diff --git a/docs/modules/sys.md b/docs/modules/sys.md
index ab9ac723..9cdf1ec7 100644
--- a/docs/modules/sys.md
+++ b/docs/modules/sys.md
@@ -15,4 +15,8 @@ May be one of:
 + `darwin`
 + `android`
 + `ios`
-+ `emscripten`
\ No newline at end of file
++ `emscripten`
+
+### `sys.argv`
+
+The command line arguments. Set by `vm->set_main_argv`.