claude-code-review-run.yml

name: Claude Code Review (run)

# Stage 2 (privileged): triggered when the "Claude Code Review" workflow above
# completes. workflow_run executes in the base-repo context, so it has access
# to secrets and id-token even for PRs from forks. This is what makes reviewing
# external contributors' PRs possible.
#
# Security: the triggering workflow file is fork-controlled, so the uploaded
# artifact is untrusted. We validate the PR number is purely numeric before
# using it, and we only check out the base ref (never the PR head into the
# workspace root) so untrusted code is never executed here. See
# https://securitylab.github.com/research/github-actions-preventing-pwn-requests/
on:
  workflow_run:
    workflows: ["Claude Code Review"]
    types: [completed]

jobs:
  gate:
    # Only react to PR runs that finished successfully.
    if: >
      github.event.workflow_run.event == 'pull_request' &&
      github.event.workflow_run.conclusion == 'success'
    runs-on: ubuntu-latest
    permissions:
      actions: read
    outputs:
      number: ${{ steps.read.outputs.number }}
      found: ${{ steps.check.outputs.found }}
    steps:
      - name: Check for PR-number artifact
        id: check
        uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v7
        with:
          script: |
            const { data } = await github.rest.actions.listWorkflowRunArtifacts({
              owner: context.repo.owner,
              repo: context.repo.repo,
              run_id: context.payload.workflow_run.id,
            });
            core.setOutput('found', data.artifacts.some(a => a.name === 'pr-number') ? 'true' : 'false');

      - name: Download PR number
        if: steps.check.outputs.found == 'true'
        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v4
        with:
          name: pr-number
          run-id: ${{ github.event.workflow_run.id }}
          github-token: ${{ secrets.GITHUB_TOKEN }}

      - name: Read and validate PR number
        id: read
        if: steps.check.outputs.found == 'true'
        run: |
          num="$(cat pr-number.txt)"
          # Artifact comes from the fork-controlled trigger workflow — never trust it blindly.
          if ! [[ "$num" =~ ^[0-9]+$ ]]; then
            echo "Refusing to proceed: PR number is not numeric ($num)" >&2
            exit 1
          fi
          echo "number=$num" >> "$GITHUB_OUTPUT"

  claude-review:
    needs: gate
    if: needs.gate.outputs.found == 'true'
    runs-on: ubuntu-latest
    permissions:
      contents: read
      pull-requests: write # post the review on the PR
      issues: read
      id-token: write
      statuses: write # mirror the review result onto the PR head commit
    concurrency:
      group: claude-review-run-${{ needs.gate.outputs.number }}
      cancel-in-progress: true
    steps:
      # workflow_run runs are detached and never show up in the PR's checks, so
      # publish a commit status on the PR head SHA. This surfaces a "Claude Code
      # Review" check next to the regular CI jobs.
      - name: Report review pending
        uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v7
        with:
          script: |
            await github.rest.repos.createCommitStatus({
              owner: context.repo.owner,
              repo: context.repo.repo,
              sha: context.payload.workflow_run.head_sha,
              context: 'Claude Code Review',
              state: 'pending',
              description: 'Review in progress',
              target_url: `${context.serverUrl}/${context.repo.owner}/${context.repo.repo}/actions/runs/${context.runId}`,
            });

      # Default checkout (base ref) only — do NOT check out the untrusted PR head.
      - name: Checkout repository
        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v4
        with:
          fetch-depth: 1

      - name: Run Claude Code Review
        id: review
        continue-on-error: true # always report status below, even on failure
        # pinned: v1 (Claude Code 2.1.216) fails every Bash call with
        # "bwrap: Can't create file at /home/.mcp.json: Permission denied"
        uses: anthropics/claude-code-action@a874e9ecd7bb36efdad65429c6b35815f5a08f10 # v1 @ 2.1.215
        with:
          claude_code_oauth_token: ${{ secrets.CLAUDE_CODE_OAUTH_TOKEN }}
          # Provided explicitly so the review can post on fork PRs; also required
          # for allowed_non_write_users to take effect.
          github_token: ${{ secrets.GITHUB_TOKEN }}
          # Review PRs from external contributors who lack write access. The diff
          # is fetched read-only and never executed; the subprocess env is scrubbed.
          allowed_non_write_users: "*"
          # review dependency bumps opened by Dependabot
          allowed_bots: "dependabot[bot]"
          plugin_marketplaces: "https://github.com/anthropics/claude-code.git"
          plugins: "code-review@claude-code-plugins"
          # --comment lets the plugin post to the PR; without it the review only
          # prints to the hidden CI log. By default the plugin also posts a "No
          # issues found" summary on clean reviews - the override below drops that
          # so a comment appears only when there are actual findings.
          prompt: |
            /code-review:code-review ${{ github.repository }}/pull/${{ needs.gate.outputs.number }} --comment

            Only post a PR comment if you find issues. If the review is clean with
            no findings, do not post any comment - skip the "No issues found"
            summary and stop silently.
          # See https://github.com/anthropics/claude-code-action/blob/main/docs/usage.md
          # or https://code.claude.com/docs/en/cli-reference for available options

      - name: Report review result
        if: always()
        env:
          OUTCOME: ${{ steps.review.outcome }}
        uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v7
        with:
          script: |
            const ok = process.env.OUTCOME === 'success';
            await github.rest.repos.createCommitStatus({
              owner: context.repo.owner,
              repo: context.repo.repo,
              sha: context.payload.workflow_run.head_sha,
              context: 'Claude Code Review',
              state: ok ? 'success' : 'failure',
              description: ok ? 'Review complete' : 'Review failed',
              target_url: `${context.serverUrl}/${context.repo.owner}/${context.repo.repo}/actions/runs/${context.runId}`,
            });
            if (!ok) core.setFailed('Claude Code Review failed');