diff --git a/src/client/EditorHost.tsx b/src/client/EditorHost.tsx
index a732a9f..37479c1 100644
--- a/src/client/EditorHost.tsx
+++ b/src/client/EditorHost.tsx
@@ -83,7 +83,7 @@ function treeWidthOf(tab: SidebarTab): number {
 
 /** Merge a patch into the tab's persisted meta (rides the layout). */
 function patchMeta(ctx: Context, tab: SidebarTab, patch: Record<string, unknown>): void {
-  ctx.betterSidebar?.updateTab(tab.id, { meta: { ...metaOf(tab), ...patch } })
+  ctx.get('betterSidebar')?.updateTab(tab.id, { meta: { ...metaOf(tab), ...patch } })
 }
 
 /** Clamp one dock width into the contract range. */
@@ -134,7 +134,7 @@ export function EditorHost(props: {
    */
   const openFile = (absolute: string): void => {
     if (inPlace) {
-      ctx.betterSidebar?.updateTab(tab.id, { path: absolute, title: baseName(absolute) })
+      ctx.get('betterSidebar')?.updateTab(tab.id, { path: absolute, title: baseName(absolute) })
     } else {
       openSidebarFile(ctx, store, scope.sessionId, absolute)
     }
@@ -300,7 +300,7 @@ export function EditorHost(props: {
               content: result.kind === 'text' ? result.content : '',
               truncated: result.truncated,
               head: result.kind === 'binary' ? result.head : undefined,
-            }, (head) => ctx.betterSidebar?.matchFileViewer(path, head), mediaUrlOf)
+            }, (head) => ctx.get('betterSidebar')?.matchFileViewer(path, head), mediaUrlOf)
             apply(outcome)
           }).catch((error: unknown) => {
             if (cancelled) return
@@ -309,7 +309,7 @@ export function EditorHost(props: {
           return
       }
     }
-    apply(planFirstMatch(ctx.betterSidebar?.matchFileViewer(path), mediaUrlOf))
+    apply(planFirstMatch(ctx.get('betterSidebar')?.matchFileViewer(path), mediaUrlOf))
     return () => { cancelled = true; controller.abort() }
   }, [scope.sessionId, scope.cwd, path, ctx, showEmpty])
 
diff --git a/src/client/SideChatView.tsx b/src/client/SideChatView.tsx
index 5fe9f0f..775d396 100644
--- a/src/client/SideChatView.tsx
+++ b/src/client/SideChatView.tsx
@@ -295,7 +295,7 @@ export function SideChatView(props: {
     setError(null)
     try {
       const { childId } = await api.sidechatStart(scope.sessionId)
-      ctx.betterSidebar?.updateTab(tab.id, { meta: { threadId: childId } })
+      ctx.get('betterSidebar')?.updateTab(tab.id, { meta: { threadId: childId } })
     } catch (cause) {
       setError(cause instanceof Error ? cause.message : String(cause))
     } finally {
@@ -319,7 +319,7 @@ export function SideChatView(props: {
     const title = threadDisplayTitle(display)
     if (title !== '' && title !== tab.title) {
       try {
-        ctx.betterSidebar?.updateTab(tab.id, { title })
+        ctx.get('betterSidebar')?.updateTab(tab.id, { title })
       } catch {
         // A stale title is cosmetic; the thread keeps working.
       }
@@ -422,7 +422,7 @@ export function SideChatView(props: {
    *  creates the thread on mount). */
   const openNewThread = (): void => {
     setMenuOpen(false)
-    ctx.betterSidebar?.openTab({ type: 'sidechat' }, scope)
+    ctx.get('betterSidebar')?.openTab({ type: 'sidechat' }, scope)
   }
 
   /** Switch to an existing thread: parked for createTab, deduped to the
@@ -431,7 +431,7 @@ export function SideChatView(props: {
     setMenuOpen(false)
     if (id === threadId) return
     parkSidechatReopen(id)
-    ctx.betterSidebar?.openTab({ type: 'sidechat' }, scope)
+    ctx.get('betterSidebar')?.openTab({ type: 'sidechat' }, scope)
   }
 
   const menuItems = useMemo<MenuEntry[]>(() => {
diff --git a/src/client/Sidebar.tsx b/src/client/Sidebar.tsx
index d7c8c07..0f12d3f 100644
--- a/src/client/Sidebar.tsx
+++ b/src/client/Sidebar.tsx
@@ -135,7 +135,7 @@ interface TabContentProps extends TabContentMemoKey {
 const TabContent = memo(function TabContent(props: TabContentProps) {
   const { tab, sessionId, cwd, expanded, onToggleDir, onReferenceFile, ctx, store, visible, onSubagentJump, onOpenDiff } = props
   const scope = { sessionId, cwd }
-  const descriptor = ctx.betterSidebar?.getTab(tab.type)
+  const descriptor = ctx.get('betterSidebar')?.getTab(tab.type)
   if (descriptor === undefined) {
     return <OrphanedTab ctx={ctx} store={store} scope={scope} tab={tab} visible={visible} />
   }
@@ -163,7 +163,7 @@ const TabContent = memo(function TabContent(props: TabContentProps) {
  * Tabs the user disabled in the side card settings are filtered out
  * entirely — re-enabling them is the settings page's job. */
 function buildNewTabOptions(state: SidebarState, ctx: Context, scope: SessionScope): NewTabOption[] {
-  const service = ctx.betterSidebar
+  const service = ctx.get('betterSidebar')
   if (service === undefined) return []
   return service.getTabs()
     .filter(d => !d.hidden && service.isTabEnabled(d.id))
@@ -229,7 +229,7 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
   // from going stale, mirroring the localeRevision mechanism above.
   const [tabsVersion, setTabsVersion] = useState(0)
   useEffect(() => {
-    const service = ctx.betterSidebar
+    const service = ctx.get('betterSidebar')
     if (service === undefined) return
     return service.subscribe(() => setTabsVersion(version => version + 1))
   }, [ctx])
@@ -419,7 +419,7 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
         try {
           const list = JSON.parse(event.data) as Array<{ uuid: string; title: string; command: string; exited: boolean }>
           if (!Array.isArray(list)) return
-          store.reduce(s => ctx.betterSidebar?.isTabEnabled('terminal') === false
+          store.reduce(s => ctx.get('betterSidebar')?.isTabEnabled('terminal') === false
             ? s
             : reconcileAgentTerminals(s, list))
         } catch {
@@ -475,13 +475,13 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
       autoOpenPendingRef.current = null
       if (!detectNewDirectSubagent(baseline, ctx.sessions.list.getSnapshot(), sessionId)) return
       if (!store.getPrefs().autoOpenSubagent) return
-      if (ctx.betterSidebar?.isTabEnabled('subagent') === false) return
+      if (ctx.get('betterSidebar')?.isTabEnabled('subagent') === false) return
       store.reduce(s => s.panelOpen ? s : togglePanel(s))
       // Pin the landing to the right panel: the auto-opened Subagent page must
       // appear where the panel just expanded, not in a bottom-panel pane the
       // user last touched.
       store.reduce(s => ({ ...s, activePane: firstLeaf(s.splits).id }))
-      ctx.betterSidebar?.openTab({ type: 'subagent', title: t('subagent') })
+      ctx.get('betterSidebar')?.openTab({ type: 'subagent', title: t('subagent') })
     }, AUTO_OPEN_DEBOUNCE_MS)
     autoOpenPendingRef.current = { baseline, timer }
   }, [sessionList, sessionId, store, ctx])
@@ -509,10 +509,10 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
     if (sessionId === undefined || prev === undefined) return
     if (!detectNewJob(prev, sessionList, sessionId)) return
     if (!store.getPrefs().autoOpenJobs) return
-    if (ctx.betterSidebar?.isTabEnabled('subagent') === false) return
+    if (ctx.get('betterSidebar')?.isTabEnabled('subagent') === false) return
     store.reduce(s => s.panelOpen ? s : togglePanel(s))
     store.reduce(s => ({ ...s, activePane: firstLeaf(s.splits).id }))
-    ctx.betterSidebar?.openTab({ type: 'subagent', title: t('subagent') })
+    ctx.get('betterSidebar')?.openTab({ type: 'subagent', title: t('subagent') })
   }, [sessionList, sessionId, store, ctx])
 
   /**
@@ -533,7 +533,7 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
     subagentJumpRef.current = undefined
     store.reduce(s => s.panelOpen ? s : togglePanel(s))
     store.reduce(s => ({ ...s, activePane: firstLeaf(s.splits).id }))
-    ctx.betterSidebar?.openTab({ type: 'subagent', title: t('subagent') })
+    ctx.get('betterSidebar')?.openTab({ type: 'subagent', title: t('subagent') })
   }, [sessionId, store, ctx])
 
   // The app shell's center column: the bottom panel spans ONLY that column
@@ -705,11 +705,11 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
     if (wasOpen === undefined || wasOpen || !state.bottomOpen) return
     if (state.bottomOpenedOnce) return
     if (store.getPrefs().bottomPanelAutoTerminal === false) return
-    if (ctx.betterSidebar?.isTabEnabled('terminal') === false) return
+    if (ctx.get('betterSidebar')?.isTabEnabled('terminal') === false) return
     // Land the tab in the bottom panel's first pane; the once-flag is set
     // atomically so later expansions never repeat the auto-open.
     store.reduce(s => ({ ...s, activePane: firstLeaf(s.bottomSplits).id, bottomOpenedOnce: true }))
-    ctx.betterSidebar?.openTab({ type: 'terminal' })
+    ctx.get('betterSidebar')?.openTab({ type: 'terminal' })
   }, [state, store, ctx, narrow])
 
   // Panel drags: the right panel's width (left edge strip), the bottom
@@ -980,7 +980,7 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
       // Route through the service: the tab-bar close is the canonical close
       // path (finds the pane itself, fires descriptor.onClose); the session
       // scope (with its cwd) rides to the callback.
-      ctx.betterSidebar?.closeTab(tabId, sessionId === undefined ? undefined : { sessionId, cwd })
+      ctx.get('betterSidebar')?.closeTab(tabId, sessionId === undefined ? undefined : { sessionId, cwd })
       if (tab?.type === 'terminal') {
         if (isAgentTabId(tabId)) {
           const uuid = agentUuidOf(tabId)
@@ -994,7 +994,7 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
       // Route through the service: same reducer (finds the pane in EITHER
       // tree, sets the active pane) and fires descriptor.onActivate; the
       // session scope (with its cwd) rides to the callback.
-      ctx.betterSidebar?.activateTab(tabId, sessionId === undefined ? undefined : { sessionId, cwd })
+      ctx.get('betterSidebar')?.activateTab(tabId, sessionId === undefined ? undefined : { sessionId, cwd })
     },
     focusPane: (paneId) => { store.reduce(s => ({ ...s, activePane: paneId })) },
     moveTabToEdge: (payload: TabDragPayload, toPane: string, zone: DropZone) => {
@@ -1051,9 +1051,9 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
   }
 
   const onNewTab = (optionId: string): void => {
-    const service = ctx.betterSidebar
+    const service = ctx.get('betterSidebar')
     const descriptor = service?.getTab(optionId)
-    if (descriptor === undefined) return
+    if (service === undefined || descriptor === undefined) return
     const title = typeof descriptor.title === 'function' ? descriptor.title() : descriptor.title
     // The session scope rides along: lifecycle callbacks receive it (and
     // the open stays in the current session, as before).
@@ -1068,7 +1068,7 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
    */
   /** The tab icon from the tab-type registry (shared by every workbench). */
   const tabIconOf = (tab: SidebarTab): ReactNode => {
-    const descriptor = ctx.betterSidebar?.getTab(tab.type)
+    const descriptor = ctx.get('betterSidebar')?.getTab(tab.type)
     if (descriptor === undefined) return null
     return typeof descriptor.icon === 'function' ? descriptor.icon(14) : descriptor.icon
   }
@@ -1079,7 +1079,7 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
    * strip must never break because a plugin's badge computation failed.
    */
   const tabBadgeOf = (tab: SidebarTab): ReactNode => {
-    const descriptor = ctx.betterSidebar?.getTab(tab.type)
+    const descriptor = ctx.get('betterSidebar')?.getTab(tab.type)
     if (descriptor?.badge === undefined) return null
     let value: string | number | null | undefined
     try {
diff --git a/src/client/index.tsx b/src/client/index.tsx
index 95b9530..6d973d6 100644
--- a/src/client/index.tsx
+++ b/src/client/index.tsx
@@ -363,7 +363,7 @@ export function apply(ctx: Context): void {
               let title: string | undefined
               try { title = new URL(url).hostname } catch { /* keep the default title */ }
               const type = urlTargetOf(new URL(url)) ?? 'browser'
-              ctx.betterSidebar?.openTab({ type, url, title })
+              ctx.get('betterSidebar')?.openTab({ type, url, title })
             },
             selfOrigin: window.location.origin,
           })
diff --git a/src/client/intercept.tsx b/src/client/intercept.tsx
index 7095c7a..eb4830f 100644
--- a/src/client/intercept.tsx
+++ b/src/client/intercept.tsx
@@ -22,7 +22,7 @@ export function openSidebarFile(ctx: Context, store: SidebarStore, sessionId: st
   const title = at === -1 ? absolute : absolute.slice(at + 1)
   // Route through the sidebar service so the editor descriptor's dedupeKey
   // (per-path) applies; the id is path-derived so multiple editors coexist.
-  ctx.betterSidebar?.openTab({ type: 'editor', title, path: absolute, id: `editor:${absolute}` })
+  ctx.get('betterSidebar')?.openTab({ type: 'editor', title, path: absolute, id: `editor:${absolute}` })
 }
 
 /** The intercepted produced-files row (visual twin of the deliverables chips). */
diff --git a/tests/bottom-auto-terminal.spec.tsx b/tests/bottom-auto-terminal.spec.tsx
index dfba81d..5cb23c4 100644
--- a/tests/bottom-auto-terminal.spec.tsx
+++ b/tests/bottom-auto-terminal.spec.tsx
@@ -65,6 +65,7 @@ function mountSidebar(): MountedSidebar {
     locale: { subscribe: () => () => {}, getSnapshot: () => localeSnapshot },
     sessions: { list: { subscribe: () => () => {}, getSnapshot: () => sessionsSnapshot } },
     betterSidebar: service,
+    get: (name: string) => name === 'betterSidebar' ? service : undefined,
   }
   const root: Root = createRoot(container)
   act(() => { root.render(createElement(Sidebar, { ctx: ctx as never, store })) })
diff --git a/tests/editor-host.spec.tsx b/tests/editor-host.spec.tsx
index 34bdf7f..b82257e 100644
--- a/tests/editor-host.spec.tsx
+++ b/tests/editor-host.spec.tsx
@@ -40,6 +40,7 @@ function setup(): {
   const sessionsSnapshot = { byId: { 'editor-home-session': { cwd: '/tmp' } }, current: 'editor-home-session' }
   const ctx = {
     betterSidebar: service,
+    get: (name: string) => name === 'betterSidebar' ? service : undefined,
     sessions: { list: { subscribe: () => () => {}, getSnapshot: () => sessionsSnapshot } },
   } as unknown as Context
   return { store, ctx, homeTab }
diff --git a/tests/openpath-intercept.spec.ts b/tests/openpath-intercept.spec.ts
index 763003f..8ad7bdc 100644
--- a/tests/openpath-intercept.spec.ts
+++ b/tests/openpath-intercept.spec.ts
@@ -108,6 +108,9 @@ describe('open-path interception wiring', () => {
       },
       workspaces: funnel,
       betterSidebar: { openTab: (seed: unknown) => { opened.push(seed as Record<string, unknown>) } },
+      get: (name: string) => name === 'betterSidebar'
+        ? { openTab: (seed: unknown) => { opened.push(seed as Record<string, unknown>) } }
+        : undefined,
     } as unknown as Context
     const store = createSidebarStore()
     const original = ctx.workspaces.openPath
diff --git a/tests/sidebar-crash.spec.tsx b/tests/sidebar-crash.spec.tsx
index 095ef86..e99fce9 100644
--- a/tests/sidebar-crash.spec.tsx
+++ b/tests/sidebar-crash.spec.tsx
@@ -68,6 +68,7 @@ function mountSidebar(): MountedSidebar {
     locale: { subscribe: () => () => {}, getSnapshot: () => localeSnapshot },
     sessions: { list: { subscribe: () => () => {}, getSnapshot: () => sessionsSnapshot } },
     betterSidebar: service,
+    get: (name: string) => name === 'betterSidebar' ? service : undefined,
   }
   const root: Root = createRoot(container)
   act(() => { root.render(createElement(Sidebar, { ctx: ctx as never, store })) })
diff --git a/tests/turn-tail-intercept.spec.ts b/tests/turn-tail-intercept.spec.ts
index 8504fa1..d709454 100644
--- a/tests/turn-tail-intercept.spec.ts
+++ b/tests/turn-tail-intercept.spec.ts
@@ -75,13 +75,17 @@ const producedOwner = (paths: string[]): unknown => ({
 const emptyOwner = (): unknown => ({ nodes: [{ kind: 'assistant', seq: 1, turn: 1 }], seq: 1 })
 
 /** The minimal client-context fake the registration (and its seats) touch. */
-const clientCtx = (slots: unknown): Context => ({
-  slots,
-  sessions: {
-    list: { getSnapshot: () => ({ current: 's1', byId: { s1: { id: 's1', cwd: '/w', displayTitle: 's1' } } }) },
-  },
-  betterSidebar: { openTab: vi.fn() },
-} as unknown as Context)
+const clientCtx = (slots: unknown): Context => {
+  const betterSidebar = { openTab: vi.fn() }
+  return {
+    slots,
+    sessions: {
+      list: { getSnapshot: () => ({ current: 's1', byId: { s1: { id: 's1', cwd: '/w', displayTitle: 's1' } } }) },
+    },
+    betterSidebar,
+    get: (name: string) => name === 'betterSidebar' ? betterSidebar : undefined,
+  } as unknown as Context
+}
 
 describe('turn-tail interception registration (issue #15)', () => {
   it('registers through slots.inject and lands once the slot is already declared', () => {