diff --git a/docs/config.md b/docs/config.md
index 3b9be73ec..a4461521b 100644
--- a/docs/config.md
+++ b/docs/config.md
@@ -98,6 +98,7 @@ config :pleroma, Pleroma.Emails.Mailer,
   * `Pleroma.Web.ActivityPub.MRF.RejectNonPublic`: Drops posts with non-public visibility settings (See ``:mrf_rejectnonpublic`` section)
   * `Pleroma.Web.ActivityPub.MRF.EnsureRePrepended`: Rewrites posts to ensure that replies to posts with subjects do not have an identical subject and instead begin with re:.
   * `Pleroma.Web.ActivityPub.MRF.AntiLinkSpamPolicy`: Rejects posts from likely spambots by rejecting posts from new users that contain links.
+  * `Pleroma.Web.ActivityPub.MRF.VocabularyPolicy`: Restricts activities to a configured set of vocabulary. (see `:mrf_vocabulary` section)
 * `public`: Makes the client API in authentificated mode-only except for user-profiles. Useful for disabling the Local Timeline and The Whole Known Network.
 * `quarantined_instances`: List of ActivityPub instances where private(DMs, followers-only) activities will not be send.
 * `managed_config`: Whenether the config for pleroma-fe is configured in this config or in ``static/config.json``
@@ -266,6 +267,10 @@ config :pleroma, :mrf_subchain,
 * `federated_timeline_removal`: A list of patterns which result in message being removed from federated timelines (a.k.a unlisted), each pattern can be a string or a [regular expression](https://hexdocs.pm/elixir/Regex.html)
 * `replace`: A list of tuples containing `{pattern, replacement}`, `pattern` can be a string or a [regular expression](https://hexdocs.pm/elixir/Regex.html)
 
+## :mrf_vocabulary
+* `accept`: A list of ActivityStreams terms to accept.  If empty, all messages are accepted.
+* `reject`: A list of ActivityStreams terms to reject.  If empty, no messages are rejected.
+
 ## :media_proxy
 * `enabled`: Enables proxying of remote media to the instance’s proxy
 * `base_url`: The base URL to access a user-uploaded file. Useful when you want to proxy the media files via another host/CDN fronts.