diff --git a/skills/github-project/references/actionlint-guide.md b/skills/github-project/references/actionlint-guide.md
index 5164e93..af63ce0 100644
--- a/skills/github-project/references/actionlint-guide.md
+++ b/skills/github-project/references/actionlint-guide.md
@@ -459,3 +459,20 @@ Complex matrix expressions with `fromJSON()` may cause type-check warnings. Thes
 ignore:
   - 'fromJSON'
 ```
+
+### yamllint `empty-lines` rejects trailing blank lines
+
+Unrelated to actionlint itself, but bites right next to it in CI: if you run `yamllint` in the same lane, its default `empty-lines` rule rejects a file that ends with more than one newline. Workflow files end with exactly one newline.
+
+Generators that use `echo "$CONTENT" > file.yml` frequently add a trailing blank; prefer:
+
+```bash
+printf '%s\n' "$CONTENT" > file.yml
+```
+
+Verify after writing:
+
+```bash
+# Bytes at end of file — should be `0a` (one newline), not `0a0a`.
+tail -c 2 file.yml | xxd -p
+```
diff --git a/skills/github-project/references/auto-merge-guide.md b/skills/github-project/references/auto-merge-guide.md
index 27539fd..047f094 100644
--- a/skills/github-project/references/auto-merge-guide.md
+++ b/skills/github-project/references/auto-merge-guide.md
@@ -122,6 +122,48 @@ For each unresolved thread:
 
 **Re-sweep after follow-up PRs merge.** Copilot often reviews the follow-up PR itself and posts new threads. The sweep isn't one-shot — run it again until the count hits zero across all touched PRs.
 
+## CI Annotations — Always Check Before Declaring a PR Clean
+
+CI checks can report `success` at the status-run level while still emitting **warning annotations** (typical for actionlint / shellcheck via reviewdog, CodeQL deprecation notices, YAML-lint). These annotations don't show up in `gh pr checks` or in the PR summary page — they only appear on the job's detail page or on the Files-Changed tab. Declaring a PR "clean" based on `gh pr checks` alone leaves real findings un-addressed.
+
+**Check explicitly:**
+
+```bash
+# Annotations on a specific check run:
+gh api repos/OWNER/REPO/check-runs/CHECK_RUN_ID/annotations --jq \
+  '.[] | {message, annotation_level, path, start_line}'
+
+# All check runs for a commit that have any annotations:
+gh api "repos/OWNER/REPO/commits/SHA/check-runs" --jq \
+  '.check_runs[] | select(.output.annotations_count > 0) |
+   {name, annotations: .output.annotations_count}'
+```
+
+**Make warnings blocking.** reviewdog-based linters default to posting warnings that don't fail the workflow. Configure them to fail:
+
+```yaml
+- uses: reviewdog/action-actionlint@v1   # or -shellcheck, -yamllint, etc.
+  with:
+    fail_level: error
+```
+
+`fail_level: error` is the modern input; the deprecated `fail_on_error` + `level` combination still works but is going away. When a new reviewdog-based linter is added, grep the caller for `fail_level:` and set it to `error` up front — otherwise real findings silently accumulate.
+
+## CI Re-runs Replay the Same Commit
+
+`gh run rerun <run-id>` **re-executes the ORIGINAL commit SHA**, not `HEAD`. If you push a fix and re-run a failed old workflow, the rerun still fails against the pre-fix code.
+
+**Right way:** push the fix, then either wait for the automatic run triggered by the push, or re-run the LATEST run:
+
+```bash
+# Latest run ID for a workflow on a branch:
+gh api "repos/OWNER/REPO/actions/runs?per_page=5" --jq \
+  '.workflow_runs[] | select(.name == "CI") | {id, head_sha: .head_sha[:7]}' \
+  | head -1
+
+gh api repos/OWNER/REPO/actions/runs/RUN_ID/rerun -X POST
+```
+
 ## Merge Queue Behavior and Pitfalls
 
 ### Sequential Processing
diff --git a/skills/github-project/references/merge-strategy.md b/skills/github-project/references/merge-strategy.md
index 31b6cb8..b8c344a 100644
--- a/skills/github-project/references/merge-strategy.md
+++ b/skills/github-project/references/merge-strategy.md
@@ -164,6 +164,26 @@ EOF
 
 **Fix:** Update auto-merge workflow to use `--merge` flag instead of `--rebase` or `--squash`.
 
+### Rulesets cannot block merge on a pending review
+
+Neither branch protection nor rulesets support "block merge while any requested reviewer hasn't submitted yet". The options available are adjacent but not equivalent:
+
+| Setting | What it does | Not what you want |
+|---|---|---|
+| `required_approving_review_count: 1` | Needs **one approval** | Doesn't wait for other requested reviewers |
+| `required_review_thread_resolution: true` | Blocks on **unresolved threads** | Doesn't block before any thread is created |
+
+If you need to hold merge until Copilot (or any other requested reviewer) has actually posted its review, the workaround is a custom GitHub Actions status check that queries pending reviewers and fails if any are outstanding — then require that check in branch protection.
+
+```bash
+# Example: fail the check if any reviewer is still requested.
+pending=$(gh api "repos/$REPO/pulls/$PR" --jq '.requested_reviewers | length')
+if [[ "$pending" -gt 0 ]]; then
+  echo "::error::Still waiting on $pending requested reviewer(s)"
+  exit 1
+fi
+```
+
 ## References
 
 - [GitHub Branch Protection](https://docs.github.com/en/repositories/configuring-branches-and-merges-in-your-repository/managing-protected-branches)
diff --git a/skills/github-project/references/multi-repo-operations.md b/skills/github-project/references/multi-repo-operations.md
index 3e13e33..4bc754c 100644
--- a/skills/github-project/references/multi-repo-operations.md
+++ b/skills/github-project/references/multi-repo-operations.md
@@ -26,6 +26,40 @@ name specific repos to skip.)
 
 Wait for "go" (or an equivalent affirmative). Silence is not approval.
 
+## Pre-Flight Per-Repo Checks
+
+Before touching each repo in the batch, check three things the dry-run manifest won't catch — they tend to surface as 30 silent failures across a fleet loop:
+
+### 1. Default branch name
+
+Not every repo uses `main`. Some legacy repos are on `master`; forks can be on anything.
+
+```bash
+DEFAULT_BRANCH=$(gh api "repos/$REPO" --jq '.default_branch')
+```
+
+Use `$DEFAULT_BRANCH` everywhere a script would otherwise hard-code `main`. Pushing to the wrong branch either silently creates a new branch or fails with a confusing rejection.
+
+### 2. Archived repos
+
+Archived repos reject most writes with a generic permission error. Dependabot/Renovate sometimes still open PRs on them (via the pre-archive config), and a batch loop that tries to merge them fails cryptically.
+
+```bash
+ARCHIVED=$(gh api "repos/$REPO" --jq '.archived')
+if [[ "$ARCHIVED" == "true" ]]; then
+  # Skip, or handle specially: unarchive → close PR → re-archive.
+  continue
+fi
+```
+
+Never enable auto-merge on archived repos — the auto-merge plumbing fails at set-up time with "archived" errors.
+
+### 3. Contents API vs branch protection
+
+`gh api -X PUT repos/.../contents/...` is the fastest path for tiny single-file edits across a fleet — but it returns HTTP 409 on any repo that requires PRs, a merge queue, or signed commits. If your batch mixes repos with and without branch protection, this path breaks mid-loop and leaves half the fleet updated.
+
+**Safer default for batch file edits**: open a one-commit PR per repo even when the Contents API would work. Gives you a reviewable diff, matches any future signing/protection rule tightening, and keeps behavior consistent across the fleet.
+
 ## Parallel PR Rebasing
 
 For N PRs that need rebasing on their default branches, dispatch parallel subagents — one per PR — with failure isolation.