Use apple facetime --help and subcommand help as the first reference.
Common reads and previews:
apple facetime contacts resolve --query Ada --json
apple facetime calls prepare --to +15555550100 --jsonStarting a call uses the DryRun safety flow:
apple facetime calls start --to +15555550100 --dry-run --jsonThe detailed capability boundary lives in
../../Architecture/FaceTime/CapabilityList.md.