diff --git a/packages/ai/src/providers/cursor.ts b/packages/ai/src/providers/cursor.ts
index c11278e15..35232ce74 100644
--- a/packages/ai/src/providers/cursor.ts
+++ b/packages/ai/src/providers/cursor.ts
@@ -503,7 +503,7 @@ export const streamCursor: StreamFunction<"cursor-agent"> = (
 
 			stream.push({ type: "start", partial: output });
 
-			let pendingBuffer = Buffer.alloc(0);
+			let pendingBuffer: Buffer = Buffer.alloc(0);
 			let currentTextBlock: (TextContent & { [kStreamingBlockIndex]: number }) | null = null;
 			let currentThinkingBlock: (ThinkingContent & { [kStreamingBlockIndex]: number }) | null = null;
 			let currentToolCall: ToolCallState | null = null;
@@ -557,7 +557,9 @@ export const streamCursor: StreamFunction<"cursor-agent"> = (
 						log?.write(chunk);
 					});
 				}
-				pendingBuffer = Buffer.concat([pendingBuffer, chunk]);
+				// Steady state drains fully per chunk; alias the fresh h2 chunk instead
+				// of copying it through Buffer.concat (see aws-eventstream.ts).
+				pendingBuffer = pendingBuffer.length === 0 ? chunk : Buffer.concat([pendingBuffer, chunk]);
 
 				while (pendingBuffer.length >= 5) {
 					const flags = pendingBuffer[0];