I am using swagger in java.
I am reading a header called callerId through requestAttributes in the code. I am not using the header through the annotation @HeaderParam.
You can add parameters to an operation using @ApiImplicitParams and @ApiImplicitParam.
The following wiki documentation should provide you with an explanation on how to use these annotations - https://github.com/swagger-api/swagger-core/wiki/Annotations#apiimplicitparam-apiimplicitparams
Keep in mind I assume here that this is not a security header but actually part of the API (at least based on the description you gave). If you're looking for a security header, there's an alternative method. Please leave a comment and I'll edit this response.