fly.toml not written during `fly machine launch`

I’m trying to create a new machine from a fresh repo with a working Dockerfile but fly.toml is not generated

$ fly machine launch
? Choose an app name (leave blank to generate one): my-app
? Select Organization: MyOrg
Created app schedule-image in org MyOrg
? Select region: London, United Kingdom (lhr)
Detected a Dockerfile app
? Does this app run an HTTP service? Yes
? Which port does your service listen on? 8080
Wrote to fly.toml
? Would you like to deploy now? No
Your app is ready. Deploy with `flyctl deploy`
$ ls fly.toml
"fly.toml": No such file or directory (os error 2)

any thoughts?

oh wait… fly machine launch seems to be undocumented and I can’t now remember where I found it mentioned.

I’m guessing this functionality is still in beta and I just need to use the API

Hi T, fly m run might work for your use case. The API does have more functionality for machines than flyctl right now, so you’re on the right track in using the API if flyctl doesn’t meet the need.

Well, maybe I just need to know what a minimum viable fly.toml is for a machine

right now I have

app = "my-app"
image = "my-org/my-app-image:latest"

  PORT = "8080"

Anything else I should put in there to make life easy?