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Step Templates Now Honor Your Configured Delimiters

· 3 min read
Erik Osterman
Erik Osterman
Founder @ Cloud Posse

The templates.settings.delimiters setting changes the delimiters that Atmos templates use, but it only ever reached stack manifests. Workflow, custom command, and lifecycle hook steps kept parsing {{ }} no matter what you configured. A project that moved to [[ ]] to keep Go-template-looking text such as a docker inspect --format '{{.State.Status}}' argument out of the template engine still had to mark each of those step fields !literal, or fail with a template error.

The Problem​

Configure custom delimiters once:

atmos.yaml
templates:
  settings:
    delimiters: ["[[", "]]"]

Stack manifests then render [[ .vars.stage ]]. A step in a workflow, a custom command, or a lifecycle hook ignored the setting and still rendered {{ .steps.first.value }}. One project could therefore have two template syntaxes depending on where a value was written.

The Fix​

Step templates now use the configured delimiters. With the configuration above:

  • [[ .steps.first.value ]] renders in a step field.
  • {{ .steps.first.value }} stays literal text, so shell commands and scripts can contain it unchanged.

This covers the template fields of every step in workflows, custom commands, and lifecycle hooks, including the children of parallel and matrix steps and the multi-pass rendering that protects flag values from being rendered a second time.

How to Use It​

A custom command using the configured delimiters:

atmos.yaml
templates:
  settings:
    delimiters: ["[[", "]]"]

commands:
  - name: show-container
    steps:
      - name: first
        type: shell
        command: echo first
      - type: shell
        command: |
          echo "got [[ .steps.first.value ]]"
          docker inspect --format '{{.State.Status}}' my-container

The second step prints got first and passes {{.State.Status}} to Docker as written.

Compatibility​

This change is selected by your edition, as of 2026-10-19:

  • Before: workflow, custom command, and hook step templates always used {{ }}, even when templates.settings.delimiters was set.
  • After: step templates use templates.settings.delimiters. Without that setting, or with the default ["{{", "}}"], nothing changes.

The new behavior applies to unpinned projects and to projects pinned to 2026-10-19 or later. To keep the previous behavior, pin an edition before the transition:

atmos.yaml
edition: "2026-10-18"

Projects with custom delimiters that write {{ }} in step fields need one of two changes when they adopt the new behavior: rewrite those fields with the configured delimiters, or keep the earlier pin. Run atmos describe edition to see every behavior an edition pin selects.

Get Involved​

Try custom delimiters in one workflow and share what you find in GitHub Discussions.