ruby on rails - Why can't I use a param called "action"?

Question

Is "action" as a input field name forbidden? Because everything works except the assignment of the "action" param.

Answer 1

because action, controller are prohibited words.

Look around debug params

--- !map:ActiveSupport::HashWithIndifferentAccess 
action: index
controller: main

so you can't use those params. Because they will be REWRITED AUTOMATICALLY