From 72d1fa4da56aa68bd5ce36862ed80130b1b8919c Mon Sep 17 00:00:00 2001
From: Peter Steinberger <steipete@gmail.com>
Date: Sat, 3 Jan 2026 01:48:38 +0100
Subject: [PATCH] fix: dedupe repeated block replies

---
 src/agents/pi-embedded-subscribe.test.ts | 49 ++++++++++++++++++++++++
 src/agents/pi-embedded-subscribe.ts      | 15 ++++++++
 2 files changed, 64 insertions(+)

diff --git a/src/agents/pi-embedded-subscribe.test.ts b/src/agents/pi-embedded-subscribe.test.ts
index 4b16f5fcb4..97ab7a62c1 100644
--- a/src/agents/pi-embedded-subscribe.test.ts
+++ b/src/agents/pi-embedded-subscribe.test.ts
@@ -182,6 +182,55 @@ describe("subscribeEmbeddedPiSession", () => {
     expect(subscription.assistantTexts).toEqual(["Hello block"]);
   });
 
+  it("does not emit duplicate block replies when text_end repeats", () => {
+    let handler: ((evt: unknown) => void) | undefined;
+    const session: StubSession = {
+      subscribe: (fn) => {
+        handler = fn;
+        return () => {};
+      },
+    };
+
+    const onBlockReply = vi.fn();
+
+    const subscription = subscribeEmbeddedPiSession({
+      session: session as unknown as Parameters<
+        typeof subscribeEmbeddedPiSession
+      >[0]["session"],
+      runId: "run",
+      onBlockReply,
+      blockReplyBreak: "text_end",
+    });
+
+    handler?.({
+      type: "message_update",
+      message: { role: "assistant" },
+      assistantMessageEvent: {
+        type: "text_delta",
+        delta: "Hello block",
+      },
+    });
+
+    handler?.({
+      type: "message_update",
+      message: { role: "assistant" },
+      assistantMessageEvent: {
+        type: "text_end",
+      },
+    });
+
+    handler?.({
+      type: "message_update",
+      message: { role: "assistant" },
+      assistantMessageEvent: {
+        type: "text_end",
+      },
+    });
+
+    expect(onBlockReply).toHaveBeenCalledTimes(1);
+    expect(subscription.assistantTexts).toEqual(["Hello block"]);
+  });
+
   it("waits for auto-compaction retry and clears buffered text", async () => {
     const listeners: SessionEventHandler[] = [];
     const session = {
diff --git a/src/agents/pi-embedded-subscribe.ts b/src/agents/pi-embedded-subscribe.ts
index 646dc96c25..fb2b8b6f87 100644
--- a/src/agents/pi-embedded-subscribe.ts
+++ b/src/agents/pi-embedded-subscribe.ts
@@ -78,6 +78,7 @@ export function subscribeEmbeddedPiSession(params: {
   const blockReplyBreak = params.blockReplyBreak ?? "text_end";
   let deltaBuffer = "";
   let lastStreamedAssistant: string | undefined;
+  let lastBlockReplyText: string | undefined;
   let assistantTextBaseline = 0;
   let compactionInFlight = false;
   let pendingCompactionRetry = 0;
@@ -152,6 +153,7 @@ export function subscribeEmbeddedPiSession(params: {
     toolMetaById.clear();
     deltaBuffer = "";
     lastStreamedAssistant = undefined;
+    lastBlockReplyText = undefined;
     assistantTextBaseline = 0;
     toolDebouncer.flush();
   };
@@ -304,6 +306,12 @@ export function subscribeEmbeddedPiSession(params: {
             }
 
             if (evtType === "text_end" && blockReplyBreak === "text_end") {
+              if (next && next === lastBlockReplyText) {
+                deltaBuffer = "";
+                lastStreamedAssistant = undefined;
+                return;
+              }
+              lastBlockReplyText = next || undefined;
               if (next) assistantTexts.push(next);
               if (next && params.onBlockReply) {
                 const { text: cleanedText, mediaUrls } =
@@ -349,6 +357,12 @@ export function subscribeEmbeddedPiSession(params: {
             text &&
             params.onBlockReply
           ) {
+            if (text === lastBlockReplyText) {
+              deltaBuffer = "";
+              lastStreamedAssistant = undefined;
+              return;
+            }
+            lastBlockReplyText = text;
             const { text: cleanedText, mediaUrls } = splitMediaFromOutput(text);
             if (cleanedText || (mediaUrls && mediaUrls.length > 0)) {
               void params.onBlockReply({
@@ -359,6 +373,7 @@ export function subscribeEmbeddedPiSession(params: {
           }
           deltaBuffer = "";
           lastStreamedAssistant = undefined;
+          lastBlockReplyText = undefined;
         }
       }