response. Please try again.", isError: true }],
+    });
+
+    expect(replyPayloads).toHaveLength(1);
+    expect(replyPayloads[0]).toMatchObject({
+      text: "Agent couldn't generate a response. Please try again.",
+      isError: true,
+    });
+  });
+
   it("drops all final payloads during silent turns, including media-only payloads", async () => {
     const { replyPayloads } = await buildReplyPayloads({
       ...baseParams,

src/auto-reply/reply/agent-runner-payloads.ts

@@ -215,7 +215,7 @@ export async function buildReplyPayloads(params: {
     : dedupedPayloads;
   // Filter out payloads already sent via pipeline or directly during tool flush.
   const filteredPayloads = shouldDropFinalPayloads
-    ? []
+    ? mediaFilteredPayloads.filter((payload) => payload.isError)
     : params.blockStreamingEnabled
       ? mediaFilteredPayloads.filter(
           (payload) => !params.blockReplyPipeline?.hasSentPayload(payload),