diff --git a/internal/paymentkit/README.md b/internal/paymentkit/README.md
index 8459592..6dd1543 100644
--- a/internal/paymentkit/README.md
+++ b/internal/paymentkit/README.md
@@ -1,5 +1,6 @@
 # Payment Utilities
 
 Stateless payment protocol helpers live here: amount conversion, status
-normalization, JSON/XML extraction, and request signing. Provider adapters and
-their SDK clients remain under `internal/integration/payment`.
+normalization, JSON extraction, and request signing. Provider adapters and
+their SDK clients remain under `internal/integration/payment`; test-only XML
+fixtures stay beside the provider integration tests.