diff --git a/.changeset/tidy-client-cookie-docs.md b/.changeset/tidy-client-cookie-docs.md
new file mode 100644
index 00000000000..50ee515503f
--- /dev/null
+++ b/.changeset/tidy-client-cookie-docs.md
@@ -0,0 +1,5 @@
+---
+'@clerk/shared': patch
+---
+
+Clarify that `ClientResource.cookieExpiresAt` is nullable, can change when Clerk refreshes the client cookie, and reflects the cookie Device Trust uses to recognize a browser.
diff --git a/packages/shared/src/types/client.ts b/packages/shared/src/types/client.ts
index aeae7ce8142..6032ee44a6c 100644
--- a/packages/shared/src/types/client.ts
+++ b/packages/shared/src/types/client.ts
@@ -82,7 +82,10 @@ export interface ClientResource extends ClerkResource {
    */
   captchaBypass: boolean;
   /**
-   * The date and time when the client's authentication cookie will expire.
+   * The date and time when the client authentication cookie is currently set to expire. Clerk can refresh this
+   * cookie, so the value can change. Returns `null` when the expiration is unavailable.
+   *
+   * [Device Trust](https://clerk.com/docs/guides/secure/device-trust) uses the client cookie to recognize a known browser.
    */
   cookieExpiresAt: Date | null;
   /**