Just to say, thank you for wanting to cite tools. From our investigations, we've found that over 2/3 of the papers that mention Ensembl do not cite our papers. No idea how many more than that use our stuff and don't even bother to mention us. It's as if people think that building a bioinformatic database or tool is not real science, so doesn't need acknowledgement. In science, citations are currency, and using someone's work without citing them is essentially theft.
I would also try to include the DOI into the citation. If the software is in biorxiv, it will already get a doi, else if the software is in Github, the owner of the repository can also acquire one from zenodo (https://zenodo.org/).