You could do “clean room engineering” approach where the reversing agent generates a specification from its findings, and then have a separate agent reimplement the code without seeing the original binaries/code.
You’d just have to make sure the specification doesn’t include actual source snippets (the AI will try this if you don’t specify). Pseudo code would be sufficient I guess where necessary.
Unless you develop your AI agent from scratch or you clone a never-released game, it would be extremely easy for the rightholders to claim that both agents have most certainly ingested the binary during their training phase, since it's well known that the hyperscalers have pirated everything that could be pirated to train their LLMs. Which is why malus.sh is a parody, not a real service.
One should be honest about what one builds. The F-15 project does that: the aim is the reconstruction of the original game, down to the opcodes; on the other hands it requires the user to provide the original game assets.