I use the latest "hasura/graphql-engine:v1.2.0-beta.1", after testing actions I found that it responds in different formats for 5xx and 4xx errors.
For 5xx errors I could get from the response any custom objects with data from the server

{
  "errors": [
    {
      "extensions": {
        "internal": {
          "webhook_response": {
            "errors": [
              {
                "status": 500,
                "code": "Error",
                "detail": "hello world"
              }
            ]
          }
        },
        "path": "$",
        "code": "unexpected"
      },
      "message": "internal error"
    }
  ]
}

When for 4xx it only accepts {"message": "error message"} any custom options will not be displayed at "extensions" - "internal" like for 5xx error.

I would like to have 4xx support any custom formats with the ability to path more information rather than just a "message" field.