Resilient PR homepage screenshot publishing with token fallback

.github/scripts/publish_pr_homepage_screenshot.js

@@ -16,7 +16,10 @@ const sha = process.env.GITHUB_SHA;
 const prNumber = process.env.PR_NUMBER;
 const prHeadRef = process.env.PR_HEAD_REF;
 
-if (!token) throw new Error('GITHUB_TOKEN or GH_TOKEN is required.');
+if (!token) {
+  console.warn('Warning: GITHUB_TOKEN or GH_TOKEN is not set. Skipping PR screenshot publish step.');
+  process.exit(0);
+}
 if (!repository || !prNumber || !runId || !prHeadRef || !sha) {
   throw new Error('Missing one or more required GitHub environment variables.');
 }

.github/workflows/pr_frontend_e2e.yml

@@ -67,7 +67,7 @@ jobs:
       - name: Publish screenshot to PR comment
         if: github.event_name == 'pull_request' && github.event.pull_request.head.repo.fork == false
         env:
-          GITHUB_TOKEN: ${{ secrets.CRAZYGO_PAT }}
+          GITHUB_TOKEN: ${{ secrets.GH_TOKEN || github.token }}
           GITHUB_REPOSITORY: ${{ github.repository }}
           GITHUB_RUN_ID: ${{ github.run_id }}
           GITHUB_SHA: ${{ github.sha }}

docs/plans/2026-04-02-14-20-UTC-pr-homepage-screenshot-token-fallback.md

@@ -0,0 +1,24 @@
+# Background
+The `PR Frontend E2E` workflow can fail in the `Publish screenshot to PR comment` step when no dedicated PAT-like secret is configured. The publish script currently throws immediately if neither `GITHUB_TOKEN` nor `GH_TOKEN` is present, which causes the job to fail even though screenshot generation itself succeeded.
+
+# Goals
+1. Prevent false-negative workflow failures caused by missing optional custom token configuration.
+2. Keep PR screenshot publishing functional by using built-in GitHub token fallbacks.
+3. Provide clearer script behavior when no token is available.
+
+# Implementation Plan (phased)
+## Phase 1: Workflow token fallback
+- Update `.github/workflows/pr_frontend_e2e.yml` so the publish step injects `GITHUB_TOKEN` from a fallback chain (`GH_TOKEN`, then default `github.token`).
+
+## Phase 2: Script resilience
+- Update `.github/scripts/publish_pr_homepage_screenshot.js` to avoid hard failure when no token is available.
+- Add a warning and exit successfully when token is missing so E2E validation/artifact upload still pass.
+
+## Phase 3: Validation
+- Run targeted checks (`node --check`) for the updated script and verify git diff for workflow/script consistency.
+
+# Acceptance Criteria
+1. A PR run without custom PAT configuration no longer fails solely due to missing token in screenshot publish step.
+2. Screenshot publish step still attempts to post/update PR comment when any valid token is available.
+3. If no token is present, logs show a clear warning and the step exits without failing the full workflow.
+4. Updated script passes `node --check .github/scripts/publish_pr_homepage_screenshot.js`.