We didn't have an agreement because we sort of agreed to play it by ear. That is probably not a good idea because people can end up on such differnt pages with alot of hurt feeling. In our case it worked pretty well because neither the birthfamily or I are good at schedules (euphamisim for both of us being flakey). We are totally ok with just dropping in. I think THAT would not work for most people but in our case we have personalities where we are totally spontaneous (drives our SOs crazy) and neither of us are particularly territorial about our Sam.
With our other open adoption it is more formal because it is new. While the adoption happened 14 years ago we only just reconnected last year. We still call and arrange times to get together. It takes more scheduling because I still feel like I need to devote my full attention to the visit. With Sam's birthmom she just goes with the flow. For instance with Rachel's birthmom I set aside a special time because it is still new and I don't want to be disrespectful. With Sam's birthmom if we are cleaning the house on Saturday afternoon and she is in the area she'll come over and fold towels and sort socks. If I have to spend the day at a swim meet near her house I'll call to see if she can meet us there and hang out for a couple of hours. I think the difference is that "A" is family and can see the warts but "T" is still a guest and we still want to put on a good show for her. I suspect that will change as the contact becomes more frequent. In a couple of months we'll have her folding towels too.
I would talk about what each of you are comfrotable with now and say that this is a first draft that can be revised at a alter date. Talk about the need or lack of need for a real schedule. There is no right or wrong only what does or doesn't work for all of the parties involved.
lisa