diff --git a/src/renderer/src/lib/agent-launch-routing.test.ts b/src/renderer/src/lib/agent-launch-routing.test.ts
index cb3a2b70b00..6bcc5e97287 100644
--- a/src/renderer/src/lib/agent-launch-routing.test.ts
+++ b/src/renderer/src/lib/agent-launch-routing.test.ts
@@ -76,6 +76,7 @@ describe('resolveAgentLaunchRoute', () => {
 
   it('fails closed for missing capability, unsupported providers, and explicit TUI options', () => {
     expect(route({ hostCapabilities: [] })).toBe('legacy-native-chat')
+    expect(route({ hostCapabilities: null })).toBe('legacy-native-chat')
     // openclaude and grok render native chat but have no structured adapter.
     expect(route({ agent: 'openclaude' })).toBe('legacy-native-chat')
     expect(route({ agent: 'grok' })).toBe('legacy-native-chat')
diff --git a/src/renderer/src/lib/launch-agent-structured-chat-guard.test.ts b/src/renderer/src/lib/launch-agent-structured-chat-guard.test.ts
index 179f6203d0b..8e083618925 100644
--- a/src/renderer/src/lib/launch-agent-structured-chat-guard.test.ts
+++ b/src/renderer/src/lib/launch-agent-structured-chat-guard.test.ts
@@ -14,7 +14,7 @@ const mockRefreshLocalStructuredSessionTabs = vi.fn()
 const mockToastError = vi.fn()
 const mockCallStructuredAgentSession = vi.fn()
 const STRUCTURED_HOST_CAPABILITIES = ['agent-session.structured.v1']
-let hostCapabilities: readonly string[] = STRUCTURED_HOST_CAPABILITIES
+let hostCapabilities: readonly string[] | null = STRUCTURED_HOST_CAPABILITIES
 
 function structuredLaunchIntent(worktreeId: string, sessionId = 'codex-session-1') {
   return {
@@ -113,7 +113,7 @@ vi.mock('@/runtime/local-structured-session-tabs-sync', () => ({
   LOCAL_STRUCTURED_SESSION_OWNER: 'local-structured-session'
 }))
 vi.mock('@/runtime/local-runtime-capabilities', () => ({
-  readLocalRuntimeCapabilities: () => hostCapabilities
+  readLocalRuntimeCapabilitiesOrUnknown: () => hostCapabilities
 }))
 vi.mock('@/lib/worktree-runtime-owner', () => ({
   getExecutionHostIdForWorktree: () =>
@@ -233,16 +233,19 @@ describe('structured chat adoption guard on the launch path', () => {
     expect(mockToastError).not.toHaveBeenCalled()
   })
 
-  it('routes every structured launch through the shared host capability gate', async () => {
-    hostCapabilities = []
-    const { launchAgentInNewTab } = await import('./launch-agent-in-new-tab')
+  it.each([[], null])(
+    'preserves terminal-backed launches with capability answer %s',
+    async (capabilities) => {
+      hostCapabilities = capabilities
+      const { launchAgentInNewTab } = await import('./launch-agent-in-new-tab')
 
-    launchAgentInNewTab({ agent: 'claude', worktreeId: 'wt-1' })
-    launchAgentInNewTab({ agent: 'codex', worktreeId: 'wt-1' })
+      launchAgentInNewTab({ agent: 'claude', worktreeId: 'wt-1' })
+      launchAgentInNewTab({ agent: 'codex', worktreeId: 'wt-1' })
 
-    expect(mockCreateStructuredCodexSessionLaunchIntent).not.toHaveBeenCalled()
-    expect(mockCreateTab).toHaveBeenCalledTimes(2)
-  })
+      expect(mockCreateStructuredCodexSessionLaunchIntent).not.toHaveBeenCalled()
+      expect(mockCreateTab).toHaveBeenCalledTimes(2)
+    }
+  )
 
   /** The toggle is hidden under Terminal chat but its persisted value survives, so the launch
    *  path must re-check the default view rather than trust a stale opt-in. */
diff --git a/src/renderer/src/runtime/local-runtime-capabilities.test.ts b/src/renderer/src/runtime/local-runtime-capabilities.test.ts
index 264fcdb1403..eedd31a748a 100644
--- a/src/renderer/src/runtime/local-runtime-capabilities.test.ts
+++ b/src/renderer/src/runtime/local-runtime-capabilities.test.ts
@@ -3,6 +3,7 @@
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 import {
   readLocalRuntimeCapabilities,
+  readLocalRuntimeCapabilitiesOrUnknown,
   refreshLocalRuntimeCapabilities,
   setLocalRuntimeCapabilitiesForTests
 } from './local-runtime-capabilities'
@@ -12,6 +13,22 @@ describe('local runtime capabilities', () => {
     setLocalRuntimeCapabilitiesForTests([])
   })
 
+  it('starts unknown while the array reader stays compatible', async () => {
+    vi.resetModules()
+    const fresh = await import('./local-runtime-capabilities')
+    expect(fresh.readLocalRuntimeCapabilitiesOrUnknown()).toBeNull()
+    expect(fresh.readLocalRuntimeCapabilities()).toEqual([])
+  })
+
+  it.each([{}, { capabilities: [] }])(
+    'treats a successful legacy or empty response as known denial: %j',
+    async (status) => {
+      Object.assign(window, { api: { runtime: { getStatus: vi.fn(async () => status) } } })
+      await expect(refreshLocalRuntimeCapabilities()).resolves.toEqual([])
+      expect(readLocalRuntimeCapabilitiesOrUnknown()).toEqual([])
+    }
+  )
+
   it('fails closed until the live host advertises support', async () => {
     const getStatus = vi.fn(async () => ({ capabilities: ['agent-session.structured.v1'] }))
     Object.assign(window, { api: { runtime: { getStatus } } })
@@ -21,6 +38,7 @@ describe('local runtime capabilities', () => {
       'agent-session.structured.v1'
     ])
     expect(readLocalRuntimeCapabilities()).toEqual(['agent-session.structured.v1'])
+    expect(readLocalRuntimeCapabilitiesOrUnknown()).toEqual(['agent-session.structured.v1'])
   })
 
   it('coalesces concurrent live status reads', async () => {
@@ -38,6 +56,7 @@ describe('local runtime capabilities', () => {
       ['agent-session.structured.v1'],
       ['agent-session.structured.v1']
     ])
+    expect(first).toBe(second)
     expect(getStatus).toHaveBeenCalledOnce()
   })
 
@@ -55,5 +74,12 @@ describe('local runtime capabilities', () => {
 
     await expect(refreshLocalRuntimeCapabilities()).resolves.toEqual([])
     expect(readLocalRuntimeCapabilities()).toEqual([])
+    expect(readLocalRuntimeCapabilitiesOrUnknown()).toBeNull()
+
+    window.api.runtime.getStatus = vi
+      .fn()
+      .mockResolvedValue({ capabilities: ['agent-session.structured.v1'] })
+    await refreshLocalRuntimeCapabilities()
+    expect(readLocalRuntimeCapabilitiesOrUnknown()).toEqual(['agent-session.structured.v1'])
   })
 })