diff --git a/addons/mrp/procurement.py b/addons/mrp/procurement.py
index 00d0cc00fd7..7064589b1ee 100644
--- a/addons/mrp/procurement.py
+++ b/addons/mrp/procurement.py
@@ -35,6 +35,7 @@ class procurement_order(osv.osv):
     }
 
     def check_produce_product(self, cr, uid, procurement, context=None):
+        ''' Depict the capacity of the procurement workflow to produce products (not services)'''
         return True
 
     def check_bom_exists(self, cr, uid, ids, context=None):
diff --git a/addons/procurement/procurement.py b/addons/procurement/procurement.py
index 68360152399..29fe7881db2 100644
--- a/addons/procurement/procurement.py
+++ b/addons/procurement/procurement.py
@@ -234,12 +234,14 @@ class procurement_order(osv.osv):
         return False
 
     def check_produce_service(self, cr, uid, procurement, context=None):
+        """ Depicts the capacity of the procurement workflow to deal with production of services.
+            By default, it's False. Overwritten by project_mrp module.
+        """
         return False
 
     def check_produce_product(self, cr, uid, procurement, context=None):
-        """ Finds BoM of a product if not found writes exception message.
-        @param procurement: Current procurement.
-        @return: True or False.
+        """ Depicts the capacity of the procurement workflow to deal with production of products.
+            By default, it's False. Overwritten by mrp module.
         """
         return False
 
@@ -274,7 +276,8 @@ class procurement_order(osv.osv):
         return True
 
     def check_buy(self, cr, uid, ids):
-        """ability of the workflow to manage the supply_method == 'buy'.
+        """ Depicts the capacity of the procurement workflow to manage the supply_method == 'buy'.
+            By default, it's False. Overwritten by purchase module.
         """
         return False
 
diff --git a/addons/procurement/procurement_workflow.xml b/addons/procurement/procurement_workflow.xml
index ff17c2e6b73..d5708e23382 100644
--- a/addons/procurement/procurement_workflow.xml
+++ b/addons/procurement/procurement_workflow.xml
@@ -159,6 +159,11 @@
         </record>
 
         <record id="trans_confirm_mto_make_done" model="workflow.transition">
+            <!-- This transition is there to unblock products that would be in MTO with a supply method that would be
+                 produce or buy without MRP or purchase module installed. These modules overwrite the check_produce()
+                 and check_buy() methods -so that it invalidates their part of this 'bypass transition'-,  and define
+                 their own workflow paths.
+            -->
             <field name="act_from" ref="act_confirm_mto"/>
             <field name="act_to" ref="act_make_done"/>
             <field name="condition">not check_produce() and not check_buy()</field>