From 1f06dbd04ceddfc98980886d88173b94487d12e6 Mon Sep 17 00:00:00 2001
From: Sanjay Santhanam <51058514+Sanjays2402@users.noreply.github.com>
Date: Sat, 25 Apr 2026 00:35:03 -0700
Subject: [PATCH] fix(agent): recover blank streamed replies from final answer

---
 .../pi-embedded-runner/run/payloads.test.ts   | 23 +++++++++++++++++++
 src/agents/pi-embedded-runner/run/payloads.ts | 10 ++++----
 2 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/src/agents/pi-embedded-runner/run/payloads.test.ts b/src/agents/pi-embedded-runner/run/payloads.test.ts
index 0674e7e5116..a414add27ce 100644
--- a/src/agents/pi-embedded-runner/run/payloads.test.ts
+++ b/src/agents/pi-embedded-runner/run/payloads.test.ts
@@ -65,6 +65,29 @@ describe("buildEmbeddedRunPayloads tool-error warnings", () => {
     expectSinglePayloadText(payloads, "Done.");
   });
 
+  it("falls back to final-answer assistant text when streamed text only contains blanks", () => {
+    const payloads = buildPayloads({
+      assistantTexts: ["   "],
+      lastAssistant: {
+        role: "assistant",
+        stopReason: "stop",
+        content: [
+          {
+            type: "text",
+            text: "Fixed.",
+            textSignature: JSON.stringify({
+              v: 1,
+              id: "item_final",
+              phase: "final_answer",
+            }),
+          },
+        ],
+      } as AssistantMessage,
+    });
+
+    expectSinglePayloadText(payloads, "Fixed.");
+  });
+
   it("suppresses exec tool errors when verbose mode is off", () => {
     expectNoPayloads({
       lastToolError: { toolName: "exec", error: "command failed" },
diff --git a/src/agents/pi-embedded-runner/run/payloads.ts b/src/agents/pi-embedded-runner/run/payloads.ts
index d0ecf81ae90..2d68b3b23dc 100644
--- a/src/agents/pi-embedded-runner/run/payloads.ts
+++ b/src/agents/pi-embedded-runner/run/payloads.ts
@@ -293,20 +293,22 @@ export function buildEmbeddedRunPayloads(params: {
     const parsed = parseReplyDirectives(text);
     return (parsed.mediaUrls?.length ?? 0) > 0 || parsed.audioAsVoice;
   });
-  const normalizedAssistantTexts = normalizeTextForComparison(params.assistantTexts.join("\n\n"));
+  const nonEmptyAssistantTexts = params.assistantTexts.filter((text) => text.trim().length > 0);
+  const normalizedAssistantTexts = normalizeTextForComparison(nonEmptyAssistantTexts.join("\n\n"));
   const normalizedRawAnswerText = normalizeTextForComparison(rawAnswerDirectiveState?.text ?? "");
   const shouldPreferRawAnswerText =
     rawAnswerHasMedia &&
-    (!params.assistantTexts.length ||
+    (!nonEmptyAssistantTexts.length ||
       (!assistantTextsHaveMedia &&
         normalizedAssistantTexts.length > 0 &&
         normalizedAssistantTexts === normalizedRawAnswerText));
+  const hasAssistantTextPayload = nonEmptyAssistantTexts.length > 0;
   const answerTexts = suppressAssistantArtifacts
     ? []
     : (shouldPreferRawAnswerText && fallbackRawAnswerText
         ? [fallbackRawAnswerText]
-        : params.assistantTexts.length
-          ? params.assistantTexts
+        : hasAssistantTextPayload
+          ? nonEmptyAssistantTexts
           : fallbackAnswerText
             ? [fallbackAnswerText]
             : []