diff --git a/lib/mutant/matcher/method.rb b/lib/mutant/matcher/method.rb
index 134475d0..2fcbf679 100644
--- a/lib/mutant/matcher/method.rb
+++ b/lib/mutant/matcher/method.rb
@@ -128,6 +128,7 @@ module Mutant
       end
       memoize :subject
 
+      # Visitor to find last match inside AST
       class Finder
 
         # Run finder
diff --git a/lib/mutant/matcher/methods.rb b/lib/mutant/matcher/methods.rb
index c9824952..bb22887c 100644
--- a/lib/mutant/matcher/methods.rb
+++ b/lib/mutant/matcher/methods.rb
@@ -89,6 +89,7 @@ module Mutant
       #
       abstract_method :candidate_scope
 
+      # Matcher for singleton methods
       class Singleton < self
         MATCHER = Matcher::Method::Singleton
 
@@ -119,6 +120,7 @@ module Mutant
 
       end # Singleton
 
+      # Matcher for instance methods
       class Instance < self
         MATCHER = Matcher::Method::Instance
 
diff --git a/lib/mutant/mutator/node/arguments.rb b/lib/mutant/mutator/node/arguments.rb
index 55deb5af..c6c20a0f 100644
--- a/lib/mutant/mutator/node/arguments.rb
+++ b/lib/mutant/mutator/node/arguments.rb
@@ -1,6 +1,7 @@
 module Mutant
   class Mutator
     class Node
+      # Mutator for arguments node
       class Arguments < self
 
         handle(:args)
diff --git a/lib/mutant/mutator/node/literal/hash.rb b/lib/mutant/mutator/node/literal/hash.rb
index c869be6e..c1896913 100644
--- a/lib/mutant/mutator/node/literal/hash.rb
+++ b/lib/mutant/mutator/node/literal/hash.rb
@@ -26,6 +26,7 @@ module Mutant
             end
           end
 
+          # Mutator for hash pairs
           class Pair < Node
 
             handle(:pair)
diff --git a/lib/mutant/mutator/node/mlhs.rb b/lib/mutant/mutator/node/mlhs.rb
index 0c162a2b..3235f7ed 100644
--- a/lib/mutant/mutator/node/mlhs.rb
+++ b/lib/mutant/mutator/node/mlhs.rb
@@ -1,6 +1,7 @@
 module Mutant
   class Mutator
     class Node
+      # Mutator for multiple assignment left hand side nodes
       class MLHS < self
 
         handle(:mlhs)
diff --git a/lib/mutant/strategy/rspec/dm2/lookup/method.rb b/lib/mutant/strategy/rspec/dm2/lookup/method.rb
index 93675903..b2a8224d 100644
--- a/lib/mutant/strategy/rspec/dm2/lookup/method.rb
+++ b/lib/mutant/strategy/rspec/dm2/lookup/method.rb
@@ -3,6 +3,8 @@ module Mutant
     class Rspec
       class DM2
         class Lookup
+
+          # Base class for dm2 style method lookup
           class Method < self
 
             # Return spec files
@@ -91,6 +93,7 @@ module Mutant
               "#{base_path}/*_spec.rb"
             end
 
+            # Instance method dm2 style method lookup
             class Instance < self
               handle(Subject::Method::Instance)
 
@@ -112,6 +115,7 @@ module Mutant
 
             end # Instance
 
+            # Singleton method dm2 style method lookup
             class Singleton < self
               handle(Subject::Method::Singleton)