Clarification of Definition for Functional version of TSP The decision version of $TSP$ is $NPComplete$. I was reading about the functional version of $TSP$ i.e. the class $FP^{SAT}$.

It is mentioned in the original paper that TSP is complete for the class $FP^{SAT}[n^{O(1)}]$. By definition of the class, it means TSP can be solved in polynomial time by making $[..]$ calls to an $NP$ Oracle.

But I am still confused what $n$ is in case of a TSP instance?
In definitions of complexity classes, $n$ is always the input length in bits.

Often the definitions are invariant under polynomial blowup (for example, polytime and logspace), and in such cases you can also take $n$ to be other parameters of the input, the resulting class being the same. For example, if the input is an unweighted graph, you can take $n$ to be the number of vertices.