Abstract. The development and verification of safety-critical systems increasingly relies on the use of tools which automate/replace/supplement complex verification and/or development tasks. The safety of such systems risks to be compromised, if the tools fail. To mitigate this risk, safety standards (e.g. DO-178C/DO330, IEC 61508) define prescriptive tool qualification processes. Compliance with these processes can be required for (re-)certification purposes. To enable reuse and thus reduce time and cost related to certification, cross-domain tool manufacturers need to understand what varies and what remains in common when transiting from one domain to another. To ease reuse, in this paper we focus on verification tools and model a cross-domain tool qualification process line. Finally, we discuss how reusable cross-domain process-based arguments can be obtained.