Use @agentstack/sdk from React Native or Expo with the same resolveAgentStackApiBase() and sdk.platform.auth. Prefer sdk.messenger embed helpers for chat surfaces.
Hosted AgentStack apps can be installable; Web Push for DMs requires user permission and a registered service worker on your origin when self-hosting UI. On agentstack.tech, push is wired for messenger when enabled.
Related: messenger/OFFLINE_AND_RELIABILITY.md · auth/OAUTH_DEVICE_FLOW.md