YAML has far too many features and doesn't let you structure data well for this use-case. There's no concise way to provide typings for its fields, for instance

YAML has far too many features and doesn't let you structure data well for this use-case. There's no concise way to provide typings for its fields, for instance - note how every field requires two lines in the examples, far too verbose. I don't really know what to tell you other than that YAML is not well-suited to this domain, and designing a domain-specific language which meets the particular needs of the system, and only just, would be better. You could base it off of C structs or Rust types or s-expressions or whatever else, the exact syntax isn't important so long as it allows you to concisely and precisely specify the semantics of the tool.