FSharp.Analyzers.SDK is a library used for building custom analyzers for FSAC / F# editors. F# analyzers are live, real-time, project-based plugins that enables diagnosis of source code and surfacing of custom errors, warnings and code fixes into the editor. They're heavily influenced and inspired by Roslyn Analyzers.
Read more about F# Analyzers here - https://medium.com/lambda-factory/introducing-f-analyzers-772487889429 (Note that the API has changed since this article.)
Check out the FSharp.Analyzers.SDK documentation.