diff --git a/src/client.rs b/src/client.rs
index 64b94525..6a38d0bb 100644
--- a/src/client.rs
+++ b/src/client.rs
@@ -385,7 +385,8 @@ impl rustls_client_config_builder {
     ///
     /// The provided `ech_config_list_bytes` and `rustls_hpke` must not be NULL or an
     /// error will be returned. The caller maintains ownership of the ECH config list TLS bytes
-    /// and `rustls_hpke` instance.
+    /// and `rustls_hpke` instance. This function does not retain any reference to
+    /// `ech_config_list_bytes`.
     ///
     /// A `RUSTLS_RESULT_BUILDER_INCOMPATIBLE_TLS_VERSIONS` error is returned if the builder's
     /// TLS versions have been customized via `rustls_client_config_builder_new_custom()`
diff --git a/src/rustls.h b/src/rustls.h
index fba30a1d..1432df51 100644
--- a/src/rustls.h
+++ b/src/rustls.h
@@ -1768,7 +1768,8 @@ rustls_result rustls_client_config_builder_set_key_log(struct rustls_client_conf
  *
  * The provided `ech_config_list_bytes` and `rustls_hpke` must not be NULL or an
  * error will be returned. The caller maintains ownership of the ECH config list TLS bytes
- * and `rustls_hpke` instance.
+ * and `rustls_hpke` instance. This function does not retain any reference to
+ * `ech_config_list_bytes`.
  *
  * A `RUSTLS_RESULT_BUILDER_INCOMPATIBLE_TLS_VERSIONS` error is returned if the builder's
  * TLS versions have been customized via `rustls_client_config_builder_new_custom()`