diff --git a/lib/last_fm/config.ex b/lib/last_fm/config.ex
index 8bb7fe9f..7bbc677b 100644
--- a/lib/last_fm/config.ex
+++ b/lib/last_fm/config.ex
@@ -46,7 +46,7 @@ defmodule LastFm.Config do
           )
 
   @doc NimbleOptions.docs(@schema)
-  @spec resolve(atom) :: t
+  @spec resolve(atom) :: t | no_return
   def resolve(otp_app) do
     app_config =
       Application.get_env(otp_app, LastFm)
diff --git a/lib/music_brainz/config.ex b/lib/music_brainz/config.ex
index 3f82f48c..2fee503f 100644
--- a/lib/music_brainz/config.ex
+++ b/lib/music_brainz/config.ex
@@ -20,7 +20,7 @@ defmodule MusicBrainz.Config do
           )
 
   @doc NimbleOptions.docs(@schema)
-  @spec resolve(atom) :: t
+  @spec resolve(atom) :: t | no_return
   def resolve(otp_app) do
     app_config =
       Application.get_env(otp_app, MusicBrainz)