diff --git a/src/main/runtime/graph-sync-payload-partition.test.ts b/src/main/runtime/graph-sync-payload-partition.test.ts
new file mode 100644
index 00000000000..6533a53f9fb
--- /dev/null
+++ b/src/main/runtime/graph-sync-payload-partition.test.ts
@@ -0,0 +1,264 @@
+/**
+ * The renderer withholds unchanged mobile-session snapshots from the graph
+ * payload. Main must treat those worktrees as live rather than pruning them as
+ * removed, and must ask for a republish of any it no longer holds.
+ */
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import type {
+  RuntimeMobileSessionTabsResult,
+  RuntimeMobileSessionTabsSnapshot,
+  RuntimeSyncWindowGraphResult
+} from '../../shared/runtime-types'
+import type { WorkspaceSessionState } from '../../shared/types'
+import { OrcaRuntimeService } from './orca-runtime'
+
+const WT_A = 'repo-1::/tmp/worktree-a'
+const WT_B = 'repo-1::/tmp/worktree-b'
+
+const storeBase = {
+  getRepo: () => ({
+    id: 'repo-1',
+    path: '/tmp/repo',
+    displayName: 'repo',
+    badgeColor: 'blue',
+    addedAt: 1
+  }),
+  getRepos: () => [storeBase.getRepo()],
+  addRepo: () => {},
+  updateRepo: () => undefined as never,
+  getAllWorktreeMeta: () => ({}),
+  getWorktreeMeta: () => undefined,
+  getGitHubCache: () => ({ pr: {}, issue: {} }),
+  setWorktreeMeta: () => undefined as never,
+  removeWorktreeMeta: () => {},
+  getSettings: () => ({
+    workspaceDir: '/tmp/workspaces',
+    nestWorkspaces: false,
+    refreshLocalBaseRefOnWorktreeCreate: false,
+    branchPrefix: 'none',
+    branchPrefixCustom: ''
+  })
+}
+
+function makeSession(overrides: Partial<WorkspaceSessionState> = {}): WorkspaceSessionState {
+  return {
+    activeRepoId: 'repo-1',
+    activeWorktreeId: WT_A,
+    activeTabId: null,
+    tabsByWorktree: {},
+    terminalLayoutsByTabId: {},
+    ...overrides
+  }
+}
+
+function makeTerminalTab(id: string, ptyId: string) {
+  return {
+    id,
+    ptyId,
+    worktreeId: WT_A,
+    title: `Terminal ${id}`,
+    customTitle: null,
+    color: null,
+    sortOrder: 0,
+    createdAt: 1
+  }
+}
+
+type RuntimeInternals = {
+  mobileSessionTabsByWorktree: Map<string, RuntimeMobileSessionTabsSnapshot>
+}
+
+function createRuntime() {
+  let session = makeSession()
+  const runtime = new OrcaRuntimeService({
+    ...storeBase,
+    getWorkspaceSession: () => session,
+    setWorkspaceSession: (next: WorkspaceSessionState) => {
+      session = next
+    }
+  })
+  const events: RuntimeMobileSessionTabsResult[] = []
+  runtime.onMobileSessionTabsChanged((snapshot) => events.push(snapshot))
+  const setSession = (next: WorkspaceSessionState): void => {
+    session = next
+  }
+  const sync = (
+    mobileSessionTabs: RuntimeMobileSessionTabsSnapshot[],
+    unchangedMobileSessionWorktrees?: string[]
+  ): RuntimeSyncWindowGraphResult =>
+    runtime.syncWindowGraph(1, {
+      tabs: [],
+      leaves: [],
+      mobileSessionTabs,
+      ...(unchangedMobileSessionWorktrees ? { unchangedMobileSessionWorktrees } : {})
+    })
+  return { runtime, events, sync, setSession, internals: runtime as unknown as RuntimeInternals }
+}
+
+function makeSnapshot(worktree: string, version: number): RuntimeMobileSessionTabsSnapshot {
+  return {
+    worktree,
+    publicationEpoch: 'renderer:test-epoch',
+    snapshotVersion: version,
+    activeGroupId: 'group-1',
+    activeTabId: 'tab-1::leaf-1',
+    activeTabType: 'terminal',
+    tabs: [
+      {
+        type: 'terminal',
+        id: 'tab-1::leaf-1',
+        parentTabId: 'tab-1',
+        leafId: 'leaf-1',
+        title: `Terminal ${worktree}`,
+        isActive: true
+      }
+    ]
+  }
+}
+
+describe('graph-sync mobile payload partition', () => {
+  beforeEach(() => {
+    vi.useFakeTimers()
+  })
+
+  afterEach(() => {
+    vi.useRealTimers()
+  })
+
+  it('keeps a withheld worktree alive instead of pruning it as removed', () => {
+    const { events, sync, internals } = createRuntime()
+    sync([makeSnapshot(WT_A, 1), makeSnapshot(WT_B, 2)])
+    vi.advanceTimersByTime(300)
+    const storedB = internals.mobileSessionTabsByWorktree.get(WT_B)
+    expect(storedB).toBeDefined()
+    events.length = 0
+
+    // A publishes a change; B is withheld as unchanged rather than omitted.
+    sync([makeSnapshot(WT_A, 3)], [WT_B])
+    vi.advanceTimersByTime(300)
+
+    expect(internals.mobileSessionTabsByWorktree.get(WT_B)).toBe(storedB)
+    expect(events.filter((event) => 'removed' in event && event.removed === true)).toEqual([])
+    expect(events.map((event) => event.worktree)).toEqual([WT_A])
+  })
+
+  it('still prunes a worktree the renderer omits from both lists', () => {
+    const { events, sync, internals } = createRuntime()
+    sync([makeSnapshot(WT_A, 1), makeSnapshot(WT_B, 2)])
+    vi.advanceTimersByTime(300)
+    events.length = 0
+
+    sync([makeSnapshot(WT_A, 3)], [])
+    vi.advanceTimersByTime(300)
+
+    expect(internals.mobileSessionTabsByWorktree.has(WT_B)).toBe(false)
+    const removed = events.filter((event) => 'removed' in event && event.removed === true)
+    expect(removed.map((event) => event.worktree)).toEqual([WT_B])
+  })
+
+  it('asks for a republish of a withheld worktree it dropped, and accepts the resend', () => {
+    const { sync, internals } = createRuntime()
+    sync([makeSnapshot(WT_A, 1), makeSnapshot(WT_B, 2)])
+    vi.advanceTimersByTime(300)
+
+    // Main drops B on its own (worktree metadata removal) while the renderer
+    // still believes B is delivered.
+    internals.mobileSessionTabsByWorktree.delete(WT_B)
+
+    const result = sync([], [WT_A, WT_B])
+    vi.advanceTimersByTime(300)
+    expect(result.mobileSessionResyncWorktrees).toEqual([WT_B])
+    expect(internals.mobileSessionTabsByWorktree.has(WT_A)).toBe(true)
+
+    // The renderer republishes B at the SAME (epoch, version) it last sent. The
+    // accept gate must no longer treat that as an already-accepted no-op.
+    const resend = sync([makeSnapshot(WT_B, 2)], [WT_A])
+    vi.advanceTimersByTime(300)
+    expect(resend.mobileSessionResyncWorktrees).toBeUndefined()
+    expect(internals.mobileSessionTabsByWorktree.get(WT_B)?.tabs).toEqual([
+      expect.objectContaining({ parentTabId: 'tab-1' })
+    ])
+  })
+
+  it('asks for a republish when headless hydration masks a dropped renderer snapshot', () => {
+    const { sync, setSession, internals } = createRuntime()
+    setSession(
+      makeSession({
+        tabsByWorktree: { [WT_A]: [makeTerminalTab('serve-tab', 'serve-pty-1')] }
+      })
+    )
+    sync([makeSnapshot(WT_A, 1)])
+    internals.mobileSessionTabsByWorktree.delete(WT_A)
+
+    const result = sync([], [WT_A])
+    expect(result.mobileSessionResyncWorktrees).toEqual([WT_A])
+    expect(internals.mobileSessionTabsByWorktree.get(WT_A)?.publicationEpoch).toMatch(
+      /^headless-hydrated:/
+    )
+
+    const resend = sync([makeSnapshot(WT_A, 1)], [])
+    expect(resend.mobileSessionResyncWorktrees).toBeUndefined()
+    expect(
+      internals.mobileSessionTabsByWorktree
+        .get(WT_A)
+        ?.tabs.map((tab) => (tab.type === 'terminal' ? tab.parentTabId : tab.id))
+    ).toEqual(['tab-1', 'serve-tab'])
+  })
+
+  it('requests the accepted revision again to prune a stale preserved tab', () => {
+    const { sync, setSession, internals } = createRuntime()
+    setSession(
+      makeSession({
+        tabsByWorktree: { [WT_A]: [makeTerminalTab('serve-tab', 'serve-pty-1')] }
+      })
+    )
+    sync([makeSnapshot(WT_A, 1)])
+    expect(
+      internals.mobileSessionTabsByWorktree
+        .get(WT_A)
+        ?.tabs.some((tab) => tab.type === 'terminal' && tab.parentTabId === 'serve-tab')
+    ).toBe(true)
+
+    setSession(makeSession())
+    const result = sync([], [WT_A])
+    expect(result.mobileSessionResyncWorktrees).toEqual([WT_A])
+
+    sync([makeSnapshot(WT_A, 1)], [])
+    expect(
+      internals.mobileSessionTabsByWorktree
+        .get(WT_A)
+        ?.tabs.some((tab) => tab.type === 'terminal' && tab.parentTabId === 'serve-tab')
+    ).toBe(false)
+  })
+
+  it('does not request a renderer tab rejected by the retirement fence', () => {
+    const { sync, setSession, internals } = createRuntime()
+    setSession(
+      makeSession({
+        terminalTopologyRevisionByRepoId: { 'repo-1': 1 }
+      })
+    )
+
+    sync([makeSnapshot(WT_A, 1)])
+    expect(internals.mobileSessionTabsByWorktree.get(WT_A)?.tabs).toEqual([])
+
+    expect(sync([], [WT_A]).mobileSessionResyncWorktrees).toBeUndefined()
+    expect(sync([], [WT_A]).mobileSessionResyncWorktrees).toBeUndefined()
+  })
+
+  it('leaves the legacy full-payload contract untouched when no list is sent', () => {
+    const { events, sync, internals } = createRuntime()
+    sync([makeSnapshot(WT_A, 1), makeSnapshot(WT_B, 2)])
+    vi.advanceTimersByTime(300)
+    events.length = 0
+
+    // No unchangedMobileSessionWorktrees field at all: omission still prunes.
+    sync([makeSnapshot(WT_A, 3)])
+    vi.advanceTimersByTime(300)
+
+    expect(internals.mobileSessionTabsByWorktree.has(WT_B)).toBe(false)
+    expect(
+      events.filter((event) => 'removed' in event && event.removed === true).map((e) => e.worktree)
+    ).toEqual([WT_B])
+  })
+})
diff --git a/src/main/runtime/orca-runtime.ts b/src/main/runtime/orca-runtime.ts
index 15ed6e170af..1fdabae84f2 100644
--- a/src/main/runtime/orca-runtime.ts
+++ b/src/main/runtime/orca-runtime.ts
@@ -2723,7 +2723,12 @@ export class OrcaRuntimeService {
   // resend (or stale) and is skipped without touching the stored entry.
   private acceptedRendererMobileSnapshotByWorktree = new Map<
     string,
-    { publicationEpoch: string; rendererVersion: number }
+    {
+      publicationEpoch: string
+      rendererVersion: number
+      rendererTabCount: number
+      rendererTabIdentityKeys: ReadonlySet<string>
+    }
   >()
   private clientSessionTabSelections = new ClientSessionTabSelectionStore()
   // Why: idempotency map for mobile terminal creation — a retried create with the
@@ -5375,7 +5380,12 @@ export class OrcaRuntimeService {
     const previousLeaves = this.leaves
     this.tabs = new Map(graph.tabs.map((tab) => [tab.tabId, tab]))
     const lifecycleLeaves = this.reconcileMobileSessionRetirementFences(graph.leaves)
-    const changedMobileWorktrees = this.syncMobileSessionTabs(graph.mobileSessionTabs)
+    const mobileSessionResyncWorktrees = new Set<string>()
+    const changedMobileWorktrees = this.syncMobileSessionTabs(
+      graph.mobileSessionTabs,
+      graph.unchangedMobileSessionWorktrees,
+      mobileSessionResyncWorktrees
+    )
     const nextLeaves = new Map<string, RuntimeLeafRecord>()
     const graphSyncedAt = this.nextTitleObservationSequence()
 
@@ -5551,7 +5561,10 @@ export class OrcaRuntimeService {
     return {
       ...this.getStatus(),
       ...(agentOrchestrationByPaneKey ? { agentOrchestrationByPaneKey } : {}),
-      ...(nativeChatLaunchDraftResolutions.length > 0 ? { nativeChatLaunchDraftResolutions } : {})
+      ...(nativeChatLaunchDraftResolutions.length > 0 ? { nativeChatLaunchDraftResolutions } : {}),
+      ...(mobileSessionResyncWorktrees.size > 0
+        ? { mobileSessionResyncWorktrees: [...mobileSessionResyncWorktrees] }
+        : {})
     }
   }
 
@@ -23197,6 +23210,7 @@ export class OrcaRuntimeService {
       store.removeWorktreeMeta(worktreeId)
     }
     this.mobileSessionTabsByWorktree.delete(worktreeId)
+    this.acceptedRendererMobileSnapshotByWorktree.delete(worktreeId)
     advertisedUrlWatcher.forgetWorktree(worktreeId)
     deleteWorktreeHistoryDir(worktreeId)
     this.closeHeadlessBrowserPagesForWorktree(worktreeId)
@@ -28839,7 +28853,9 @@ export class OrcaRuntimeService {
   // Returns the worktrees whose stored snapshot object changed during this
   // sync, so the caller can fan out only actually-changed worktrees.
   private syncMobileSessionTabs(
-    snapshots: RuntimeMobileSessionTabsSnapshot[] | undefined
+    snapshots: RuntimeMobileSessionTabsSnapshot[] | undefined,
+    unchangedWorktreeIds?: string[],
+    resyncWorktreeIds: Set<string> = new Set()
   ): Set<string> {
     const changedWorktreeIds = new Set<string>()
     if (snapshots === undefined) {
@@ -28874,6 +28890,38 @@ export class OrcaRuntimeService {
       })
     }
     const nextWorktrees = new Set<string>()
+    const incomingWorktreeIds = new Set(snapshots.map((snapshot) => snapshot.worktree))
+    // Why: the renderer withholds unchanged snapshots to keep the graph payload
+    // small, so these worktrees are still live and must not fall into the prune
+    // below. Ask for a republish when main no longer holds that accepted renderer
+    // publication or a formerly-preserved runtime tab has gone stale.
+    for (const worktreeId of unchangedWorktreeIds ?? []) {
+      const existing = this.mobileSessionTabsByWorktree.get(worktreeId)
+      const accepted = this.acceptedRendererMobileSnapshotByWorktree.get(worktreeId)
+      if (existing) {
+        nextWorktrees.add(worktreeId)
+      }
+      if (
+        existing &&
+        accepted &&
+        (existing.publicationEpoch === accepted.publicationEpoch ||
+          existing.publicationEpoch.startsWith(`${accepted.publicationEpoch}:headless-merge:`)) &&
+        existing.tabs.length >= accepted.rendererTabCount &&
+        (existing.tabs.length === accepted.rendererTabCount ||
+          !this.storedMobileSnapshotHasStalePreservedTab(
+            existing,
+            accepted.rendererTabIdentityKeys
+          ))
+      ) {
+        continue
+      }
+      if (!incomingWorktreeIds.has(worktreeId)) {
+        resyncWorktreeIds.add(worktreeId)
+      }
+      // Why: the accept gate compares against the renderer's last accepted pair,
+      // which outlives the dropped snapshot and would reject the republish.
+      this.acceptedRendererMobileSnapshotByWorktree.delete(worktreeId)
+    }
     for (const snapshot of snapshots) {
       nextWorktrees.add(snapshot.worktree)
       const existing = this.mobileSessionTabsByWorktree.get(snapshot.worktree)
@@ -28898,7 +28946,7 @@ export class OrcaRuntimeService {
         !(
           existing &&
           snapshot.snapshotVersion === accepted.rendererVersion &&
-          this.storedMobileSnapshotHasStalePreservedTab(existing, snapshot)
+          this.storedMobileSnapshotHasStalePreservedTab(existing, accepted.rendererTabIdentityKeys)
         )
       ) {
         continue
@@ -28922,7 +28970,11 @@ export class OrcaRuntimeService {
       )
       this.acceptedRendererMobileSnapshotByWorktree.set(snapshot.worktree, {
         publicationEpoch: snapshot.publicationEpoch,
-        rendererVersion: snapshot.snapshotVersion
+        rendererVersion: snapshot.snapshotVersion,
+        rendererTabCount: fencedSnapshot.tabs.length,
+        rendererTabIdentityKeys: new Set(
+          fencedSnapshot.tabs.flatMap((tab) => this.getMobileSessionSnapshotTabIdentityKeys(tab))
+        )
       })
     }
     for (const [worktreeId, existing] of [...this.mobileSessionTabsByWorktree.entries()]) {
@@ -29044,22 +29096,19 @@ export class OrcaRuntimeService {
   }
 
   // Why: the accepted-revision no-op gate must not fossilize preserved runtime
-  // tabs. A stored merged snapshot's tabs that are absent from the incoming
-  // renderer publication exist only via preservation; if any such tab no longer
+  // tabs. A stored merged snapshot's tabs absent from the accepted renderer
+  // publication exist only via preservation; if any such tab no longer
   // passes the preservation predicate (binding removed from the live PTY table
-  // and persisted session, or browser page closed), the stored snapshot is
-  // stale even though the renderer revision is unchanged.
+  // and persisted session, or browser page closed), the stored snapshot is stale.
   private storedMobileSnapshotHasStalePreservedTab(
     existing: RuntimeMobileSessionTabsSnapshot,
-    incoming: RuntimeMobileSessionTabsSnapshot
+    rendererTabIdentityKeys: ReadonlySet<string>
   ): boolean {
-    const incomingIds = new Set(
-      incoming.tabs.flatMap((tab) => this.getMobileSessionSnapshotTabIdentityKeys(tab))
-    )
     return existing.tabs.some(
       (tab) =>
-        !this.getMobileSessionSnapshotTabIdentityKeys(tab).some((id) => incomingIds.has(id)) &&
-        !this.shouldPreserveHeadlessMobileSessionTab(existing, tab)
+        !this.getMobileSessionSnapshotTabIdentityKeys(tab).some((id) =>
+          rendererTabIdentityKeys.has(id)
+        ) && !this.shouldPreserveHeadlessMobileSessionTab(existing, tab)
     )
   }
 
diff --git a/src/renderer/src/runtime/sync-runtime-graph-payload-partition.test.ts b/src/renderer/src/runtime/sync-runtime-graph-payload-partition.test.ts
new file mode 100644
index 00000000000..aac5de9b2b7
--- /dev/null
+++ b/src/renderer/src/runtime/sync-runtime-graph-payload-partition.test.ts
@@ -0,0 +1,209 @@
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import {
+  scheduleRuntimeGraphSync,
+  setRuntimeGraphStoreStateGetter,
+  setRuntimeGraphSyncEnabled
+} from './sync-runtime-graph'
+import type { AppState } from '../store/types'
+import type { RuntimeSyncWindowGraph } from '../../../shared/runtime-types'
+
+function leafIdFor(index: number): string {
+  return `${String(index).padStart(8, '0')}-1111-4111-8111-111111111111`
+}
+
+/** Distinct ids per test: the publication memo is module state shared in this file. */
+function makeState(prefix: string, worktreeCount: number, titles: string[] = []): AppState {
+  const tabsByWorktree: Record<string, unknown[]> = {}
+  const terminalLayoutsByTabId: Record<string, unknown> = {}
+  for (let i = 0; i < worktreeCount; i++) {
+    const tabId = `${prefix}-term-${i}`
+    tabsByWorktree[`repo::/${prefix}-wt-${i}`] = [
+      { id: tabId, title: titles[i] ?? `Agent ${i}`, customTitle: null, ptyId: null }
+    ]
+    terminalLayoutsByTabId[tabId] = {
+      root: { type: 'leaf', leafId: leafIdFor(i) },
+      activeLeafId: leafIdFor(i),
+      expandedLeafId: null
+    }
+  }
+  return {
+    tabsByWorktree,
+    terminalLayoutsByTabId,
+    runtimePaneTitlesByTabId: {},
+    groupsByWorktree: {},
+    activeGroupIdByWorktree: {},
+    layoutByWorktree: {},
+    unifiedTabsByWorktree: {},
+    tabBarOrderByWorktree: {},
+    activeFileId: null,
+    activeFileIdByWorktree: {},
+    openFiles: [],
+    editorDrafts: {},
+    activeTabId: null,
+    agentStatusByPaneKey: {},
+    browserTabsByWorktree: {}
+  } as unknown as AppState
+}
+
+function graphOf(call: unknown[] | undefined): RuntimeSyncWindowGraph {
+  return call?.[0] as RuntimeSyncWindowGraph
+}
+
+function publishedWorktrees(call: unknown[] | undefined): string[] {
+  return (graphOf(call).mobileSessionTabs ?? []).map((snapshot) => snapshot.worktree).sort()
+}
+
+function withheldWorktrees(call: unknown[] | undefined): string[] {
+  return [...(graphOf(call).unchangedMobileSessionWorktrees ?? [])].sort()
+}
+
+async function flushSync(): Promise<void> {
+  await vi.advanceTimersByTimeAsync(20)
+  await Promise.resolve()
+  await Promise.resolve()
+}
+
+afterEach(() => {
+  setRuntimeGraphSyncEnabled(false)
+  setRuntimeGraphStoreStateGetter(null)
+  vi.useRealTimers()
+  vi.unstubAllGlobals()
+})
+
+function startSync(
+  state: AppState,
+  syncWindowGraph: ReturnType<typeof vi.fn>
+): { setState: (next: AppState) => void } {
+  let current = state
+  vi.useFakeTimers()
+  vi.stubGlobal('window', { api: { runtime: { syncWindowGraph } } })
+  vi.stubGlobal('HTMLElement', class HTMLElement {})
+  setRuntimeGraphStoreStateGetter(() => current)
+  setRuntimeGraphSyncEnabled(true)
+  return {
+    setState: (next: AppState) => {
+      current = next
+    }
+  }
+}
+
+describe('mobile session graph payload partition', () => {
+  it('withholds every unchanged worktree from the republished payload', async () => {
+    const syncWindowGraph = vi.fn().mockResolvedValue({})
+    startSync(makeState('a', 3), syncWindowGraph)
+
+    await flushSync()
+    expect(publishedWorktrees(syncWindowGraph.mock.calls[0])).toEqual([
+      'repo::/a-wt-0',
+      'repo::/a-wt-1',
+      'repo::/a-wt-2'
+    ])
+    expect(withheldWorktrees(syncWindowGraph.mock.calls[0])).toEqual([])
+
+    scheduleRuntimeGraphSync()
+    await flushSync()
+
+    expect(syncWindowGraph).toHaveBeenCalledTimes(2)
+    expect(publishedWorktrees(syncWindowGraph.mock.calls[1])).toEqual([])
+    expect(withheldWorktrees(syncWindowGraph.mock.calls[1])).toEqual([
+      'repo::/a-wt-0',
+      'repo::/a-wt-1',
+      'repo::/a-wt-2'
+    ])
+  })
+
+  it('publishes only the worktree whose snapshot changed', async () => {
+    const syncWindowGraph = vi.fn().mockResolvedValue({})
+    const { setState } = startSync(makeState('b', 3), syncWindowGraph)
+    await flushSync()
+
+    setState(makeState('b', 3, ['Agent 0', 'Agent 1 (done)', 'Agent 2']))
+    scheduleRuntimeGraphSync()
+    await flushSync()
+
+    expect(publishedWorktrees(syncWindowGraph.mock.calls[1])).toEqual(['repo::/b-wt-1'])
+    expect(withheldWorktrees(syncWindowGraph.mock.calls[1])).toEqual([
+      'repo::/b-wt-0',
+      'repo::/b-wt-2'
+    ])
+  })
+
+  it('republishes a changed worktree whose publication threw before it was acknowledged', async () => {
+    const syncWindowGraph = vi.fn().mockResolvedValue({})
+    const { setState } = startSync(makeState('c', 3), syncWindowGraph)
+    await flushSync()
+
+    // The publication carrying c-wt-1's new snapshot fails in flight.
+    setState(makeState('c', 3, ['Agent 0', 'Agent 1 (done)', 'Agent 2']))
+    syncWindowGraph.mockRejectedValueOnce(new Error('ipc closed'))
+    scheduleRuntimeGraphSync()
+    await flushSync()
+    expect(publishedWorktrees(syncWindowGraph.mock.calls[1])).toEqual(['repo::/c-wt-1'])
+
+    // Nothing changed since, but main never acknowledged it: resend, don't withhold.
+    scheduleRuntimeGraphSync()
+    await flushSync()
+
+    expect(syncWindowGraph).toHaveBeenCalledTimes(3)
+    expect(publishedWorktrees(syncWindowGraph.mock.calls[2])).toEqual(['repo::/c-wt-1'])
+    expect(withheldWorktrees(syncWindowGraph.mock.calls[2])).toEqual([
+      'repo::/c-wt-0',
+      'repo::/c-wt-2'
+    ])
+  })
+
+  it('resends everything when the first publication throws', async () => {
+    const syncWindowGraph = vi.fn().mockRejectedValueOnce(new Error('ipc closed'))
+    syncWindowGraph.mockResolvedValue({})
+    startSync(makeState('d', 3), syncWindowGraph)
+    await flushSync()
+    expect(publishedWorktrees(syncWindowGraph.mock.calls[0])).toHaveLength(3)
+
+    scheduleRuntimeGraphSync()
+    await flushSync()
+
+    expect(publishedWorktrees(syncWindowGraph.mock.calls[1])).toEqual([
+      'repo::/d-wt-0',
+      'repo::/d-wt-1',
+      'repo::/d-wt-2'
+    ])
+    expect(withheldWorktrees(syncWindowGraph.mock.calls[1])).toEqual([])
+  })
+
+  it('republishes worktrees main reports it dropped after acknowledging them', async () => {
+    const syncWindowGraph = vi.fn().mockResolvedValue({})
+    startSync(makeState('e', 3), syncWindowGraph)
+    await flushSync()
+
+    syncWindowGraph.mockResolvedValueOnce({ mobileSessionResyncWorktrees: ['repo::/e-wt-2'] })
+    scheduleRuntimeGraphSync()
+    await flushSync()
+    expect(withheldWorktrees(syncWindowGraph.mock.calls[1])).toHaveLength(3)
+
+    // The resync reply schedules its own republish; no store change is needed.
+    await flushSync()
+
+    expect(syncWindowGraph).toHaveBeenCalledTimes(3)
+    expect(publishedWorktrees(syncWindowGraph.mock.calls[2])).toEqual(['repo::/e-wt-2'])
+    expect(withheldWorktrees(syncWindowGraph.mock.calls[2])).toEqual([
+      'repo::/e-wt-0',
+      'repo::/e-wt-1'
+    ])
+  })
+
+  it('drops a removed worktree from both the payload and the withheld list', async () => {
+    const syncWindowGraph = vi.fn().mockResolvedValue({})
+    const { setState } = startSync(makeState('f', 3), syncWindowGraph)
+    await flushSync()
+
+    setState(makeState('f', 2))
+    scheduleRuntimeGraphSync()
+    await flushSync()
+
+    expect(publishedWorktrees(syncWindowGraph.mock.calls[1])).toEqual([])
+    expect(withheldWorktrees(syncWindowGraph.mock.calls[1])).toEqual([
+      'repo::/f-wt-0',
+      'repo::/f-wt-1'
+    ])
+  })
+})
diff --git a/src/renderer/src/runtime/sync-runtime-graph.ts b/src/renderer/src/runtime/sync-runtime-graph.ts
index 63f578c7dfb..0f8e28b7fe6 100644
--- a/src/renderer/src/runtime/sync-runtime-graph.ts
+++ b/src/renderer/src/runtime/sync-runtime-graph.ts
@@ -217,6 +217,9 @@ const EMPTY_WORKTREE_UNIFIED_TABS: AppState['unifiedTabsByWorktree'][string] = [
 const EMPTY_WORKTREE_TAB_GROUPS: AppState['groupsByWorktree'][string] = []
 const EMPTY_WORKTREE_OPEN_FILE_IDS: readonly string[] = []
 const mobileSessionPublicationEpoch = `renderer:${createBrowserUuid()}`
+// Why: the snapshot object main last acknowledged per worktree; anything still
+// identical is withheld from the graph payload instead of re-cloned across IPC.
+const publishedMobileSessionSnapshotByWorktree = new Map<string, RuntimeMobileSessionTabsSnapshot>()
 
 export function setRuntimeGraphStoreStateGetter(getter: (() => AppState) | null): void {
   getStoreState = getter
@@ -698,10 +701,13 @@ async function syncRuntimeGraph(): Promise<void> {
       .map((tab) => [tab.id, tab])
   )
   const generatedTitlesEnabled = state.settings?.tabAutoGenerateTitle === true
+  const mobileSessionTabs = buildMobileSessionTabSnapshots(state, systemPrefersDark)
+  const publication = partitionMobileSessionPublication(mobileSessionTabs)
   const graph: RuntimeSyncWindowGraph = {
     tabs: [],
     leaves: [],
-    mobileSessionTabs: buildMobileSessionTabSnapshots(state, systemPrefersDark)
+    mobileSessionTabs: publication.changed,
+    unchangedMobileSessionWorktrees: publication.unchangedWorktrees
   }
 
   for (const [tabId, registeredTab] of registeredTabs) {
@@ -811,6 +817,9 @@ async function syncRuntimeGraph(): Promise<void> {
 
   try {
     const result = await window.api.runtime.syncWindowGraph(graph)
+    // Why: only an acknowledged publication may be treated as delivered. A throw
+    // leaves the memo behind, so the retry resends every worktree in full.
+    commitMobileSessionPublication(mobileSessionTabs, result?.mobileSessionResyncWorktrees)
     const currentState = getStoreState()
     currentState?.setRuntimeAgentOrchestrationByPaneKey?.(result?.agentOrchestrationByPaneKey ?? {})
     for (const resolution of result?.nativeChatLaunchDraftResolutions ?? []) {
@@ -821,11 +830,53 @@ async function syncRuntimeGraph(): Promise<void> {
         })
       }
     }
+    if (result?.mobileSessionResyncWorktrees?.length) {
+      scheduleRuntimeGraphSync()
+    }
   } catch (error) {
     console.error('[runtime] Failed to sync renderer graph:', error)
   }
 }
 
+function partitionMobileSessionPublication(snapshots: RuntimeMobileSessionTabsSnapshot[]): {
+  changed: RuntimeMobileSessionTabsSnapshot[]
+  unchangedWorktrees: string[]
+} {
+  const changed: RuntimeMobileSessionTabsSnapshot[] = []
+  const unchangedWorktrees: string[] = []
+  for (const snapshot of snapshots) {
+    // Why: buildMobileSessionTabSnapshots returns the cached object for a worktree
+    // it did not rebuild, so identity — not a deep compare — settles this.
+    if (publishedMobileSessionSnapshotByWorktree.get(snapshot.worktree) === snapshot) {
+      unchangedWorktrees.push(snapshot.worktree)
+    } else {
+      changed.push(snapshot)
+    }
+  }
+  return { changed, unchangedWorktrees }
+}
+
+function commitMobileSessionPublication(
+  snapshots: RuntimeMobileSessionTabsSnapshot[],
+  resyncWorktrees: string[] | undefined
+): void {
+  const published = new Set<string>()
+  for (const snapshot of snapshots) {
+    published.add(snapshot.worktree)
+    publishedMobileSessionSnapshotByWorktree.set(snapshot.worktree, snapshot)
+  }
+  for (const worktreeId of publishedMobileSessionSnapshotByWorktree.keys()) {
+    if (!published.has(worktreeId)) {
+      publishedMobileSessionSnapshotByWorktree.delete(worktreeId)
+    }
+  }
+  // Why: main dropped these after acknowledging them, so forget the delivery and
+  // let the scheduled resync republish them in full.
+  for (const worktreeId of resyncWorktrees ?? []) {
+    publishedMobileSessionSnapshotByWorktree.delete(worktreeId)
+  }
+}
+
 function narrowRecordByKeys<T>(
   source: Record<string, T> | undefined,
   keys: readonly string[]
diff --git a/src/shared/runtime-types.ts b/src/shared/runtime-types.ts
index c8291e35fb1..06821f7ff7f 100644
--- a/src/shared/runtime-types.ts
+++ b/src/shared/runtime-types.ts
@@ -143,7 +143,11 @@ export type RuntimeSyncedLeaf = {
 export type RuntimeSyncWindowGraph = {
   tabs: RuntimeSyncedTab[]
   leaves: RuntimeSyncedLeaf[]
+  /** Only worktrees whose snapshot changed since the last acknowledged publication. */
   mobileSessionTabs?: RuntimeMobileSessionTabsSnapshot[]
+  /** Worktrees the renderer is still publishing unchanged; main must keep their
+   *  stored snapshots alive instead of pruning them as removed. */
+  unchangedMobileSessionWorktrees?: string[]
 }
 
 export type RuntimeNativeChatLaunchDraftResolution = {
@@ -157,6 +161,9 @@ export type RuntimeSyncWindowGraphResult = RuntimeStatus & {
    *  parent metadata needed by title-derived agent rows without name guessing. */
   agentOrchestrationByPaneKey?: Record<string, AgentStatusOrchestrationContext>
   nativeChatLaunchDraftResolutions?: RuntimeNativeChatLaunchDraftResolution[]
+  /** Worktrees the renderer withheld as unchanged that main holds no snapshot
+   *  for — it dropped them independently, so the renderer must republish them. */
+  mobileSessionResyncWorktrees?: string[]
 }
 
 export type RuntimeMobileSessionTerminalTab = {