diff --git a/.agents/notes/implemented/architecture/2026-08-03-per-session-agent-presets.i18n.yaml b/.agents/notes/implemented/architecture/2026-08-03-per-session-agent-presets.i18n.yaml
index 07a35fa473..db91c82d4c 100644
--- a/.agents/notes/implemented/architecture/2026-08-03-per-session-agent-presets.i18n.yaml
+++ b/.agents/notes/implemented/architecture/2026-08-03-per-session-agent-presets.i18n.yaml
@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write .agents/notes/implemented/architecture/2026-08-03-per-session-agent-presets.md
-2026-08-03-per-session-agent-presets.md: ee6303e5f52234d7eaf6768043c92a15e4e5399f
-2026-08-03-per-session-agent-presets.zh.md: 5a2e1c3d8d0564f06c75785e1080b53740751355
+2026-08-03-per-session-agent-presets.md: dbe4188fe16a01b51f01cddf8a2387471e5e00a9
+2026-08-03-per-session-agent-presets.zh.md: aa7792a7db3a686b74f19ace130ad8f7b6d2feb6
diff --git a/.agents/notes/implemented/architecture/2026-08-03-per-session-agent-presets.md b/.agents/notes/implemented/architecture/2026-08-03-per-session-agent-presets.md
index ee6303e5f5..dbe4188fe1 100644
--- a/.agents/notes/implemented/architecture/2026-08-03-per-session-agent-presets.md
+++ b/.agents/notes/implemented/architecture/2026-08-03-per-session-agent-presets.md
@@ -29,6 +29,8 @@ Mounting is per-session by default. Measured cost for a twelve-row composition i
 
 **A directly-plugged subtree is invisible to the boot audit.** It never links itself to an `Entry`, so it is absent from `ctx.loader.entries()` and `assertEntriesActivated` cannot see it. The mount audits its own rows instead, reading the tree through an `Include` subclass that publishes it.
 
+**A preset can only name a group because the app registers one.** Sharing a realm across rows is a `cordis:group` row, and a preset living outside this workspace — the authored ones under the Harness home, which is the point — cannot resolve `@cordisjs/plugin-group` by name: Node's upward `node_modules` walk never reaches the harness from there. `boot()` therefore registers `cordis:group` beside `cordis:include` as a loader builtin, so both load through the ambient module pipeline rather than through the included tree's own specifier resolution. Without it the `isolate` vocabulary above is expressible one row at a time only, and a provider could never be grouped with its consumers.
+
 **A preset may not publish into the root service realm.** Such a service is process-global rather than per-session, so the second session mounting the same preset collides with the first — and the collision surfaces as an unhandled rejection that `setup` never observes, leaving a half-composed agent that looks healthy. The mount rejects it instead, and the package invariant re-checks on every service notification because a row publishing from a timer or an asynchronous continuation would escape a one-shot audit.
 
 **Failure rolls the agent back.** `setup` runs before publication, so a rejected mount fails `ctx.agents.create()` and leaves nothing behind. This is why `setup` is the one supported call site.
diff --git a/.agents/notes/implemented/architecture/2026-08-03-per-session-agent-presets.zh.md b/.agents/notes/implemented/architecture/2026-08-03-per-session-agent-presets.zh.md
index 5a2e1c3d8d..aa7792a7db 100644
--- a/.agents/notes/implemented/architecture/2026-08-03-per-session-agent-presets.zh.md
+++ b/.agents/notes/implemented/architecture/2026-08-03-per-session-agent-presets.zh.md
@@ -29,6 +29,8 @@ Status: implemented
 
 **直接挂载的子树对启动审计不可见。** 它不会把自己关联到 `Entry`，因此不在 `ctx.loader.entries()` 中，`assertEntriesActivated` 也看不到它。改由挂载过程自行校验各行，通过一个会公开自身 tree 的 `Include` 子类读取。
 
+**preset 能写出 group，是因为 app 注册了它。** 跨行共享 realm 就是一个 `cordis:group` 行，而住在本工作区之外的 preset——也就是 Harness home 下由人或 agent 创作的那些，正是这套设计的目的——无法按名字解析 `@cordisjs/plugin-group`：Node 向上查找 `node_modules` 的路径从那里永远走不到 harness。因此 `boot()` 把 `cordis:group` 与 `cordis:include` 并排注册为 loader builtin，两者都经由环境模块管线加载，而不依赖被包含树自身的说明符解析。没有它，上文那套 `isolate` 词汇就只能一行一行地表达，提供方也永远无法与它的消费方归入同一组。
+
 **preset 不得把服务发布进根 realm。** 这类服务是进程级全局而非按会话的，因此第二个挂载同一 preset 的会话会与第一个相撞——而这次相撞表现为 `setup` 永远观察不到的未处理 rejection，留下一个看起来健康、实则组装到一半的 agent。挂载改为直接拒绝它；本包的运行时不变量还会在每次服务通知时复查，因为从定时器或异步续体中发布的行会绕过一次性审计。
 
 **失败会让 agent 回滚。** `setup` 在发布之前运行，因此挂载被拒绝会让 `ctx.agents.create()` 失败且不留残留。这正是 `setup` 是唯一受支持调用点的原因。
diff --git a/packages/preset/agent-presets/README.i18n.yaml b/packages/preset/agent-presets/README.i18n.yaml
index b27e89ec7b..da74ba925a 100644
--- a/packages/preset/agent-presets/README.i18n.yaml
+++ b/packages/preset/agent-presets/README.i18n.yaml
@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/preset/agent-presets/README.md
-README.md: 5d66c23f24717d1c30a9e729c7b0528715692d41
-README.zh.md: 9cdcd8b11a8a37d6d789c393e9a1500e4fbfd503
+README.md: e53a52f145b3f66ab115b93c614561fed8194719
+README.zh.md: 39b470002816f309c8ec9af1d72e04495b020ad7
diff --git a/packages/preset/agent-presets/README.md b/packages/preset/agent-presets/README.md
index 5d66c23f24..e53a52f145 100644
--- a/packages/preset/agent-presets/README.md
+++ b/packages/preset/agent-presets/README.md
@@ -58,5 +58,4 @@ Prefix-stable for the life of an agent: a composition is installed once, before
 
 - **A preset cannot be changed on a live agent** — the mount happens once during creation, so switching a running session's composition would mean unwinding its subtree mid-turn, dropping tools the model may already have called. Changing the default affects only sessions created afterwards.
 - **Display names are the directory id** — a preset carries no manifest, so pickers and settings surfaces show the id until a consumer needs richer metadata.
-- **`isolate` realms cannot be expressed across rows without `cordis:group`** — an entry-local realm works on a single row, but grouping a provider with its consumers under one shared realm needs the group builtin, which `dsh-app-boot` does not register.
 - **Root scans are not watched** — every read hits the filesystem instead, which keeps the roster fresh but puts one `readdir` per root on each `list()`.
diff --git a/packages/preset/agent-presets/README.zh.md b/packages/preset/agent-presets/README.zh.md
index 9cdcd8b11a..39b4700028 100644
--- a/packages/preset/agent-presets/README.zh.md
+++ b/packages/preset/agent-presets/README.zh.md
@@ -58,5 +58,4 @@ Indirectly, through the plugins a mounted composition registers, which own every
 
 - **无法在存活的 agent 上更换 preset** —— 挂载只在创建时发生一次，因此切换运行中会话的组装意味着要在轮次进行途中卸载其子树，抽走模型可能已经调用的工具。更改默认值只影响此后创建的会话。
 - **展示名称就是目录 id** —— preset 不携带 manifest，因此选择器与设置界面在有消费方需要更丰富的元数据之前，只显示 id。
-- **跨多行的 `isolate` realm 需要 `cordis:group` 才能表达** —— 单行可用 entry 本地 realm，但要把一个提供方与它的消费方归入同一个共享 realm，需要 group 内建插件，而 `dsh-app-boot` 并未注册它。
 - **根目录扫描不做监听** —— 每次读取都实际访问文件系统，这让名单保持新鲜，但每次 `list()` 会对每个根目录产生一次 `readdir`。
diff --git a/packages/ui/app-boot/README.i18n.yaml b/packages/ui/app-boot/README.i18n.yaml
index 398ec6e923..9ff7452391 100644
--- a/packages/ui/app-boot/README.i18n.yaml
+++ b/packages/ui/app-boot/README.i18n.yaml
@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/ui/app-boot/README.md
-README.md: cdd78047b6ad71148c6ebeba598b63b4ae4cfa7b
-README.zh.md: ee2b07884e68510e2b59b9f2c27053c263d15f1a
+README.md: 56df424b44564d6e8f6ccd0a61c258dacf9748d3
+README.zh.md: ddd8103e849bc6798b056cae92c88e5f84551108
diff --git a/packages/ui/app-boot/README.md b/packages/ui/app-boot/README.md
index cdd78047b6..56df424b44 100644
--- a/packages/ui/app-boot/README.md
+++ b/packages/ui/app-boot/README.md
@@ -14,7 +14,7 @@ Shared boot glue for the app bins ([`dsh`](../../../apps/cli/README.md), [`dsh-c
 | `assertEntriesActivated(ctx, binName)` | Include the `assertEntriesLoaded` check, then await every enabled entry after the Loader settles; throw with each failed plugin's original stack or each pending plugin's unresolved services |
 | `loadOptionalPatches(binName, file)` | Parse an optional patch-list file (a profile's `cordis.patch.yml`) — a top-level YAML array of include `PatchOptions` (id-targeted config overrides, `insert` lists, `!!js` allowed); absent file → `undefined`, an unreadable/unparsable/non-array file throws |
 | `loadOverlayPatches(binName, file)` | Parse a required patch-list file with the same shape; a missing file also throws, because the caller named it |
-| `mountRootInclude(ctx, absoluteConfigPath, patches?)` | Mount the statically imported Include builtin and retain the exact root entry used by user patch-layer HMR |
+| `mountRootInclude(ctx, absoluteConfigPath, patches?)` | Register the statically imported `cordis:include` and `cordis:group` builtins, mount the include, and retain the exact root entry used by user patch-layer HMR |
 | `watchUserPatches(ctx, options)` | Register the named patch file with the existing Cordis HMR service; each add/change/removal transactionally recomposes the full patch list through the caller's `compose` closure (app-owned layers around the current user layer) and returns an async disposer |
 | `resolveProfileDir` / `initProfile` / `loadProfile` / `readProfileManifest` / `writeProfileManifest` / `resolveBundleDir` / `composeEntries` / `healProfilesModuleFallback` / `PROFILE_TEMPLATES` / `DEFAULT_PROFILE_BUNDLES` / `PROFILES_DIR` / `PROFILE_PATCH_FILENAME` | Profile machinery (see [Profiles](#profiles)) |
 | `boot(binName, absoluteConfigPath, patches?, prepare?)` | Create the root context, expose `dshHomePath(...segments)` to Loader `!!js` config expressions, install Loader, run optional host preparation before config-tree entries mount (`prepare` may use Loader and provide launcher-owned context slots), then mount and await the include tree, assert entries loaded and activated, and return the root context — or dispose the partial context and reject a labelled error |
@@ -26,6 +26,8 @@ Loader settlement rejects import and lifecycle failures with the failing entry a
 
 The Loader mounts entries concurrently, so a surface can already own the terminal when something else fails: exiting without the tree's own teardown would leave raw mode, bracketed paste, and the keyboard protocol set on the user's shell, and an in-flight terminal query's reply would land as literal text at the next prompt. A config-tree failure settles through `boot()`, whose disposal of the partial context runs the surface's own shutdown before the labelled rejection. For the rejections `boot()` cannot see — a plugin's detached async work rejecting during or after mounting — a terminal-owning bin passes `release` to dispose the tree before the exit commits; `dsh` captures the root context in `boot()`'s `prepare` hook rather than from its return value so the hook covers the whole mounting window. While a release is in flight the handler stays installed and latched: the first rejection is the reported one, and later rejections (teardown's own included) are swallowed rather than becoming uncaught and killing the process mid-teardown.
 
+`cordis:group` is registered beside `cordis:include` so a composition can give one `isolate` realm to a provider and its consumers together. Both load through the ambient module pipeline rather than the included tree's own specifier resolution, which is what lets a composition outside this workspace — an agent preset under the Harness home — use a group row at all.
+
 Bare plugin specifiers in a config (`@deepseek-ai/dsh-*`, npm packages) resolve through the Cordis Loader's internal module loader. Repository bins install Loader's optional `node-addon-require-builtin` peer; external callers must supply it or install plugins where plain Node import resolution can find them. Relative specifiers resolve against the config directory without the native helper. The built `dsh-app-boot` artifact embeds the statically mounted Include implementation while leaving Loader external, so the include tree and host bind to one Loader peer. The `dsh` source launcher additionally maps manifest-declared workspace packages to their TypeScript source; its configuration gate requires every shipped raw/Web bare plugin to appear in the resolver manifest's `dependencies`.
 
 This package carries no loader hooks and no dev-mode surface. The [`dsh` app](../../../apps/cli/README.md) owns its Node source-launch hook and consumes these helpers for the boot sequence; built consumers continue to use plain Node package resolution.
diff --git a/packages/ui/app-boot/README.zh.md b/packages/ui/app-boot/README.zh.md
index ee2b07884e..ddd8103e84 100644
--- a/packages/ui/app-boot/README.zh.md
+++ b/packages/ui/app-boot/README.zh.md
@@ -14,7 +14,7 @@
 | `assertEntriesActivated(ctx, binName)` | 先执行 `assertEntriesLoaded` 检查，再在 Loader 结算后等待每个已启用配置项；抛出的错误包含每个失败插件的原始错误堆栈，或每个等待中插件尚未解析的服务 |
 | `loadOptionalPatches(binName, file)` | 解析一份可选的 patch 列表文件（即 profile 的 `cordis.patch.yml`）：其顶层是一个 YAML 数组，内容为 include 的 `PatchOptions`（按 id 定位的配置覆盖、`insert` 列表，允许 `!!js`）；文件不存在时返回 `undefined`，文件不可读、不可解析或内容不是数组时抛出异常 |
 | `loadOverlayPatches(binName, file)` | 解析一份形状相同的必需 patch 列表文件；文件缺失同样抛出异常，因为该文件是调用方指名的 |
-| `mountRootInclude(ctx, absoluteConfigPath, patches?)` | 挂载静态导入的 Include builtin，并保留用户 patch 层 HMR（热模块替换）使用的确切根配置项 |
+| `mountRootInclude(ctx, absoluteConfigPath, patches?)` | 注册静态导入的 `cordis:include` 与 `cordis:group` builtin，挂载 include，并保留用户 patch 层 HMR（热模块替换）使用的确切根配置项 |
 | `watchUserPatches(ctx, options)` | 向现有 Cordis HMR 服务注册指名的 patch 文件；每次新增、变更或移除都会通过调用方的 `compose` 闭包（应用自有层围绕当前用户层）以事务方式重新组合完整 patch 列表，并返回异步 disposer |
 | `resolveProfileDir` / `initProfile` / `loadProfile` / `readProfileManifest` / `writeProfileManifest` / `resolveBundleDir` / `composeEntries` / `healProfilesModuleFallback` / `PROFILE_TEMPLATES` / `DEFAULT_PROFILE_BUNDLES` / `PROFILES_DIR` / `PROFILE_PATCH_FILENAME` | Profile 机制（见 [Profile](#profiles)） |
 | `boot(binName, absoluteConfigPath, patches?, prepare?)` | 创建根上下文，向 Loader `!!js` 配置表达式暴露 `dshHomePath(...segments)` 并安装 Loader，在配置树条目挂载前执行可选的宿主准备操作（`prepare` 可以使用 Loader，也可以提供由启动器拥有的上下文插槽），再挂载并等待 include 树结算，断言所有条目均已加载并激活，最后返回根上下文——失败时 dispose（资源释放）部分构造的上下文，并以带标签的错误 reject |
@@ -26,6 +26,8 @@ Loader 结算会在导入或生命周期失败时 reject，并携带失败的配
 
 Loader 并发挂载各个条目，因此当其他环节失败时，某个界面可能已经持有终端：此时不经过整棵树自身的拆卸就退出，会把 raw 模式、bracketed paste 和键盘协议残留在用户的 shell 上，而尚未返回的终端查询响应会在下一个提示符处显示为字面文本。配置树失败会经 `boot()` 结算：它先释放部分构建的上下文（从而执行该界面自身的 shutdown），再抛出带标签的 rejection。对于 `boot()` 看不到的 rejection（插件游离的异步工作在挂载期间或挂载完成后失败），持有终端的 bin 会传入 `release`，在提交退出前释放整棵树；`dsh` 在 `boot()` 的 `prepare` 回调中捕获根上下文，而不是取其返回值，使该回调覆盖整个挂载窗口。release 执行期间处理函数保持注册并加闩：被报告的始终是第一个 rejection，后续 rejection（包括拆卸自身的）会被吞掉，而不会变成未捕获错误、在拆卸中途杀死进程。
 
+`cordis:group` 与 `cordis:include` 一并注册，使一份组装能把一个提供方与它的消费方放进同一个 `isolate` realm。两者都通过宿主的模块管线加载，而非被包含树自身的说明符解析，这正是让本工作区之外的组装——放在 Harness home 下的 agent preset——能够使用 group 行的原因。
+
 配置中的裸插件 specifier（`@deepseek-ai/dsh-*`、npm 包（package））通过 Cordis Loader 的内部模块 loader 解析。仓库 bin 会安装 Loader 的可选 peer `node-addon-require-builtin`；外部调用方必须提供该组件，或者把插件安装到普通 Node import 解析可以找到的位置。相对 specifier 无需原生 helper，并以配置目录为基准解析。构建后的 `dsh-app-boot` 产物内嵌静态挂载的 Include 实现，但仍将 Loader 保持为外部依赖，因此 include 树与 host 会绑定到同一个 Loader peer。`dsh` 源码启动器还会将 manifest（元数据清单）声明的 workspace 包映射到其 TypeScript 源码；其配置门禁要求每个已交付的原始／Web 裸插件都出现在解析所用 manifest 的 `dependencies` 中。
 
 此包不包含 loader 钩子，也不提供开发模式接口。[`dsh` 应用](../../../apps/cli/README.md)持有自己的 Node 源码启动钩子，并在启动序列中使用这些 helper；构建后的消费方仍使用普通 Node 包解析。
diff --git a/packages/ui/app-boot/package.json b/packages/ui/app-boot/package.json
index c1214953a5..1766ec765b 100644
--- a/packages/ui/app-boot/package.json
+++ b/packages/ui/app-boot/package.json
@@ -28,6 +28,7 @@
     "js-yaml": "^4.2.0"
   },
   "peerDependencies": {
+    "@cordisjs/plugin-group": "^1.0.0",
     "@cordisjs/plugin-hmr": "^1.0.15",
     "@cordisjs/plugin-include": "^1.0.4",
     "@cordisjs/plugin-loader": "^1.0.0-rc.5",
@@ -42,6 +43,7 @@
     }
   },
   "devDependencies": {
+    "@cordisjs/plugin-group": "workspace:^",
     "@cordisjs/plugin-hmr": "workspace:^",
     "@cordisjs/plugin-include": "workspace:^",
     "@cordisjs/plugin-loader": "workspace:^",
diff --git a/packages/ui/app-boot/src/index.ts b/packages/ui/app-boot/src/index.ts
index e14b249f5c..73f1900ef5 100644
--- a/packages/ui/app-boot/src/index.ts
+++ b/packages/ui/app-boot/src/index.ts
@@ -13,6 +13,7 @@ import * as yaml from 'js-yaml'
 import { Context, type FiberState } from 'cordis'
 import Loader, { type Entry, type EntryOptions } from '@cordisjs/plugin-loader'
 import Include, { applyEntryPatches, entryListSchema, type PatchOptions } from '@cordisjs/plugin-include'
+import Group from '@cordisjs/plugin-group'
 import { dshHomePath } from '@deepseek-ai/dsh-paths'
 import type {} from '@cordisjs/plugin-hmr'
 // Side-effect type import: resolves `ctx.get('systemPrompt')` to the service.
@@ -376,6 +377,12 @@ export async function mountRootInclude(
   patches: readonly PatchOptions[] = [],
 ): Promise<Entry | undefined> {
   ctx.loader.builtins.include = Include
+  // `cordis:group` alongside it: a group row is how a composition gives one
+  // `isolate` realm to a provider and its consumers together, and an agent
+  // preset living outside this workspace cannot resolve `@cordisjs/plugin-group`
+  // by name. Both builtins load through the ambient module pipeline, so neither
+  // depends on the included tree's own specifier resolution.
+  ctx.loader.builtins.group = Group
   // Pinned id: the bootstrap include is app glue, not a config row, and its
   // id appears in Loader failure chains — a random id would make startup
   // diagnostics unstable across runs (and snapshot fixtures).
diff --git a/packages/ui/app-boot/tests/config-reload.spec.ts b/packages/ui/app-boot/tests/config-reload.spec.ts
index 45eab9ea7d..9cbe3d1a58 100644
--- a/packages/ui/app-boot/tests/config-reload.spec.ts
+++ b/packages/ui/app-boot/tests/config-reload.spec.ts
@@ -8,9 +8,8 @@ import { mkdtempSync, writeFileSync } from 'node:fs'
 import { tmpdir } from 'node:os'
 import { join } from 'node:path'
 import { describe, expect, it } from 'vitest'
-import type { Context } from 'cordis'
+import { Context } from 'cordis'
 import type { Include } from '@cordisjs/plugin-include'
-import { Group } from '@cordisjs/plugin-loader'
 import { boot } from '../src/index.ts'
 
 const NAME = 'dsh-test-bin'
@@ -219,8 +218,10 @@ describe('loader tree replacement', () => {
   })
 
   it('stops and restores descendants when an ancestor group is disabled and re-enabled', async () => {
+    // No manual builtin registration: `boot()` supplies `cordis:group` beside
+    // `cordis:include`, which is what lets a composition give one `isolate`
+    // realm to a provider and its consumers together.
     const { ctx, dir, include } = await bootTree('- id: noop\n  name: ./noop.mjs\n')
-    ctx.loader.builtins.group = Group
     try {
       const config = (disabled: boolean) => [
         '- id: parent',
@@ -253,7 +254,6 @@ describe('loader tree replacement', () => {
     const { ctx } = await bootTree('- id: noop\n  name: ./noop.mjs\n', {
       'movable.mjs': plugin('movablePlugin', 'if (config.fail) throw new Error("candidate config failed")'),
     })
-    ctx.loader.builtins.group = Group
     try {
       const groupId = await ctx.loader.create({ name: 'cordis:group', group: true, config: [] })
       const targetId = await ctx.loader.create({ name: './movable.mjs', config: { fail: false } })
@@ -386,3 +386,46 @@ describe('include patches layered over one base', () => {
     }
   })
 })
+
+describe('shipped builtins', () => {
+  it('lets a booted composition share one isolate realm across a group of rows', async () => {
+    // The reason `boot()` registers `cordis:group`: a composition — notably an
+    // agent preset living outside this workspace, which cannot resolve
+    // `@cordisjs/plugin-group` by name — gives a provider and its consumer one
+    // named realm so the service stays out of the root realm while remaining
+    // visible to the rows that need it.
+    const { ctx } = await bootTree([
+      '- id: realm',
+      '  name: cordis:group',
+      '  isolate:',
+      '    demoRealmSvc: true',
+      '  config:',
+      '    - id: provider',
+      '      name: ./provider.mjs',
+      '    - id: consumer',
+      '      name: ./consumer.mjs',
+      '',
+    ].join('\n'), {
+      'provider.mjs': 'export const name = "provider"\n'
+        + 'export function apply(ctx) { ctx.effect(() => ctx.reflect.provide("demoRealmSvc", { tag: "realm" })) }\n',
+      'consumer.mjs': 'export const name = "consumer"\n'
+        + 'export const inject = ["demoRealmSvc"]\n'
+        + 'export function apply(ctx) { globalThis.__REALM_SEEN__ = ctx.get("demoRealmSvc").tag }\n',
+    })
+    try {
+      expect((globalThis as { __REALM_SEEN__?: string }).__REALM_SEEN__).toBe('realm')
+      // `provide` mints the root symbol unconditionally (cordis `reflect.ts`),
+      // so the name IS in the root realm — pinned here because it is the half
+      // that looks like the claim and is not. The claim is the other half: no
+      // implementation is stored under that symbol, so the root realm cannot
+      // resolve the service and a second composition mounting the same rows
+      // cannot collide with this one.
+      const rootKey = ctx.root[Context.isolate].demoRealmSvc
+      expect(rootKey).toBeDefined()
+      expect(ctx.reflect.store[rootKey!]).toBeUndefined()
+    } finally {
+      delete (globalThis as { __REALM_SEEN__?: string }).__REALM_SEEN__
+      await ctx.fiber.dispose()
+    }
+  })
+})
diff --git a/packages/ui/app-boot/tsconfig.json b/packages/ui/app-boot/tsconfig.json
index beb61317dc..9ec64c31fc 100644
--- a/packages/ui/app-boot/tsconfig.json
+++ b/packages/ui/app-boot/tsconfig.json
@@ -17,6 +17,9 @@
     {
       "path": "../../../vendor/include"
     },
+    {
+      "path": "../../../vendor/group"
+    },
     {
       "path": "../../../vendor/hmr"
     },
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index f18d43bbc8..a612f4af93 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -5975,6 +5975,9 @@ importers:
         specifier: ^4.2.0
         version: 4.2.0
     devDependencies:
+      '@cordisjs/plugin-group':
+        specifier: workspace:^
+        version: link:../../../vendor/group
       '@cordisjs/plugin-hmr':
         specifier: workspace:^
         version: link:../../../vendor/hmr
@@ -6570,6 +6573,9 @@ importers:
 
   python/sdk-runtime:
     dependencies:
+      '@cordisjs/plugin-group':
+        specifier: workspace:^
+        version: link:../../vendor/group
       '@cordisjs/plugin-include':
         specifier: workspace:^
         version: link:../../vendor/include
diff --git a/python/sdk-runtime/package.json b/python/sdk-runtime/package.json
index 4fd7291633..450f7d5333 100644
--- a/python/sdk-runtime/package.json
+++ b/python/sdk-runtime/package.json
@@ -5,6 +5,7 @@
   "private": true,
   "type": "module",
   "dependencies": {
+    "@cordisjs/plugin-group": "workspace:^",
     "@cordisjs/plugin-include": "workspace:^",
     "@cordisjs/plugin-loader": "workspace:^",
     "@cordisjs/plugin-timer": "workspace:^",