Currently, Custom Error Response rules support using Error Tokens like ::RAY_ID:: in the body of the custom error response. This is a useful feature because it allows for adding an error page that is custom but nonetheless retains useful features of the default error page, such as the Ray ID that the customer can reference when contacting our company’s customer support.
There is a different custom response case, described here in “Configuring a custom response for blocked requests”. While this case also supports a custom HTML error response, it does not allow use of Error Tokens. I’d like to request Error Token replacement for this case as well, because we’re not able to use it effectively until the response can include a Ray ID, just like the Custom Error Response rule does.