--- a/tools/docs/mach_commands.py
+++ b/tools/docs/mach_commands.py
@@ -23,16 +23,18 @@ here = os.path.abspath(os.path.dirname(_
 @CommandProvider
 class Documentation(MachCommandBase):
     """Helps manage in-tree documentation."""
 
     def __init__(self, context):
         super(Documentation, self).__init__(context)
 
         self._manager = None
+        self._project = None
+        self._version = None
 
     @Command('doc', category='devenv',
              description='Generate and serve documentation from the tree.')
     @CommandArgument('path', default=None, metavar='DIRECTORY', nargs='?',
                      help='Path to documentation to build and display.')
     @CommandArgument('--format', default='html', dest='fmt',
                      help='Documentation format to write.')
     @CommandArgument('--outdir', default=None, metavar='DESTINATION',
@@ -70,32 +72,30 @@ class Documentation(MachCommandBase):
         path = path or os.path.join(self.topsrcdir, 'tools')
         path = os.path.normpath(os.path.abspath(path))
 
         docdir = self._find_doc_dir(path)
         if not docdir:
             return die('failed to generate documentation:\n'
                        '%s: could not find docs at this location' % path)
 
-        props = self._project_properties(docdir)
         result = self._run_sphinx(docdir, savedir, fmt=fmt)
         if result != 0:
             return die('failed to generate documentation:\n'
                        '%s: sphinx return code %d' % (path, result))
         else:
             print('\nGenerated documentation:\n%s' % savedir)
 
         if archive:
-            archive_path = os.path.join(outdir,
-                                        '%s.tar.gz' % props['project'])
+            archive_path = os.path.join(outdir, '%s.tar.gz' % self.project)
             create_tarball(archive_path, savedir)
             print('Archived to %s' % archive_path)
 
         if upload:
-            self._s3_upload(savedir, props['project'], props['version'])
+            self._s3_upload(savedir, self.project, self.version)
 
         if not serve:
             index_path = os.path.join(savedir, 'index.html')
             if auto_open and os.path.isfile(index_path):
                 webbrowser.open(index_path)
             return
 
         # Create livereload server. Any files modified in the specified docdir
@@ -129,33 +129,43 @@ class Documentation(MachCommandBase):
 
     @property
     def manager(self):
         if not self._manager:
             from moztreedocs import manager
             self._manager = manager
         return self._manager
 
-    def _project_properties(self, path):
+    def _read_project_properties(self):
         import imp
         path = os.path.normpath(self.manager.conf_py_path)
         with open(path, 'r') as fh:
             conf = imp.load_module('doc_conf', fh, path,
                                    ('.py', 'r', imp.PY_SOURCE))
 
         # Prefer the Mozilla project name, falling back to Sphinx's
         # default variable if it isn't defined.
         project = getattr(conf, 'moz_project_name', None)
         if not project:
             project = conf.project.replace(' ', '_')
 
-        return {
-            'project': project,
-            'version': getattr(conf, 'version', None)
-        }
+        self._project = project,
+        self._version = getattr(conf, 'version', None)
+
+    @property
+    def project(self):
+        if not self._project:
+            self._read_project_properties()
+        return self._project
+
+    @property
+    def version(self):
+        if not self._version:
+            self._read_project_properties()
+        return self._version
 
     def _find_doc_dir(self, path):
         if os.path.isfile(path):
             return
 
         valid_doc_dirs = ('doc', 'docs')
         if os.path.basename(path) in valid_doc_dirs:
             return path