https://www.history.com/topics/united-states-constitution/constitution
“Reporters and other visitors were barred from the convention sessions, which were held in secret to avoid outside pressures. However, Virginia’s James Madison (1751-1836) kept a detailed account of what transpired behind closed doors. (In 1837, Madison’s widow Dolley sold some of his papers, including his notes from the convention debates, to the federal government for $30,000.)”
https://en.m.wikipedia.org/wiki/Constitutional_Convention_(United_States)
“George Washington was unanimously elected president of the Convention,[13] and it was agreed that the discussions and votes would be kept secret until the conclusion of the meeting.[5]:11 Despite the sweltering summer heat, the windows of the meeting hall were nailed shut to keep the proceedings a secret from the public.”