feat(agentic): scaffold Code Review Action trigger (NOP)

.github/workflows/auto_assign_reviewer.yml

@@ -0,0 +1,54 @@
+name: Auto-assign Code Review
+
+on:
+  pull_request:
+    types: [opened, ready_for_review]
+
+permissions:
+  contents: read
+  pull-requests: write
+
+concurrency:
+  group: auto-assign-review-${{ github.event.pull_request.number }}
+  cancel-in-progress: false
+
+jobs:
+  assign:
+    runs-on: ubuntu-latest
+    # Self-authored PRs (opened by openlibrary-bot itself) are excluded here --
+    # GitHub rejects requesting a PR's own author as a reviewer (422). Those are
+    # handled directly by code_review_action.yml's own opened/ready_for_review
+    # trigger instead, bypassing the reviewer-request mechanism entirely.
+    if: >
+      !github.event.pull_request.draft &&
+      github.event.pull_request.user.login != 'openlibrary-bot'
+    steps:
+      - name: Request openlibrary-bot as reviewer if not already present
+        uses: actions/github-script@v9
+        with:
+          script: |
+            const owner = context.repo.owner;
+            const repo = context.repo.repo;
+            const prNumber = context.payload.pull_request.number;
+
+            const { data: requested } = await github.rest.pulls.listRequestedReviewers({
+              owner, repo, pull_number: prNumber,
+            });
+            if (requested.users.some((u) => u.login === 'openlibrary-bot')) {
+              core.info(`PR #${prNumber} already has openlibrary-bot requested -- skipping.`);
+              return;
+            }
+
+            const reviews = await github.paginate(github.rest.pulls.listReviews, {
+              owner, repo, pull_number: prNumber, per_page: 100,
+            });
+            if (reviews.some((r) => r.user.login === 'openlibrary-bot')) {
+              core.info(`PR #${prNumber} already has an openlibrary-bot review -- skipping.`);
+              return;
+            }
+
+            await github.rest.pulls.requestReviewers({
+              owner, repo, pull_number: prNumber,
+              reviewers: ['openlibrary-bot'],
+            });
+            core.info(`Requested openlibrary-bot as reviewer on PR #${prNumber}.`);

.github/workflows/code_review_action.yml

@@ -0,0 +1,117 @@
+name: Code Review Action
+
+on:
+  pull_request:
+    types: [review_requested, opened, ready_for_review]
+  issue_comment:
+    types: [created]
+  workflow_dispatch:
+    inputs:
+      pr_number:
+        description: "Debug: manually run the code review trigger on a specific existing PR"
+        required: true
+        type: string
+
+permissions:
+  contents: read
+  pull-requests: write
+  issues: write
+
+concurrency:
+  group: code-review-${{ github.event.pull_request.number || github.event.issue.number || inputs.pr_number }}
+  cancel-in-progress: false
+
+jobs:
+  respond:
+    runs-on: ubuntu-latest
+    # Placeholder scaffold for #13163 -- trigger wiring only, no review logic yet.
+    #
+    # Three trigger paths:
+    #   1. review_requested with openlibrary-bot as the reviewer -- covers both a
+    #      human manually requesting it, and auto_assign_reviewer.yml's automated
+    #      request. No staff-login check here: requesting *any* reviewer already
+    #      requires write/triage access on GitHub's side, so this isn't an open door.
+    #   2. opened / ready_for_review where the PR's own author is openlibrary-bot --
+    #      GitHub rejects requesting a PR's own author as a reviewer (422), so a
+    #      self-authored PR can never reach this workflow via path 1. This is the
+    #      direct substitute for "add openlibrary-bot as a reviewer on its own PR",
+    #      which is not literally possible.
+    #   3. issue_comment @-mention on a PR -- open to any commenter, including
+    #      external contributors with only read access, so this path keeps an
+    #      explicit staff allowlist (mirrors pr_autoresponder.yml / issue_enrichment.md).
+    #
+    # Draft PRs never trigger a review, on any path -- enforced again defensively
+    # inside the job itself (see Step 1), since issue_comment's payload has no
+    # PR draft field to check at the `if:` level.
+    if: >
+      github.event_name == 'workflow_dispatch' ||
+      (
+        github.event_name == 'pull_request' &&
+        !github.event.pull_request.draft &&
+        (
+          github.event.requested_reviewer.login == 'openlibrary-bot' ||
+          github.event.pull_request.user.login == 'openlibrary-bot'
+        )
+      ) || (
+        github.event_name == 'issue_comment' &&
+        github.event.issue.pull_request != null &&
+        contains(github.event.comment.body, '@openlibrary-bot') &&
+        github.event.comment.user.login != 'openlibrary-bot' &&
+        contains(fromJSON('["mekarpeles","cdrini","jimchamp","hornc","scottbarnes","seabelis","RayBB","lokesh"]'), github.event.comment.user.login)
+      )
+    steps:
+      - name: Acknowledge trigger (placeholder -- no review logic yet)
+        uses: actions/github-script@v9
+        with:
+          script: |
+            const owner = context.repo.owner;
+            const repo = context.repo.repo;
+            const prNumber = context.eventName === 'workflow_dispatch'
+              ? Number(context.payload.inputs.pr_number)
+              : (context.payload.pull_request
+                  ? context.payload.pull_request.number
+                  : context.payload.issue.number);
+
+            // Defensive draft check -- issue_comment's payload has no PR draft
+            // field, and this also re-confirms the pull_request-path checks
+            // above in case GitHub's payload state lagged the actual PR state.
+            const { data: pr } = await github.rest.pulls.get({
+              owner, repo, pull_number: prNumber,
+            });
+            if (pr.draft) {
+              core.info(`PR #${prNumber} is a draft -- skipping.`);
+              return;
+            }
+
+            // Idempotency: this workflow can be reached by multiple overlapping
+            // paths (e.g. opened -> auto-assign -> review_requested), so guard
+            // against posting more than one placeholder.
+            const comments = await github.paginate(github.rest.issues.listComments, {
+              owner, repo, issue_number: prNumber, per_page: 100,
+            });
+            if (comments.some((c) => (c.body || '').includes('<!-- ol-pr-review-bot -->'))) {
+              core.info(`PR #${prNumber} already has a placeholder comment -- skipping.`);
+              return;
+            }
+
+            let trigger;
+            if (context.eventName === 'workflow_dispatch') {
+              trigger = 'a manual debug dispatch';
+            } else if (context.eventName === 'issue_comment') {
+              trigger = 'an @-mention';
+            } else if (pr.user.login === 'openlibrary-bot') {
+              trigger = 'its own PR being opened (self-authored, cannot request itself as reviewer)';
+            } else {
+              trigger = 'a reviewer request';
+            }
+
+            await github.rest.issues.createComment({
+              owner, repo, issue_number: prNumber,
+              body: [
+                `👀 Code review was requested via ${trigger}, but the automated reviewer isn't built yet — tracked in #13163.`,
+                '',
+                'This comment only confirms the trigger fired correctly. No review was performed.',
+                '',
+                '<!-- ol-pr-review-bot -->',
+              ].join('\n'),
+            });