diff --git a/ast.rb b/ast.rb
index afb8f4df93..28165d811c 100644
--- a/ast.rb
+++ b/ast.rb
@@ -9,6 +9,16 @@ class RubyVM
   # This class is MRI specific as it exposes implementation details
   # of the MRI abstract syntax tree.
   #
+  # This class is experimental and its API is not stable, therefore it might
+  # change without notice. As examples, the order of children nodes is not
+  # guaranteed, the number of children nodes might change, there is no way to
+  # access children nodes by name, etc.
+  #
+  # If you are looking for a stable API or an API working under multiple Ruby
+  # implementations, consider using the +parser+ gem or Ripper. If you would
+  # like to make RubyVM::AbstractSyntaxTree stable, please join the discussion
+  # at https://bugs.ruby-lang.org/issues/14844.
+  #
   module AbstractSyntaxTree
 
     #  call-seq: