What are the design rules for a given fabrication process?
The design constraints on the different layers for the processes available from MOSIS are given in three general groups of rules. The scalable CMOS (SCMOS) rules, the submicron revisions to the design rules (SCMOS_SUBM) and the deep submicron revisions (SCMOS_DEEP) for the most aggressively scaled down processes. MOSIS has an extensive discussion on this topic, that you can read here. The details of the SCMOS rules can be accessed by clicking on the "rule section" of Table 4.
The design rules for the bonding pads don't follow any scalable design rules; MOSIS requires at least a 60 x 60 um opening in the glass layer for bonding. For more details of the design rules that pertain to the bonding pads see the MOSIS description here.