how do you check if the user is on the phone or computer?

for now user-agent: "warpcast" is the best bet

this one has been surprisingly tricky to nail down the best way

we could add something to the sdk context object but then it's not available to servers

on mobile mini apps are rendered in an Embedded WebView where we control over request headers so we can override the agent

but on web mini apps are rendered in Iframes where we have zero control over request headers

been hard to find a satisfactory solution that gives a single, simple way to identify that 1) the request is coming in the context of a mini app, 2) identifies if it's a mobile/WebView or web/iFrame based request

but does seem like user-agent includes Warpcast is the best option for your use case

we could standardize the WebView user agent to something like
"<client username> / farcaster" to client future proof

father, meditator and freelance miniapp builder and consultant