--- a/scid/crud.h	Thu Aug 04 14:59:33 2022 +0200
+++ b/scid/crud.h	Thu Aug 04 16:47:10 2022 +0200
@@ -19,14 +19,47 @@
 #ifndef SCID_CRUD_H
 #define SCID_CRUD_H
 
+/**
+ * \file crud.h
+ * \brief Convenient helpers for API pages.
+ *
+ * This module uses the database to fetch or insert data and finally show the
+ * result as HTTP response.
+ *
+ * This module logs message with tag `crud`.
+ */
+
 #include <jansson.h>
 
 struct kreq;
 
+/**
+ * Decode the JSON input and insert them using the appropriate database
+ * function provided.
+ *
+ * \pre r != NULL
+ * \pre saver != NULL
+ * \pre topic != NULL
+ * \param r the request
+ * \param saver the function to save in database
+ * \param topic the log topic for diagnostic
+ */
 void
-crud_insert(struct kreq *, int (*)(json_t *), const char *);
+crud_insert(struct kreq *r, int (*saver)(json_t *), const char *topic);
 
+/**
+ * Convert the JSON provided value.
+ *
+ * For convenience, if the document is NULL (which happen if the database
+ * access failed) it will send a HTTP 500 error. Otherwise it is listed and
+ * free'd.
+ *
+ * \pre r != NULL
+ * \param r the request
+ * \param doc the document to send (maybe NULL)
+ * \warning The document will be destroyed using json_decref.
+ */
 void
-crud_list(struct kreq *, json_t *);
+crud_list(struct kreq *r, json_t *doc);
 
 #endif /* !SCID_CRUD_H */