public function CHECK_IN_args() {
		$ticket_label_singular_lower = esc_html( tribe_get_ticket_label_singular_lowercase( 'rest_qr' ) );

		return [
			// QR fields.
			'api_key'       => [
				'required'          => true,
				'validate_callback' => [ $this->validator, 'is_string' ],
				'type'              => 'string',
				'description'       => __( 'The API key to authorize check in.', 'event-tickets' ),
			],
			'ticket_id'     => [
				'required'          => true,
				'validate_callback' => [ $this->validator, 'is_numeric' ],
				'type'              => 'string',
				'description'       => esc_html(
					sprintf(
						// Translators: %s is the 'ticket' label (singular, lowercase).
						__( 'The ID of the %s to check in.', 'event-tickets' ),
						$ticket_label_singular_lower
					)
				),
			],
			'security_code' => [
				'required'          => true,
				'validate_callback' => [ $this->validator, 'is_string' ],
				'type'              => 'string',
				'description'       => esc_html(
					sprintf(
						// Translators: %s is the 'ticket' label (singular, lowercase).
						__( 'The security code of the %s to verify for check in.', 'event-tickets' ),
						$ticket_label_singular_lower
					)
				),
			],
		];
	}