opys CLI

Command-line interface for building and launching Minecraft client installations from declarative manifests.

Install

npm install -g @opys/cli

Or run directly without installing:

npx @opys/cli <command>

Commands

opys build

Reads a JS config file, fetches Mojang metadata, and writes a opys.json manifest.

opys build [--input opys.config.mjs] [--output opys.json]

| Flag | Short | Default | Description | | ---------- | ----- | ---------------------- | --------------------------------- | | --input | -i | opys.config.mjs | Path to the JS config file | | --output | -o | value from config file | Output path for the manifest JSON |

If --output is omitted and the config has no output field, the manifest is written to stdout.

opys launch

Installs missing artifacts and spawns the JVM.

opys launch [manifest] [--var key=value ...]

Common vars to pass at launch: username, uuid, token.

Config file (opys.config.mjs)

import {
  defineConfig,
  resolveMinecraft,
  artifactScanner,
} from '@opys/minecraft';

export default defineConfig(async () => {
  const mc = await resolveMinecraft({ version: '1.20.1' });

  return {
    output: 'opys.json',
    manifest: {
      artifacts: [
        mc.artifacts,
        artifactScanner({
          directory: 'mods',
          url: 'https://cdn.example.com/mods/${path}',
          path: '${root}/mods/${path}',
        }),
      ],
      vars: mc.vars,
      launch: mc.launch,
    },
  };
});

Exit codes

| Code | Meaning | | ---- | ------------------------------- | | 0 | Success | | 1 | Usage error (bad args / config) | | 2 | Network error | | 3 | Integrity check failed | | 4 | Extraction failure |