Cyclic homology with coefficients

We propose a category which can serve as the category of coefficients for the cyclic homology HC_*(A) of an associative algebra A over a field k. The construction is categorical in nature, and essentially uses only the tensor category A-bimod of A-bimodules; objects of our category are A-bimodules with an additional structure. We also generalize the construction to a more general tensor k-linear tensor category C instead of A-bimod. We add some remarks about Getzler's version of the Gauss-Manin connection for the periodic cyclic homology HP_*(A).