interface ServiceURLResponseAccess echoes the enabled LangSmith login level ("restricted"/"workspace"); omitted in token mode.
EmbedOrigins echoes the origins that may embed the URL, normalized; omitted when there are none.
EmbedURL opens the service in an iframe: the token rides the URL fragment, which no server, log or Referer header sees, and the page it loads trades it for the cookie. Append &redirect=/path to land elsewhere than /. Omitted in LangSmith login mode.
Token and ExpiresAt are empty in LangSmith login mode (no token is minted).