Is it safe to step foot on a roof?

It depends on the pitch of the roof. If it is a flat or a low pitch roof it should be safe. I have stepped on flat roofs a lot, over 20 years, and I have felt completely safe.

If the roofs pitch is steep, it isn't safe and you would need a rope to secure yourself to a chimney. Medium pitch roofs are okay to walk on if your are careful, but it may require a rope secured to a chimney to be safe.

Also, the roofing material can be a factor in making it safe or not. Metal, shake, tile and shingles. Weather can also be a factor like snow, icy, rain and windy.

if you tie yourself to the chimney with rope then , yes .