Currently are two file formats supported ksv and grammar files. For defining slot-values or entities you
can use the syntax of value files.
The syntax of ksv files are an invention of René Kilczan and [Melanie Weitz].
The syntax of grammar files is invented by Kay Lerch for his Alexa Skill Utterance and Schema Generator.
The restriction of grammar files is that you cannot define your prompts, reprompts and suggestions. Why you should my still prefer this tool instead of the Utterance Generator, is that each generated utterance is cached. That makes the generation of the Alexa Schema much faster. You could even generate millions of utterances within an acceptable time frame. Even if you plan to migrate you can use just your grammar files for the beginning.
The best thing is we have a cli which is a faster and has a lower memory footprint.
Check also the guide for migrate your grammar files and full specification of the grammar file format.
Please note that for right now the intent names have to be in its independed line, that inline syntax is currently not supported. Also the slot value inline format is current not supported. The workaround is to copy that blocks to own files. E.g. you have
{Ingredient}: Egg, Suggar, Floor, Water
You need to store those values in a file called values/Ingredient.values with the content:
Egg
Suggar
Floor
Water
Extending system slots like in this example is not supported too:
{AMAZON.US_CITY}: new york, big apple