no-duplicate-composite-step-id

Rule catalog ID: R051

Targeted pattern scope

Composite action runs.steps[*].id declarations.

What this rule reports

Reports duplicate step IDs in composite actions.

Why this rule exists

Duplicate step IDs create ambiguous references and break output wiring.

❌ Incorrect

runs:
  using: composite
  steps:
    - id: setup
      run: echo one
      shell: bash
    - id: setup
      run: echo two
      shell: bash

✅ Correct

runs:
  using: composite
  steps:
    - id: setup
      run: echo one
      shell: bash
    - id: finish
      run: echo two
      shell: bash

Additional examples

For larger repositories, this rule is often enabled together with one of the published presets so violations are caught in pull requests before workflow changes are merged.

ESLint flat config example

import githubActions from "eslint-plugin-github-actions-2";

export default [
  {
    files: ["**/*.{yml,yaml}"],
    plugins: {
      "github-actions": githubActions,
    },
    rules: {
      "github-actions/no-duplicate-composite-step-id": "error",
    },
  },
];

When not to use it

You can disable this rule when its policy does not match your repository standards, or when equivalent enforcement is already handled by another policy tool.

Targeted pattern scope​

What this rule reports​

Why this rule exists​

❌ Incorrect​

✅ Correct​

Additional examples​

ESLint flat config example​

When not to use it​

Further reading​