diff --git a/lib/phx_tools_web/plugs/curl_detector.ex b/lib/phx_tools_web/plugs/curl_detector.ex
index 28eb033c..a4e704e8 100644
--- a/lib/phx_tools_web/plugs/curl_detector.ex
+++ b/lib/phx_tools_web/plugs/curl_detector.ex
@@ -27,8 +27,8 @@ defmodule PhxToolsWeb.CurlDetector do
     end
   end
 
-  defp request_sent_from_curl?(nil), do: false
-  defp request_sent_from_curl?(user_agent), do: String.starts_with?(user_agent, "curl")
+  defp request_sent_from_curl?("curl" <> _rest), do: true
+  defp request_sent_from_curl?(_user_agent), do: false
 
   defp script_content do
     :phx_tools
diff --git a/test/phx_tools_web/plugs/curl_detector_test.exs b/test/phx_tools_web/plugs/curl_detector_test.exs
index 8aa774b3..c2426ffa 100644
--- a/test/phx_tools_web/plugs/curl_detector_test.exs
+++ b/test/phx_tools_web/plugs/curl_detector_test.exs
@@ -44,5 +44,10 @@ defmodule PhxToolsWeb.CurlDetectorTest do
       assert conn.status == 200
       assert String.contains?(conn.resp_body, @script_content)
     end
+
+    test "doesn't crash when User-Agent is nil", %{conn: conn} do
+      conn = get(conn, "/")
+      assert conn.status == 200
+    end
   end
 end