Reference

Dovetail is extended through MSBuild items. You declare one in a project file, and the build writes the C# for it into obj/ before the compiler runs. MSBuild targets expand the items, not the Roslyn source generator, so there is nothing to configure and nothing to call at run time. These pages list every metadata value an item reads, with its default, so you do not have to read the .targets files.

DovetailJointDeclare a joint kind: a typed extension point other code can contribute to.

DovetailHostDeclare the ConfigureDovetail entry points for a host builder.

DovetailTemplateShip C# source from a package and have it written into only the projects that should get it.

For how to write the joints these items produce, and how Dovetail orders and runs them, see Defining Dovetails.