she is basically spherical about the size of a basketball, and has fanlike wings which are used for expression rather than for flight.
To create a sentient machine is not legal, and he did not intend to do so but she just sort of came to life accidentally. Once it is created it is respected as any other sentient creature. Harris keeps her sentience secret. Sen'tran suspects but pointedly doesn't make an issue of it.
She is inseparably connected to Harris's memory implant, so when he goes to Kaar-taal he can't just turn off his implant because it can't be separated from her and he can't take her. When his implant is removed to go to Kaar-Taal it is implanted into Anton to keep her alive until he returns. this also creates the illusion that Harris is still there and Anton is forced [willingly of course] to take over his role as navigator.
When Jason fights Thearon, after Thearon takes Harris's implant, Jason takes it back from Thearon and implants it into himself desiring to take control of Sylvia so she can heal Harris. Somehow in doing this he manages to separate her from Harris's Implant turning her into an independent being.
from a 2012 note in the History of Paragangia file:[found also on the Harris's light saber page]
Harris has made himself a light saber and is playing Jedi with Jonathan, Jonathan being the Jedi master training Harris. Sen’tran doesn’t entirely approve of this game, thinking perhaps Jonathan is not the best role modal for his son.
When Desmond goes to leave is message in the wall, Harris finds him there and has the light saber and Desmond talks to him, leaves him a coded message in his lost memories. he also takes the light saber from him and knights him with it as a Jedi Knight of Paragangia, and blesses him that he will be the protector of the Paragan child, that he will know and serve him without a doubt whenever and however they may meet, and he blesses his light Saber, and any other objects like unto that which Harris would create, that they will faithfully serve Paragan and be what he needs when he needs it
Unknown to any of them, this blessing give Jason the power to do things with that light saber that no-one else can do, and also gives Sylvia the power to become what she becomes and to do what Jason needs her to do in the battle with Thearon, and she is set free and made an independent being through the power of that blessing, and through her love for Harris, her creator, and her loyalty to Paragan,