Libra
What is already familiar, instinctive, and ready to be carried forward.
Scorpio
What is arriving, stretching the old shape, and asking for a new response.
A cusp is best understood as a threshold image: Libra's air cardinal quality meets Scorpio's water fixed quality. The Sun is still in one sign at a time, while the neighboring symbolism can describe the season around it.
Libra brings
Libra is ruled by Venus and speaks through air cardinal movement. Its familiar lesson is about the mediator.
Scorpio arrives
Scorpio is ruled by Mars and Pluto and changes the texture toward water fixed expression. Its invitation is to practice the alchemist.
A boundary, not a loophole
If you were born near a sign boundary, use an accurate birth time and place when a precise chart matters. The cusp language can be a useful metaphor, but it should not replace the actual Sun sign.