> For the complete documentation index, see [llms.txt](https://docs.tryterra.co/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.tryterra.co/faq/help-topics/connecting/apple-health-health-connect-and-mobile-sdk/use-terra-avengers-companion-app.md).

# Why doesn't use\_terra\_avengers\_app open the native app?

`use_terra_avengers_app` must be passed **inside the JSON body** of `/auth/generateWidgetSession` (for example `{"reference_id": "...", "use_terra_avengers_app": true}`). Appending it as a query parameter to the returned widget URL has no effect.

With it set, pressing Connect for an SDK-only provider redirects the user to the prebuilt Terra companion app, which sets up permissions, the auth webhook and background delivery automatically.

A few notes:

* The Python client library does not support this parameter, so create the session with a direct HTTP request and pass `use_terra_avengers_app` as the string `"true"`.
* Test on a real device with the companion app installed from the app store.
* The companion app is currently iOS-only, with no Android equivalent yet.

See the [Terra widget docs](https://docs.tryterra.co/health-and-fitness-api/user-authentication/implementation-terra-widget) for context.