diff --git a/src/possum/at_uri.gleam b/src/possum/at_uri.gleam
index c328470..5422c5b 100644
--- a/src/possum/at_uri.gleam
+++ b/src/possum/at_uri.gleam
@@ -31,6 +31,7 @@ pub type Authority {
   Did(value: did.Did)
 }
 
+/// A URI scheme for addressing atproto repository data.
 pub opaque type AtUri {
   AtUri(
     /// Identifier, can be a DID or a Handle