In the past few weeks, there were a couple of questions about useless cmp instead of actual components' names in stacktraces of exceptions thrown from within render functions of Reagent components. I just created this issue which suggests a possible fix: https://github.com/reagent-project/reagent/issues/549 Note that even if it's never incorporated into the Reagent's source code, you can still use it in your own sources by simply copying the whole file with the reagent.impl.component namespace into your own sources and making that change.