- `--name` leaves OPTIONS: the game still takes it, but the contract doesn't
promise offline play. The guide's first step is now the owner rule, and a
session the game can't read is stated as a fact, not an option.
- A bad value names its option (`Horizon: --width: invalid digit ...`), since
a launcher shows that line to the player.
- Session errors say "the session", true for --session-stdin too.
- --quickPlaySingleplayer takes one folder name of saves/, as vanilla's level
id; a path is refused. --world still takes a path for harnesses.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
The game's side of the Launch API, experimental, version 0.1.0:
--game-dir (vanilla's --gameDir), --home, --fullscreen (vanilla's, not
saved to options.txt), --session-stdin and --launch-api, which prints
the API version and the options a launcher may pass as JSON.
A refused command line now exits 2 without a crash report; errors keep
1 and panics 101. The crash report's path stays the last stderr line,
its prefix now a constant (crash::SAVED_LINE).
docs/api/launch.md is the surface page; docs/api/launch-reference.md is
generated from game/launch_api.rs and a test keeps the two together.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
