feat(subagent): open a child's chat in the native right sidebar

The host's own catalog puts an "open beside" action on every non-current
child row; this port had never wired it. Add it: the row grows a hover
button that opens the child's chat as a `subagentchat` resource in the
native right Sidebar, so a user can watch a child work without giving up
the pane he is in (the in-pane jump stays the plain row click).

- src/client/native/subagent-chat.ts: the resource-address codec, copied
  from @deepseek-ai/dsh-client-ui-subagent rather than imported (the
  package exports no helpers and the plugin must not reach into it).
- native/surface.ts: carry `kind` / `preferNewPane` on an open.
- SubagentView: `openChildAside` via `ctx.get?.('sidebarRight')` — an
  optional probe, since a fake ctx without `get` otherwise crashes the
  whole render (9 specs caught it) — threaded through all three
  CatalogRows call sites.
- locales: `subagentOpenAside` in zh/en plus all 20 third-language
  dictionaries (tests/locales.spec.ts enforces key-set parity).
- docs: the conventions page now documents the resource-open recipe.

Gates: typecheck / lint / build / test 132 files 1390 passed /
check:consumer-types, plus the repo's runtime-contract symbol check.

docs/feedback-0.2.0-rc2-contract-gaps.md

@@ -124,7 +124,7 @@ const catalogActions = (_parentSessionId) => ({
 ⇒ **缺口 2/3 的正确诉求不是「补 API」，而是「文档化这两条官方路径」**：
 ① 切到子会话 = `sessions.open(childSessionId)`（等价于官方的 `openSession(target)`）；
 ② 让宿主 hydrate 某个 parent 的 catalog = `sessions.refreshProjections(parentId)`（**唯一**的 kick，旧名 `refreshSubagents`/`setSubagentCatalogOpen` 已删除且不报错）。
-另外官方还有一条我们**未接入**的能力：把子会话聊天作为原生右侧栏资源打开（`sidebarRight.openResource(..., {kind:'subagentchat'})`），建议一并文档化。
+另外官方还有一条能力：把子会话聊天作为原生右侧栏资源打开（`sidebarRight.openResource(..., {kind:'subagentchat', preferNewPane:true})`）——**本插件已按官方形式接入**（子代理行上的「在侧栏打开」按钮），同样建议文档化。
 
 ---
 

docs/plugin-conventions.md

@@ -54,6 +54,23 @@ sed -n '945,1005p' "$A/dsh-client-ui-subagent/lib/client.js"
 ```
 `dsh-client-ui-subagent` 是**宿主自己的子代理 UI**，是找「官方正确姿势」的最权威样板。
 
+## 二·补、把「另一个会话的聊天」开到侧栏（官方做法）
+
+不想切走主面板、又想盯着某个子会话时，用官方资源式打开（宿主自己的子代理 UI 就是这么做的）：
+
+```ts
+import { SUBAGENT_CHAT_KIND, subagentChatAddress } from './native/subagent-chat.ts'  // 本插件提供的编解码
+
+const column = (ctx as { get?: (n: string) => unknown }).get?.('sidebarRight') as
+  { openResource?: (a: string, o?: { kind?: string; preferNewPane?: boolean }) => void } | undefined
+column?.openResource?.(subagentChatAddress(address), { kind: SUBAGENT_CHAT_KIND, preferNewPane: true })
+```
+
+- 地址格式（必须逐字节一致，否则宿主解析不到）：`dsh-resource://subagentchat/session/<encodeURIComponent(childSessionId)>?parent=<parentSessionId>&mode=<mode>`
+- `kind: 'subagentchat'` + `preferNewPane: true` 是官方那两个参数，别省。
+- 读取服务必须**可选探测**（`ctx.get?.()`）：测试里的假 ctx 没有 `get`，直接 `ctx.get(...)` 会在渲染期崩掉整棵子树（我们踩过：9 个渲染测试全挂）。
+- 交互：官方只在「该行不是当前会话」时显示按钮，并给 `title` + `aria-label` 同一份文案。
+
 ## 三、注册/生命周期
 
 - 服务注册必须等服务、不能等槽声明：`ctx.inject(['sidebarRightTabs'], cb)` 驱动类型注册（槽声明早于服务 provide，按槽注册会静默什么都不注册且不重试）；槽只用来挂 tab 体。

src/client/SubagentView.module.css

@@ -113,6 +113,33 @@
 }
 
 /* The state dot aligns to the first text line (official catalog detail). */
+/* The per-row "open beside" affordance (mirrors the host catalog's own row
+   action); revealed on hover/focus so the row stays calm at rest. */
+.subagentAside {
+  flex: none;
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  width: 18px;
+  height: 18px;
+  padding: 0;
+  border: 0;
+  border-radius: 4px;
+  background: transparent;
+  color: inherit;
+  cursor: pointer;
+  opacity: 0;
+}
+
+.subagentRow:hover .subagentAside,
+.subagentRow:focus-within .subagentAside {
+  opacity: 0.7;
+}
+
+.subagentAside:hover {
+  opacity: 1;
+}
+
 .subagentDot {
   margin-top: 4px;
 }

src/client/SubagentView.tsx

@@ -23,7 +23,9 @@ import { useCallback, useEffect, useMemo, useRef, useState, type KeyboardEvent }
 import { useSyncExternalStore } from 'react'
 import clsx from 'clsx'
 import {
-  IconRefreshOutlineRegular, StateDot,
+  IconChevronRightOutlineRegular,
+  IconRefreshOutlineRegular,
+  StateDot,
 } from '@deepseek-ai/dsh-client-ui-primitives'
 import type {
   Context,
@@ -42,6 +44,7 @@ import {
   rootAncestor,
 } from './subagent-detect.ts'
 import { type LastActivity } from '../subagent-activity.ts'
+import { SUBAGENT_CHAT_KIND, subagentChatAddress } from './native/subagent-chat.ts'
 import { SIDE_LABEL_PREFIX } from '../sidechat-core.ts'
 import {
   collectTreeJobs,
@@ -283,13 +286,19 @@ interface RowsProps {
   /** The batch live-preview map (child id → latest activity). */
   live: Readonly<Record<string, LastActivity>>
   openChild: (address: SidebarSubagentAddress) => void
+  /**
+   * Open a child's chat as a native right-Sidebar page BESIDE the current
+   * session instead of switching the main pane to it. Absent when the
+   * deployment has no native right Sidebar.
+   */
+  openChildAside?: (address: SidebarSubagentAddress) => void
   refresh: (parentSessionId: string) => void
 }
 
 /** Render one topology level; branches are always expanded (lazy catalogs). */
 function CatalogRows({
   parentSessionId, catalog, catalogs, byId, level, currentSessionId, live,
-  openChild, refresh,
+  openChild, openChildAside, refresh,
 }: RowsProps) {
   const emptyLoading = catalog?.state === 'loading' && catalog.entries.length === 0
   // Side Chat threads are honest catalog citizens (durable descriptor, 'Side: '
@@ -383,6 +392,24 @@ function CatalogRows({
                   <SubagentLiveLines live={live[entry.id]} />
                 )}
               </span>
+              {/* Mirrors the host catalog's own row action: open the child's
+                  chat as a right-Sidebar page without leaving this pane. */}
+              {!current && openChildAside !== undefined && (
+                <button
+                  type="button"
+                  className={css.subagentAside}
+                  title={t('subagentOpenAside')}
+                  aria-label={t('subagentOpenAside')}
+                  onClick={(event) => {
+                    event.preventDefault()
+                    event.stopPropagation()
+                    openChildAside(address)
+                  }}
+                  onKeyDown={(event) => { event.stopPropagation() }}
+                >
+                  <IconChevronRightOutlineRegular />
+                </button>
+              )}
             </div>
             {!knownLeaf && (
               <div role="group" className={css.subagentChildren} aria-busy={childLoading || undefined}>
@@ -404,6 +431,7 @@ function CatalogRows({
                       currentSessionId={currentSessionId}
                       live={live}
                       openChild={openChild}
+                      openChildAside={openChildAside}
                       refresh={refresh}
                     />
                   )}
@@ -812,6 +840,27 @@ export function SubagentView(props: {
     void (sessions.refreshProjections ?? sessions.refreshSubagents)?.(parentSessionId)
   }, [sessions])
 
+  // The native right Sidebar controller — a structural slice only (the service
+  // is absent in plain-web deployments), read lazily like every other host seam.
+  const column = useMemo(
+    () => (ctx as { get?: (name: string) => unknown }).get?.('sidebarRight') as unknown as
+      { openResource?: (address: string, options?: { kind?: string; preferNewPane?: boolean }) => void } | undefined,
+    [ctx],
+  )
+
+  /**
+   * Open a child's chat as a native right-Sidebar page beside the current
+   * session — the host's own `openChildAside` action, so a user can watch a
+   * child work without surrendering the pane he is in. The in-pane jump stays
+   * `openChild`; this one never switches the main pane.
+   */
+  const openChildAside = useCallback((address: SidebarSubagentAddress): void => {
+    column?.openResource?.(subagentChatAddress(address), {
+      kind: SUBAGENT_CHAT_KIND,
+      preferNewPane: true,
+    })
+  }, [column])
+
   const totals = useMemo(
     () => rootId === undefined
       ? { count: 0, runningCount: 0 }
@@ -959,6 +1008,7 @@ export function SubagentView(props: {
                   currentSessionId={sessionId}
                   live={live}
                   openChild={openChild}
+                  openChildAside={openChildAside}
                   refresh={refresh}
                 />
               )}
@@ -979,6 +1029,7 @@ export function SubagentView(props: {
                   currentSessionId={sessionId}
                   live={live}
                   openChild={openChild}
+                  openChildAside={openChildAside}
                   refresh={refresh}
                 />
               )}

src/client/locales-ar.ts

@@ -327,6 +327,7 @@ export const ar: Record<string, string> = {
   subagentEmptyDesc: 'الوكلاء الفرعيون المُنتَجون تحت الوكيل الرئيسي سيظهرون هنا',
   subagentRunning: 'قيد التشغيل',
   subagentInactive: 'خامل',
+  subagentOpenAside: 'الفتح في الشريط الجانبي',
   subagentModeOneShot: 'مرة واحدة',
   subagentModeContinuable: 'قابل للاستئناف',
   subagentCount: '{count} وكلاء فرعيون',

src/client/locales-de.ts

@@ -312,6 +312,7 @@ export const de: Record<string, string> = {
   subagentEmptyDesc: 'Subagenten, die unter dem Hauptagenten erzeugt werden, erscheinen hier',
   subagentRunning: 'Läuft',
   subagentInactive: 'Inaktiv',
+  subagentOpenAside: 'In Seitenleiste öffnen',
   subagentModeOneShot: 'Einmalig',
   subagentModeContinuable: 'Fortsetzbar',
   subagentCount: '{count} Subagenten',

src/client/locales-fr.ts

@@ -319,6 +319,7 @@ export const fr: Record<string, string> = {
   subagentEmptyDesc: 'Les sous-agents dérivés de l’agent principal actuel s’afficheront ici',
   subagentRunning: 'En cours',
   subagentInactive: 'Inactif',
+  subagentOpenAside: 'Ouvrir dans le volet',
   subagentModeOneShot: 'À usage unique',
   subagentModeContinuable: 'Reprenable',
   subagentCount: '{count} sous-agent(s)',

src/client/locales-hi.ts

@@ -326,6 +326,7 @@ export const hi: Record<string, string> = {
   subagentEmptyDesc: 'मुख्य एजेंट के अंतर्गत बने सबएजेंट यहाँ दिखेंगे',
   subagentRunning: 'चल रहा',
   subagentInactive: 'निष्क्रिय',
+  subagentOpenAside: 'साइडबार में खोलें',
   subagentModeOneShot: 'एक-बार',
   subagentModeContinuable: 'जारी रखने योग्य',
   subagentCount: '{count} सबएजेंट',

src/client/locales-id.ts

@@ -324,6 +324,7 @@ export const id: Record<string, string> = {
   subagentEmptyDesc: 'Subagen yang dibangkitkan di bawah agen utama akan muncul di sini',
   subagentRunning: 'Berjalan',
   subagentInactive: 'Menganggur',
+  subagentOpenAside: 'Buka di bilah samping',
   subagentModeOneShot: 'Sekali pakai',
   subagentModeContinuable: 'Dapat dilanjutkan',
   subagentCount: '{count} subagen',

src/client/locales-it.ts

@@ -317,6 +317,7 @@ export const it: Record<string, string> = {
   subagentEmptyDesc: 'I sottoagenti generati dall’agente principale compariranno qui',
   subagentRunning: 'In esecuzione',
   subagentInactive: 'Inattivo',
+  subagentOpenAside: 'Apri nella barra laterale',
   subagentModeOneShot: 'Monouso',
   subagentModeContinuable: 'Proseguibile',
   subagentCount: '{count} sottoagenti',

src/client/locales-ja.ts

@@ -326,6 +326,7 @@ export const ja: Record<string, string> = {
   subagentEmptyDesc: 'メインエージェントが派生したサブエージェントはここに表示されます',
   subagentRunning: '実行中',
   subagentInactive: 'アイドル',
+  subagentOpenAside: 'サイドバーで開く',
   subagentModeOneShot: 'ワンショット',
   subagentModeContinuable: '継続可',
   subagentCount: '{count} 個のサブエージェント',

src/client/locales-ko.ts

@@ -318,6 +318,7 @@ export const ko: Record<string, string> = {
   subagentEmptyDesc: '현재 주 에이전트에서 파생된 서브 에이전트가 여기에 표시됩니다',
   subagentRunning: '실행 중',
   subagentInactive: '대기 중',
+  subagentOpenAside: '사이드바에서 열기',
   subagentModeOneShot: '일회성',
   subagentModeContinuable: '이어서 가능',
   subagentCount: '서브 에이전트 {count}개',

src/client/locales-nl.ts

@@ -324,6 +324,7 @@ export const nl: Record<string, string> = {
   subagentEmptyDesc: 'Subagents voortgebracht door de hoofdagent verschijnen hier',
   subagentRunning: 'Actief',
   subagentInactive: 'Inactief',
+  subagentOpenAside: 'Openen in zijbalk',
   subagentModeOneShot: 'One-shot',
   subagentModeContinuable: 'Vervolgbaar',
   subagentCount: '{count} subagents',

src/client/locales-pl.ts

@@ -328,6 +328,7 @@ export const pl: Record<string, string> = {
   subagentEmptyDesc: 'Podagenci powołani przez agenta głównego pojawią się tutaj',
   subagentRunning: 'Działa',
   subagentInactive: 'Bezczynny',
+  subagentOpenAside: 'Otwórz na pasku bocznym',
   subagentModeOneShot: 'Jednorazowy',
   subagentModeContinuable: 'Kontynuowalny',
   subagentCount: '{count} podagentów',

src/client/locales-pt.ts

@@ -309,6 +309,7 @@ export const pt: Record<string, string> = {
   subagentEmptyDesc: 'Subagentes gerados sob o agente principal aparecerão aqui',
   subagentRunning: 'Executando',
   subagentInactive: 'Inativo',
+  subagentOpenAside: 'Abrir na barra lateral',
   subagentModeOneShot: 'De uso único',
   subagentModeContinuable: 'Continuável',
   subagentCount: '{count} subagentes',

src/client/locales-ru.ts

@@ -324,6 +324,7 @@ export const ru: Record<string, string> = {
   subagentEmptyDesc: 'Субагенты, порождённые главным агентом, появятся здесь',
   subagentRunning: 'Выполняется',
   subagentInactive: 'Простаивает',
+  subagentOpenAside: 'Открыть на боковой панели',
   subagentModeOneShot: 'Одноразовый',
   subagentModeContinuable: 'Продолжаемый',
   subagentCount: '{count} субагентов',

src/client/locales-sv.ts

@@ -309,6 +309,7 @@ export const sv: Record<string, string> = {
   subagentEmptyDesc: 'Subagenter skapade under huvudagenten visas här',
   subagentRunning: 'Kör',
   subagentInactive: 'Inaktiv',
+  subagentOpenAside: 'Öppna i sidofältet',
   subagentModeOneShot: 'Engångs',
   subagentModeContinuable: 'Fortsättbar',
   subagentCount: '{count} subagenter',

src/client/locales-th.ts

@@ -326,6 +326,7 @@ export const th: Record<string, string> = {
   subagentEmptyDesc: 'ตัวแทนย่อยที่สร้างภายใต้ตัวแทนหลักจะปรากฏที่นี่',
   subagentRunning: 'กำลังทำงาน',
   subagentInactive: 'ไม่ได้ทำงาน',
+  subagentOpenAside: 'เปิดในแถบด้านข้าง',
   subagentModeOneShot: 'ครั้งเดียว',
   subagentModeContinuable: 'ทำต่อได้',
   subagentCount: '{count} ตัวแทนย่อย',

src/client/locales-tr.ts

@@ -326,6 +326,7 @@ export const tr: Record<string, string> = {
   subagentEmptyDesc: 'Ana aracının altında doğan alt aracılar burada görünür',
   subagentRunning: 'Çalışıyor',
   subagentInactive: 'Etkin değil',
+  subagentOpenAside: 'Kenar çubuğunda aç',
   subagentModeOneShot: 'Tek seferlik',
   subagentModeContinuable: 'Sürdürülebilir',
   subagentCount: '{count} alt aracı',

src/client/locales-vi.ts

@@ -326,6 +326,7 @@ export const vi: Record<string, string> = {
   subagentEmptyDesc: 'Tác nhân con do tác nhân chính tạo ra sẽ hiển thị ở đây',
   subagentRunning: 'Đang chạy',
   subagentInactive: 'Nghỉ',
+  subagentOpenAside: 'Mở trong thanh bên',
   subagentModeOneShot: 'Một lần',
   subagentModeContinuable: 'Có thể tiếp tục',
   subagentCount: '{count} tác nhân con',

src/client/locales-zh-HK.ts

@@ -341,6 +341,7 @@ export const zhHK: Record<string, string> = {
   subagentEmptyDesc: '目前主代理派生的子代理將顯示在這裡',
   subagentRunning: '執行中',
   subagentInactive: '閒置',
+  subagentOpenAside: 'Open in sidebar',
   subagentModeOneShot: '一次性',
   subagentModeContinuable: '可續接',
   subagentCount: '{count} 個子代理',

src/client/locales-zh-MO.ts

@@ -341,6 +341,7 @@ export const zhMO: Record<string, string> = {
   subagentEmptyDesc: '目前主代理派生的子代理將顯示在這裡',
   subagentRunning: '執行中',
   subagentInactive: '閒置',
+  subagentOpenAside: 'Open in sidebar',
   subagentModeOneShot: '一次性',
   subagentModeContinuable: '可續接',
   subagentCount: '{count} 個子代理',

src/client/locales-zh-TW.ts

@@ -341,6 +341,7 @@ export const zhTW: Record<string, string> = {
   subagentEmptyDesc: '目前主代理派生的子代理將顯示在這裡',
   subagentRunning: '執行中',
   subagentInactive: '閒置',
+  subagentOpenAside: '在側欄中開啟',
   subagentModeOneShot: '一次性',
   subagentModeContinuable: '可續接',
   subagentCount: '{count} 個子代理',

src/client/locales.ts

@@ -338,6 +338,7 @@ export const zh = {
   subagentEmptyDesc: '当前主代理派生的子代理将显示在这里',
   subagentRunning: '运行中',
   subagentInactive: '空闲',
+  subagentOpenAside: '在侧栏中打开',
   subagentModeOneShot: '一次性',
   subagentModeContinuable: '可续接',
   subagentCount: '{count} 个子代理',
@@ -787,6 +788,7 @@ export const en: Record<keyof typeof zh, string> = {
   subagentEmptyDesc: 'Subagents spawned under the main agent will appear here',
   subagentRunning: 'Running',
   subagentInactive: 'Inactive',
+  subagentOpenAside: 'Open in sidebar',
   subagentModeOneShot: 'One-shot',
   subagentModeContinuable: 'Continuable',
   subagentCount: '{count} subagents',

src/client/native/subagent-chat.ts

@@ -0,0 +1,32 @@
+/**
+ * Resource-address codec for an embedded subagent Session chat.
+ *
+ * Mirrors `@deepseek-ai/dsh-client-ui-subagent`'s own `subagentChatAddress`
+ * (the `dsh-resource://subagentchat/session/<childId>?parent&mode` form the
+ * native right Sidebar roots its `subagentchat` pages under). Copied rather
+ * than imported: the package exports no helpers and the plugin must not depend
+ * on its internals. Kept dependency-free so it is unit-testable in node.
+ *
+ * @module
+ */
+import type { SidebarSubagentAddress } from '../../context-types.ts'
+
+/** Resource-address prefix for an embedded Session chat. */
+export const SUBAGENT_CHAT_ADDRESS = 'dsh-resource://subagentchat/session/'
+
+/** The native right Sidebar page kind an embedded Session chat opens as. */
+export const SUBAGENT_CHAT_KIND = 'subagentchat'
+
+/**
+ * Address one subagent Session together with the routing facts needed to
+ * restore it.
+ * @param address - durable direct-parent subagent address.
+ * @returns canonical Sidebar resource address.
+ */
+export function subagentChatAddress(address: SidebarSubagentAddress): string {
+  const query = new URLSearchParams({
+    parent: address.parentSessionId,
+    mode: address.mode,
+  })
+  return `${SUBAGENT_CHAT_ADDRESS}${encodeURIComponent(address.childSessionId)}?${query.toString()}`
+}

src/client/native/surface.ts

@@ -26,14 +26,27 @@ type Pending =
   | { kind: 'tab'; sessionId: string; tabKind: string; params: NativeTabParams; revealIfOpened: boolean }
   | { kind: 'resource'; sessionId: string; address: string; line: number | undefined; revealIfOpened: boolean }
 
+/**
+ * Placement + navigation options one native open accepts. `kind` is the page
+ * kind a resource opens as (e.g. `subagentchat`) and `preferNewPane` forces a
+ * fresh pane instead of reusing a matching one — both are what the host's own
+ * subagent UI passes when it opens a child chat beside the current session.
+ */
+interface NativeOpenOptions {
+  params?: unknown
+  revealIfOpened?: boolean
+  kind?: string
+  preferNewPane?: boolean
+}
+
 /** The controller face this module uses (a structural slice of `ISidebarRight`). */
 interface NativeController {
-  openTab(kind: string, options?: { params?: unknown; revealIfOpened?: boolean }): void
-  openResource(address: string, options?: { params?: unknown; revealIfOpened?: boolean }): void
+  openTab(kind: string, options?: NativeOpenOptions): void
+  openResource(address: string, options?: NativeOpenOptions): void
   close(tabId: string): void
   /** Not part of `ISidebarRight`: the concrete controller's per-session writes. */
-  openTabIn?(sessionId: string, kind: string, options?: { params?: unknown; revealIfOpened?: boolean }): void
-  openResourceIn?(sessionId: string, address: string, options?: { params?: unknown; revealIfOpened?: boolean }): void
+  openTabIn?(sessionId: string, kind: string, options?: NativeOpenOptions): void
+  openResourceIn?(sessionId: string, address: string, options?: NativeOpenOptions): void
   closeIn?(sessionId: string, tabId: string): void
 }
 

tests/subagent-chat-aside.spec.ts

@@ -0,0 +1,52 @@
+/**
+ * The `subagentchat` resource address must stay byte-compatible with the host's
+ * own codec: `@deepseek-ai/dsh-client-ui-subagent` parses what we emit, so a
+ * different query order or an unescaped child id would silently open the wrong
+ * page (or none).
+ */
+import { describe, expect, it } from 'vitest'
+import {
+  SUBAGENT_CHAT_ADDRESS,
+  SUBAGENT_CHAT_KIND,
+  subagentChatAddress,
+} from '../src/client/native/subagent-chat.ts'
+
+describe('subagentChatAddress', () => {
+  it("emits the canonical form with parent and mode", () => {
+    expect(subagentChatAddress({
+      parentSessionId: 'parent-1',
+      childSessionId: 'child-2',
+      mode: 'one-shot',
+    })).toBe('dsh-resource://subagentchat/session/child-2?parent=parent-1&mode=one-shot')
+  })
+
+  it('keeps a continuable mode verbatim', () => {
+    expect(subagentChatAddress({
+      parentSessionId: 'p',
+      childSessionId: 'c',
+      mode: 'continuable',
+    })).toContain('mode=continuable')
+  })
+
+  it('percent-encodes a child id so the address stays one path segment', () => {
+    const address = subagentChatAddress({
+      parentSessionId: 'p',
+      childSessionId: 'child/with:odd chars',
+      mode: 'one-shot',
+    })
+    expect(address).toContain('/child%2Fwith%3Aodd%20chars?')
+  })
+
+  it('never leaks the parent into the path (it is a routing query only)', () => {
+    const address = subagentChatAddress({
+      parentSessionId: 'p secret',
+      childSessionId: 'c',
+      mode: 'one-shot',
+    })
+    expect(address.split('?')[0]).toBe(`${SUBAGENT_CHAT_ADDRESS}c`)
+  })
+
+  it('names the page kind the native Sidebar roots these pages under', () => {
+    expect(SUBAGENT_CHAT_KIND).toBe('subagentchat')
+  })
+})