From 01f559efc0155caf44be4d85b9100ec718bf48ff Mon Sep 17 00:00:00 2001
From: Markus Ylisiurunen <markus.ylisiurunen@gmail.com>
Date: Wed, 21 Jan 2026 21:01:31 +0200
Subject: [PATCH] guard azure responses deltas before content parts

---
 packages/ai/src/providers/azure-openai-responses.ts | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/packages/ai/src/providers/azure-openai-responses.ts b/packages/ai/src/providers/azure-openai-responses.ts
index cd25a3e1..de26ba49 100644
--- a/packages/ai/src/providers/azure-openai-responses.ts
+++ b/packages/ai/src/providers/azure-openai-responses.ts
@@ -194,6 +194,9 @@ export const streamAzureOpenAIResponses: StreamFunction<"azure-openai-responses"
 					}
 				} else if (event.type === "response.output_text.delta") {
 					if (currentItem && currentItem.type === "message" && currentBlock && currentBlock.type === "text") {
+						if (!currentItem.content || currentItem.content.length === 0) {
+							continue;
+						}
 						const lastPart = currentItem.content[currentItem.content.length - 1];
 						if (lastPart && lastPart.type === "output_text") {
 							currentBlock.text += event.delta;
@@ -208,6 +211,9 @@ export const streamAzureOpenAIResponses: StreamFunction<"azure-openai-responses"
 					}
 				} else if (event.type === "response.refusal.delta") {
 					if (currentItem && currentItem.type === "message" && currentBlock && currentBlock.type === "text") {
+						if (!currentItem.content || currentItem.content.length === 0) {
+							continue;
+						}
 						const lastPart = currentItem.content[currentItem.content.length - 1];
 						if (lastPart && lastPart.type === "refusal") {
 							currentBlock.text += event.delta;