Get the Current Stage

USD itself does not currently have a notion of a user session associated with a current stage. This is handled by higher-level facilities in USD applications such as usdviewApi in USDView and omni.usd in Omniverse Kit.

Kit (omni.usd)

import omni.usd

stage = omni.usd.get_context().get_stage()

USDView

stage = usdviewApi.stage