Regarding regular and special meetings of the council, the only requirement under the Open Public Meetings Act (OPMA) is to post a preliminary agenda online at least 24 hours in advance for regular meetings (see RCW 42.30.077) and to provide a meeting notice at least 24 hours in advance for a special meeting that specifies the time and place of the meeting and the business to be transacted (see RCW 42.30.080).
In general (although see caveat below), there is no state law requirement to provide a council packet or materials pertinent to an action to the public prior to the council taking final action. However, there may be local rules about making a council packet available to the public prior to the meeting.
In addition, certain legislative and quasi-judicial actions of the council may require that notice and/or information be made available to the public prior to the action occurring. I do not have an exhaustive list of the actions for which specific notice and/or information must be provided, but some examples include the notice associated with a street vacation (see RCW 35.79.020), notice associated with municipal annexations (see, e.g., RCW 35A.14.130), and State Environmental Policy Act (SEPA) threshold determinations on certain project and non-project actions (see Chapter 43.21C RCW). I recommend consulting with your city attorney if you have questions about any specific action of the council to see what type of notice and information must be made available.