Rangers counted record numbers on the mudflats a fortnight ahead of schedule.
Officials spent most of the night in a side room, trading drafts until the wording on the final clause satisfied every delegation. The agreement still needs a formal vote, but nobody expects a surprise.
What happens next
For people living near the line the change will be practical rather than historic: shorter queues, fewer forms and a single office to call when something goes wrong.
Neighbouring governments have asked for copies of the text. Several say they will use it as a template for talks of their own next spring.
