diff --git a/docs/api.rst b/docs/api.rst
index df3f4b0e..87b28182 100644
--- a/docs/api.rst
+++ b/docs/api.rst
@@ -10,6 +10,7 @@ This project exposes 2 modules:
    :members:
    :undoc-members:
    :show-inheritance:
+   :special-members: __call__
 
 ``build.env`` module
 --------------------