diff --git a/sys/include/net/gcoap.h b/sys/include/net/gcoap.h
index 09cfb99bfb..fdd4efdda6 100644
--- a/sys/include/net/gcoap.h
+++ b/sys/include/net/gcoap.h
@@ -96,7 +96,7 @@
  * ## Client Operation ##
  *
  * Client operation includes two phases: creating and sending a request, and
- * handling the response aynchronously in a client supplied callback. See
+ * handling the response asynchronously in a client supplied callback. See
  * `examples/gcoap/gcoap_cli.c` for a simple example of sending a request and
  * reading the response.
  *
@@ -147,6 +147,13 @@
  * take any action to support Observe client registration. However, gcoap
  * limits registration for a given resource to a _single_ observer.
  *
+ * It is [suggested] (https://tools.ietf.org/html/rfc7641#section-6) that a
+ * server adds the 'obs' attribute to resources that are useful for observation
+ * (i.e. will produce notifications) as a hint. Keep in mind that this is not
+ * mandatory in order to enable the mechanism in RIOT, nor will prevent a client
+ * from observing a resource that does not have this attribute in the link
+ * description.
+ *
  * An Observe notification is considered a response to the original client
  * registration request. So, the Observe server only needs to create and send
  * the notification -- no further communication or callbacks are required.