diff --git a/mobile/src/agent-history/MobileAgentSessionHistoryPanel.tsx b/mobile/src/agent-history/MobileAgentSessionHistoryPanel.tsx
index abad3a84780..2b0b6cdf560 100644
--- a/mobile/src/agent-history/MobileAgentSessionHistoryPanel.tsx
+++ b/mobile/src/agent-history/MobileAgentSessionHistoryPanel.tsx
@@ -9,6 +9,7 @@ import type { RpcSuccess } from '../transport/types'
 import type { RpcClient } from '../transport/rpc-client'
 import { getWorktreeLabel } from '../session/worktree-label'
 import {
+  activateStructuredAiVaultSession,
   buildMobileAiVaultResumeLaunch,
   createMobileAiVaultResumeMutationRegistry,
   readMobileRuntimeHostPlatform,
@@ -154,16 +155,19 @@ export function MobileAgentSessionHistoryPanel({
         triggerError()
         return
       }
-      if (!session.sessionId) {
-        setResumeMessage('This session is missing a resume id.')
-        triggerError()
-        return
-      }
-
       resumeLaunchInFlightRef.current = true
       setResumingSessionId(session.id)
       setResumeMessage(null)
       try {
+        const structuredWorkspaceId = await activateStructuredAiVaultSession(client, session)
+        if (structuredWorkspaceId) {
+          router.push(
+            `/h/${encodeURIComponent(hostId)}/session/${encodeURIComponent(structuredWorkspaceId)}` as Parameters<
+              typeof router.push
+            >[0]
+          )
+          return
+        }
         const {
           repos,
           folderWorkspaces,
diff --git a/mobile/src/session/ai-vault-resume-launch.test.ts b/mobile/src/session/ai-vault-resume-launch.test.ts
index 9efc0e50f1a..274c75f0778 100644
--- a/mobile/src/session/ai-vault-resume-launch.test.ts
+++ b/mobile/src/session/ai-vault-resume-launch.test.ts
@@ -2,6 +2,7 @@ import { describe, expect, it, vi } from 'vitest'
 import type { AiVaultSession } from '../../../src/shared/ai-vault-types'
 import { buildAgentResumeStartupPlan } from '../../../src/shared/tui-agent-startup'
 import {
+  activateStructuredAiVaultSession,
   buildMobileAiVaultResumeLaunch,
   buildMobileAiVaultResumeCommand,
   createMobileAiVaultResumeMutationRegistry,
@@ -12,6 +13,34 @@ import {
 } from './ai-vault-resume-launch'
 import { RESUME_RPC_TIMEOUT_MS } from './ai-vault-resume-preparation'
 
+describe('activateStructuredAiVaultSession', () => {
+  it('activates the native structured tab instead of creating a legacy terminal', async () => {
+    const sendRequest = vi.fn().mockResolvedValue({ ok: true, result: {} })
+
+    await expect(
+      activateStructuredAiVaultSession(
+        { sendRequest },
+        {
+          structuredSession: {
+            sessionId: 'native-session-1',
+            workspaceId: 'worktree-1'
+          }
+        }
+      )
+    ).resolves.toBe('worktree-1')
+    expect(sendRequest).toHaveBeenCalledOnce()
+    expect(sendRequest).toHaveBeenCalledWith(
+      'session.tabs.activate',
+      {
+        worktree: 'id:worktree-1',
+        tabId: 'agent-session:native-session-1',
+        navigation: 'caller'
+      },
+      { timeoutMs: RESUME_RPC_TIMEOUT_MS }
+    )
+  })
+})
+
 function session(overrides: Partial<AiVaultSession> = {}): AiVaultSession {
   return {
     id: 'claude:1',
diff --git a/mobile/src/session/ai-vault-resume-launch.ts b/mobile/src/session/ai-vault-resume-launch.ts
index aa8c1bf98a6..b1bc6c8e4d6 100644
--- a/mobile/src/session/ai-vault-resume-launch.ts
+++ b/mobile/src/session/ai-vault-resume-launch.ts
@@ -79,6 +79,29 @@ export type MobileAiVaultResumeLaunch = {
   launchAgent?: TuiAgent
 }
 
+export async function activateStructuredAiVaultSession(
+  client: Pick<RpcClient, 'sendRequest'>,
+  session: Pick<AiVaultSession, 'structuredSession'>
+): Promise<string | null> {
+  const structured = session.structuredSession
+  if (!structured) {
+    return null
+  }
+  const response = await client.sendRequest(
+    'session.tabs.activate',
+    {
+      worktree: `id:${structured.workspaceId}`,
+      tabId: `agent-session:${structured.sessionId}`,
+      navigation: 'caller'
+    },
+    { timeoutMs: RESUME_RPC_TIMEOUT_MS }
+  )
+  if (!response.ok) {
+    throw new Error(response.error?.message || 'Failed to open structured agent session')
+  }
+  return structured.workspaceId
+}
+
 export function buildMobileAiVaultResumeLaunch(args: {
   session: Pick<AiVaultSession, 'agent' | 'sessionId' | 'cwd' | 'codexHome'> &
     Partial<Pick<AiVaultSession, 'filePath'>>
diff --git a/mobile/src/session/ai-vault-resume-preparation.test.ts b/mobile/src/session/ai-vault-resume-preparation.test.ts
index a0eed5515c6..d5db8c03ceb 100644
--- a/mobile/src/session/ai-vault-resume-preparation.test.ts
+++ b/mobile/src/session/ai-vault-resume-preparation.test.ts
@@ -91,6 +91,7 @@ describe('prepareMobileAiVaultSessionResume', () => {
       'aiVault.prepareSessionResume',
       {
         agent: 'codex',
+        sessionId: legacy.sessionId,
         filePath: legacy.filePath,
         codexHome: LEGACY_CODEX_HOME,
         executionHostId: 'local'
@@ -151,6 +152,7 @@ describe('prepareMobileAiVaultSessionResume', () => {
       'aiVault.prepareSessionResume',
       {
         agent: 'codex',
+        sessionId: current.sessionId,
         filePath: current.filePath,
         codexHome: PER_ACCOUNT_HOME,
         executionHostId: 'local'
diff --git a/mobile/src/session/ai-vault-resume-preparation.ts b/mobile/src/session/ai-vault-resume-preparation.ts
index 4265442ff66..cd015240f46 100644
--- a/mobile/src/session/ai-vault-resume-preparation.ts
+++ b/mobile/src/session/ai-vault-resume-preparation.ts
@@ -30,6 +30,7 @@ export async function prepareMobileAiVaultSessionResume(
     'aiVault.prepareSessionResume',
     {
       agent: session.agent,
+      sessionId: session.sessionId,
       filePath: session.filePath,
       codexHome: session.codexHome,
       executionHostId: session.executionHostId
diff --git a/src/main/ai-vault/session-list-result-validation.ts b/src/main/ai-vault/session-list-result-validation.ts
index abcdd1612b3..fbd184a5493 100644
--- a/src/main/ai-vault/session-list-result-validation.ts
+++ b/src/main/ai-vault/session-list-result-validation.ts
@@ -67,6 +67,12 @@ const aiVaultSessionSchema = z.object({
   queuedMessageCount: z.number().default(0),
   subagentTranscriptCount: z.number().default(0),
   resumeCommand: z.string(),
+  structuredSession: z
+    .object({
+      sessionId: z.string().min(1).max(512),
+      workspaceId: z.string().min(1).max(512)
+    })
+    .optional(),
   subagent: z
     .object({
       parentSessionId: z.string(),
diff --git a/src/main/ai-vault/structured-session-ownership.test.ts b/src/main/ai-vault/structured-session-ownership.test.ts
new file mode 100644
index 00000000000..27ef4fc61c8
--- /dev/null
+++ b/src/main/ai-vault/structured-session-ownership.test.ts
@@ -0,0 +1,133 @@
+import { afterEach, describe, expect, it } from 'vitest'
+import { agentSessionLeaseFixture } from '../../shared/agent-session-record.test-fixture'
+import type { AiVaultListResult, AiVaultSession } from '../../shared/ai-vault-types'
+import type { StructuredProviderSessionOwnership } from '../native-chat/agent-session-wire/structured-provider-session-ownership'
+import { agentSessionRecordFixture } from '../../shared/agent-session-record.test-fixture'
+import { setStructuredAgentSessionHost } from '../native-chat/agent-session-wire/structured-agent-session-registry'
+import {
+  assertLegacyAiVaultResumeAllowed,
+  assertLegacyAiVaultResumeCommandAllowed,
+  projectStructuredAiVaultSessions
+} from './structured-session-ownership'
+
+const PROVIDER_SESSION = '019fd532-7c11-7a90-b6de-4e1a2c3d5f60'
+
+describe('structured AI Vault ownership', () => {
+  afterEach(() => setStructuredAgentSessionHost(null))
+
+  it('hides owned rows from legacy clients and annotates them for capable clients', () => {
+    installOwnership()
+    const result = listResult()
+
+    expect(projectStructuredAiVaultSessions(result, false).sessions).toEqual([])
+    expect(projectStructuredAiVaultSessions(result, true).sessions[0]).toMatchObject({
+      structuredSession: { sessionId: 'session-alpha', workspaceId: 'workspace-1' }
+    })
+  })
+
+  it('keeps Claude rows hidden until provider support is negotiated', () => {
+    installOwnership({ provider: 'claude', providerSessionId: 'claude-owned-session' })
+    const result = listResult({
+      agent: 'claude',
+      sessionId: 'claude-owned-session',
+      filePath: '/sessions/claude-owned-session.jsonl',
+      resumeCommand: 'claude --resume claude-owned-session'
+    })
+
+    expect(
+      projectStructuredAiVaultSessions(result, true, (provider) => provider === 'codex').sessions
+    ).toEqual([])
+    expect(projectStructuredAiVaultSessions(result, true, () => true).sessions[0]).toMatchObject({
+      structuredSession: { sessionId: 'session-alpha', workspaceId: 'workspace-1' }
+    })
+  })
+
+  it('derives typed refusals from the single writer predicate for live and proving leases', async () => {
+    installOwnership()
+    expect(() =>
+      assertLegacyAiVaultResumeAllowed({
+        agent: 'codex',
+        filePath: `/sessions/rollout-${PROVIDER_SESSION}.jsonl`,
+        codexHome: null,
+        executionHostId: 'local'
+      })
+    ).toThrow('agent_session_conflict')
+
+    installOwnership({
+      lease: agentSessionLeaseFixture({
+        handoffStage: 'new-owner-proving',
+        claimStatus: 'reserved',
+        ownerProcess: null
+      })
+    })
+    await expect(
+      assertLegacyAiVaultResumeCommandAllowed(
+        `codex resume '${PROVIDER_SESSION}'`,
+        async () => undefined
+      )
+    ).rejects.toThrow('agent_session_ownership_unknown')
+  })
+})
+
+function installOwnership(overrides: Partial<StructuredProviderSessionOwnership> = {}): void {
+  const ownership: StructuredProviderSessionOwnership = {
+    sessionId: 'session-alpha',
+    workspaceId: 'workspace-1',
+    provider: 'codex',
+    providerSessionId: PROVIDER_SESSION,
+    lease: agentSessionLeaseFixture(),
+    ...overrides
+  }
+  const record = agentSessionRecordFixture(ownership.lease)
+  setStructuredAgentSessionHost({
+    deps: {
+      store: {
+        listRecords: () => [
+          {
+            ...record,
+            sessionId: ownership.sessionId,
+            location: { ...record.location, workspaceId: ownership.workspaceId },
+            provider: ownership.provider,
+            providerHandleChain: [
+              {
+                ...record.providerHandleChain[0]!,
+                handle:
+                  ownership.provider === 'codex'
+                    ? { provider: 'codex', threadId: ownership.providerSessionId }
+                    : { provider: 'claude', sessionId: ownership.providerSessionId }
+              }
+            ],
+            lease: { ...ownership.lease, sessionId: ownership.sessionId }
+          }
+        ]
+      }
+    }
+  } as never)
+}
+
+function listResult(overrides: Partial<AiVaultSession> = {}): AiVaultListResult {
+  const session: AiVaultSession = {
+    id: `local:codex:${PROVIDER_SESSION}`,
+    executionHostId: 'local',
+    agent: 'codex',
+    sessionId: PROVIDER_SESSION,
+    title: 'Owned',
+    cwd: '/repo',
+    branch: null,
+    model: null,
+    filePath: `/sessions/rollout-${PROVIDER_SESSION}.jsonl`,
+    codexHome: null,
+    createdAt: null,
+    updatedAt: null,
+    modifiedAt: '2026-08-11T00:00:00.000Z',
+    messageCount: 1,
+    totalTokens: 0,
+    previewMessages: [],
+    queuedMessageCount: 0,
+    subagentTranscriptCount: 0,
+    resumeCommand: `codex resume '${PROVIDER_SESSION}'`,
+    subagent: null,
+    ...overrides
+  }
+  return { sessions: [session], issues: [], scannedAt: '2026-08-11T00:00:00.000Z' }
+}
diff --git a/src/main/ai-vault/structured-session-ownership.ts b/src/main/ai-vault/structured-session-ownership.ts
new file mode 100644
index 00000000000..6fe9995c46f
--- /dev/null
+++ b/src/main/ai-vault/structured-session-ownership.ts
@@ -0,0 +1,142 @@
+import { agentSessionLeaseAdmitsWriter } from '../../shared/agent-session-lease-adjudication'
+import type { AiVaultListResult, AiVaultSession } from '../../shared/ai-vault-types'
+import type { AiVaultPrepareSessionResumeArgs } from '../../shared/ai-vault-resume-preparation'
+import { getStructuredAgentSessionHost } from '../native-chat/agent-session-wire/structured-agent-session-registry'
+import {
+  listStructuredProviderSessionOwnership,
+  type StructuredProviderSessionOwnership
+} from '../native-chat/agent-session-wire/structured-provider-session-ownership'
+
+export function projectStructuredAiVaultSessions(
+  result: AiVaultListResult,
+  structuredSupported: boolean,
+  providerSupported: (provider: StructuredProviderSessionOwnership['provider']) => boolean = () =>
+    true
+): AiVaultListResult {
+  const host = getStructuredAgentSessionHost()
+  if (!host) {
+    return result
+  }
+  const sessions = result.sessions.flatMap((session) => {
+    const ownership = findSessionOwnership(session)
+    if (!ownership) {
+      return [session]
+    }
+    if (!structuredSupported || !providerSupported(ownership.provider)) {
+      return []
+    }
+    return [
+      {
+        ...session,
+        structuredSession: {
+          sessionId: ownership.sessionId,
+          workspaceId: ownership.workspaceId
+        }
+      }
+    ]
+  })
+  return sessions.length === result.sessions.length &&
+    sessions.every((row, index) => row === result.sessions[index])
+    ? result
+    : { ...result, sessions }
+}
+
+export function assertLegacyAiVaultResumeAllowed(args: AiVaultPrepareSessionResumeArgs): void {
+  const ownership = findResumeOwnership(args)
+  if (ownership) {
+    refuseLegacyWriter(ownership)
+  }
+}
+
+export async function assertLegacyAiVaultResumeCommandAllowed(
+  command: string,
+  ensureHost: () => Promise<void>
+): Promise<void> {
+  if (!isPotentialStructuredResumeCommand(command)) {
+    return
+  }
+  await ensureHost()
+  const host = getStructuredAgentSessionHost()
+  if (!host) {
+    return
+  }
+  for (const ownership of listOwnership()) {
+    if (isResumeCommandFor(command, ownership)) {
+      refuseLegacyWriter(ownership)
+    }
+  }
+}
+
+function isPotentialStructuredResumeCommand(command: string): boolean {
+  return (
+    /\bcodex(?:\.exe)?\b[\s\S]*\bresume\b/i.test(command) ||
+    /\bclaude(?:\.exe)?\b[\s\S]*--resume\b/i.test(command)
+  )
+}
+
+function findSessionOwnership(session: AiVaultSession): StructuredProviderSessionOwnership | null {
+  if (session.agent !== 'codex' && session.agent !== 'claude') {
+    return null
+  }
+  return findOwnership(session.agent, session.sessionId)
+}
+
+function findResumeOwnership(
+  args: AiVaultPrepareSessionResumeArgs
+): StructuredProviderSessionOwnership | null {
+  if (args.agent !== 'codex' && args.agent !== 'claude') {
+    return null
+  }
+  const host = getStructuredAgentSessionHost()
+  if (!host) {
+    return null
+  }
+  const exact = args.sessionId ? findOwnership(args.agent, args.sessionId) : null
+  if (exact) {
+    return exact
+  }
+  const fileName = args.filePath.split(/[\\/]/).at(-1) ?? ''
+  return (
+    listOwnership().find(
+      (ownership) =>
+        ownership.provider === args.agent && fileName.includes(ownership.providerSessionId)
+    ) ?? null
+  )
+}
+
+function findOwnership(
+  provider: 'claude' | 'codex',
+  providerSessionId: string
+): StructuredProviderSessionOwnership | null {
+  return (
+    listOwnership().find(
+      (ownership) =>
+        ownership.provider === provider && ownership.providerSessionId === providerSessionId
+    ) ?? null
+  )
+}
+
+function listOwnership(): StructuredProviderSessionOwnership[] {
+  const host = getStructuredAgentSessionHost()
+  return host ? listStructuredProviderSessionOwnership(host.deps.store.listRecords()) : []
+}
+
+function isResumeCommandFor(
+  command: string,
+  ownership: StructuredProviderSessionOwnership
+): boolean {
+  if (!command.includes(ownership.providerSessionId)) {
+    return false
+  }
+  return ownership.provider === 'codex'
+    ? /\bcodex(?:\.exe)?\b[\s\S]*\bresume\b/i.test(command)
+    : /\bclaude(?:\.exe)?\b[\s\S]*--resume\b/i.test(command)
+}
+
+function refuseLegacyWriter(ownership: StructuredProviderSessionOwnership): never {
+  throw new Error(
+    agentSessionLeaseAdmitsWriter(ownership.lease)
+      ? 'agent_session_conflict'
+      : 'agent_session_ownership_unknown'
+  )
+}
diff --git a/src/main/ipc/ai-vault-resume.ts b/src/main/ipc/ai-vault-resume.ts
index a5618c0041d..e8f56516b08 100644
--- a/src/main/ipc/ai-vault-resume.ts
+++ b/src/main/ipc/ai-vault-resume.ts
@@ -5,8 +5,10 @@ import type {
   AiVaultSessionResumePreparation
 } from '../../shared/ai-vault-resume-preparation'
 import { parseExecutionHostId } from '../../shared/execution-host'
+import { assertLegacyAiVaultResumeAllowed } from '../ai-vault/structured-session-ownership'
 
 export type AiVaultResumeHandlerOptions = {
+  ensureStructuredSessionOwnership?: () => Promise<void>
   prepareSessionResume?: AiVaultSessionResumePreparation
   prepareRuntimeSessionResume?: (
     environmentId: string,
@@ -24,6 +26,8 @@ export async function prepareAiVaultSessionResume(
   args: AiVaultPrepareSessionResumeArgs,
   options: AiVaultResumeHandlerOptions
 ): Promise<AiVaultPrepareSessionResumeResult> {
+  await options.ensureStructuredSessionOwnership?.()
+  assertLegacyAiVaultResumeAllowed(args)
   const executionHost = parseExecutionHostId(args.executionHostId)
   if (executionHost?.kind === 'runtime') {
     if (!options.prepareRuntimeSessionResume) {
diff --git a/src/main/ipc/ai-vault.ts b/src/main/ipc/ai-vault.ts
index 5701b97f230..face1485517 100644
--- a/src/main/ipc/ai-vault.ts
+++ b/src/main/ipc/ai-vault.ts
@@ -48,6 +48,7 @@ import {
   scanHostLegWithCache
 } from './ai-vault-host-leg-cache'
 import { requestedAiVaultSessionDepth } from '../../shared/ai-vault-session-depth'
+import { projectStructuredAiVaultSessions } from '../ai-vault/structured-session-ownership'
 
 const AI_VAULT_ALL_HOST_RUNTIME_TIMEOUT_MS = 3_000
 // Why: a remote home with many agent roots routinely needs seconds to walk,
@@ -267,7 +268,9 @@ export function registerAiVaultHandlers(options: AiVaultHandlerOptions = {}): vo
         : undefined
     const controller = listCancellations.begin(event, requestToken)
     try {
-      return await listAiVaultSessions(args, { signal: controller?.signal })
+      await handlerOptions.ensureStructuredSessionOwnership?.()
+      const result = await listAiVaultSessions(args, { signal: controller?.signal })
+      return projectStructuredAiVaultSessions(result, true)
     } catch (error) {
       // Why: superseding a scan is normal control flow, but Electron logs every
       // rejected handler — report it as a result so the log stays truthful.
@@ -297,8 +300,7 @@ export function registerAiVaultHandlers(options: AiVaultHandlerOptions = {}): vo
     handleAiVaultGetFirstUserPrompt(args)
   )
   registerAiVaultDeleteHandler(aiVaultDeleteDeps)
-  // DOM focus/visibility events don't fire in the renderer on macOS app
-  // activation, so refresh-on-refocus needs this main-process signal.
+  // macOS app activation skips DOM focus events, so emit the refresh signal here.
   app.on('browser-window-focus', (_event, window) => {
     if (!window.isDestroyed()) {
       window.webContents.send('aiVault:windowFocused')
diff --git a/src/main/ipc/register-core-handlers.ts b/src/main/ipc/register-core-handlers.ts
index 90f1a0e647d..0bde2f17b13 100644
--- a/src/main/ipc/register-core-handlers.ts
+++ b/src/main/ipc/register-core-handlers.ts
@@ -216,6 +216,7 @@ export function registerCoreHandlers(
   registerRuntimeEnvironmentHandlers(store)
   registerEphemeralVmHandlers(store, pluginService)
   registerAiVaultHandlers({
+    ensureStructuredSessionOwnership: () => runtime.ensureStructuredAgentSessionHost(),
     getAdditionalCodexHomePaths: lifecycleOptions.getAdditionalAiVaultCodexHomePaths,
     prepareSessionResume: lifecycleOptions.prepareAiVaultSessionResume,
     getActiveRuntimeAiVaultHostInfos: () =>
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-host.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-host.ts
index 6975c8d6902..d4fb7f6409c 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-host.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-host.ts
@@ -95,7 +95,7 @@ export class StructuredAgentSessionHost {
   private readonly eventSinks = new Map<string, DeferredStructuredAgentSessionEventSink>()
   private readonly reconcileLeases: (sessionId: string) => Promise<AgentSessionWireRefusal | null>
 
-  constructor(private readonly deps: StructuredAgentSessionHostDeps) {
+  constructor(readonly deps: StructuredAgentSessionHostDeps) {
     this.reconcileLeases = createRestartReconciler({
       store: deps.store,
       probe: (record) => this.probeRecord(record),
diff --git a/src/main/native-chat/agent-session-wire/structured-provider-session-ownership.ts b/src/main/native-chat/agent-session-wire/structured-provider-session-ownership.ts
new file mode 100644
index 00000000000..ad211902433
--- /dev/null
+++ b/src/main/native-chat/agent-session-wire/structured-provider-session-ownership.ts
@@ -0,0 +1,24 @@
+import type { AgentSessionLease, AgentSessionRecord } from '../../../shared/agent-session-record'
+
+export type StructuredProviderSessionOwnership = {
+  sessionId: string
+  workspaceId: string
+  provider: 'claude' | 'codex'
+  providerSessionId: string
+  lease: AgentSessionLease
+}
+
+export function listStructuredProviderSessionOwnership(
+  records: readonly AgentSessionRecord[]
+): StructuredProviderSessionOwnership[] {
+  return records.flatMap((record) =>
+    record.providerHandleChain.map((link) => ({
+      sessionId: record.sessionId,
+      workspaceId: record.location.workspaceId,
+      provider: record.provider,
+      providerSessionId:
+        link.handle.provider === 'codex' ? link.handle.threadId : link.handle.sessionId,
+      lease: record.lease
+    }))
+  )
+}
diff --git a/src/main/runtime/rpc/methods/ai-vault.test.ts b/src/main/runtime/rpc/methods/ai-vault.test.ts
index 7e053daa613..a036b1df428 100644
--- a/src/main/runtime/rpc/methods/ai-vault.test.ts
+++ b/src/main/runtime/rpc/methods/ai-vault.test.ts
@@ -64,6 +64,7 @@ function makeDispatcher(): RpcDispatcher {
   // which delegates to the shared cache module the IPC handler also uses.
   const runtime = {
     getRuntimeId: () => 'test-runtime',
+    ensureStructuredAgentSessionHost: vi.fn(async () => undefined),
     listAiVaultSessions: (args?: Parameters<typeof listAiVaultSessions>[0]) =>
       listAiVaultSessions(args)
   } as unknown as OrcaRuntimeService
@@ -127,6 +128,7 @@ describe('aiVault.prepareSessionResume', () => {
     const prepareAiVaultSessionResume = vi.fn().mockResolvedValue({ useRealCodexHome: true })
     const runtime = {
       getRuntimeId: () => 'test-runtime',
+      ensureStructuredAgentSessionHost: vi.fn(async () => undefined),
       prepareAiVaultSessionResume
     } as unknown as OrcaRuntimeService
     const dispatcher = new RpcDispatcher({ runtime, methods: AI_VAULT_METHODS })
diff --git a/src/main/runtime/rpc/methods/ai-vault.ts b/src/main/runtime/rpc/methods/ai-vault.ts
index 70acf5dab67..6ebe68662c0 100644
--- a/src/main/runtime/rpc/methods/ai-vault.ts
+++ b/src/main/runtime/rpc/methods/ai-vault.ts
@@ -3,7 +3,16 @@ import { defineMethod, type RpcMethod } from '../core'
 import { OptionalBoolean } from '../schemas'
 import { restampAiVaultListResult } from '../../../ai-vault/session-list-results'
 import { AI_VAULT_AGENTS, AI_VAULT_SCOPE_PATHS_MAX_COUNT } from '../../../../shared/ai-vault-types'
+import type { AiVaultPrepareSessionResumeArgs } from '../../../../shared/ai-vault-resume-preparation'
 import { LOCAL_EXECUTION_HOST_ID, parseExecutionHostId } from '../../../../shared/execution-host'
+import {
+  CLAUDE_STRUCTURED_AGENT_SESSION_RUNTIME_CAPABILITY,
+  STRUCTURED_AGENT_SESSION_RUNTIME_CAPABILITY
+} from '../../../../shared/protocol-version'
+import {
+  assertLegacyAiVaultResumeAllowed,
+  projectStructuredAiVaultSessions
+} from '../../../ai-vault/structured-session-ownership'
 
 // Why: bound limit + scopePaths so a client cannot force an unbounded scan.
 // Each scopePath is a host-local match prefix (validated/capped, never used for
@@ -54,6 +63,7 @@ export const AiVaultListSessionsParams = z
 
 export const AiVaultPrepareSessionResumeParams = z.object({
   agent: z.enum(AI_VAULT_AGENTS),
+  sessionId: z.string().min(1).max(512).optional(),
   filePath: z.string().min(1).max(AI_VAULT_SCOPE_PATH_MAX_LENGTH),
   codexHome: z.string().min(1).max(AI_VAULT_SCOPE_PATH_MAX_LENGTH).nullable(),
   executionHostId: z.string().optional()
@@ -63,7 +73,8 @@ export const AI_VAULT_METHODS: RpcMethod[] = [
   defineMethod({
     name: 'aiVault.listSessions',
     params: AiVaultListSessionsParams,
-    handler: async (params, { runtime }) => {
+    handler: async (params, { runtime, clientKind, clientCapabilities }) => {
+      await runtime.ensureStructuredAgentSessionHost()
       const result = await runtime.listAiVaultSessions({
         limit: params.unlimited ? undefined : params.limit,
         unlimited: params.unlimited,
@@ -72,22 +83,37 @@ export const AI_VAULT_METHODS: RpcMethod[] = [
       })
       // Why: web clients consume this response directly (no parent-side retag),
       // so sessions must come back stamped as the runtime host they addressed.
-      return params.executionHostId
+      const stamped = params.executionHostId
         ? restampAiVaultListResult(result, params.executionHostId)
         : result
+      return projectStructuredAiVaultSessions(
+        stamped,
+        clientKind === undefined ||
+          (clientCapabilities?.includes(STRUCTURED_AGENT_SESSION_RUNTIME_CAPABILITY) ?? false),
+        (provider) =>
+          provider !== 'claude' ||
+          clientKind === undefined ||
+          (clientCapabilities?.includes(CLAUDE_STRUCTURED_AGENT_SESSION_RUNTIME_CAPABILITY) ??
+            false)
+      )
     }
   }),
   defineMethod({
     name: 'aiVault.prepareSessionResume',
     params: AiVaultPrepareSessionResumeParams,
-    handler: (params, { runtime }) =>
-      runtime.prepareAiVaultSessionResume({
+    handler: async (params, { runtime }) => {
+      const args: AiVaultPrepareSessionResumeArgs = {
         agent: params.agent,
+        ...(params.sessionId ? { sessionId: params.sessionId } : {}),
         filePath: params.filePath,
         codexHome: params.codexHome,
         // Why: the RPC executes on the transcript-owning host; never let a
         // client-provided runtime/SSH stamp escape that host boundary.
         executionHostId: LOCAL_EXECUTION_HOST_ID
-      })
+      }
+      await runtime.ensureStructuredAgentSessionHost()
+      assertLegacyAiVaultResumeAllowed(args)
+      return runtime.prepareAiVaultSessionResume(args)
+    }
   })
 ]
diff --git a/src/main/runtime/rpc/methods/session-tabs.ts b/src/main/runtime/rpc/methods/session-tabs.ts
index ba5dd29ecde..57e5d9ba0e6 100644
--- a/src/main/runtime/rpc/methods/session-tabs.ts
+++ b/src/main/runtime/rpc/methods/session-tabs.ts
@@ -14,6 +14,7 @@ import { SESSION_TAB_CLOSE_METHODS } from './session-tab-close-methods'
 import { projectSessionTabAgentStatus } from './session-tab-agent-status-projection'
 import { restoreStructuredTabsIfSupported } from './structured-session-tab-restore'
 import { MOBILE_MARKDOWN_TAB_METHODS } from './mobile-markdown-tab-methods'
+import { assertLegacyAiVaultResumeCommandAllowed } from '../../../ai-vault/structured-session-ownership'
 
 export const SESSION_TAB_METHODS: RpcAnyMethod[] = [
   defineMethod({
@@ -59,8 +60,13 @@ export const SESSION_TAB_METHODS: RpcAnyMethod[] = [
   defineMethod({
     name: 'session.tabs.createTerminal',
     params: CreateTerminalTab,
-    handler: async (params, { runtime, signal, clientKind, pairedDeviceId }) =>
-      runtime.createMobileSessionTerminal(params.worktree, {
+    handler: async (params, { runtime, signal, clientKind, pairedDeviceId }) => {
+      if (params.command) {
+        await assertLegacyAiVaultResumeCommandAllowed(params.command, () =>
+          runtime.ensureStructuredAgentSessionHost()
+        )
+      }
+      return runtime.createMobileSessionTerminal(params.worktree, {
         afterTabId: params.afterTabId,
         targetGroupId: params.targetGroupId,
         command: params.command,
@@ -86,6 +92,7 @@ export const SESSION_TAB_METHODS: RpcAnyMethod[] = [
         // of running down the timeout and rolling back a live tab (#7718).
         signal
       })
+    }
   }),
   defineMethod({
     name: 'session.tabs.move',
diff --git a/src/main/runtime/rpc/methods/terminal.ts b/src/main/runtime/rpc/methods/terminal.ts
index 8d45ad5c0bc..578b375686b 100644
--- a/src/main/runtime/rpc/methods/terminal.ts
+++ b/src/main/runtime/rpc/methods/terminal.ts
@@ -38,6 +38,7 @@ import {
 } from '../terminal-stream-byte-length'
 import { isTuiAgent } from '../../../../shared/tui-agent-config'
 import { isTerminalQueryReply } from '../../../../shared/terminal-query-reply'
+import { assertLegacyAiVaultResumeCommandAllowed } from '../../../ai-vault/structured-session-ownership'
 import {
   EMPTY_TERMINAL_REPLY_QUERY_SCAN_STATE,
   scanTerminalReplyQuerySequences,
@@ -1221,6 +1222,16 @@ export const TERMINAL_METHODS: RpcAnyMethod[] = [
     handler: async (params, { runtime, clientId }) => {
       await assertTerminalSendTextWithinLimit(params.text)
       await assertTerminalSendTextWithinLimit(params.resolvedLaunchDraft?.text)
+      if (params.text) {
+        await assertLegacyAiVaultResumeCommandAllowed(params.text, () =>
+          runtime.ensureStructuredAgentSessionHost()
+        )
+      }
+      if (params.resolvedLaunchDraft?.text) {
+        await assertLegacyAiVaultResumeCommandAllowed(params.resolvedLaunchDraft.text, () =>
+          runtime.ensureStructuredAgentSessionHost()
+        )
+      }
       const queryReplyClientId = clientId ?? params.client?.id
       if (
         params.inputKind === 'query-reply' &&
diff --git a/src/renderer/src/components/right-sidebar/AiVaultSessionRow.tsx b/src/renderer/src/components/right-sidebar/AiVaultSessionRow.tsx
index 9e2f1702f7c..cc79cbb8933 100644
--- a/src/renderer/src/components/right-sidebar/AiVaultSessionRow.tsx
+++ b/src/renderer/src/components/right-sidebar/AiVaultSessionRow.tsx
@@ -100,6 +100,7 @@ export function VaultSessionRow({
       writeAiVaultSessionDragData(event.dataTransfer, {
         agent: session.agent,
         sessionId: session.sessionId,
+        ...(session.structuredSession ? { structuredSession: session.structuredSession } : {}),
         title: session.title,
         command: resumeStartup.command,
         sessionFilePath: session.filePath,
diff --git a/src/renderer/src/components/right-sidebar/ai-vault-session-launch-actions.ts b/src/renderer/src/components/right-sidebar/ai-vault-session-launch-actions.ts
index 43504842aaa..c4a0329a3e2 100644
--- a/src/renderer/src/components/right-sidebar/ai-vault-session-launch-actions.ts
+++ b/src/renderer/src/components/right-sidebar/ai-vault-session-launch-actions.ts
@@ -2,8 +2,7 @@ import { useCallback, useState } from 'react'
 import { toast } from 'sonner'
 import {
   buildAiVaultResumeCopyCommandForWorktree,
-  buildAiVaultResumeStartupForWorktree,
-  type AiVaultResumeStartup
+  buildAiVaultResumeStartupForWorktree
 } from '@/lib/ai-vault-resume-command'
 import { launchAiVaultSessionInNewTab } from '@/lib/launch-ai-vault-session'
 import {
@@ -29,6 +28,7 @@ import {
 import { prepareAiVaultSessionContinuation } from './ai-vault-session-continuation'
 import type { AgentSessionContinuationRequest } from '@/lib/agent-session-continuation'
 import { findWorktreeById } from '@/store/slices/worktree-helpers'
+import { activateAiVaultStructuredSession } from '@/lib/activate-ai-vault-structured-session'
 
 export function useAiVaultSessionLaunchActions({
   activeWorktree,
@@ -40,14 +40,7 @@ export function useAiVaultSessionLaunchActions({
   activeWorktreeId: string | null
   targetState: AiVaultSessionResumeTargetState
   agentCmdOverrides?: Partial<Record<AiVaultAgent, string | null>>
-}): {
-  buildResumeStartup: (session: AiVaultSession, worktreeId?: string | null) => AiVaultResumeStartup
-  copyResumeCommand: (session: AiVaultSession, worktreeId?: string | null) => Promise<void>
-  handleResume: (session: AiVaultSession, targetWorktreeId?: string) => void
-  handleContinueInNewSession: (session: AiVaultSession, targetWorktreeId: string) => void
-  continuationRequest: AgentSessionContinuationRequest | null
-  handleContinuationDialogOpenChange: (open: boolean) => void
-} {
+}) {
   const [continuationRequest, setContinuationRequest] =
     useState<AgentSessionContinuationRequest | null>(null)
 
@@ -93,6 +86,9 @@ export function useAiVaultSessionLaunchActions({
 
   const handleResume = useCallback(
     (session: AiVaultSession, targetWorktreeId?: string): void => {
+      if (activateAiVaultStructuredSession(session)) {
+        return
+      }
       const targetId = resolveAiVaultSessionLaunchTargetOrNotify({
         sessionFilePath: session.filePath,
         sessionExecutionHostId: session.executionHostId,
diff --git a/src/renderer/src/components/tab-group/AiVaultSessionDropLayer.tsx b/src/renderer/src/components/tab-group/AiVaultSessionDropLayer.tsx
index 3c9ddd26369..8504d255813 100644
--- a/src/renderer/src/components/tab-group/AiVaultSessionDropLayer.tsx
+++ b/src/renderer/src/components/tab-group/AiVaultSessionDropLayer.tsx
@@ -23,6 +23,7 @@ import { resolveDropZone } from './tab-drop-zone'
 import type { TabDropZone } from './useTabDragSplit'
 import { translate } from '@/i18n/i18n'
 import type { AiVaultPrepareSessionResumeResult } from '../../../../shared/ai-vault-resume-preparation'
+import { activateStructuredAgentSessionById } from '@/lib/structured-agent-session-tab-activation'
 
 type PaneDropTarget = {
   groupId: string
@@ -175,6 +176,13 @@ export default function AiVaultSessionDropLayer({
         )
         return true
       }
+      if (payload.structuredSession) {
+        const { sessionId, workspaceId } = payload.structuredSession
+        if (!activateStructuredAgentSessionById({ worktreeId: workspaceId, sessionId })) {
+          toast.error('The structured agent session is not available yet. Retry in a moment.')
+        }
+        return true
+      }
 
       const state = useAppStore.getState()
       const targetStatus = getAiVaultResumeWorkspaceTargetStatus(state, worktreeId)
@@ -224,6 +232,7 @@ export default function AiVaultSessionDropLayer({
         })
           ? window.api.aiVault.prepareSessionResume({
               agent: payload.agent,
+              sessionId: payload.sessionId,
               filePath: payload.sessionFilePath,
               executionHostId: payload.sessionExecutionHostId,
               codexHome: payload.codexHome
diff --git a/src/renderer/src/lib/activate-ai-vault-structured-session.ts b/src/renderer/src/lib/activate-ai-vault-structured-session.ts
new file mode 100644
index 00000000000..bffcee51b8b
--- /dev/null
+++ b/src/renderer/src/lib/activate-ai-vault-structured-session.ts
@@ -0,0 +1,25 @@
+import { toast } from 'sonner'
+import type { AiVaultSession } from '../../../shared/ai-vault-types'
+import { activateAndRevealWorktree } from './worktree-activation'
+import { activateStructuredAgentSessionById } from './structured-agent-session-tab-activation'
+import { useAppStore } from '@/store'
+
+export function activateAiVaultStructuredSession(session: AiVaultSession): boolean {
+  const structured = session.structuredSession
+  if (!structured) {
+    return false
+  }
+  if (
+    !activateStructuredAgentSessionById({
+      worktreeId: structured.workspaceId,
+      sessionId: structured.sessionId
+    })
+  ) {
+    toast.error('The structured agent session is not available yet. Retry in a moment.')
+    return true
+  }
+  if (useAppStore.getState().activeWorktreeId !== structured.workspaceId) {
+    activateAndRevealWorktree(structured.workspaceId)
+  }
+  return true
+}
diff --git a/src/renderer/src/lib/ai-vault-session-drag.ts b/src/renderer/src/lib/ai-vault-session-drag.ts
index 69c17c5caa6..536616fdf81 100644
--- a/src/renderer/src/lib/ai-vault-session-drag.ts
+++ b/src/renderer/src/lib/ai-vault-session-drag.ts
@@ -11,6 +11,7 @@ export const AI_VAULT_SESSION_DRAG_PAYLOAD_MAX_BYTES = 16 * 1024
 export type AiVaultSessionDragPayload = {
   agent: AiVaultAgent
   sessionId: string
+  structuredSession?: { sessionId: string; workspaceId: string }
   title: string
   command: string
   // Why: drop targets must know where the session file lives (host vs local
@@ -49,6 +50,16 @@ function isNonEmptyString(value: unknown): value is string {
   return typeof value === 'string' && value.trim().length > 0
 }
 
+function isStructuredSession(
+  value: unknown
+): value is NonNullable<AiVaultSessionDragPayload['structuredSession']> {
+  if (!value || typeof value !== 'object') {
+    return false
+  }
+  const structured = value as Record<string, unknown>
+  return isNonEmptyString(structured.sessionId) && isNonEmptyString(structured.workspaceId)
+}
+
 function isStringRecord(value: unknown): value is Record<string, string> {
   if (!value || typeof value !== 'object' || Array.isArray(value)) {
     return false
@@ -87,6 +98,7 @@ function isSerializedPayload(value: unknown): value is SerializedAiVaultSessionD
     payload.version === 1 &&
     isAiVaultAgent(payload.agent) &&
     isNonEmptyString(payload.sessionId) &&
+    (payload.structuredSession === undefined || isStructuredSession(payload.structuredSession)) &&
     isNonEmptyString(payload.title) &&
     isNonEmptyString(payload.command) &&
     (payload.sessionFilePath === undefined || isNonEmptyString(payload.sessionFilePath)) &&
@@ -165,6 +177,7 @@ export function readAiVaultSessionDragData(
     const {
       agent,
       sessionId,
+      structuredSession,
       title,
       command,
       sessionFilePath,
@@ -179,6 +192,7 @@ export function readAiVaultSessionDragData(
     return {
       agent,
       sessionId,
+      ...(structuredSession ? { structuredSession } : {}),
       title,
       command,
       ...(sessionFilePath ? { sessionFilePath } : {}),
diff --git a/src/renderer/src/lib/ai-vault-session-resume-preparation.test.ts b/src/renderer/src/lib/ai-vault-session-resume-preparation.test.ts
index 2ff2d5be6ab..1a26b8b80b7 100644
--- a/src/renderer/src/lib/ai-vault-session-resume-preparation.test.ts
+++ b/src/renderer/src/lib/ai-vault-session-resume-preparation.test.ts
@@ -19,6 +19,7 @@ describe('prepareAiVaultSessionForResume', () => {
     expect(prepared.codexHome).toBeNull()
     expect(prepareSessionResume).toHaveBeenCalledWith({
       agent: 'codex',
+      sessionId: legacy.sessionId,
       filePath: legacy.filePath,
       codexHome: legacy.codexHome,
       executionHostId: 'local'
@@ -55,6 +56,7 @@ describe('prepareAiVaultSessionForResume', () => {
     expect(prepared.codexHome).toBe('/tmp/orca/codex-accounts/account-2/home')
     expect(prepareSessionResume).toHaveBeenCalledWith({
       agent: 'codex',
+      sessionId: current.sessionId,
       filePath: current.filePath,
       codexHome: current.codexHome,
       executionHostId: 'local'
diff --git a/src/renderer/src/lib/ai-vault-session-resume-preparation.ts b/src/renderer/src/lib/ai-vault-session-resume-preparation.ts
index fc78dbed0c1..9c7fa8740ff 100644
--- a/src/renderer/src/lib/ai-vault-session-resume-preparation.ts
+++ b/src/renderer/src/lib/ai-vault-session-resume-preparation.ts
@@ -8,11 +8,12 @@ import { LOCAL_EXECUTION_HOST_ID } from '../../../shared/execution-host'
 export async function prepareAiVaultSessionForResume(
   session: AiVaultSession
 ): Promise<AiVaultSession> {
-  if (!aiVaultSessionNeedsResumePreparation(session)) {
+  if (!session.structuredSession && !aiVaultSessionNeedsResumePreparation(session)) {
     return session
   }
   const result = await window.api.aiVault.prepareSessionResume({
     agent: session.agent,
+    sessionId: session.sessionId,
     filePath: session.filePath,
     codexHome: session.codexHome,
     executionHostId: session.executionHostId
diff --git a/src/renderer/src/lib/structured-agent-session-tab-activation.test.ts b/src/renderer/src/lib/structured-agent-session-tab-activation.test.ts
new file mode 100644
index 00000000000..dda79aeede1
--- /dev/null
+++ b/src/renderer/src/lib/structured-agent-session-tab-activation.test.ts
@@ -0,0 +1,89 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+import type { Tab } from '../../../shared/types'
+
+const mocks = vi.hoisted(() => ({
+  activateTab: vi.fn(),
+  callRuntimeRpc: vi.fn(async () => ({ ok: true })),
+  focusGroup: vi.fn(),
+  setActiveTabType: vi.fn(),
+  state: { unifiedTabsByWorktree: {} } as Record<string, unknown>
+}))
+
+vi.mock('@/store', () => ({
+  useAppStore: { getState: () => mocks.state }
+}))
+
+vi.mock('./worktree-runtime-owner', () => ({
+  getRuntimeEnvironmentIdForWorktree: () => 'env-1'
+}))
+
+vi.mock('@/runtime/runtime-rpc-client', () => ({
+  callRuntimeRpc: mocks.callRuntimeRpc,
+  getActiveRuntimeTarget: ({
+    activeRuntimeEnvironmentId
+  }: {
+    activeRuntimeEnvironmentId: string
+  }) => ({ kind: 'environment', environmentId: activeRuntimeEnvironmentId })
+}))
+
+vi.mock('@/runtime/runtime-worktree-selector', () => ({
+  toRuntimeWorktreeSelector: (worktreeId: string) => `id:${worktreeId}`
+}))
+
+import {
+  activateStructuredAgentSessionById,
+  activateStructuredAgentSessionTab
+} from './structured-agent-session-tab-activation'
+
+describe('activateStructuredAgentSessionTab', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+    const tab = {
+      id: 'structured-tab-1',
+      worktreeId: 'wt-1',
+      groupId: 'group-1',
+      contentType: 'agent-session',
+      entityId: 'session-1',
+      label: 'Codex Chat',
+      customLabel: null,
+      color: null,
+      sortOrder: 0,
+      createdAt: 0,
+      isPinned: false,
+      agentSessionAgent: 'codex'
+    } satisfies Tab
+    mocks.state = {
+      unifiedTabsByWorktree: { 'wt-1': [tab] },
+      focusGroup: mocks.focusGroup,
+      activateTab: mocks.activateTab,
+      setActiveTabType: mocks.setActiveTabType
+    }
+  })
+
+  it('selects the unified tab and synchronizes host focus', () => {
+    expect(
+      activateStructuredAgentSessionTab({ worktreeId: 'wt-1', tabId: 'structured-tab-1' })
+    ).toBe(true)
+
+    expect(mocks.focusGroup).toHaveBeenCalledWith('wt-1', 'group-1')
+    expect(mocks.activateTab).toHaveBeenCalledWith('structured-tab-1', { worktreeId: 'wt-1' })
+    expect(mocks.setActiveTabType).toHaveBeenCalledWith('agent-session')
+    expect(mocks.callRuntimeRpc).toHaveBeenCalledWith(
+      { kind: 'environment', environmentId: 'env-1' },
+      'session.tabs.activate',
+      { worktree: 'id:wt-1', tabId: 'agent-session:session-1' }
+    )
+  })
+
+  it('routes a provider-owned vault row through its structured session id', () => {
+    expect(activateStructuredAgentSessionById({ worktreeId: 'wt-1', sessionId: 'session-1' })).toBe(
+      true
+    )
+    expect(mocks.activateTab).toHaveBeenCalledWith('structured-tab-1', { worktreeId: 'wt-1' })
+    expect(mocks.callRuntimeRpc).toHaveBeenCalledWith(
+      { kind: 'environment', environmentId: 'env-1' },
+      'session.tabs.activate',
+      { worktree: 'id:wt-1', tabId: 'agent-session:session-1' }
+    )
+  })
+})
diff --git a/src/renderer/src/lib/structured-agent-session-tab-activation.ts b/src/renderer/src/lib/structured-agent-session-tab-activation.ts
new file mode 100644
index 00000000000..e4d6eed92bc
--- /dev/null
+++ b/src/renderer/src/lib/structured-agent-session-tab-activation.ts
@@ -0,0 +1,43 @@
+import { getRuntimeEnvironmentIdForWorktree } from './worktree-runtime-owner'
+import { useAppStore } from '@/store'
+import { callRuntimeRpc, getActiveRuntimeTarget } from '@/runtime/runtime-rpc-client'
+import { toRuntimeWorktreeSelector } from '@/runtime/runtime-worktree-selector'
+
+export function activateStructuredAgentSessionTab(args: {
+  worktreeId: string
+  tabId: string
+}): boolean {
+  const state = useAppStore.getState()
+  const tab = (state.unifiedTabsByWorktree[args.worktreeId] ?? []).find(
+    (candidate) => candidate.id === args.tabId && candidate.contentType === 'agent-session'
+  )
+  if (!tab) {
+    return false
+  }
+  state.focusGroup(args.worktreeId, tab.groupId)
+  state.activateTab(tab.id, { worktreeId: args.worktreeId })
+  state.setActiveTabType('agent-session')
+  const environmentId = getRuntimeEnvironmentIdForWorktree(state, args.worktreeId)
+  void callRuntimeRpc(
+    getActiveRuntimeTarget({ activeRuntimeEnvironmentId: environmentId }),
+    'session.tabs.activate',
+    {
+      worktree: toRuntimeWorktreeSelector(args.worktreeId),
+      tabId: `agent-session:${tab.entityId}`
+    }
+  )
+  return true
+}
+
+export function activateStructuredAgentSessionById(args: {
+  worktreeId: string
+  sessionId: string
+}): boolean {
+  const tab = (useAppStore.getState().unifiedTabsByWorktree[args.worktreeId] ?? []).find(
+    (candidate) =>
+      candidate.contentType === 'agent-session' && candidate.entityId === args.sessionId
+  )
+  return tab
+    ? activateStructuredAgentSessionTab({ worktreeId: args.worktreeId, tabId: tab.id })
+    : false
+}
diff --git a/src/shared/ai-vault-resume-preparation.ts b/src/shared/ai-vault-resume-preparation.ts
index 39edd01038a..64797710537 100644
--- a/src/shared/ai-vault-resume-preparation.ts
+++ b/src/shared/ai-vault-resume-preparation.ts
@@ -3,7 +3,8 @@ import type { AiVaultSession } from './ai-vault-types'
 export type AiVaultPrepareSessionResumeArgs = Pick<
   AiVaultSession,
   'agent' | 'filePath' | 'codexHome' | 'executionHostId'
->
+> &
+  Partial<Pick<AiVaultSession, 'sessionId'>>
 
 export type AiVaultPrepareSessionResumeResult = {
   useRealCodexHome: boolean
diff --git a/src/shared/ai-vault-types.ts b/src/shared/ai-vault-types.ts
index 6e132fce990..a30761538a0 100644
--- a/src/shared/ai-vault-types.ts
+++ b/src/shared/ai-vault-types.ts
@@ -116,6 +116,11 @@ export type AiVaultSession = {
   subagentTranscriptCount: number
   resumeCommand: string
   subagent: AiVaultSessionSubagentInfo | null
+  /** Present only when the negotiated client can open the native structured owner. */
+  structuredSession?: {
+    sessionId: string
+    workspaceId: string
+  }
 }
 
 export type AiVaultSubagentListArgs = {
diff --git a/tests/e2e/cross-version-wire/cross-version-agent-session-wire.unit.test.ts b/tests/e2e/cross-version-wire/cross-version-agent-session-wire.unit.test.ts
index 90aa844efa2..13e486f0b1c 100644
--- a/tests/e2e/cross-version-wire/cross-version-agent-session-wire.unit.test.ts
+++ b/tests/e2e/cross-version-wire/cross-version-agent-session-wire.unit.test.ts
@@ -18,7 +18,10 @@ import { setStructuredAgentSessionHost } from '../../../src/main/native-chat/age
 import { AgentSessionRecordStore } from '../../../src/main/runtime/agent-session-record-store'
 import { computeAgentSessionPayloadFingerprint } from '../../../src/shared/agent-session-mutation-envelope'
 import type { AgentSessionSubscribeEvent } from '../../../src/shared/agent-session-wire'
-import { STRUCTURED_AGENT_SESSION_RUNTIME_CAPABILITY } from '../../../src/shared/protocol-version'
+import {
+  CLAUDE_STRUCTURED_AGENT_SESSION_RUNTIME_CAPABILITY,
+  STRUCTURED_AGENT_SESSION_RUNTIME_CAPABILITY
+} from '../../../src/shared/protocol-version'
 import { resolveBaselineReleaseRef } from './release-checkout'
 import {
   loadAgentSessionWireBuild,
@@ -34,6 +37,8 @@ const SUITE_TIMEOUT_MS = 180_000
 const SESSION = 'session-alpha'
 const WORKSPACE = 'workspace-1'
 const THREAD = '019fd532-7c11-7a90-b6de-4e1a2c3d5f60'
+const CLAUDE_SESSION = 'session-claude'
+const CLAUDE_PROVIDER_SESSION = '6de39f04-fdec-4f96-9d38-d0c1169db382'
 const NOW = 1_800_000_000_000
 
 /** Every method the structured surface publishes, paired with the host method it
@@ -116,6 +121,38 @@ function attachParams(fence: number | null): Record<string, unknown> {
   }
 }
 
+function claudeAttachParams(): Record<string, unknown> {
+  const params = {
+    envelope: {
+      sessionId: CLAUDE_SESSION,
+      clientOperationId: operationId(),
+      expectedRuntimeFence: null
+    },
+    location: {
+      executionHostId: 'local',
+      wslDistro: null,
+      workspaceId: WORKSPACE,
+      workspaceKind: 'git-worktree'
+    },
+    provider: 'claude',
+    agent: 'claude',
+    accountHome: { variable: 'CLAUDE_CONFIG_DIR', path: '/home/dev/.claude' },
+    runtimeKind: 'native',
+    providerHandle: { kind: 'claude', sessionId: CLAUDE_PROVIDER_SESSION, leafUuid: null }
+  }
+  return {
+    ...params,
+    envelope: {
+      ...params.envelope,
+      payloadFingerprint: computeAgentSessionPayloadFingerprint({
+        method: 'agentSession.attach',
+        sessionId: CLAUDE_SESSION,
+        fields: attachFingerprintFields(params as unknown as AgentSessionAttachParams)
+      })
+    }
+  }
+}
+
 function createIntentParams(): Record<string, unknown> {
   const worktree = `id:${WORKSPACE}`
   const fields = { worktree, agent: 'codex' }
@@ -162,6 +199,7 @@ function runtimeStub(): unknown {
   const cleanups = new Map<string, () => void>()
   return {
     getRuntimeId: () => 'runtime-1',
+    ensureStructuredAgentSessionHost: async () => undefined,
     getStructuredAgentSessionCreateSupport: async () => ({ supported: true }),
     resolveStructuredAgentSessionCreateIntent: async () => {
       const {
@@ -321,6 +359,263 @@ describe('cross-version structured agent sessions', () => {
     })
   })
 
+  describe('an old client against a structured-owned AI Vault row', () => {
+    let root: string
+    let store: AgentSessionRecordStore
+    let runtime: ReturnType<typeof runtimeStub> & Record<string, unknown>
+    let createMobileSessionTerminal: ReturnType<typeof vi.fn>
+
+    beforeEach(async () => {
+      root = await mkdtemp(join(tmpdir(), 'orca-cross-version-ai-vault-'))
+      store = await AgentSessionRecordStore.open({
+        directory: join(root, 'store'),
+        hostId: 'local'
+      })
+      const host = new StructuredAgentSessionHost({
+        store,
+        adapter: {
+          acquire: async ({ fence, identity }) => ({
+            process: {
+              hostId: 'local',
+              pid: 4242,
+              processStartTimeMs: NOW,
+              spawnToken:
+                store.getRecord(identity.sessionId)?.lease.reservedSpawnToken ?? 'spawn-vault'
+            },
+            link: {
+              linkId: `link-${fence}`,
+              handle:
+                identity.agent === 'claude'
+                  ? { provider: 'claude', sessionId: CLAUDE_PROVIDER_SESSION, leafUuid: null }
+                  : { provider: 'codex', threadId: THREAD },
+              origin: 'created',
+              mintedAtFence: fence,
+              observedAt: NOW
+            }
+          }),
+          dispatch: async () => ({ state: 'accepted' }),
+          cancelTurn: async () => ({ cancelled: true }),
+          answerPrompt: async () => undefined,
+          setOption: async () => undefined
+        },
+        journalRoot: root,
+        claimKeyId: 'key-1',
+        mintSpawnToken: () => 'spawn-vault',
+        now: () => NOW
+      })
+      setStructuredAgentSessionHost(host)
+      const attached = await host.attach({ callerKey: 'test' }, attachParams(null) as never)
+      expect(attached.ok).toBe(true)
+      const claudeAttached = await host.attach({ callerKey: 'test' }, claudeAttachParams() as never)
+      expect(claudeAttached.ok).toBe(true)
+      createMobileSessionTerminal = vi.fn()
+      runtime = {
+        ...(runtimeStub() as Record<string, unknown>),
+        listAiVaultSessions: vi.fn(async () => ({
+          sessions: [
+            {
+              id: `local:codex:${THREAD}:/home/dev/.codex/sessions/rollout-${THREAD}.jsonl`,
+              executionHostId: 'local',
+              agent: 'codex',
+              sessionId: THREAD,
+              title: 'Owned thread',
+              cwd: '/repo',
+              branch: null,
+              model: null,
+              filePath: `/home/dev/.codex/sessions/rollout-${THREAD}.jsonl`,
+              codexHome: '/home/dev/.codex',
+              createdAt: null,
+              updatedAt: null,
+              modifiedAt: '2026-08-11T00:00:00.000Z',
+              messageCount: 1,
+              totalTokens: 0,
+              previewMessages: [],
+              queuedMessageCount: 0,
+              subagentTranscriptCount: 0,
+              resumeCommand: `codex resume '${THREAD}'`,
+              subagent: null
+            },
+            {
+              id: `local:claude:${CLAUDE_PROVIDER_SESSION}`,
+              executionHostId: 'local',
+              agent: 'claude',
+              sessionId: CLAUDE_PROVIDER_SESSION,
+              title: 'Owned Claude session',
+              cwd: '/repo',
+              branch: null,
+              model: null,
+              filePath: `/home/dev/.claude/projects/repo/${CLAUDE_PROVIDER_SESSION}.jsonl`,
+              codexHome: null,
+              createdAt: null,
+              updatedAt: null,
+              modifiedAt: '2026-08-11T00:00:00.000Z',
+              messageCount: 1,
+              totalTokens: 0,
+              previewMessages: [],
+              queuedMessageCount: 0,
+              subagentTranscriptCount: 0,
+              resumeCommand: `claude --resume '${CLAUDE_PROVIDER_SESSION}'`,
+              subagent: null
+            }
+          ],
+          issues: [],
+          scannedAt: '2026-08-11T00:00:00.000Z'
+        })),
+        prepareAiVaultSessionResume: vi.fn(),
+        createMobileSessionTerminal
+      }
+    })
+
+    afterEach(async () => {
+      setStructuredAgentSessionHost(null)
+      await rm(root, { recursive: true, force: true })
+    })
+
+    it('hides the row from the old client and annotates it for a capable client', async () => {
+      const oldReply = (
+        await callBuild(
+          current,
+          'aiVault.listSessions',
+          {},
+          {
+            clientKind: 'mobile',
+            clientCapabilities: baseline.capabilities
+          },
+          runtime
+        )
+      )[0]
+      expect(oldReply).toMatchObject({ ok: true, result: { sessions: [] } })
+
+      const capableReply = (
+        await callBuild(
+          current,
+          'aiVault.listSessions',
+          {},
+          {
+            clientKind: 'mobile',
+            clientCapabilities: [STRUCTURED_AGENT_SESSION_RUNTIME_CAPABILITY]
+          },
+          runtime
+        )
+      )[0]
+      expect(capableReply).toMatchObject({
+        ok: true,
+        result: {
+          sessions: [
+            {
+              structuredSession: { sessionId: SESSION, workspaceId: WORKSPACE }
+            }
+          ]
+        }
+      })
+
+      const claudeCapableReply = (
+        await callBuild(
+          current,
+          'aiVault.listSessions',
+          {},
+          {
+            clientKind: 'mobile',
+            clientCapabilities: [
+              STRUCTURED_AGENT_SESSION_RUNTIME_CAPABILITY,
+              CLAUDE_STRUCTURED_AGENT_SESSION_RUNTIME_CAPABILITY
+            ]
+          },
+          runtime
+        )
+      )[0]
+      expect(claudeCapableReply).toMatchObject({
+        ok: true,
+        result: {
+          sessions: [
+            { structuredSession: { sessionId: SESSION, workspaceId: WORKSPACE } },
+            { structuredSession: { sessionId: CLAUDE_SESSION, workspaceId: WORKSPACE } }
+          ]
+        }
+      })
+    })
+
+    it('refuses cached prepare and both legacy launch deliveries before a second writer starts', async () => {
+      const params = {
+        agent: 'codex',
+        filePath: `/home/dev/.codex/sessions/rollout-${THREAD}.jsonl`,
+        codexHome: '/home/dev/.codex'
+      }
+      expect(
+        (
+          await callBuild(
+            current,
+            'aiVault.prepareSessionResume',
+            params,
+            {
+              clientKind: 'mobile',
+              clientCapabilities: baseline.capabilities
+            },
+            runtime
+          )
+        )[0]
+      ).toMatchObject({ ok: false, error: { code: 'agent_session_conflict' } })
+
+      expect(
+        (
+          await callBuild(
+            current,
+            'session.tabs.createTerminal',
+            { worktree: `id:${WORKSPACE}`, command: `codex resume '${THREAD}'` },
+            { clientKind: 'mobile', clientCapabilities: baseline.capabilities },
+            runtime
+          )
+        )[0]
+      ).toMatchObject({ ok: false, error: { code: 'agent_session_conflict' } })
+      expect(
+        (
+          await callBuild(
+            current,
+            'terminal.send',
+            { terminal: 'terminal-1', text: `codex resume '${THREAD}'`, enter: true },
+            { clientKind: 'mobile', clientCapabilities: baseline.capabilities },
+            runtime
+          )
+        )[0]
+      ).toMatchObject({ ok: false, error: { code: 'agent_session_conflict' } })
+      expect(createMobileSessionTerminal).not.toHaveBeenCalled()
+
+      expect(
+        (
+          await callBuild(
+            current,
+            'aiVault.prepareSessionResume',
+            {
+              agent: 'claude',
+              filePath: `/home/dev/.claude/projects/repo/${CLAUDE_PROVIDER_SESSION}.jsonl`,
+              codexHome: null
+            },
+            {
+              clientKind: 'mobile',
+              clientCapabilities: baseline.capabilities
+            },
+            runtime
+          )
+        )[0]
+      ).toMatchObject({ ok: false, error: { code: 'agent_session_conflict' } })
+      expect(
+        (
+          await callBuild(
+            current,
+            'session.tabs.createTerminal',
+            {
+              worktree: `id:${WORKSPACE}`,
+              command: `claude --resume '${CLAUDE_PROVIDER_SESSION}'`
+            },
+            { clientKind: 'mobile', clientCapabilities: baseline.capabilities },
+            runtime
+          )
+        )[0]
+      ).toMatchObject({ ok: false, error: { code: 'agent_session_conflict' } })
+      expect(createMobileSessionTerminal).not.toHaveBeenCalled()
+    })
+  })
+
   describe('a cursor across a host restart', () => {
     let root: string
     let store: AgentSessionRecordStore
diff --git a/tests/e2e/cross-version-wire/versioned-agent-session-wire.ts b/tests/e2e/cross-version-wire/versioned-agent-session-wire.ts
index 1b2eb3dae97..241585e141b 100644
--- a/tests/e2e/cross-version-wire/versioned-agent-session-wire.ts
+++ b/tests/e2e/cross-version-wire/versioned-agent-session-wire.ts
@@ -89,10 +89,13 @@ function capabilityStrings(module: Record<string, unknown>): readonly string[] {
 }
 
 async function loadWorkingTreeBuild(): Promise<AgentSessionWireBuild> {
-  const [protocol, dispatcher, structured] = await Promise.all([
+  const [protocol, dispatcher, structured, aiVault, sessionTabs, terminal] = await Promise.all([
     import('../../../src/shared/protocol-version'),
     import('../../../src/main/runtime/rpc/dispatcher'),
-    import('../../../src/main/runtime/rpc/methods/structured-agent-session')
+    import('../../../src/main/runtime/rpc/methods/structured-agent-session'),
+    import('../../../src/main/runtime/rpc/methods/ai-vault'),
+    import('../../../src/main/runtime/rpc/methods/session-tabs'),
+    import('../../../src/main/runtime/rpc/methods/terminal')
   ])
   const module = dispatcher as unknown as DispatcherModule
   return {
@@ -104,7 +107,12 @@ async function loadWorkingTreeBuild(): Promise<AgentSessionWireBuild> {
     createDispatcher: (runtime) =>
       new module.RpcDispatcher({
         runtime,
-        methods: structured.STRUCTURED_AGENT_SESSION_METHODS as unknown[]
+        methods: [
+          ...(structured.STRUCTURED_AGENT_SESSION_METHODS as unknown[]),
+          ...(aiVault.AI_VAULT_METHODS as unknown[]),
+          ...(sessionTabs.SESSION_TAB_METHODS as unknown[]),
+          ...(terminal.TERMINAL_METHODS as unknown[])
+        ]
       })
   }
 }