Fast exact simulation for near-Clifford quantum circuits.

clifft helps researchers simulate early fault-tolerant circuits that are mostly Clifford but depend on localized non-Clifford operations. It accepts Stim-format circuits, extends them with non-Clifford gates, and compiles them into bytecode for a high-performance simulator, preserving the compile-once, sample-many workflow used in QEC studies while keeping the expensive dense-state work focused on the active non-Clifford dimension.