The CodeAssist language SPI: the neutral syntax tree, resolution, file types, completion, formatting, folding, and a language's compilation context.

The CodeAssist index SPI: persisted, incrementally maintained project indexes.

The CodeAssist analysis SPI: analyzers, the diagnostic model, quick fixes, and editor action providers.

The CodeAssist block-editor SPI: the projection of a language's syntax tree onto a block surface, and the mapping a language contributes to define it.