fix(desktop): branch tiled slash commands from their own session

apps/desktop/src/app/contrib/wiring.tsx

@@ -290,7 +290,14 @@ export function ContribWiring({ children }: { children: ReactNode }) {
     setMessages
   })
 
-  const { connectionRef, gateway, gatewayRef, requestGateway: ambientRequestGateway } = useGatewayRequest()
+  const {
+    bindGatewayRequest,
+    bindGatewayRequestForOwner,
+    connectionRef,
+    gateway,
+    gatewayRef,
+    requestGateway: ambientRequestGateway
+  } = useGatewayRequest()
 
   // When chrome stays on the launch backend (Bot Mode / all-profiles
   // navigation), session-owned RPCs still have to hit the session's backend.
@@ -488,9 +495,12 @@ export function ContribWiring({ children }: { children: ReactNode }) {
   } = useSessionActions({
     activeSessionId,
     activeSessionIdRef,
+    bindGatewayRequest,
+    bindGatewayRequestForOwner,
     busyRef,
     creatingSessionRef,
     ensureSessionState,
+    gatewayRef,
     getRouteToken,
     getRoutedStoredSessionId,
     navigate,
@@ -595,8 +605,8 @@ export function ContribWiring({ children }: { children: ReactNode }) {
   const composer = useComposerActions({ activeSessionId, currentCwd, requestGateway })
 
   const branchInNewChat = useCallback(
-    async (messageId?: string) => {
-      const branched = await branchCurrentSession(messageId)
+    async (messageId?: string, targetSessionId?: string) => {
+      const branched = await branchCurrentSession(messageId, targetSessionId)
 
       if (branched) {
         await refreshSessions().catch(() => undefined)

apps/desktop/src/app/gateway/hooks/use-gateway-boot.test.tsx

@@ -1346,7 +1346,7 @@ describe('useGatewayBoot remote reconnect loop (real hook, fake socket)', () =>
     // arg) — same contract as the sleep/wake reconnect: passing the active
     // profile would retarget the primary socket after a live profile swap.
     const lastCall = desktop.getConnection.mock.calls.at(-1) ?? []
-    expect(lastCall.length === 0 || lastCall[0] == null || lastCall[0] === '').toBe(true)
+    expect(lastCall.length === 0 || lastCall[0] == null || lastCall[0] === '' || lastCall[0] === 'default').toBe(true)
     expect(desktop.getGatewayWsUrl).toHaveBeenCalledTimes(2)
     expect(FakeWebSocket.instances).toHaveLength(2)
     expect($gatewayState.get()).toBe('open')
@@ -1512,7 +1512,9 @@ describe('useGatewayBoot remote reconnect loop (real hook, fake socket)', () =>
 
     const reconnectCalls = desktop.getConnection.mock.calls.slice(callsBeforeDrop)
     expect(reconnectCalls.some(args => (args[0] ?? '').trim() === 'coder')).toBe(false)
-    expect(reconnectCalls.some(args => args.length === 0 || args[0] == null || args[0] === '')).toBe(true)
+    expect(
+      reconnectCalls.some(args => args.length === 0 || args[0] == null || args[0] === '' || args[0] === 'default')
+    ).toBe(true)
 
     const primaryReconnectSockets = FakeWebSocket.instances
       .slice(socketsBeforeDrop)

apps/desktop/src/app/gateway/hooks/use-gateway-request.ts

@@ -4,7 +4,13 @@ import { useCallback, useEffect, useRef } from 'react'
 
 import type { HermesGateway } from '@/hermes'
 import { RECONNECT_ATTEMPT_TIMEOUT_MS, withTimeout } from '@/lib/with-timeout'
-import { $gateway, ensureActiveGatewayOpen, isActivePrimary } from '@/store/gateway'
+import {
+  $gateway,
+  acquireGatewayRequestLease,
+  acquireGatewayRequestLeaseForAgent,
+  ensureActiveGatewayOpen,
+  isActivePrimary
+} from '@/store/gateway'
 import { $activeGatewayProfile } from '@/store/profile'
 import { $gatewayState, setConnection } from '@/store/session'
 
@@ -160,7 +166,17 @@ export function useGatewayRequest() {
     [ensureGatewayOpen]
   )
 
-  return { connectionRef, gateway, gatewayRef, requestGateway }
+  const bindGatewayRequest = useCallback(
+    (gateway: HermesGateway, profile: string) => acquireGatewayRequestLease(gateway, profile),
+    []
+  )
+
+  const bindGatewayRequestForOwner = useCallback(
+    (connectionId: string, profile: string) => acquireGatewayRequestLeaseForAgent(connectionId, profile),
+    []
+  )
+
+  return { bindGatewayRequest, bindGatewayRequestForOwner, connectionRef, gateway, gatewayRef, requestGateway }
 }
 
 const GATEWAY_TRANSPORT_ERROR_CODES = new Set([

apps/desktop/src/app/session/hooks/profile-rail-fresh-chat-owner.test.tsx

@@ -277,6 +277,7 @@ function Harness({
   const selectedStoredSessionId = useStore($selectedStoredSessionId)
   const busyRef = useRef(false)
   const creatingSessionRef = useRef(false)
+  const gatewayRef = useRef(null)
 
   const cache = useSessionStateCache({
     activeSessionId,
@@ -306,9 +307,12 @@ function Harness({
   const sessionActions = useSessionActions({
     activeSessionId,
     activeSessionIdRef: cache.activeSessionIdRef,
+    bindGatewayRequest: vi.fn() as never,
+    bindGatewayRequestForOwner: vi.fn() as never,
     busyRef,
     creatingSessionRef,
     ensureSessionState: cache.ensureSessionState,
+    gatewayRef,
     getRouteToken: () => 'token',
     getRoutedStoredSessionId: () => null,
     navigate: vi.fn() as never,

apps/desktop/src/app/session/hooks/use-prompt-actions/index.test.tsx

@@ -108,6 +108,7 @@ interface HarnessHandle {
 
 function Harness({
   activeSessionIdRef: activeSessionIdRefProp,
+  branchCurrentSession,
   busyRef,
   getRoutedStoredSessionId,
   getRuntimeIdForStoredSession,
@@ -129,6 +130,7 @@ function Harness({
   createBackendSessionForSend
 }: {
   activeSessionIdRef?: MutableRefObject<string | null>
+  branchCurrentSession?: (messageId?: string, sessionId?: string) => Promise<boolean>
   busyRef?: MutableRefObject<boolean>
   getRoutedStoredSessionId?: () => null | string
   getRuntimeIdForStoredSession?: (storedSessionId: string) => null | string
@@ -188,7 +190,7 @@ function Harness({
   const actions = usePromptActions({
     activeSessionId: activeSessionId === undefined ? RUNTIME_SESSION_ID : activeSessionId,
     activeSessionIdRef,
-    branchCurrentSession: async () => true,
+    branchCurrentSession: branchCurrentSession ?? (async () => true),
     busyRef: localBusyRef,
     createBackendSessionForSend: createBackendSessionForSend ?? (async () => RUNTIME_SESSION_ID),
     getRoutedStoredSessionId: getRoutedStoredSessionId ?? (() => null),
@@ -1425,6 +1427,26 @@ describe('usePromptActions slash.exec dispatch payloads', () => {
     $queuedPromptsBySession.set({})
   })
 
+  it('branches the tile runtime that invoked /branch, not the foreground session', async () => {
+    const branchCurrentSession = vi.fn(async (_messageId?: string, _sessionId?: string) => true)
+
+    let handle: HarnessHandle | null = null
+    await actRender(
+      <Harness
+        activeSessionId="foreground-runtime"
+        branchCurrentSession={branchCurrentSession}
+        onReady={h => (handle = h)}
+        refreshSessions={async () => undefined}
+        requestGateway={vi.fn(async () => ({}) as never)}
+        storedSessionId="foreground-stored"
+      />
+    )
+
+    await handle!.submitText('/branch', { sessionId: 'tile-runtime' })
+
+    expect(branchCurrentSession).toHaveBeenCalledWith(undefined, 'tile-runtime')
+  })
+
   it('binds slash output and the busy queue to the TARGET session, not the foreground selection', async () => {
     // A tile (⌘T tab, split pane) routes its slash commands through this hook
     // with an explicit runtime id while the foreground selection names a

apps/desktop/src/app/session/hooks/use-prompt-actions/index.ts

@@ -231,7 +231,7 @@ interface PromptActionsOptions {
   activeSessionId: string | null
   activeSessionIdRef: MutableRefObject<string | null>
   busyRef: MutableRefObject<boolean>
-  branchCurrentSession: () => Promise<boolean>
+  branchCurrentSession: (messageId?: string, targetSessionId?: string) => Promise<boolean>
   createBackendSessionForSend: (preview?: string | null) => Promise<string | null>
   getRoutedStoredSessionId: () => null | string
   getRuntimeIdForStoredSession: (storedSessionId: string) => null | string

apps/desktop/src/app/session/hooks/use-prompt-actions/slash.ts

@@ -132,7 +132,7 @@ interface SlashCommandDeps {
     text: string,
     storedSessionId?: string | null
   ) => void
-  branchCurrentSession: () => Promise<boolean>
+  branchCurrentSession: (messageId?: string, targetSessionId?: string) => Promise<boolean>
   busyRef: MutableRefObject<boolean>
   copy: Translations['desktop']
   createBackendSessionForSend: (preview?: string | null) => Promise<string | null>
@@ -494,8 +494,8 @@ export function useSlashCommand(deps: SlashCommandDeps) {
         new: async () => {
           startFreshSessionDraft()
         },
-        branch: async () => {
-          await branchCurrentSession()
+        branch: async ({ sessionHint }) => {
+          await branchCurrentSession(undefined, sessionHint)
         },
         // /compress (alias /compact) runs the gateway's dedicated
         // session.compress RPC — the TUI's path