"Author" of os8088 here. You're right, it's hand-prompted.

Claude's Opus and Fable have done a really great job helping me and another contributor shape this operating system. It's been a really interesting way to learn about the different techniques that other operating systems have used to get the performance we saw in LisaOS, MacOS, Windows, GEOS, etc... performance at 640x480 on an XT class machine is tricky! Also, the 64KB segment limitations were very interesting to overcome!