diff --git a/src/renderer/src/lib/agent-hibernation-coordinator.test.ts b/src/renderer/src/lib/agent-hibernation-coordinator.test.ts
index bbb83ea5cca..855fc5ff2b2 100644
--- a/src/renderer/src/lib/agent-hibernation-coordinator.test.ts
+++ b/src/renderer/src/lib/agent-hibernation-coordinator.test.ts
@@ -543,6 +543,53 @@ describe('agent sleep coordinator', () => {
     ).toHaveLength(3)
   })
 
+  it('revalidates a confirmed pane without listing unrelated runtime worktrees', async () => {
+    installRuntimeListResponses(...Array.from({ length: 5 }, () => runtimeListResult(['pty-1'])))
+    const shutdown = installEligibleState(vi.fn().mockResolvedValue(undefined), {
+      settings: {
+        experimentalAgentHibernation: true,
+        agentHibernationIdleMs: DEFAULT_AGENT_HIBERNATION_IDLE_MS,
+        activeRuntimeEnvironmentId: 'runtime-1'
+      } as never,
+      worktreesByRepo: {
+        'fixture-repo': [
+          {
+            id: 'wt-bg',
+            repoId: 'fixture-repo',
+            hostId: 'runtime:runtime-1',
+            runtimeOwnerEnvironmentId: 'runtime-1'
+          },
+          {
+            id: 'wt-unrelated',
+            repoId: 'fixture-repo',
+            hostId: 'runtime:runtime-2',
+            runtimeOwnerEnvironmentId: 'runtime-2'
+          }
+        ]
+      } as never,
+      tabsByWorktree: {
+        'wt-bg': [tab()],
+        'wt-unrelated': [{ ...tab(), id: 'tab-2', worktreeId: 'wt-unrelated' }]
+      },
+      ptyIdsByTabId: { 'tab-1': [] }
+    })
+
+    await runAgentHibernationTick()
+    await runAgentHibernationTick()
+
+    expect(shutdown).toHaveBeenCalledTimes(1)
+    const listCalls = mockRuntimeEnvironmentCall.mock.calls.filter(
+      ([args]) => args.method === 'terminal.list'
+    )
+    // Two global confirmation samples list both worktrees; the destructive
+    // recheck lists only the candidate's owner: 2W + C, not 2W + C×W.
+    expect(listCalls).toHaveLength(5)
+    expect(listCalls.at(-1)?.[0]).toMatchObject({
+      selector: 'runtime-1',
+      params: { worktree: expect.anything() }
+    })
+  })
+
   it('uses fresh store state after awaiting runtime liveness before shutdown', async () => {
     vi.useFakeTimers()
     const delayed = deferred<ReturnType<typeof runtimeListResult>>()
diff --git a/src/renderer/src/lib/agent-hibernation-coordinator.ts b/src/renderer/src/lib/agent-hibernation-coordinator.ts
index 2dfc59c20f5..63dbde0b374 100644
--- a/src/renderer/src/lib/agent-hibernation-coordinator.ts
+++ b/src/renderer/src/lib/agent-hibernation-coordinator.ts
@@ -63,13 +63,16 @@ type RuntimePtyLivenessSample = {
 function snapshotFromState(
   state: AppState,
   now: number,
-  runtimeLiveness: RuntimePtyLivenessSample
+  runtimeLiveness: RuntimePtyLivenessSample,
+  targetWorktreeId?: string
 ): AgentHibernationPlannerSnapshot {
   return {
     settings: state.settings,
     activeWorktreeId: state.activeWorktreeId,
     foregroundTerminalTabIds: getForegroundTerminalTabIds(),
-    tabsByWorktree: state.tabsByWorktree,
+    tabsByWorktree: targetWorktreeId
+      ? { [targetWorktreeId]: state.tabsByWorktree[targetWorktreeId] ?? [] }
+      : state.tabsByWorktree,
     terminalLayoutsByTabId: state.terminalLayoutsByTabId,
     ptyIdsByTabId: state.ptyIdsByTabId,
     runtimeLivePtyIdsByWorktreeId: runtimeLiveness.runtimeLivePtyIdsByWorktreeId,
@@ -90,9 +93,17 @@ function snapshotFromState(
   }
 }
 
-function getRuntimeLivenessTargetWorktrees(state: AppState): Map<string, string> {
+function getRuntimeLivenessTargetWorktrees(
+  state: AppState,
+  targetWorktreeId?: string
+): Map<string, string> {
   const targets = new Map<string, string>()
-  for (const worktreeId of Object.keys(state.tabsByWorktree)) {
+  const worktreeIds = targetWorktreeId
+    ? Object.hasOwn(state.tabsByWorktree, targetWorktreeId)
+      ? [targetWorktreeId]
+      : []
+    : Object.keys(state.tabsByWorktree)
+  for (const worktreeId of worktreeIds) {
     const runtimeEnvironmentId = getRuntimeEnvironmentIdForWorktree(state, worktreeId)
     if (runtimeEnvironmentId) {
       targets.set(worktreeId, runtimeEnvironmentId)
@@ -111,8 +122,11 @@ function getTypedRuntimePtyId(terminal: RuntimeTerminalSummary): string | null {
   return null
 }
 
-async function collectRuntimePtyLiveness(state: AppState): Promise<RuntimePtyLivenessSample> {
-  const targets = getRuntimeLivenessTargetWorktrees(state)
+async function collectRuntimePtyLiveness(
+  state: AppState,
+  targetWorktreeId?: string
+): Promise<RuntimePtyLivenessSample> {
+  const targets = getRuntimeLivenessTargetWorktrees(state, targetWorktreeId)
   const runtimeLivePtyIdsByWorktreeId: Record<string, string[]> = {}
   const runtimeLivenessRequiredWorktreeIds = [...targets.keys()]
   await Promise.all(
@@ -152,8 +166,8 @@ async function collectRuntimePtyLiveness(state: AppState): Promise<RuntimePtyLiv
   return { runtimeLivePtyIdsByWorktreeId, runtimeLivenessRequiredWorktreeIds }
 }
 
-async function currentCandidates(now: number) {
-  const runtimeLiveness = await collectRuntimePtyLiveness(useAppStore.getState())
+async function currentCandidates(now: number, targetWorktreeId?: string) {
+  const runtimeLiveness = await collectRuntimePtyLiveness(useAppStore.getState(), targetWorktreeId)
   const freshState = useAppStore.getState()
   // Why: age the PTY bindings from the same state the plan is built from, so a pane
   // observed for the first time this pass cannot also be judged long-idle in it.
@@ -163,7 +177,9 @@ async function currentCandidates(now: number) {
     now,
     idleMs: getEffectiveAgentHibernationIdleMs(freshState.settings?.agentHibernationIdleMs)
   })
-  return planAgentHibernationCandidates(snapshotFromState(freshState, now, runtimeLiveness))
+  return planAgentHibernationCandidates(
+    snapshotFromState(freshState, now, runtimeLiveness, targetWorktreeId)
+  )
     .filter((candidate) => {
       const runtimeEnvironmentId = getRuntimeEnvironmentIdForWorktree(
         freshState,
@@ -186,7 +202,9 @@ async function hibernatePaneIfStillEligible(
   if (coordinator.shuttingDownCandidateIds.has(id)) {
     return
   }
-  const candidates = await currentCandidates(coordinator.now())
+  // Why: the confirmed pane can only be authorized by its owning worktree. A
+  // global sweep here made C pane teardowns issue C×W fresh runtime listings.
+  const candidates = await currentCandidates(coordinator.now(), worktreeId)
   const stillEligible = candidates.some(
     (candidate) =>
       candidate.id === confirmedCandidate.id && candidate.signature === confirmedCandidate.signature
diff --git a/src/renderer/src/lib/agent-hibernation-pane-age.test.ts b/src/renderer/src/lib/agent-hibernation-pane-age.test.ts
index ba1c61184d0..a23d6a730dc 100644
--- a/src/renderer/src/lib/agent-hibernation-pane-age.test.ts
+++ b/src/renderer/src/lib/agent-hibernation-pane-age.test.ts
@@ -65,16 +65,21 @@ describe('hibernation PTY binding age', () => {
     // The planner already fails closed during the gap; dropping the binding here would
     // hand the same PTY a fresh idle window every time the layout flickers.
     observe('pty-1', 1_000)
+    recordHibernationBoundaryResolved(PANE, 1_500)
     observe(null, 2_000)
     expect(getHibernationPtyBindingFirstSeenAtByPaneKey()[PANE]).toBe(1_000)
+    expect(getHibernationBoundaryResolvedAtByPaneKey()[PANE]).toBe(1_500)
     observe('pty-1', 3_000)
     expect(getHibernationPtyBindingFirstSeenAtByPaneKey()[PANE]).toBe(1_000)
+    expect(getHibernationBoundaryResolvedAtByPaneKey()[PANE]).toBe(1_500)
   })
 
   it('expires an unseen binding once it is older than the idle window', () => {
     observe('pty-1', 1_000)
+    recordHibernationBoundaryResolved(PANE, 1_000)
     observe(null, 1_000 + IDLE_MS + 1)
     expect(getHibernationPtyBindingFirstSeenAtByPaneKey()[PANE]).toBeUndefined()
+    expect(getHibernationBoundaryResolvedAtByPaneKey()[PANE]).toBeUndefined()
   })
 
   it('drops bindings and boundary stamps when the tab is authoritatively gone', () => {
diff --git a/src/renderer/src/lib/agent-hibernation-pane-age.ts b/src/renderer/src/lib/agent-hibernation-pane-age.ts
index 882e1a63f12..21b940b4600 100644
--- a/src/renderer/src/lib/agent-hibernation-pane-age.ts
+++ b/src/renderer/src/lib/agent-hibernation-pane-age.ts
@@ -63,7 +63,10 @@ export function observeHibernationPtyBindings(args: {
   }
   for (const paneKey of boundaryResolvedAtByPaneKey.keys()) {
     const tabId = paneKey.slice(0, paneKey.indexOf(':'))
-    if (!liveTabIds.has(tabId)) {
+    // Why: closed split panes mint fresh leaf ids when reopened. Once their
+    // retained binding expires, keeping the boundary stamp would leak one map
+    // entry per closed pane for the renderer's lifetime.
+    if (!liveTabIds.has(tabId) || !ptyBindingByPaneKey.has(paneKey)) {
       boundaryResolvedAtByPaneKey.delete(paneKey)
     }
   }