diff --git a/ui/build/rbe.go b/ui/build/rbe.go
index 1d17216..6479925 100644
--- a/ui/build/rbe.go
+++ b/ui/build/rbe.go
@@ -60,6 +60,7 @@
 		"RBE_exec_root":     config.rbeExecRoot(),
 		"RBE_output_dir":    config.rbeProxyLogsDir(),
 		"RBE_proxy_log_dir": config.rbeProxyLogsDir(),
+		"RBE_cache_dir":     config.rbeCacheDir(),
 		"RBE_platform":      "container-image=" + remoteexec.DefaultImage,
 	}
 	if config.StartRBE() {