diff --git a/crates/lib/artcraft_client_identity/src/user_agents.rs b/crates/lib/artcraft_client_identity/src/user_agents.rs
index 254289b105..d4c54aeab5 100644
--- a/crates/lib/artcraft_client_identity/src/user_agents.rs
+++ b/crates/lib/artcraft_client_identity/src/user_agents.rs
@@ -5,6 +5,11 @@ pub const ARTCRAFT_DESKTOP_USER_AGENT: &str = "storyteller-client/1.0";
 
 /// `User-Agent` sent to third parties: the default of the OS webview Tauri runs on
 /// (WKWebView on macOS, WebView2 on Windows, WebKitGTK on Linux).
+///
+/// NB: These are hardcoded snapshots and WILL go out of date as the OS webviews update
+/// (especially WebView2's Chrome/Edge version, which auto-updates on Windows). Rust can't read
+/// the webview's real `navigator.userAgent`, so refresh these periodically by checking
+/// `navigator.userAgent` in the desktop app's devtools on each OS.
 #[cfg(target_os = "macos")]
 pub const WEBVIEW_USER_AGENT: &str =
   "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko)";
diff --git a/docs/desktop-session-regression.md b/docs/desktop-session-regression.md
index f6da64adbc..28a87afb90 100644
--- a/docs/desktop-session-regression.md
+++ b/docs/desktop-session-regression.md
@@ -35,6 +35,10 @@ values from one place, `crates/lib/artcraft_client_identity`
 - The native Rust client (`artcraft_client`) sends the Origin and User-Agent on
   every API request via `storyteller_client_builder`; it previously sent no
   Origin.
+- The "OS webview" User-Agents are hardcoded snapshots in
+  `artcraft_client_identity/src/user_agents.rs` and go out of date as the
+  webviews update (notably WebView2's Edge version on Windows). Refresh them
+  from `navigator.userAgent` in the desktop app's devtools on each OS.
 - The vendored HTTP plugin only replaces the webview's own origin (packaged
   `tauri://localhost` etc., or a loopback Vite origin), and only sets the
   User-Agent when the frontend didn't.