I will discuss how to construct a gravitational open extension of the effective field theory of inflation in the Schwinger-Keldysh framework. While physical symmetries allow many open operators in the Schwinger-Keldysh action, most of them overconstrain the equations of motion, yielding inconsistent dynamics. By identifying the minimal open operators compatible with propagating scalar and tensor modes, I will construct a local gravitational Schwinger-Keldysh action, recovering dissipative models of inflation such as warm inflation. I will also briefly discuss how stochastic inflation fits into this program.
