Hi @jacovangelder , I have created a `variables.yaml` file i.e.

 
variables:
  job_cluster_key:
    description: Databricks job cluster
    default: job_cluster

 

and while I am trying to refer this variable in my `job.yaml` file like this:

tasks:
        - task_key: Sum_Task
          job_cluster_key: ${var.job_cluster_key}
          spark_python_task:
            python_file: ../src/sum.py
 
and when I tried to validate it using `databricks bundle validate`, I got this error:
 
**Error: reference does not exist: ${variables.job_cluster_key}**
 
However, when I added variables in the same job.yaml file it is validated successfully.
 
Any reasons, why is that?