  In this note, we study color-kinematics duality in generic spacetimes. We
work with a contact representation for on shell correlators. The position-space
integrand is encoded by enumerated differential operators. This setup
generalizes certain features of S-matrix kinematics to curved space.
Differences between flat and curved space are captured by commutators. We study
the nonlinear sigma model at four points as an explicit example and find that
color-kinematics duality holds in generic spacetimes. We illustrate our
approach in the AdS transition amplitude, a type of on shell correlation
function. We find a double copy procedure at four points that connects the
nonlinear sigma model, the biadjoint scalar theory, and the special Galileon
theory.
