# Idl


`IdlBuilder` refines `CodeGenBuilder` with `idlFormat` and
`idlSource`, encoding "this generator is driven by an IDL document"
in the type.

`fromProtobuf { name; protos; languages; options?; languageConfigs?; }`
builds a fully-typed `IdlBuilder` spec for `protoc`. The default
language config covers the standard protoc backends; pass
`languageConfigs` to override or extend.