Having grown up an only child, my children's behaviors towards their siblings are sometimes foreign to me. They make me think, "Oh, so that's how brothers and sisters do things..."
For example, I never ever had to negotiate. I also never had to tattle or get tattled on. Any directing I did was aimed towards my dolls so my make-believe always went the way I wanted it.
Tulip and Luna were playing and sooner or later Tulip hollered, "Mama, Luna won't blabbety blab." I'm not diminishing Tulip's concern, but it wasn't really a thing. I've learned to say, "You two will have to work it out." As a mom with limited personal experience in sibling disagreements, I am apt to jump right in with an incredibly appropriate, gentle, forward-thinking though creative parental tactic. But one day it hit me...I don't have to do it all. They are going to be siblings a lot longer than I am going to be their mother.
I overheard Tulip say, "Luna, don't you want to go see Papa?" How clever. Send the baby away. Humph.
Tulip is funny. She has this tactic where she tells the other person what to say while they're playing. For example, she might be creating something in the pretend kitchen and she'll say to Wolfie, "Wolfie, I want you to say 'I wish I had some Parmesan toast.'" Wolfie will say just that and she'll swoop in as the waitress-chef with a fresh batch of Parmesan toast. She'll follow up with, "Wolfie, I want you to say 'Do you have any tomatoes?'" while she holds some wooden tomatoes behind her back.
Later today I heard her say, "Wolfie, I want you to say 'Tulip, don't you want to be the first to be served dessert?'" Oh she is a clever one.