How to Create a Composite Action in GitHub Actions

A composite action packages multiple steps behind a single uses reference you can share across repos.

Create an action.yml with runs.using: composite and a steps: list. Call it from any workflow with uses: pointing at the action path.

Steps

• Create action.yml in a folder (e.g. .github/actions/setup).
• Set runs.using: composite and list steps:.
• Declare inputs: and reference them as ${{ inputs.<name> }}.

action.yml

name: 'Setup project'
inputs:
  node-version:
    default: '20'
runs:
  using: composite
  steps:
    - uses: actions/setup-node@v4
      with:
        node-version: ${{ inputs.node-version }}
    - run: npm ci
      shell: bash

Gotchas

• Every run: step in a composite action must declare a shell:.
• Reference the action with uses: ./.github/actions/setup from a workflow.

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