How can we complete nixos options
Nixd do these kind of completion now, but it is based on string manipulation, not for ASTs, (the AST-based implementation is working in progress).
package names
It is already implemented. See this example: Nixd 1.1.0 released
document hover
The documentation + example are provided with the completion list. “Hover” documentation is working in progress.
package description
v1.1.0 release has support “goto definition” for packages. The description & version is somehow easy to implemented, how about submit a formal issue (for feature-request) on github?