diff --git a/apps/desktop/src/app/chat/composer/status-stack/coding-row.tsx b/apps/desktop/src/app/chat/composer/status-stack/coding-row.tsx
index 6ad820765e5..4d25320d952 100644
--- a/apps/desktop/src/app/chat/composer/status-stack/coding-row.tsx
+++ b/apps/desktop/src/app/chat/composer/status-stack/coding-row.tsx
@@ -16,8 +16,6 @@ import { DiffCount } from '@/components/ui/diff-count'
 import type { HermesGitBranch } from '@/global'
 import { useI18n } from '@/i18n'
 import {
-  $repoStatus,
-  $repoWorktrees,
   registerRepoStatusCwd,
   repoStatusForCwd,
   repoWorktreesForCwd
@@ -69,10 +67,13 @@ export const CodingStatusRow = memo(function CodingStatusRow({
   const s = t.statusStack.coding
   const p = t.sidebar.projects
   const resolvedRepoPath = repoPath?.trim() || undefined
-  // Per-cwd slice when this surface knows its worktree (tiles); otherwise the
-  // primary main-pane computed — so a blank/missing repoPath still paints.
-  const status = useStore(resolvedRepoPath ? repoStatusForCwd(resolvedRepoPath) : $repoStatus)
-  const worktrees = useStore(resolvedRepoPath ? repoWorktreesForCwd(resolvedRepoPath) : $repoWorktrees)
+  // This surface's OWN worktree, always — never the primary's. The row used to
+  // fall back to the global `$repoStatus` for a blank repoPath, which painted
+  // the main pane's branch/± onto a tile whose cwd hadn't resolved yet. That
+  // fallback bought nothing (the primary's computed is keyed to `$currentCwd`,
+  // which is blank in exactly the same case) and cost a wrong-tree rail.
+  const status = useStore(repoStatusForCwd(resolvedRepoPath))
+  const worktrees = useStore(repoWorktreesForCwd(resolvedRepoPath))
 
   // While mounted, keep this worktree in the coding-status refresh set so the
   // turn-settle / tool-complete / focus edges re-probe it too (tiles otherwise
diff --git a/apps/desktop/src/app/session/hooks/use-session-actions/index.ts b/apps/desktop/src/app/session/hooks/use-session-actions/index.ts
index 266a33b65fd..9bcabd6d3bb 100644
--- a/apps/desktop/src/app/session/hooks/use-session-actions/index.ts
+++ b/apps/desktop/src/app/session/hooks/use-session-actions/index.ts
@@ -504,7 +504,9 @@ export function useSessionActions({
           upsertOptimisticSession(created, stored, null, null)
         }
 
-        const runtimeInfo = applyRuntimeInfo(created.info)
+        // A tile lives in its OWN worktree — it must not publish its cwd/branch
+        // into the composer atoms the main pane renders from.
+        const runtimeInfo = applyRuntimeInfo(created.info, { foreground: false })
         updateSessionState(created.session_id, state => (runtimeInfo ? { ...state, ...runtimeInfo } : state), stored)
 
         openSessionTile(stored, dir)
@@ -1182,7 +1184,9 @@ export function useSessionActions({
           routedSessionId
         )
 
-        const runtimeInfo = applyRuntimeInfo(branched.info)
+        // The branch opens as its own tile in the parent's worktree, not as the
+        // primary session — keep its runtime out of the main composer atoms.
+        const runtimeInfo = applyRuntimeInfo(branched.info, { foreground: false })
         patchSessionWorkspace(routedSessionId, runtimeInfo?.cwd)
 
         if (runtimeInfo) {
diff --git a/apps/desktop/src/app/session/hooks/use-session-actions/utils.test.ts b/apps/desktop/src/app/session/hooks/use-session-actions/utils.test.ts
index a83f8a38402..ea40e7705ad 100644
--- a/apps/desktop/src/app/session/hooks/use-session-actions/utils.test.ts
+++ b/apps/desktop/src/app/session/hooks/use-session-actions/utils.test.ts
@@ -4,6 +4,7 @@ import type { ChatMessage } from '@/lib/chat-messages'
 import { $approvalModes, approvalModeForProfile } from '@/store/approval-mode'
 import { $desktopOnboarding } from '@/store/onboarding'
 import { $activeGatewayProfile } from '@/store/profile'
+import { $currentBranch, $currentCwd, setCurrentBranch, setCurrentCwd } from '@/store/session'
 import type { SessionInfo } from '@/types/hermes'
 
 import {
@@ -65,6 +66,36 @@ describe('applyRuntimeInfo credential warnings', () => {
   })
 })
 
+describe('applyRuntimeInfo foreground scoping', () => {
+  beforeEach(() => {
+    setCurrentCwd('/main-repo')
+    setCurrentBranch('main')
+  })
+
+  afterEach(() => {
+    setCurrentCwd('')
+    setCurrentBranch('')
+  })
+
+  it('publishes a foreground runtime into the composer atoms', () => {
+    const patch = applyRuntimeInfo({ branch: 'bb/feature', cwd: '/main-repo/worktree' })
+
+    expect($currentCwd.get()).toBe('/main-repo/worktree')
+    expect($currentBranch.get()).toBe('bb/feature')
+    expect(patch).toMatchObject({ branch: 'bb/feature', cwd: '/main-repo/worktree' })
+  })
+
+  it('keeps a background runtime out of the composer atoms but still returns its patch', () => {
+    const patch = applyRuntimeInfo({ branch: 'bb/tile', cwd: '/other-worktree' }, { foreground: false })
+
+    // The main pane's rail must stay on its own tree.
+    expect($currentCwd.get()).toBe('/main-repo')
+    expect($currentBranch.get()).toBe('main')
+    // ...while the caller still gets everything it needs for its own session.
+    expect(patch).toMatchObject({ branch: 'bb/tile', cwd: '/other-worktree' })
+  })
+})
+
 describe('isSessionGoneError', () => {
   it('is true for 404 / session-not-found, false otherwise', () => {
     expect(isSessionGoneError(new Error('Request failed 404'))).toBe(true)
diff --git a/apps/desktop/src/app/session/hooks/use-session-actions/utils.ts b/apps/desktop/src/app/session/hooks/use-session-actions/utils.ts
index 2c0913fb6dc..1f86fd7c406 100644
--- a/apps/desktop/src/app/session/hooks/use-session-actions/utils.ts
+++ b/apps/desktop/src/app/session/hooks/use-session-actions/utils.ts
@@ -706,13 +706,72 @@ type SessionRuntimeStatePatch = Partial<
   >
 >
 
-export function applyRuntimeInfo(info: SessionRuntimeInfo | undefined): SessionRuntimeStatePatch | null {
+interface ApplyRuntimeInfoOptions {
+  /**
+   * Whether this runtime belongs to the session the MAIN pane is showing.
+   * Foreground (the default) mirrors into the composer atoms every main-pane
+   * surface reads.
+   *
+   * A tile or a background branch must pass `false`: it owns a different
+   * worktree, and writing its cwd into `$currentCwd` re-pointed the main
+   * composer's coding rail (and the persisted workspace cwd) at the tile's
+   * repo — the main rail painted a branch from a tree its session was never
+   * in. The returned patch still carries every field, so the caller's own
+   * per-session state is unaffected.
+   */
+  foreground?: boolean
+}
+
+/** Mirror a session's runtime state into the composer atoms the MAIN pane
+ *  renders from. Foreground sessions only — see ApplyRuntimeInfoOptions. */
+function publishRuntimeToComposer(state: SessionRuntimeStatePatch): void {
+  if (state.model !== undefined) {
+    setCurrentModel(state.model)
+  }
+
+  if (state.provider !== undefined) {
+    setCurrentProvider(state.provider)
+  }
+
+  if (state.cwd !== undefined) {
+    setCurrentCwd(state.cwd)
+  }
+
+  if (state.branch !== undefined) {
+    setCurrentBranch(state.branch)
+  }
+
+  if (state.personality !== undefined) {
+    setCurrentPersonality(state.personality)
+  }
+
+  if (state.reasoningEffort !== undefined) {
+    setCurrentReasoningEffort(state.reasoningEffort)
+  }
+
+  if (state.serviceTier !== undefined) {
+    setCurrentServiceTier(state.serviceTier)
+  }
+
+  if (state.fast !== undefined) {
+    setCurrentFastMode(state.fast)
+  }
+
+  if (state.yolo !== undefined) {
+    setYoloActive(state.yolo)
+  }
+}
+
+export function applyRuntimeInfo(
+  info: SessionRuntimeInfo | undefined,
+  { foreground = true }: ApplyRuntimeInfoOptions = {}
+): SessionRuntimeStatePatch | null {
   if (!info) {
     return null
   }
 
-  const sessionState: SessionRuntimeStatePatch = {}
-
+  // App/profile-level reporting is session-independent — a tile's runtime
+  // reports backend skew and credential warnings just as usefully.
   reportBackendContract(info.desktop_contract)
 
   if (info.approval_mode !== undefined) {
@@ -723,54 +782,50 @@ export function applyRuntimeInfo(info: SessionRuntimeInfo | undefined): SessionR
 
   reportInstallMethodWarning(info.install_warning)
 
+  const sessionState: SessionRuntimeStatePatch = {}
+
   if (typeof info.model === 'string') {
-    setCurrentModel(info.model)
     sessionState.model = info.model
   }
 
   if (typeof info.provider === 'string') {
-    setCurrentProvider(info.provider)
     sessionState.provider = info.provider
   }
 
   if (info.cwd) {
-    setCurrentCwd(info.cwd)
     sessionState.cwd = info.cwd
   }
 
   if (info.branch !== undefined) {
-    setCurrentBranch(info.branch || '')
     sessionState.branch = info.branch || ''
   }
 
   if (typeof info.personality === 'string') {
-    const personality = normalizePersonalityValue(info.personality)
-    setCurrentPersonality(personality)
-    sessionState.personality = personality
+    sessionState.personality = normalizePersonalityValue(info.personality)
   }
 
   if (typeof info.reasoning_effort === 'string') {
-    setCurrentReasoningEffort(info.reasoning_effort)
     sessionState.reasoningEffort = info.reasoning_effort
   }
 
   if (typeof info.service_tier === 'string') {
-    setCurrentServiceTier(info.service_tier)
     sessionState.serviceTier = info.service_tier
   }
 
   if (typeof info.fast === 'boolean') {
-    setCurrentFastMode(info.fast)
     sessionState.fast = info.fast
   }
 
   if (typeof info.yolo === 'boolean') {
-    setYoloActive(info.yolo)
     sessionState.yolo = info.yolo
   }
 
-  if (info.usage) {
-    setCurrentUsage(current => ({ ...current, ...info.usage }))
+  if (foreground) {
+    publishRuntimeToComposer(sessionState)
+
+    if (info.usage) {
+      setCurrentUsage(current => ({ ...current, ...info.usage }))
+    }
   }
 
   return sessionState