jenkins pipeline step to run a command in second container when first container generates a file

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Team,

my goal is to write from container that is spin using jenkinspipeline to the host file.

I have a use case where I am performing a test of code in one container main and this generates a file in volume mounted emptydir on both the containers as you will see the pod spec and then I want to run a scan on the code with that generated file as a parameter such that scan posts results to server with the code coverage results.
The unit-tests.sh creates a file myfile under /coverage-data path in main from where scan container is to read.

I have two concerns
1 - my pipeline is failing with below syntax error.
2 - I did not test my logic yet due to 1 error above but am I on right track? like checking the condition COVERAGE_FILE which is set by container main if it generates file and writes on share emptydir?

org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
Only one agent type is allowed per agent section 
       agent {
       ^

: No agent type specified. Must be one of [any, kubernetes, label, none] 
       agent {
       ^
2 errors

ex: main container to run code coverage then in sonar-scan container pipeline runs a command to scan

jenkinsfile


pipeline {
    agent {
        label 'label-coverage-cli'
        docker {
            args '-v /:/hosts-root/'
        }
    }

    environment {
        COVERAGE_FILE = fileExists '/coverage-data/myfile'
    }

    stages {
        stage('Code Coverage Tests') {
            steps {
                container('main') {
                        sh '''
                        unit-tests.sh
                        '''.stripIndent()
                }
            }
        }
        stage('Code Coverage Scan') {
            when { expression { COVERAGE_FILE == 'true' } }
            steps {
                container('sonar-scan') {
                        sh '''
                        src/ui/scripts/ci/scan.sh
                        '''.stripIndent()
                }
            }
        }
    }
}

pod template for jenkins

apiVersion: v1
kind: Pod
spec:
  imagePullSecrets:
    - name: artifactory-build-project
  volumes:
    - name: shared-data
      emptyDir: {}
  containers:
    - name: main
      image: registry/tci-sonar-scanner:latest
      resources:
        requests:
          memory: 32Gi
          cpu: 18
        limits:
          memory: 48Gi
          cpu: 24
      volumeMounts:
      - name: shared-data
        mountPath: /coverage-data
      command:
        - /sbin/tini
      args:
        - --
        - sleep
        - infinity
    - name: sonar-scanner
      image: registry/sonarqube-scanner:4.7.0.2747
      resources:
        requests:
          memory: 12Gi
          cpu: 8
        limits:
          memory: 18Gi
          cpu: 12
      volumeMounts:
      - name: shared-data
        mountPath: /coverage-data
      securityContext:
        privileged: true
      command:
        - tail
      args:
      - "-f"
      - "/dev/null"