argo-cd/docs/user-guide/build-environment.md

Build Environment

Custom tools, Helm, Jsonnet, and Kustomize support the following build env vars:

Variable	Description
ARGOCD_APP_NAME	The name of the application.
ARGOCD_APP_NAMESPACE	The destination namespace of the application.
ARGOCD_APP_PROJECT_NAME	The name of the project the application belongs to.
ARGOCD_APP_REVISION	The resolved revision, e.g. f913b6cbf58aa5ae5ca1f8a2b149477aebcbd9d8.
ARGOCD_APP_REVISION_SHORT	The resolved short revision, e.g. f913b6c.
ARGOCD_APP_REVISION_SHORT_8	The resolved short revision with length 8, e.g. f913b6cb.
ARGOCD_APP_SOURCE_PATH	The path of the app within the source repo.
ARGOCD_APP_SOURCE_REPO_URL	The source repo URL.
ARGOCD_APP_SOURCE_TARGET_REVISION	The target revision from the spec, e.g. master.
KUBE_VERSION	The semantic version of Kubernetes without trailing metadata.
KUBE_API_VERSIONS	The version of the Kubernetes API.

In case you don't want a variable to be interpolated, $ can be escaped via $$.

command:
  - sh
  - -c
  - |
    echo $$FOO