diff --git a/include/psa/crypto_adjust_auto_enabled.h b/include/psa/crypto_adjust_auto_enabled.h
index 63fb29e..e2618d1 100644
--- a/include/psa/crypto_adjust_auto_enabled.h
+++ b/include/psa/crypto_adjust_auto_enabled.h
@@ -2,6 +2,8 @@
  * \file psa/crypto_adjust_auto_enabled.h
  * \brief Adjust PSA configuration: enable always-on features
  *
+ * This is an internal header. Do not include it directly.
+ *
  * Always enable certain features which require a negligible amount of code
  * to implement, to avoid some edge cases in the configuration combinatorics.
  */
diff --git a/include/psa/crypto_adjust_config_key_pair_types.h b/include/psa/crypto_adjust_config_key_pair_types.h
index 63afc0e..8308ac7 100644
--- a/include/psa/crypto_adjust_config_key_pair_types.h
+++ b/include/psa/crypto_adjust_config_key_pair_types.h
@@ -2,6 +2,8 @@
  * \file psa/crypto_adjust_config_key_pair_types.h
  * \brief Adjust PSA configuration for key pair types.
  *
+ * This is an internal header. Do not include it directly.
+ *
  * See docs/proposed/psa-conditional-inclusion-c.md.
  * - Support non-basic operations in a keypair type implicitly enables basic
  *   support for that keypair type.
diff --git a/include/psa/crypto_adjust_config_synonyms.h b/include/psa/crypto_adjust_config_synonyms.h
index 332b622..ad71050 100644
--- a/include/psa/crypto_adjust_config_synonyms.h
+++ b/include/psa/crypto_adjust_config_synonyms.h
@@ -2,6 +2,8 @@
  * \file psa/crypto_adjust_config_synonyms.h
  * \brief Adjust PSA configuration: enable quasi-synonyms
  *
+ * This is an internal header. Do not include it directly.
+ *
  * When two features require almost the same code, we automatically enable
  * both when either one is requested, to reduce the combinatorics of
  * possible configurations.