  Among many modified gravity theories, the Chern-Simons modified gravity
stands out as one of the few examples whose Dirichlet boundary problem has been
well studied. Known solutions to this theory include the Schwarzschild black
hole and a slowly rotating black hole. Making use of the Dirichlet boundary
term of this theory, we calculate the late-time action growth rates of the
Wheeler-DeWitt patch for the Schwarzschild and the slowly rotating solutions.
In light of the conjecture of complexity/action duality, the result has
implications on the quantum complexity of a state in the dual field theory.
