Tinker is a collection of different programs and tools that perform various kinds of calculations on systems described using classical molecular mechanics (MM) . By coupling Tinker with ddX we want to allow Tinker to include solvation contributions to energy and forces computed with ddX. This requires four main modifications to Tinker: i) as customary in Tinker, implementing a global data structure that contains all the ddX intermediates and parameters; ii) changing the input parsing to read also ddX parameters; iii) changing the way the energy is computed; iv) changing the way the forces are computed.