How To Tell My Mother In Law That I'm The Boss?

Well SIL is a nice person.Good.
Secondly,if you prefer you are being informed you can ask through your husband to your inlaws without putting you in the picture.

Or as an hint,you can invite SIL happily and let her know something like"Oh!If you have informed me before u r here,I was planning to make a delicacy but would have made it today or better arrange my schedule to spend more time with you"...something like that

Also, inlaws maybe traditional people and not doing it intentionally.Cut them
Some slack.

At the end of the day,family is everything.Enjoy your time with them.

 

I feel if your SIL is a good person and not causing any trouble to you , you can ignore . I feel it's nothing much of a problem

after narriage, one doesn't even have complete authority over oneself , forget the house . So better to accept the tolerable stuff and only make fuss for big things which negatively affect your life .

The only option you can also do same went your relatives , invite often and without notice to MIL.

I still think maybe your MIL has good intention , but still try it if it gives you peace of mind .