The OpenAPI spec defines some Int64(ulong) values with a default of 9223372036854776000, however the largest int64 value is 9223372036854775807.
This causes the OpenApi C# generator to generate code with errors.
Furthermore the OpenApi spec that is downloadable in the documentation is version 3.1.0, and the OpenApiTools generator still only supports version 3.0, so it would be lovely to have both available 
however the largest int64 value is 9223372036854775807
Yes! Have fixed it.
Note that this is the maximum of the signed int64 (2^63-1) and not ulong.
the OpenApiTools generator still only supports version 3.0
Couldn’t you replace the version on your side if it works with your tools? I’m unsure why exactly we did change it to 3.1.0, but I think there was a technical reason
Super, thank you
Sadly there are breaking changes in the specification that makes it break. I tried changing the version, but that just cascaded into a lot of other errors
Hm, yes, this indicates that we intentionally made the switch to 3.1.0.
Anyway, maybe the old version 3.0 works for you. Note that it is already several months old: directions-api-old-3.0-openapi-spec.yaml · GitHub