That’s not how it works. Comptime Zig is Zig, not an embedded scripting language. You can’t run comptime code separately, it only runs as part of compiling a Zig program. Think of it like Rust macros.
Yes and no. It is just Zig, but that is the advantage. And compiling it to an special function that could work as an end seems to be a doable thing, so you would just have to have the compiler in your agent.
Possibly, I'm not really interested in learning Zig though (or learning to embed it in Rust). I'm sure that'd be a cool project for someone else to try :).