How to Validate an array size

I have one parameter called tags I am getting that parameter in tags[1,2,3,4,5] format now I need to validate that thing to only 4 values allow in tags parameter.

How can i do that ?

I tried various methods but not succeed.

$rules = array( 'ids' => 'required', 'note' => 'required|array|min:3', 'tags' => 'required|array|max:4',
);

I am not able validating that thing properly.

I am not even allow 4 parameters to be entered.

via Chebli Mohamed