pipeline {
    agent none
    options {
        ansiColor('xterm')
        skipDefaultCheckout()
        durabilityHint('PERFORMANCE_OPTIMIZED')
    }
    parameters {
        booleanParam(
            name: 'lazyBuild',
            defaultValue: true,
            description: 'Skip build'
        )
    }
    stages {
        stage('WTF') {
            agent {
                label 'master'
            }
            environment {
                IS_LAZY = "${(params.lazyBuild) ? 't' : 'f'}"
                IS_NOT_LAZY = "${(!params.lazyBuild) ? 't' : 'f'}"
            }

            steps {
                sh 'echo IS_LAZY: $IS_LAZY'
                sh 'echo IS_NOT_LAZY: $IS_NOT_LAZY'
            }
        }
    }
}

[00-build] Running shell script
+ echo IS_LAZY: t
IS_LAZY: t
[Pipeline] sh
[00-build] Running shell script
+ echo IS_NOT_LAZY: t
IS_NOT_LAZY: t