Creating an agenda

Someone drafts it, but the board adopts it

A lot of new board members assume the president just decides what gets discussed. That is not how it works under standard parliamentary practice, and where a state open meeting law applies, it is not how it works there either.

"It is wrong to assume, as many do, that the president 'sets the agenda.' It is common for the president to prepare a proposed agenda, but that becomes binding only if it is adopted by the full assembly."

Source: Robert's Rules of Order Newly Revised, 12th ed., Frequently Asked Questions, Robert's Rules Association

So a proposed agenda is a draft until the board votes to accept it. In practice, where an open meeting statute applies, the effect is even stronger: the board is bound by whatever agenda went out with the notice, no matter who wrote it. See Who controls the agenda? for the fuller picture.

The agenda is often part of your legal notice

In states with an HOA open meeting statute, the agenda is not just a courtesy handout. It has to go out with the meeting notice, on a schedule the statute sets.

"[Notice] shall be given at least four days before the meeting and shall contain the agenda for the meeting."

Source: California Civil Code §4920, Davis-Stirling Common Interest Development Act, California Legislature

Exactly how many days, and whether the statute names the agenda specifically, varies by state: California requires four days and names the agenda, Washington's condominium and common interest ownership statute requires fourteen days with the agenda stated, and Florida's timing runs differently again. Check your state's common interest community statute and your own bylaws for the number that actually applies to you. Your governing documents can require more notice than the statute, never less. See Meeting notice requirements for the full breakdown by state.

Once it is posted, you cannot just tack things on

An agenda that has already gone out with the notice is not a rough sketch. In states with an open meeting statute, adding a new item mid meeting and voting on it is tightly restricted, not a judgment call for whoever is chairing.

California allows a board to act on an item that was not on the agenda only in narrow circumstances, such as a genuine emergency, a matter that arose after the agenda was distributed and requires a supermajority vote to add, or an item that already appeared on an agenda within the prior month, and even then the board must openly identify the item before discussing it. Whether your state has an equivalent rule, and how narrow it is, is not confirmed here for states outside California. Ask your manager or attorney what your own state and bylaws allow. A called special meeting is even tighter under standard parliamentary practice: only the business named in the notice can be taken up at all. See Adding agenda items and Special meetings.