diff --git a/1/README.md b/1/README.md
index 42e8088..90c65c6 100644
--- a/1/README.md
+++ b/1/README.md
@@ -44,6 +44,8 @@ The metadata keys are mostly self-explanatory. Note:
 * `date`, if present, will be set as the `published_at` date.
 * If `published` is set to `true`, it will publish a kind 30023 event,
   otherwise a kind 30024 (draft)
+* The `d` tag (widely used as URL slug for the article) will be the filename
+  without the `.md` extension
 
 [1]: https://gitea.kosmos.org/raucao/gists/src/branch/master/1/markdown_to_nostr.sh
 [2]: https://github.com/nostr-protocol/nips/blob/master/23.md