Running checks on a GitHub-hosted runner

Your pull requests are tested on macos-15, the arm64 macOS runner GitHub hosts. You run no Mac, and the runner needs nothing installed beforehand. CI has the parts every host shares: the comment, the report and the flags.

Set it up

From your project’s folder:

mobster ci init --hosted

It writes .github/workflows/mobster.yml and prints what’s left: make a CI token (below), add it as MOBSTER_CI_TOKEN and, for checks with steps, ANTHROPIC_API_KEY as repository secrets, commit the file and open a pull request. --force replaces an existing file, and --print shows the workflow without writing it.

The workflow

.github/workflows/mobster.yml

name: mobster
on: pull_request
permissions:
  contents: read
  pull-requests: write   # the one comment Mobster keeps up to date
concurrency:
  group: mobster-${{ github.event.pull_request.number }}
  cancel-in-progress: true
env:
  MOBSTER: /Applications/Mobster.app/Contents/MacOS/mobster-agent
jobs:
  checks:
    runs-on: macos-15
    timeout-minutes: 60
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0   # the diff needs the base branch
      - name: Install Mobster
        id: mobster
        run: |
          brew install --cask radishsoftware/tap/mobster-app
          echo "version=$(brew list --cask --versions mobster-app | awk '{print $2}')" >> "$GITHUB_OUTPUT"
          echo "xcode=$(xcodebuild -version | head -1 | tr -d ' ')" >> "$GITHUB_OUTPUT"
      - name: Cache WebDriverAgent
        uses: actions/cache@v4
        with:
          path: ~/Library/Application Support/app.mobster.desktop/wda
          key: mobster-wda-${{ runner.arch }}-${{ steps.mobster.outputs.xcode }}-${{ steps.mobster.outputs.version }}
          restore-keys: |
            mobster-wda-${{ runner.arch }}-${{ steps.mobster.outputs.xcode }}-
      - name: Prepare a simulator
        run: |
          "$MOBSTER" sim doctor --fix
      - name: Test what this PR changed
        run: |
          "$MOBSTER" ci run
        env:
          MOBSTER_CI_TOKEN: ${{ secrets.MOBSTER_CI_TOKEN }}
          ANTHROPIC_API_KEY: ${{ secrets.ANTHROPIC_API_KEY }}   # only checks with steps use it
      - name: Upload the report
        id: upload
        if: always()
        uses: actions/upload-artifact@v4
        with:
          name: mobster-report
          path: .mobster/ci/
          retention-days: 14
          if-no-files-found: ignore
      - name: Comment on the PR
        if: always()
        run: |
          "$MOBSTER" ci comment
        env:
          GITHUB_TOKEN: ${{ github.token }}
          MOBSTER_ARTIFACT_URL: ${{ steps.upload.outputs.artifact-url }}

The cache holds the WebDriverAgent build, the slow part of a first job. Its key names the Xcode and Mobster versions, so a new Xcode or a new Mobster builds it once and every job after restores it. The simulator runtimes come with the runner’s Xcode. The job signs in with a CI token, not with Mobster for Mac. It is part of your plan, adds no seat and counts no runs. It licenses simulator checks only (mobster ci run and mobster test), it ends after 90 days unless you choose up to 365, and it never licenses an iPhone. Make one with mobster account ci-token create NAME or in the console under Settings › CI tokens, and revoke it from either. Store it as MOBSTER_CI_TOKEN, as a secret of the service. mobster ci doctor in the job checks that it is live and says what to fix if it isn’t.

What this runner doesn’t do

A hosted Mac has no iPhone, so the checks run on simulators. To test on a phone, use a Mac of yours. A pull request from a fork gets no repository secrets, so the token is empty there: the job says Mobster couldn’t run, and your token never reaches the fork’s code.

Run checks

Run them on every change

Your stack

App Store

Running checks on a GitHub-hosted runner

Set it up

The workflow

What this runner doesn’t do

​Set it up

​The workflow

​Sign in with a CI token

​What this runner doesn’t do

Set it up

The workflow

Sign in with a CI token

What this runner doesn’t do