diff --git a/docs/configuration.md b/docs/configuration.md
index 731437f76..d98d9ac7f 100644
--- a/docs/configuration.md
+++ b/docs/configuration.md
@@ -1439,6 +1439,11 @@ fields:
 
 # The HTTP client's configuration.
 [ http_config: <http_config> | default = global.http_config ]
+# The maximum time to wait for a slack request to complete, before failing the
+# request and allowing it to be retried. The default value of 0s indicates that
+# no timeout should be applied.
+# NOTE: This will have no effect if set higher than the group_interval.
+[ timeout: <duration> | default = 0s ]
 ```
 
 #### `<action_config>`