I dont know but in my view are appears my message but before appear the name of model, in my view i write this:
<% @cost.errors.messages.each { |m| %>
<%= m %>
<% } if @cost.errors.count > 0 %>
in my model write this:
validates_length_of :types,:minimum => 3,:message => "Precisa ter no minimo 3 caracteres."
but when the rails detect errors the message appear this:
typesPrecisa ter no minimo 3 caracteres.
Because what apeear the name of model, types in my view please
@cost.errors.full_message(or full_messages)