diff --git a/AGENTS.md b/AGENTS.md
index 812753440..47be7374e 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -59,6 +59,8 @@ Git: conventional commit messages. `[skip-sweep]` in the latest PR head commit s
 
 Docs: all contributor-facing docs are bilingual — **every such Markdown doc MUST have a Simplified Chinese version** named `<name>_zh.md` alongside it, with an `English | 中文` switcher at the top. Current pairs: `README.md`/`README_zh.md`, `CONTRIBUTING.md`/`CONTRIBUTING_zh.md`, `docs/PR_REVIEW_CHECKLIST.md`/`docs/PR_REVIEW_CHECKLIST_zh.md`. **Any edit to an English doc MUST be mirrored in its `_zh` counterpart (and vice versa) in the same PR** — same sections, links, badges, images — and a new doc must ship with its `_zh` version in the same PR. Exceptions: agent-instruction files (`AGENTS.md`, `CLAUDE.md`, `KLAUD_DEBUG.md`) and internal references under `.github/`/`utils/` are English-only; the sign-off template inside `docs/PR_REVIEW_CHECKLIST*.md` stays in English verbatim in BOTH versions, because `codeowner-signoff-verify.yml` triggers on its exact English opening phrase.
 
+Checklist ↔ sign-off verifier sync: `docs/PR_REVIEW_CHECKLIST.md` is the source of truth for the merge standard, and `.github/workflows/codeowner-signoff-verify.yml` encodes it as independently-verified checks in its Claude prompt. **Whenever `docs/PR_REVIEW_CHECKLIST.md` is updated — an item added, removed, or materially reworded — agents are allowed and expected to update `codeowner-signoff-verify.yml` to match, ideally in the same PR.** Cosmetic edits (formatting, typos, `_zh` translation sync) need no verifier change. The verifier's Check 5 already compares sign-offs against the live checklist file, so stale sign-off templates are caught automatically — but a new or removed policy item needs its own check logic added to / removed from the workflow prompt. To validate a verifier change: merge it, open a throwaway `[DO NOT MERGE]` test PR, post a sign-off comment (it must contain the exact phrase `As a PR reviewer and CODEOWNER` or the workflow won't trigger), read the posted verdict comment, then close the test PR.
+
 ### Pull Request Sweep Labels
 
 PRs do not run the sweep automatically - `run-sweep.yml` is gated on a primary sweep label. Pick exactly one of the five primary labels below; setting multiple primary labels is rejected by the workflow.