diff --git a/.changeset/6208-worktree-recipe-fetch-base.md b/.changeset/6208-worktree-recipe-fetch-base.md
new file mode 100644
index 0000000000..71c1fe61df
--- /dev/null
+++ b/.changeset/6208-worktree-recipe-fetch-base.md
@@ -0,0 +1,25 @@
+---
+---
+
+Instruction-file and PreToolUse-hook prose only: no published package's `src/` changed, so
+nothing ships.
+
+The documented worktree recipe branched off the **local** `main` ref, which nothing in the
+recipe or its surrounding prose fetches. A worktree created by following it literally starts
+as far back as whoever last happened to update that ref — and on a long-lived shared
+checkout, nobody has a reason to. `origin/main` alone would carry the same defect one layer
+down (it too is a local ref only a fetch moves), so each in-scope site now begins with an
+explicit `git fetch origin main &&` and names `origin/main` as the base:
+
+```
+git fetch origin main && git worktree add ../<repo>-<task> -b <branch> origin/main && cd ../<repo>-<task> && pnpm install
+```
+
+Four sites repaired — `CLAUDE.md`, `AGENTS.md` §9 多 agent 协作纪律, and the recipe both
+worktree guards print when they block an edit (`.claude/hooks/guard-main-checkout.sh`,
+`.claude/hooks/guard-main-checkout-bash.sh`), which is the copy an agent is most likely to
+run verbatim. The two `-cmp` comparison-tree lines are unchanged: they take an explicit ref
+from the caller and are correct as written.
+
+Ports the repair landed upstream in objectstack#11934 (objectstack#11540); this repo's copy
+was deliberately left to this card. Net ±0 lines on every file touched.
diff --git a/.claude/hooks/guard-main-checkout-bash.sh b/.claude/hooks/guard-main-checkout-bash.sh
index fc144fbff5..5f05a8d4cf 100755
--- a/.claude/hooks/guard-main-checkout-bash.sh
+++ b/.claude/hooks/guard-main-checkout-bash.sh
@@ -541,7 +541,7 @@ only, so the identical edit expressed as a shell command used to slip through in
 its HEAD switched and its tree reset under you, clobbering uncommitted work. A feature
 branch on the shared checkout is NOT enough; you need a dedicated worktree:
 
-  git worktree add ../${name}-<task> -b <branch> main
+  git fetch origin main && git worktree add ../${name}-<task> -b <branch> origin/main
   cd ../${name}-<task> && pnpm install    # then re-run the command there
 
 Always fine, no flag needed:
diff --git a/.claude/hooks/guard-main-checkout.sh b/.claude/hooks/guard-main-checkout.sh
index b68dd4f8de..fa238bf061 100755
--- a/.claude/hooks/guard-main-checkout.sh
+++ b/.claude/hooks/guard-main-checkout.sh
@@ -54,7 +54,7 @@ This repo is edited by multiple agents at once — the shared checkout gets its
 switched and tree reset under you, silently clobbering uncommitted work. A feature
 branch on the shared checkout is NOT enough; you must be in a dedicated worktree:
 
-  git worktree add ../${name}-<task> -b <branch> main
+  git fetch origin main && git worktree add ../${name}-<task> -b <branch> origin/main
   cd ../${name}-<task> && pnpm install    # then re-run your edits there
 
 This guard checks the edited file's OWN repo, so sibling repos are covered too.
diff --git a/AGENTS.md b/AGENTS.md
index 23898bbe5b..1e51e56381 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -231,7 +231,7 @@ AGENTS.md 的「只跑受影响的包」指的是**用上面的路径过滤缩
 本仓库有**多个 agent 并行**修改 —— 分支会被切换、共享文件会在你工作时被改动(正常现象,不是 bug):
 
 - **只改你任务需要的文件**;别去"修"无关的 diff、回退或别人的在途编辑,也别管整棵工作树。
-- **必须一个任务一个 git worktree**(`git worktree add ../objectui-<task> -b <branch> main`,新树里跑 `pnpm install`)做物理隔离 —— 这是强制而非「首选」。共享的 `main` checkout **不是**可用退路:HEAD 会被别的 agent 切换、你刚写的文件会在操作中途被 reset 掉。一个 **PreToolUse 钩子**(`.claude/hooks/guard-main-checkout.sh`)**强制**此规则:除非被编辑文件位于专属 **worktree** 否则拦截 `Edit`/`Write`/`NotebookEdit`——在共享 checkout 上开 feature 分支**也不行**(仍会被切走),且按**被编辑文件所属的仓库**判断(sibling 仓 `framework`/`cloud` 一并守住)(确属非任务的临时改动用 `OS_ALLOW_MAIN_EDITS=1` 放行)。即便在自己的 worktree 里,下面这些防御性条款仍然适用。
+- **必须一个任务一个 git worktree**(`git fetch origin main && git worktree add ../objectui-<task> -b <branch> origin/main`,新树里跑 `pnpm install`)做物理隔离 —— 这是强制而非「首选」。共享的 `main` checkout **不是**可用退路:HEAD 会被别的 agent 切换、你刚写的文件会在操作中途被 reset 掉。一个 **PreToolUse 钩子**(`.claude/hooks/guard-main-checkout.sh`)**强制**此规则:除非被编辑文件位于专属 **worktree** 否则拦截 `Edit`/`Write`/`NotebookEdit`——在共享 checkout 上开 feature 分支**也不行**(仍会被切走),且按**被编辑文件所属的仓库**判断(sibling 仓 `framework`/`cloud` 一并守住)(确属非任务的临时改动用 `OS_ALLOW_MAIN_EDITS=1` 放行)。即便在自己的 worktree 里,下面这些防御性条款仍然适用。
 - **绝不 `git stash` —— stash 栈不在上一条的 worktree 隔离范围内。** `git stash` 把栈存在**共享 `.git` 目录**里的 `refs/stash`,**每个 worktree 共用同一个 LIFO 栈**:上一条的物理隔离**不覆盖它**。两个 agent 各自在自己的 worktree 里 stash,push/pop 的是同一个栈 —— 你的 `pop` 取回的是对方刚压进去的改动,你自己的改动留在栈上等着被对方取走;而 `pop` **报成功**,唯一的症状是别人的文件出现在你的 `git status` 里,随后一次 `git add -A` 就把对方的在途工作合进了你的 PR。不是假想:objectui#3430 两个并行 agent 在反向验证中间踩实,双方在途改动都丢了(只能作为 unreachable commit 捞回)。替代做法只有下面这些 —— 都不碰共享状态,都在你自己的 worktree 内,且**首选先 commit 再还原**(上面反向验证那条已把它定为标准写法):
 
   ```bash
diff --git a/CLAUDE.md b/CLAUDE.md
index c0cb4ea0c4..de3a86e4b0 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -13,7 +13,7 @@ shared checkout is NOT enough** — it still gets switched under you. You MUST b
 **dedicated per-task worktree**:
 
 ```
-git worktree add ../<repo>-<task> -b <branch> main && cd ../<repo>-<task> && pnpm install
+git fetch origin main && git worktree add ../<repo>-<task> -b <branch> origin/main && cd ../<repo>-<task> && pnpm install
 ```
 
 Make all edits there, **one worktree per repo** a task spans. A PreToolUse hook