diff --git a/helper.php b/helper.php
index 68f0631..3859b0c 100644
--- a/helper.php
+++ b/helper.php
@@ -60,26 +60,79 @@ function streamOpenAiApi(object $config, string $prompt, string $content, callab
 		],
 	];
 
-	$curl_info[CURLOPT_WRITEFUNCTION] = function ($curl_info, $data) use ($task_callback, $finish_callback) {
+	$stream_buffer = '';
+	$error_buffer = '';
+	$http_error_handled = false;
+
+	$curl_info[CURLOPT_WRITEFUNCTION] = function ($curl_handle, $data) use (&$stream_buffer, &$error_buffer, &$http_error_handled, $task_callback, $finish_callback) {
 		Minz_Log::debug('Receive msg:' . $data);
 
-		// if http status code != 200, then call the finish_callback to send the error message and stop the stream
-		if (curl_getinfo($curl_info, CURLINFO_HTTP_CODE) != 200) {
-			$task_callback(_errorHtmlSuffix(json_decode($data)->error->message));
-			$finish_callback();
+		$status = curl_getinfo($curl_handle, CURLINFO_HTTP_CODE);
+
+		// Handle non-200 HTTP responses by buffering until we can decode the error payload.
+		if ($status && $status != 200) {
+			if (!$http_error_handled) {
+				$error_buffer .= $data;
+				$decoded_error = json_decode($error_buffer);
+				if ($decoded_error !== null) {
+					$message = isset($decoded_error->error->message) ? $decoded_error->error->message : _t('gen.error.unknown');
+					$task_callback(_errorHtmlSuffix($message));
+					$finish_callback();
+					$http_error_handled = true;
+				}
+			}
+
 			return strlen($data);
 		}
 
-		$msg_list = explode(PHP_EOL, trim($data));
-		foreach ($msg_list as $msg) {
-			$msg = trim(substr(trim($msg), 5));
+		$stream_buffer .= $data;
+		$stream_buffer = str_replace("\r\n", "\n", $stream_buffer);
 
-			if ($msg == '') {
-				continue;
-			} else if ($msg == "[DONE]") {
+		while (($event_separator_pos = strpos($stream_buffer, "\n\n")) !== false) {
+			$raw_event = substr($stream_buffer, 0, $event_separator_pos);
+			$stream_buffer = substr($stream_buffer, $event_separator_pos + 2);
+
+			$lines = preg_split('/\r?\n/', $raw_event);
+			$event_name = '';
+			$data_lines = [];
+
+			foreach ($lines as $line) {
+				$line = trim($line);
+				if ($line === '') {
+					continue;
+				}
+
+				if (stripos($line, 'event:') === 0) {
+					$event_name = trim(substr($line, strlen('event:')));
+					continue;
+				}
+
+				if (stripos($line, 'data:') === 0) {
+					$data_lines[] = ltrim(substr($line, strlen('data:')));
+				}
+			}
+
+			$event_data = implode("\n", $data_lines);
+
+			if ($event_name === 'done' || $event_data === '[DONE]') {
 				$finish_callback();
-			} else {
-				$task_callback(_dealResponse(json_decode($msg)));
+				continue;
+			}
+
+			if ($event_data === '') {
+				continue;
+			}
+
+			$decoded_payload = json_decode($event_data);
+			if ($decoded_payload === null) {
+				// Wait for more data if JSON is incomplete.
+				$stream_buffer = $raw_event . "\n\n" . $stream_buffer;
+				break;
+			}
+
+			$delta = _dealResponse($decoded_payload);
+			if ($delta !== '') {
+				$task_callback($delta);
 			}
 		}