diff --git a/roles/fetch-sphinx-output/README.rst b/roles/fetch-sphinx-output/README.rst
index bdcf25911..d73ee3f2f 100644
--- a/roles/fetch-sphinx-output/README.rst
+++ b/roles/fetch-sphinx-output/README.rst
@@ -1 +1,19 @@
 Collect output from a sphinx build
+
+By default, this copies the output from the sphinx build on the worker
+to the log root of the executor.
+
+**Role Variables**
+
+.. zuul:rolevar:: zuul_executor_dest
+   :default: {{ zuul.executor.log_root }}
+
+   The destination directory on the executor.  By default, the log
+   root.
+
+.. zuul:rolevar:: sphinx_output_src
+   :default: src/{{ zuul.project.canonical_name }}/doc/build/html
+
+   The location on the worker from which to fetch the generated sphinx
+   content.  By default, the HTML doc build dir of the current
+   project.