diff --git a/cmd/acb-index-builder/deploy.go b/cmd/acb-index-builder/deploy.go
index b63f3a5..656dd97 100644
--- a/cmd/acb-index-builder/deploy.go
+++ b/cmd/acb-index-builder/deploy.go
@@ -108,6 +108,7 @@ func deployToPages(cfg *Config) error {
 
 	cmd := exec.CommandContext(ctx, "wrangler", args...)
 	cmd.Env = env
+	cmd.Dir = "/tmp" // wrangler creates .wrangler/tmp relative to CWD; /app is root-owned
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr