diff --git a/core/models.py b/core/models.py
index 55866c4..b955fb3 100644
--- a/core/models.py
+++ b/core/models.py
@@ -34,6 +34,11 @@ class AtUri:
         return hash(str(self))
 
 
+def make_at_uri(did: str, collection: str, rkey: str) -> str:
+    """Build an AT URI string from its components."""
+    return f"at://{did}/{collection}/{rkey}"
+
+
 # errors
 
 
diff --git a/core/records.py b/core/records.py
index 9717429..f07b8f7 100644
--- a/core/records.py
+++ b/core/records.py
@@ -10,7 +10,7 @@ import httpx
 from core import lexicon
 from core.constellation import get_board_activity, get_replies, get_root_posts
 from core.filters import filter_moderated
-from core.models import AtUri, AuthError, BBS, Board, MiniDoc, Post, Record
+from core.models import AtUri, AuthError, BBS, Board, MiniDoc, Post, Record, make_at_uri
 from core.slingshot import (
     get_records_batch,
     get_records_by_uri,
@@ -51,7 +51,7 @@ async def hydrate_threads(
     newest posts first, the first time a thread URI appears is its most
     recent activity — giving us bump order naturally.
     """
-    board_uri = str(AtUri(bbs.identity.did, lexicon.BOARD, board.slug))
+    board_uri = make_at_uri(bbs.identity.did, lexicon.BOARD, board.slug)
     max_scans = 4
 
     # Phase 1: Scan board activity to find unique thread URIs
diff --git a/core/resolver.py b/core/resolver.py
index 43c0fc9..4f910d0 100644
--- a/core/resolver.py
+++ b/core/resolver.py
@@ -11,6 +11,7 @@ from core.models import (
     BBSNotFoundError,
     NoBBSError,
     NetworkError,
+    make_at_uri,
 )
 from core import lexicon
 from core.cache import TTLCache
@@ -51,7 +52,7 @@ async def _resolve_bbs(client: httpx.AsyncClient, handle: str) -> BBS:
         raise NetworkError("Could not reach the network.")
 
     site_value = site_record.value
-    site_uri = str(AtUri(identity.did, lexicon.SITE, "self"))
+    site_uri = make_at_uri(identity.did, lexicon.SITE, "self")
 
     # Fetch boards and news concurrently
     board_uris = site_value["boards"]
diff --git a/tui/screens/compose/news.py b/tui/screens/compose/news.py
index cc7dd16..f751fa6 100644
--- a/tui/screens/compose/news.py
+++ b/tui/screens/compose/news.py
@@ -3,7 +3,7 @@ from textual.containers import Vertical
 from textual.widgets import Footer, Input, Static, TextArea
 
 from core import lexicon, limits
-from core.models import AtUri, BBS
+from core.models import BBS, make_at_uri
 from tui.screens.compose.base import ComposeScreen
 from tui.widgets.breadcrumb import Breadcrumb
 
@@ -36,5 +36,5 @@ class ComposeNewsScreen(ComposeScreen):
         self.query_one("#compose-title", Input).focus()
 
     def get_post_params(self, title: str | None, body: str) -> dict:
-        site_uri = str(AtUri(self.bbs.identity.did, lexicon.SITE, "self"))
+        site_uri = make_at_uri(self.bbs.identity.did, lexicon.SITE, "self")
         return {"scope": site_uri, "body": body, "title": title}
diff --git a/tui/screens/compose/thread.py b/tui/screens/compose/thread.py
index c42cdca..4b606b6 100644
--- a/tui/screens/compose/thread.py
+++ b/tui/screens/compose/thread.py
@@ -3,7 +3,7 @@ from textual.containers import Vertical
 from textual.widgets import Footer, Input, Static, TextArea
 
 from core import lexicon, limits
-from core.models import AtUri, BBS, Board
+from core.models import BBS, Board, make_at_uri
 from tui.screens.compose.base import ComposeScreen
 from tui.widgets.breadcrumb import Breadcrumb
 
@@ -40,5 +40,5 @@ class ComposeThreadScreen(ComposeScreen):
         self.query_one("#compose-title", Input).focus()
 
     def get_post_params(self, title: str | None, body: str) -> dict:
-        board_uri = str(AtUri(self.bbs.identity.did, lexicon.BOARD, self.board.slug))
+        board_uri = make_at_uri(self.bbs.identity.did, lexicon.BOARD, self.board.slug)
         return {"scope": board_uri, "body": body, "title": title}
diff --git a/tui/screens/sysop/create.py b/tui/screens/sysop/create.py
index 4d09321..9fea5f3 100644
--- a/tui/screens/sysop/create.py
+++ b/tui/screens/sysop/create.py
@@ -5,7 +5,7 @@ from textual.screen import Screen
 from textual.widgets import Footer, Input
 
 from core import lexicon
-from core.models import AtUri, AuthError
+from core.models import AuthError, make_at_uri
 from core.records import put_board_record, put_site_record
 from core.resolver import invalidate_bbs_cache, resolve_bbs
 from core.util import now_iso
@@ -77,7 +77,7 @@ class SysopCreateScreen(BBSFormMixin, Screen):
                     "description": description,
                     "intro": intro,
                     "boards": [
-                        str(AtUri(session["did"], lexicon.BOARD, board["slug"]))
+                        make_at_uri(session["did"], lexicon.BOARD, board["slug"])
                         for board in self._boards
                     ],
                     "createdAt": now,
diff --git a/tui/screens/sysop/delete.py b/tui/screens/sysop/delete.py
index 14ffdd2..256a41a 100644
--- a/tui/screens/sysop/delete.py
+++ b/tui/screens/sysop/delete.py
@@ -5,7 +5,7 @@ from textual.screen import Screen
 from textual.widgets import Button, Footer, Static
 
 from core import lexicon
-from core.models import AtUri, BBS
+from core.models import AtUri, BBS, make_at_uri
 from core.constellation import get_root_posts
 from core.records import delete_record, list_pds_records
 from tui.util import make_session_updater
@@ -55,7 +55,7 @@ class SysopDeleteScreen(Screen):
                 failed.append(f"board/{board.slug}")
 
         # Delete sysop's news posts (posts scoped to site)
-        site_uri = str(AtUri(session["did"], lexicon.SITE, "self"))
+        site_uri = make_at_uri(session["did"], lexicon.SITE, "self")
         try:
             backlinks = await get_root_posts(client, site_uri)
             for ref in backlinks.records:
diff --git a/tui/screens/sysop/edit.py b/tui/screens/sysop/edit.py
index ebde77c..cdb8c57 100644
--- a/tui/screens/sysop/edit.py
+++ b/tui/screens/sysop/edit.py
@@ -5,7 +5,7 @@ from textual.screen import Screen
 from textual.widgets import Footer, Input
 
 from core import lexicon
-from core.models import AtUri, AuthError, BBS
+from core.models import AuthError, BBS, make_at_uri
 from core.records import delete_record, put_board_record, put_site_record
 from core.resolver import invalidate_bbs_cache
 from core.util import now_iso
@@ -107,7 +107,7 @@ class SysopEditScreen(BBSFormMixin, Screen):
                     "description": description,
                     "intro": intro,
                     "boards": [
-                        str(AtUri(session["did"], lexicon.BOARD, board["slug"]))
+                        make_at_uri(session["did"], lexicon.BOARD, board["slug"])
                         for board in self._boards
                     ],
                     "createdAt": self.bbs.site.created_at or now,