Every stdout reporter --reporter accepts, in help/error-message order. Exactly one is active per run — artifact outputs (--junit, --coverage) are separate additive flags. This module is a leaf (type-only imports), so Args.parse can validate against it without pulling the reporter implementations into the CLI's startup path.

REPORTERS[0]; // 'tap' — the default
REPORTERS.join(', '); // 'tap, spec, dot, github' — the order help and errors list them in