IPC-7527 is often the best starting point because it covers both the stencil and the workholding tooling.
There it was. Section 5.2.3: Edge clearance for step stencils. ipc-7527 pdf
It serves as a collection of visual guidelines to determine if solder paste has been correctly applied to a Printed Circuit Board (PCB) before component placement and reflow. IPC-7527 is often the best starting point because