Stacktrace entries for emulator calls are coming on Erlang 21: https://github.com/erlang/otp/pull/1478 https://github.com/erlang/otp/pull/1478 This means that

Stacktrace entries for emulator calls are coming on Erlang 21: https://github.com/erlang/otp/pull/1478 https://github.com/erlang/otp/pull/1478 This means that something such as 1/0 should include the line where the error happened in IEx and in general. Regarding the error messages, the reason why you have two reports is because there are two processes failing! The task fails, leading to the logger report, and then it causes the evaluator process to fail, causing it to be report an error as well. Regarding configuration, it is not at compile time, but the config.exs itself is read when the escript is built. You can change it at any time though by calling Application.put_env, so there is no need for a GenServer. I know exactly where to improve the docs for this one. Thanks for the feedback! I think I have an idea on how to improve many of those. I will do some of that and get back to you later.