Writing Plugins
Pruner plugins are WASM components that implement the pruner/plugin-api WIT interface. You can find the source for the WIT interface here.
The interface is straight-forward requiring you to implement only a format function which takes in source code as a byte-array and should return the formatted result as a byte-array.
Rust
If you are building this in Rust, Pruner exposes a pruner-plugin-api crate containing all the generated interfaces which you can reference without needing to know anything about WASM or WIT.
For a full, end-to-end walkthrough, see:
I want to write plugins in $LANGUAGE!
Theoretically anything that can compile to WASM components should be usable to write plugins for Pruner. There is no official documentation in Pruner for how to do this - but I would be happy to accept contributions to that effect.
You can find some great WASM components documentation for other languages here which should be enough to get going.