diff --git a/.gitignore b/.gitignore
index 43266408a..3f00c1606 100644
--- a/.gitignore
+++ b/.gitignore
@@ -52,3 +52,6 @@ tools/pylint_exceptions
 
 # Files created by releasenotes build
 releasenotes/build
+
+# Files created by doc build
+doc/source/api
diff --git a/doc/source/conf.py b/doc/source/conf.py
index 7a0d9b615..cc01fcb3e 100644
--- a/doc/source/conf.py
+++ b/doc/source/conf.py
@@ -91,6 +91,9 @@ if on_rtd:
 # Output file base name for HTML help builder.
 htmlhelp_basename = '%sdoc' % project
 
+# A list of ignored prefixes for module index sorting.
+modindex_common_prefix = ['mistral.']
+
 # The name for this set of Sphinx documents. If None, it defaults to
 # "<project> v<release> documentation".
 html_title = 'Mistral'
diff --git a/setup.cfg b/setup.cfg
index 70746e54d..df029d1a7 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -26,6 +26,9 @@ source-dir = doc/source
 build-dir = doc/build
 all_files = 1
 
+[pbr]
+autodoc_tree_index_modules = True
+
 [upload_sphinx]
 upload-dir = doc/build/html
 
diff --git a/tox.ini b/tox.ini
index 2a84068bd..35a000148 100644
--- a/tox.ini
+++ b/tox.ini
@@ -42,7 +42,9 @@ commands =
 [testenv:venv]
 commands = {posargs}
 
+#set PYTHONHASHSEED=0 to prevent wsmeext.sphinxext from randomly failing.
 [testenv:docs]
+setenv = PYTHONHASHSEED=0
 commands = python setup.py build_sphinx
 
 [testenv:pylint]