From 9a7669af280ca5aeda9a60c132d857f43d6229de Mon Sep 17 00:00:00 2001
From: "Thomas G. Lopes" <thomasgl@pm.me>
Date: Thu, 16 Apr 2026 11:58:44 +0100
Subject: [PATCH] fix

---
 pi/files/agent/extensions/cursor-acp.ts | 35 ++++++++++++++++++-------
 1 file changed, 25 insertions(+), 10 deletions(-)

diff --git a/pi/files/agent/extensions/cursor-acp.ts b/pi/files/agent/extensions/cursor-acp.ts
index d4c98e2..7194e54 100644
--- a/pi/files/agent/extensions/cursor-acp.ts
+++ b/pi/files/agent/extensions/cursor-acp.ts
@@ -1133,6 +1133,19 @@ function beginSse(res: ServerResponse) {
 	});
 }
 
+function getNovelStreamingDelta(previous: string, next: string): { delta: string; snapshot: string } {
+	if (!next) return { delta: "", snapshot: previous };
+	if (!previous) return { delta: next, snapshot: next };
+	if (next === previous) return { delta: "", snapshot: previous };
+	if (next.startsWith(previous)) {
+		return {
+			delta: next.slice(previous.length),
+			snapshot: next,
+		};
+	}
+	return { delta: next, snapshot: next };
+}
+
 async function handleStreamingChatRequest(
 	res: ServerResponse,
 	workspace: string,
@@ -1166,8 +1179,8 @@ async function handleStreamingChatRequest(
 	let stderrText = "";
 	let streamedAny = false;
 	let finished = false;
-	let lastAssistantDelta = "";
-	let lastThinkingDelta = "";
+	let lastAssistantSnapshot = "";
+	let lastThinkingSnapshot = "";
 
 	const finishStop = () => {
 		if (finished) return;
@@ -1207,22 +1220,24 @@ async function handleStreamingChatRequest(
 		if (!isPartial) return;
 
 		if (thinking) {
-			if (thinking !== lastThinkingDelta) {
+			const { delta, snapshot } = getNovelStreamingDelta(lastThinkingSnapshot, thinking);
+			lastThinkingSnapshot = snapshot;
+			if (delta) {
 				streamedAny = true;
-				lastThinkingDelta = thinking;
-				sendSse(res, createChatCompletionChunk(model, { reasoning_content: thinking }, null, responseMeta));
+				sendSse(res, createChatCompletionChunk(model, { reasoning_content: delta }, null, responseMeta));
 			}
 		} else {
-			lastThinkingDelta = "";
+			lastThinkingSnapshot = "";
 		}
 		if (text) {
-			if (text !== lastAssistantDelta) {
+			const { delta, snapshot } = getNovelStreamingDelta(lastAssistantSnapshot, text);
+			lastAssistantSnapshot = snapshot;
+			if (delta) {
 				streamedAny = true;
-				lastAssistantDelta = text;
-				sendSse(res, createChatCompletionChunk(model, { content: text }, null, responseMeta));
+				sendSse(res, createChatCompletionChunk(model, { content: delta }, null, responseMeta));
 			}
 		} else {
-			lastAssistantDelta = "";
+			lastAssistantSnapshot = "";
 		}
 	};