diff --git a/CHANGELOG.md b/CHANGELOG.md
index c1f3a60e..cca11b16 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 ## [Unreleased]
 
+## [1.20.1] - 2026-02-10
+
+### Fixed
+
+- Ensure configuration is built correctly inside the `after_initialize` hooks (#208).
+
 ## [1.20.0] - 2026-01-20
 
 ### Added
diff --git a/lib/rage/configuration.rb b/lib/rage/configuration.rb
index 92c6fa9c..f275fe64 100644
--- a/lib/rage/configuration.rb
+++ b/lib/rage/configuration.rb
@@ -227,6 +227,7 @@ def internal
   # @private
   def run_after_initialize!
     run_hooks_for!(:after_initialize, self)
+    __finalize
   end
 
   class LogContext
diff --git a/lib/rage/version.rb b/lib/rage/version.rb
index 7ee629cb..12dda0a6 100644
--- a/lib/rage/version.rb
+++ b/lib/rage/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Rage
-  VERSION = "1.20.0"
+  VERSION = "1.20.1"
 end
diff --git a/spec/integration/test_app/app/telemetry/test_controller_observer.rb b/spec/integration/test_app/app/telemetry/test_controller_observer.rb
new file mode 100644
index 00000000..8698d0ca
--- /dev/null
+++ b/spec/integration/test_app/app/telemetry/test_controller_observer.rb
@@ -0,0 +1,9 @@
+class TestControllerObserver < Rage::Telemetry::Handler
+  handle "controller.action.process", with: :monitor_controllers
+
+  def self.monitor_controllers(name:)
+    Rage.logger.tagged(name) do
+      yield
+    end
+  end
+end
diff --git a/spec/integration/test_app/app/telemetry/test_exception_recorder.rb b/spec/integration/test_app/app/telemetry/test_exception_recorder.rb
new file mode 100644
index 00000000..8c36d03a
--- /dev/null
+++ b/spec/integration/test_app/app/telemetry/test_exception_recorder.rb
@@ -0,0 +1,8 @@
+class TestExceptionRecorder < Rage::Telemetry::Handler
+  handle "controller.action.process", with: :record_exceptions
+
+  def self.record_exceptions
+    result = yield
+    Rage.logger.error("telemetry recorded exception #{result.exception.message}") if result.error?
+  end
+end
diff --git a/spec/integration/test_app/config/application.rb b/spec/integration/test_app/config/application.rb
index e9f23208..f9f95a02 100644
--- a/spec/integration/test_app/config/application.rb
+++ b/spec/integration/test_app/config/application.rb
@@ -18,25 +18,6 @@ def call(env)
   end
 end
 
-class TestControllerObserver < Rage::Telemetry::Handler
-  handle "controller.action.process", with: :monitor_controllers
-
-  def self.monitor_controllers(name:)
-    Rage.logger.tagged(name) do
-      yield
-    end
-  end
-end
-
-class TestExceptionRecorder < Rage::Telemetry::Handler
-  handle "controller.action.process", with: :record_exceptions
-
-  def self.record_exceptions
-    result = yield
-    Rage.logger.error("telemetry recorded exception #{result.exception.message}") if result.error?
-  end
-end
-
 Rage.configure do
   config.middleware.use TestMiddleware
   config.public_file_server.enabled = !!ENV["ENABLE_FILE_SERVER"]
@@ -66,8 +47,10 @@ def self.record_exceptions
   end
 
   if ENV["ENABLE_TELEMETRY"]
-    config.telemetry.use TestControllerObserver
-    config.telemetry.use TestExceptionRecorder
+    config.after_initialize do
+      config.telemetry.use TestControllerObserver
+      config.telemetry.use TestExceptionRecorder
+    end
   end
 
   config.after_initialize do