diff --git a/.changeset/rich-pens-buy.md b/.changeset/rich-pens-buy.md
new file mode 100644
index 000000000..e772cdb70
--- /dev/null
+++ b/.changeset/rich-pens-buy.md
@@ -0,0 +1,5 @@
+---
+"claude-dev": patch
+---
+
+Safer check for xAI reasoning content
diff --git a/src/api/providers/xai.ts b/src/api/providers/xai.ts
index 371f67af0..ed58cdda9 100644
--- a/src/api/providers/xai.ts
+++ b/src/api/providers/xai.ts
@@ -47,7 +47,7 @@ export class XAIHandler implements ApiHandler {
 				}
 			}
 
-			if ("reasoning_content" in delta && delta.reasoning_content) {
+			if (delta && "reasoning_content" in delta && delta.reasoning_content) {
 				yield {
 					type: "reasoning",
 					// @ts-ignore-next-line