The way that spindles work is that they basically just get events from repos when something happens, like a push or whatever. The spindle, if it's going to respond, eventually responds with what the results were, if any. If it looks like a spindle and quacks like a spindle, it's a spindle.
Tangled's CI happens to do this by way of receiving an event, looking at your Tangled workflow files, and using those to determine when it should actually run your CI. There's no reason it has to stay like that though.
I personally am planning on implementing a Tangled spindle that, instead of looking at Tangled workflow files, looks at just my Nix flake and builds and deploys things based on that. It's a very open solution, everything is just a protocol, there's no lock in.
Tangled's Spindle itself, as a product that conforms to the informal Spindle protocol, is pretty decent. You put in Nix dependencies and some scripts and when it should run, and you get out working CI. I have no complaints about it
What can I expect as a developer using Tangled to build (and deploy) my app? What is the native platform? What are typical other CI systems that have been adapted to work on Tangled (Dagger, Drone, whatnot, especially if there are repos to demonstrate the adaption)? What can I expect as enterprise or lone developer using Tangled or self-hosting or federation?
The system is called Spindle, but what about it? What does it take inspiration from, what are things like it that would help us spool up on this?