diff --git a/claudetool/codereview/testdata/generate_error.txtar b/claudetool/codereview/testdata/generate_error.txtar
new file mode 100644
index 0000000..e5c195f
--- /dev/null
+++ b/claudetool/codereview/testdata/generate_error.txtar
@@ -0,0 +1,30 @@
+Test go generate error handling in mechanical checks
+
+-- go.mod --
+module sketch.dev
+
+go 1.23
+
+-- .commit --
+Initial commit
+
+-- main.go --
+package main
+
+//go:generate false
+
+func main() {
+	println("Hello, world!")
+}
+
+-- .commit --
+Commit with failing go generate directive
+
+-- .run_test --
+# Errors
+
+$ go generate sketch.dev
+main.go:3: running "false": exit status 1
+
+
+Please fix before proceeding.