# stack

The workflow-level `stack` field sets the default Atmos stack applied to every `type: atmos` step in the workflow.

```yaml
workflows:
  deploy-vpc:
    stack: tenant1-ue2-dev
    steps:
      - command: terraform plan vpc
      - command: terraform apply vpc -auto-approve
```

## Precedence

Stack values are resolved from lowest to highest priority:

1. Stack flags embedded in the step `command`.
2. Workflow-level `stack`.
3. Step-level `stack`.
4. The command-line `--stack` flag.

Prefer reusable workflows that omit `stack` and receive it from the command line when the same workflow should run across environments.