diff --git a/.github/workflows/pr.yml b/.github/workflows/pr.yml
index 0862ac31fe7..a256da5112c 100644
--- a/.github/workflows/pr.yml
+++ b/.github/workflows/pr.yml
@@ -703,6 +703,7 @@ jobs:
           src/main/providers/windows-conpty-wide-char-duplication.node-pty.test.ts
           src/main/providers/pty-repaint-wide-char-buffer.node-pty.test.ts
           src/shared/child-process/windows-command-line.win32.test.ts
+          src/main/agent-hooks/windows-hook-payload-delivery.test.ts
           src/main/windows/windows-pty-job.win32.test.ts
           src/main/windows/windows-host-job.win32.test.ts
           src/main/wsl/wsl-runner.test.ts
diff --git a/docs/reference/windows-process-enumeration.md b/docs/reference/windows-process-enumeration.md
index 115cc7040a9..e4c91329c46 100644
--- a/docs/reference/windows-process-enumeration.md
+++ b/docs/reference/windows-process-enumeration.md
@@ -46,6 +46,40 @@ risk — but the headroom is roughly 2x on time and 1.7x on bytes, not the ~4x t
 parse, and the read rejects, so a busy host loses the table rather than
 receiving a wrong one.
 
+## When a read wedges
+
+The vendored reader pushes every callback onto a module-global queue and drains
+that queue only when the request holding its `requestInProgress` latch
+completes. If a Toolhelp32 snapshot never comes back — an EDR hook, a restricted
+token, a worker that dies — the latch is stuck for the life of the process and
+every later call parks another closure in that queue.
+
+Two guards, and they work together:
+
+- a **3 s deadline** on each read, so a caller gets a rejection instead of a
+  promise that never settles;
+- a **sticky wedge**: once a read misses its deadline and has not called back,
+  the module refuses every further read until that read's callback fires.
+
+The wedge used to be a 30 s cooldown that let one probe through per window. That
+bounded the *rate* of new callbacks but not the total: a permanently wedged
+reader retained one more closure every 30 s for as long as the app ran, and each
+probe also blocked its caller for the full 3 s deadline first. Gating on the
+outstanding read instead bounds retention at exactly one callback, and gives up
+nothing on recovery — a probe queued behind the latch could never have observed
+recovery anyway, whereas the stuck callback firing is the drain itself. On the
+relay's bare addon, which has no queue of its own, it is also what keeps Orca
+from re-entering `CreateToolhelp32Snapshot` while a call is still running.
+
+That last part is not just tidiness. The addon runs each read as a
+`Napi::AsyncWorker`, so a wedged read holds a libuv threadpool slot for good. On
+the relay the JS queue is not there to absorb the retries, so one probe per
+window would have pinned all four default threads inside ~2 minutes — hanging
+every async `fs` and DNS call in that process, not only the process table.
+
+A wedge does **not** engage the PowerShell fallback; see the next section for
+why only absence does.
+
 ## The relay has no binding, and falls back
 
 Relay deployment installs only `node-pty` and `@parcel/watcher` on the remote
diff --git a/src/main/agent-hooks/installer-utils.test.ts b/src/main/agent-hooks/installer-utils.test.ts
index 88c73550da2..3cf2525ba1e 100644
--- a/src/main/agent-hooks/installer-utils.test.ts
+++ b/src/main/agent-hooks/installer-utils.test.ts
@@ -604,7 +604,7 @@ describe('wrapPosixHookCommand', () => {
 })
 
 const qualifiedWindowsPowerShellCommand =
-  /^[A-Za-z]:\/[^"]*\/System32\/WindowsPowerShell\/v1\.0\/powershell\.exe -NoProfile -WindowStyle Hidden -EncodedCommand \S+$/
+  /^[A-Za-z]:\/[^"]*\/System32\/WindowsPowerShell\/v1\.0\/powershell\.exe -NoProfile -EncodedCommand \S+$/
 
 function decodeWindowsHookCommand(command: string): string {
   const encodedCommand = command.match(/ -EncodedCommand (\S+)$/)?.[1]
@@ -762,7 +762,7 @@ describe('wrapRuntimeHomeHookCommand', () => {
     // applies to the exact same string (#16003).
     const command = wrapRuntimeHomeHookCommand('claude-hook')
 
-    expect(command).toContain('powershell.exe" -NoProfile -WindowStyle Hidden -EncodedCommand ')
+    expect(command).toContain('powershell.exe" -NoProfile -EncodedCommand ')
     expect(command).not.toMatch(/-ExecutionPolicy/i)
   })
 
diff --git a/src/main/agent-hooks/windows-powershell-hook-launcher.test.ts b/src/main/agent-hooks/windows-powershell-hook-launcher.test.ts
index e58fd25c960..df307d87035 100644
--- a/src/main/agent-hooks/windows-powershell-hook-launcher.test.ts
+++ b/src/main/agent-hooks/windows-powershell-hook-launcher.test.ts
@@ -1,6 +1,7 @@
 import { describe, expect, it } from 'vitest'
 import {
   encodeWindowsPowerShellHookCommand,
+  getWindowsPowerShellExecutablePath,
   WINDOWS_POWERSHELL_HOOK_SWITCHES,
   wrapWindowsPowerShellEncodedCommand
 } from './windows-powershell-hook-launcher'
@@ -12,38 +13,41 @@ function decodePayload(command: string): string {
 }
 
 /*
- * Two reproduced Windows failures constrain this one string, in opposite
- * directions:
+ * #16003 — endpoint security (Kaspersky, Windows 11) denies process creation
+ * for the encoded launcher shape whatever the payload decodes to, and no
+ * exclusion re-enabled it. Measured on the reporting host: the denied shape
+ * exits 126 with or without the policy switch and with or without `-NoProfile`,
+ * while `-NoProfile -EncodedCommand` alone runs 5/5. So the command line spells
+ * neither the policy bypass (moved into the payload by #16576) nor the denied
+ * window switch.
  *
- * #16003 — endpoint security (Kaspersky Premium, Windows 11) denies process
- * creation for `-ExecutionPolicy Bypass -WindowStyle Hidden -EncodedCommand`
- * whatever the payload decodes to, and no exclusion re-enabled it. The triple
- * must stop being spelled.
- *
- * #14815 (+ #14828, #15117, #15447, #15767) — without `-WindowStyle Hidden`
- * every hook event allocates a console that takes foreground and eats the
- * user's keystrokes, and strands a visible window outright when the hook blocks
- * on stdin. Window suppression must stay.
- *
- * Both hold only if the flag that leaves the command line is the policy bypass,
- * which is the one with an exact in-payload equivalent.
+ * The counter-pressure is real and is NOT resolved by these assertions:
+ * #14815 (+ #14828, #15117, #15447, #15767) reported consoles taking
+ * foreground. The previous suppression switch was that fix, but its behavior
+ * was never measured — see the launcher's comment. These tests pin the shape
+ * so it cannot be restored silently; whether a console appears is a question
+ * for a live window measurement, which no unit test here can answer.
  */
 describe('windows PowerShell hook launcher', () => {
-  it('never spells the denied flag triple on the command line', () => {
+  it('never spells a denied flag on the command line', () => {
     const command = wrapWindowsPowerShellEncodedCommand('exit 0')
+    const switches = command.replace(/ -EncodedCommand \S+$/, '')
 
     expect(WINDOWS_POWERSHELL_HOOK_SWITCHES).not.toMatch(/-ExecutionPolicy/i)
-    expect(command.replace(/ -EncodedCommand \S+$/, '')).not.toMatch(/-ExecutionPolicy/i)
+    expect(switches).not.toMatch(/-ExecutionPolicy/i)
+    // Why: measured exit 126 for the denied switch paired with -EncodedCommand.
+    expect(WINDOWS_POWERSHELL_HOOK_SWITCHES).toBe('-NoProfile')
+    expect(switches).toBe(`${getWindowsPowerShellExecutablePath()} -NoProfile`)
   })
 
-  it('keeps hiding the console window on every hook event (#14815)', () => {
-    // Dropping this flag is not a cosmetic flash: the console takes foreground
-    // and swallows what the user is typing into Orca (#14828), and never closes
-    // at all when the hook blocks reading stdin (#14815).
+  it('pins the exact launcher shape so a flag cannot come back unnoticed', () => {
+    // Why this is worth a test: #16576 round 3 dropped a required launcher
+    // invariant by accident and updated the tests to match, so nothing caught
+    // it. Restoring either denied switch re-breaks every hook on an AV host.
     const command = wrapWindowsPowerShellEncodedCommand('exit 0')
 
-    expect(WINDOWS_POWERSHELL_HOOK_SWITCHES).toBe('-NoProfile -WindowStyle Hidden')
-    expect(command).toMatch(/ -NoProfile -WindowStyle Hidden -EncodedCommand [A-Za-z0-9+/=]+$/)
+    expect(WINDOWS_POWERSHELL_HOOK_SWITCHES).toBe('-NoProfile')
+    expect(command).toMatch(/ -NoProfile -EncodedCommand [A-Za-z0-9+/=]+$/)
   })
 
   it('keeps the execution-policy bypass, in the payload where AV cannot read it', () => {
diff --git a/src/main/agent-hooks/windows-powershell-hook-launcher.ts b/src/main/agent-hooks/windows-powershell-hook-launcher.ts
index aeec04380db..b9a9f6dd208 100644
--- a/src/main/agent-hooks/windows-powershell-hook-launcher.ts
+++ b/src/main/agent-hooks/windows-powershell-hook-launcher.ts
@@ -14,26 +14,33 @@ export function getWindowsPowerShellExecutablePath(): string {
  * Switches for the PowerShell that relays hook output and exit status
  * (#14818 — conhost does neither).
  *
- * `-WindowStyle Hidden` stays. It is the shipped fix for #14815 and its four
- * duplicates (#14828, #15117, #15447, #15767): without it Windows allocates a
- * console per hook event, which steals foreground from whatever the user is
- * typing into, and strands a permanently visible window whenever a hook blocks
- * reading stdin (see hook-stdin-contract.ts). Those are reported, reproduced
- * user-facing failures on every hook event of every managed agent.
+ * The command line spells no flag beyond `-NoProfile`, because AV denies the
+ * combinations. #16003 measured, on the reporting Kaspersky host:
  *
- * `-ExecutionPolicy Bypass` is the flag that leaves the command line, because
- * it is the only one of the three with an exact in-payload equivalent (below):
- * it costs nothing to move. #16003 measured `-NoProfile -ExecutionPolicy Bypass
- * -WindowStyle Hidden -EncodedCommand` as denied at CreateProcess (exit 126,
- * Kaspersky Premium on Windows 11) no matter what the payload decodes to, so
- * the triple has to stop being spelled; dropping the policy flag breaks it.
+ *   -NoProfile -ExecutionPolicy Bypass -WindowStyle Hidden -EncodedCommand  126
+ *   -NoProfile -WindowStyle Hidden -EncodedCommand                          126
+ *   -WindowStyle Hidden -EncodedCommand                                     126
+ *   -NoProfile -EncodedCommand                                              0 (5/5)
+ *   -NoProfile -ExecutionPolicy Bypass -Command                             0 (5/5)
  *
- * What is not established: that the remaining pair clears that AV signature —
- * the reporter measured no two-flag encoded shape. If it turns out not to, the
- * answer is another launcher shape that still suppresses the window, not
- * trading a reproduced regression for an unmeasured hope.
+ * The denial is at CreateProcess and is independent of the payload: `exit 0` is
+ * denied too, and bash reports it as `Permission denied`. So `-WindowStyle
+ * Hidden` + `-EncodedCommand` is the pair that has to stop being spelled.
+ * #16576 removed `-ExecutionPolicy Bypass` (kept in-payload below), which was
+ * the one flag of the three NOT in the signature — hooks kept failing.
+ *
+ * `-WindowStyle Hidden` was the shipped fix for #14815 (+#14828, #15117,
+ * #15447, #15767). Removing it is a real tradeoff and is recorded as such: its
+ * suppression was never measured — #14825 confirmed it *visually*, #16576's
+ * author stated it "remains unverified on a real box", and #15506's author
+ * argued it cannot help a `.cmd` child that has no console to inherit. The
+ * console is allocated by the parent chain, not by this command line.
+ *
+ * Do not restore the flag to fix a console report. That trades every hook on an
+ * AV host for a flicker. The answer is to shorten the interpreter chain — the
+ * shipped doctrine of #15520 and #15595 — or a launcher that owns no console.
  */
-export const WINDOWS_POWERSHELL_HOOK_SWITCHES = '-NoProfile -WindowStyle Hidden'
+export const WINDOWS_POWERSHELL_HOOK_SWITCHES = '-NoProfile'
 
 // Why: redirected PowerShell progress becomes CLIXML that can corrupt merged JSON
 // output. It must be the FIRST statement: Set-ExecutionPolicy autoloads
diff --git a/src/main/browser/browser-clicked-link-routing.test.ts b/src/main/browser/browser-clicked-link-routing.test.ts
index eee5eea35f1..24c26471c3a 100644
--- a/src/main/browser/browser-clicked-link-routing.test.ts
+++ b/src/main/browser/browser-clicked-link-routing.test.ts
@@ -64,7 +64,7 @@ describe('browser clicked-link routing', () => {
     vi.restoreAllMocks()
   })
 
-  it('routes plain target=_blank links back into the current Orca tab', () => {
+  it('routes plain target=_blank links into a new Orca tab', () => {
     const link = document.createElement('a')
     link.href = 'https://docs.example.com/guide'
     link.target = '_blank'
@@ -73,9 +73,8 @@ describe('browser clicked-link routing', () => {
 
     const { event, open } = clickLink(link)
 
-    expect(event.defaultPrevented).toBe(false)
-    expect(open).not.toHaveBeenCalled()
-    expect(link.getAttribute('target')).toBe('_self')
+    expect(event.defaultPrevented).toBe(true)
+    expect(open).toHaveBeenCalledWith('https://docs.example.com/guide', FOREGROUND_FRAME_NAME)
   })
 
   it('routes the host-platform modifier without trusting an emulated guest user agent', () => {
@@ -127,9 +126,11 @@ describe('browser clicked-link routing', () => {
 
     expect(clickLink(cancelled).open).not.toHaveBeenCalled()
     expect(cancelled.getAttribute('target')).toBe('_blank')
-    expect(clickLink(rewritten).open).not.toHaveBeenCalled()
-    expect(rewritten.href).toBe('https://example.com/rewritten')
-    expect(rewritten.getAttribute('target')).toBe('_self')
+    // The page's own handler ran first, so routing must follow the rewritten href.
+    expect(clickLink(rewritten).open).toHaveBeenCalledWith(
+      'https://example.com/rewritten',
+      FOREGROUND_FRAME_NAME
+    )
   })
 
   it('routes SVG links but leaves download links and links without href alone', () => {
@@ -145,8 +146,10 @@ describe('browser clicked-link routing', () => {
     document.body.append(svgLink, areaDownload, noHref)
     installRouting()
 
-    expect(clickLink(svgLink).open).not.toHaveBeenCalled()
-    expect(svgLink.getAttribute('target')).toBe('_self')
+    expect(clickLink(svgLink).open).toHaveBeenCalledWith(
+      'https://example.com/svg',
+      FOREGROUND_FRAME_NAME
+    )
     expect(clickLink(areaDownload).open).not.toHaveBeenCalled()
     expect(clickLink(noHref).open).not.toHaveBeenCalled()
   })
@@ -195,7 +198,7 @@ describe('browser clicked-link routing', () => {
     expect(script).not.toContain('BrowserClickedLinkRoutingState')
   })
 
-  it('routes plain iframe target=_blank links into the top-level guest', () => {
+  it('routes plain iframe target=_blank links into a new Orca tab', () => {
     const link = document.createElement('a')
     link.href = 'https://example.com/from-frame'
     link.target = '_blank'
@@ -204,9 +207,8 @@ describe('browser clicked-link routing', () => {
 
     const { event, open } = clickLink(link)
 
-    expect(event.defaultPrevented).toBe(false)
-    expect(open).not.toHaveBeenCalled()
-    expect(link.getAttribute('target')).toBe('_top')
+    expect(event.defaultPrevented).toBe(true)
+    expect(open).toHaveBeenCalledWith('https://example.com/from-frame', FOREGROUND_FRAME_NAME)
   })
 
   it('routes explicit iframe new-tab gestures through one-use frame names', () => {
diff --git a/src/main/browser/browser-clicked-link-routing.ts b/src/main/browser/browser-clicked-link-routing.ts
index 42a8bbf8232..ee6f2fc43d5 100644
--- a/src/main/browser/browser-clicked-link-routing.ts
+++ b/src/main/browser/browser-clicked-link-routing.ts
@@ -75,8 +75,9 @@ export function installBrowserClickedLinkRouting(
     const baseTarget = document.querySelector('base[target]')?.getAttribute('target') ?? ''
     const ownTarget = link.getAttribute('target')
     const effectiveTarget = (ownTarget === null ? baseTarget : ownTarget).trim().toLowerCase()
-    const opensNewContext = middleClick || modifierClick
-    if (!opensNewContext && effectiveTarget !== '_blank') {
+    // target=_blank is a new-tab request, exactly as it is in every other
+    // browser; the modifiers are the other two ways to ask for one.
+    if (!(middleClick || modifierClick || effectiveTarget === '_blank')) {
       return
     }
 
@@ -96,13 +97,6 @@ export function installBrowserClickedLinkRouting(
       return
     }
 
-    if (!opensNewContext) {
-      // Why: changing only the browsing context keeps Chromium's native anchor
-      // navigation, including referrer policy, attribution, and history.
-      link.setAttribute('target', '_self')
-      return
-    }
-
     // Why: Electron reports direct link clicks and featureless window.open()
     // with the same disposition. The private frame name preserves that one
     // distinction without weakening OAuth popups that need window.opener.
@@ -118,8 +112,8 @@ export function installBrowserClickedLinkRouting(
 }
 
 /**
- * Keeps plain target=_blank clicks inside the top-level guest when Electron's
- * isolated-world API cannot target a child frame.
+ * Same routing for links inside child frames, which Electron's isolated-world
+ * API cannot reach, so this runs in the page world against a one-use token.
  */
 export function installBrowserIframeClickedLinkRouting(
   frameName: string,
@@ -161,8 +155,7 @@ export function installBrowserIframeClickedLinkRouting(
     const baseTarget = document.querySelector('base[target]')?.getAttribute('target') ?? ''
     const ownTarget = link.getAttribute('target')
     const effectiveTarget = (ownTarget === null ? baseTarget : ownTarget).trim().toLowerCase()
-    const opensNewContext = middleClick || modifierClick
-    if (!opensNewContext && effectiveTarget !== '_blank') {
+    if (!(middleClick || modifierClick || effectiveTarget === '_blank')) {
       return
     }
 
@@ -182,13 +175,6 @@ export function installBrowserIframeClickedLinkRouting(
       return
     }
 
-    if (!opensNewContext) {
-      // Why: WebContents isolated worlds only cover the main frame. Rewriting
-      // to `_top` preserves native anchor semantics without opening a popup.
-      link.setAttribute('target', '_top')
-      return
-    }
-
     // Why: child-frame code runs in the page world, so each token is one-use.
     // A page that observes a real click cannot replay it to create more tabs.
     event.preventDefault()
diff --git a/src/main/browser/browser-manager-popup-child.test.ts b/src/main/browser/browser-manager-popup-child.test.ts
new file mode 100644
index 00000000000..bf4caf2b0ba
--- /dev/null
+++ b/src/main/browser/browser-manager-popup-child.test.ts
@@ -0,0 +1,253 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+
+const browserMocks = vi.hoisted(() => ({
+  appGetPathMock: vi.fn(() => '/downloads'),
+  menuBuildFromTemplateMock: vi.fn(),
+  guestOffMock: vi.fn(),
+  guestOnMock: vi.fn(),
+  guestSetBackgroundThrottlingMock: vi.fn(),
+  guestSetWindowOpenHandlerMock: vi.fn(),
+  guestOpenDevToolsMock: vi.fn(),
+  webContentsFromIdMock: vi.fn(),
+  browserWindowFromWebContentsMock: vi.fn(),
+  screenGetCursorScreenPointMock: vi.fn(() => ({ x: 0, y: 0 })),
+  shellOpenExternalMock: vi.fn(),
+  openPopupWithOriginBarMock: vi.fn()
+}))
+
+vi.mock('electron', () => ({
+  app: { getPath: browserMocks.appGetPathMock },
+  BrowserWindow: { fromWebContents: browserMocks.browserWindowFromWebContentsMock },
+  clipboard: { writeText: vi.fn() },
+  shell: { openExternal: browserMocks.shellOpenExternalMock },
+  Menu: { buildFromTemplate: browserMocks.menuBuildFromTemplateMock },
+  screen: { getCursorScreenPoint: browserMocks.screenGetCursorScreenPointMock },
+  webContents: { fromId: browserMocks.webContentsFromIdMock }
+}))
+
+vi.mock('./popup-origin-bar-window', () => ({
+  openPopupWithOriginBar: browserMocks.openPopupWithOriginBarMock
+}))
+
+import { browserManager } from './browser-manager'
+import {
+  createDownloadItem,
+  getDownloadItemEventHandler,
+  rendererWebContentsId,
+  resetBrowserManagerMocks,
+  resetBrowserManagerState
+} from './browser-manager-test-harness'
+
+const {
+  guestOffMock,
+  guestOnMock,
+  guestSetBackgroundThrottlingMock,
+  guestSetWindowOpenHandlerMock,
+  guestOpenDevToolsMock,
+  webContentsFromIdMock,
+  shellOpenExternalMock
+} = browserMocks
+
+describe('browserManager popup child policies', () => {
+  beforeEach(() => {
+    resetBrowserManagerMocks(browserMocks)
+    resetBrowserManagerState()
+  })
+
+  afterEach(() => {
+    vi.useRealTimers()
+  })
+
+  it('attaches guest policies to created popup child windows', () => {
+    const rendererSendMock = vi.fn()
+    const childSetBackgroundThrottlingMock = vi.fn()
+    const childSetWindowOpenHandlerMock = vi.fn()
+    const childOnMock = vi.fn()
+    const childOffMock = vi.fn()
+    const childOpenDevToolsMock = vi.fn()
+    const childGuest = {
+      id: 4040,
+      isDestroyed: vi.fn(() => false),
+      getType: vi.fn(() => 'webview'),
+      setBackgroundThrottling: childSetBackgroundThrottlingMock,
+      setWindowOpenHandler: childSetWindowOpenHandlerMock,
+      on: childOnMock,
+      off: childOffMock,
+      openDevTools: childOpenDevToolsMock
+    }
+    const guest = {
+      id: 404,
+      isDestroyed: vi.fn(() => false),
+      getType: vi.fn(() => 'webview'),
+      setBackgroundThrottling: guestSetBackgroundThrottlingMock,
+      setWindowOpenHandler: guestSetWindowOpenHandlerMock,
+      on: guestOnMock,
+      off: guestOffMock,
+      openDevTools: guestOpenDevToolsMock
+    }
+    webContentsFromIdMock.mockImplementation((id: number) => {
+      if (id === guest.id) {
+        return guest
+      }
+      if (id === rendererWebContentsId) {
+        return { isDestroyed: vi.fn(() => false), send: rendererSendMock }
+      }
+      return null
+    })
+
+    browserManager.attachGuestPolicies(guest as never)
+    browserManager.registerGuest({
+      browserPageId: 'browser-1',
+      webContentsId: guest.id,
+      rendererWebContentsId
+    })
+
+    const didCreateWindowHandler = guestOnMock.mock.calls.find(
+      ([event]) => event === 'did-create-window'
+    )?.[1] as ((window: { webContents: typeof childGuest }) => void) | undefined
+    expect(didCreateWindowHandler).toBeTypeOf('function')
+
+    didCreateWindowHandler?.({ webContents: childGuest })
+
+    expect(childSetBackgroundThrottlingMock).toHaveBeenCalledWith(false)
+    expect(childSetWindowOpenHandlerMock).toHaveBeenCalledTimes(1)
+    expect(childOnMock.mock.calls.filter(([event]) => event === 'did-create-window')).toHaveLength(
+      1
+    )
+    expect(childOnMock.mock.calls.filter(([event]) => event === 'will-navigate')).toHaveLength(1)
+    expect(childOnMock.mock.calls.filter(([event]) => event === 'will-redirect')).toHaveLength(1)
+
+    const childWindowOpenHandler = childSetWindowOpenHandlerMock.mock.calls[0][0] as (details: {
+      url: string
+    }) => { action: 'allow' | 'deny' }
+    expect(childWindowOpenHandler({ url: 'https://identity.example.com/login' })).toMatchObject({
+      action: 'allow'
+    })
+    expect(childWindowOpenHandler({ url: 'file:///etc/passwd' })).toEqual({ action: 'deny' })
+    expect(rendererSendMock).toHaveBeenCalledWith('browser:popup', {
+      browserPageId: 'browser-1',
+      origin: 'null',
+      action: 'blocked'
+    })
+    browserManager.notifyPermissionDenied({
+      guestWebContentsId: childGuest.id,
+      permission: 'notifications',
+      rawUrl: 'https://identity.example.com/login'
+    })
+    expect(rendererSendMock).toHaveBeenCalledWith('browser:permission-denied', {
+      browserPageId: 'browser-1',
+      permission: 'notifications',
+      origin: 'https://identity.example.com'
+    })
+
+    const childDidFailLoadHandler = childOnMock.mock.calls.find(
+      ([event]) => event === 'did-fail-load'
+    )?.[1] as
+      | ((
+          event: Electron.Event,
+          errorCode: number,
+          errorDescription: string,
+          validatedURL: string,
+          isMainFrame: boolean
+        ) => void)
+      | undefined
+    childDidFailLoadHandler?.(
+      {} as Electron.Event,
+      -105,
+      'Name not resolved',
+      'https://identity.example.com/unavailable',
+      true
+    )
+    expect(rendererSendMock).not.toHaveBeenCalledWith(
+      'browser:guest-load-failed',
+      expect.anything()
+    )
+
+    const childDownloadItem = createDownloadItem()
+    browserManager.handleGuestWillDownload({
+      guestWebContentsId: childGuest.id,
+      item: childDownloadItem
+    })
+    expect(rendererSendMock).toHaveBeenCalledWith(
+      'browser:download-requested',
+      expect.objectContaining({ browserPageId: 'browser-1' })
+    )
+    const childDownloadDoneHandler = getDownloadItemEventHandler(childDownloadItem, 'once', 'done')
+    childDownloadDoneHandler?.({} as Electron.Event, 'completed')
+
+    const managerState = browserManager as unknown as {
+      popupOwnerContextByGuestId: Map<number, unknown>
+    }
+    expect(managerState.popupOwnerContextByGuestId.has(childGuest.id)).toBe(true)
+
+    const cleanupChildOnMock = vi.fn()
+    const cleanupChildGuest = {
+      ...childGuest,
+      id: 4041,
+      on: cleanupChildOnMock,
+      off: vi.fn(),
+      setBackgroundThrottling: vi.fn(),
+      setWindowOpenHandler: vi.fn()
+    }
+    const childDidCreateWindowHandler = childOnMock.mock.calls.find(
+      ([event]) => event === 'did-create-window'
+    )?.[1] as ((window: { webContents: typeof cleanupChildGuest }) => void) | undefined
+    childDidCreateWindowHandler?.({ webContents: cleanupChildGuest })
+    expect(managerState.popupOwnerContextByGuestId.has(cleanupChildGuest.id)).toBe(true)
+    const cleanupChildWindowOpenHandler = cleanupChildGuest.setWindowOpenHandler.mock
+      .calls[0][0] as (details: { url: string }) => { action: 'allow' | 'deny' }
+    expect(
+      cleanupChildWindowOpenHandler({ url: 'https://identity.example.com/continue' })
+    ).toMatchObject({ action: 'allow' })
+    const cleanupChildDestroyedHandler = cleanupChildOnMock.mock.calls.find(
+      ([event]) => event === 'destroyed'
+    )?.[1] as (() => void) | undefined
+    cleanupChildDestroyedHandler?.()
+    expect(managerState.popupOwnerContextByGuestId.has(cleanupChildGuest.id)).toBe(false)
+
+    const replacementGuest = {
+      ...guest,
+      id: 405,
+      on: vi.fn(),
+      off: vi.fn(),
+      setBackgroundThrottling: vi.fn(),
+      setWindowOpenHandler: vi.fn()
+    }
+    webContentsFromIdMock.mockImplementation((id: number) => {
+      if (id === guest.id) {
+        return guest
+      }
+      if (id === replacementGuest.id) {
+        return replacementGuest
+      }
+      if (id === rendererWebContentsId) {
+        return { isDestroyed: vi.fn(() => false), send: rendererSendMock }
+      }
+      return null
+    })
+    browserManager.attachGuestPolicies(replacementGuest as never)
+    browserManager.registerGuest({
+      browserPageId: 'browser-1',
+      webContentsId: replacementGuest.id,
+      rendererWebContentsId
+    })
+
+    expect(childWindowOpenHandler({ url: 'https://identity.example.com/next' })).toEqual({
+      action: 'deny'
+    })
+    expect(shellOpenExternalMock).toHaveBeenCalledWith('https://identity.example.com/next')
+    expect(managerState.popupOwnerContextByGuestId.has(childGuest.id)).toBe(false)
+
+    const childDestroyedHandler = childOnMock.mock.calls.find(
+      ([event]) => event === 'destroyed'
+    )?.[1] as (() => void) | undefined
+    childDestroyedHandler?.()
+    expect(managerState.popupOwnerContextByGuestId.has(childGuest.id)).toBe(false)
+
+    browserManager.unregisterAll()
+
+    expect(childOffMock).toHaveBeenCalledWith('did-create-window', expect.any(Function))
+    expect(childOffMock).toHaveBeenCalledWith('will-navigate', expect.any(Function))
+    expect(childOffMock).toHaveBeenCalledWith('will-redirect', expect.any(Function))
+  })
+})
diff --git a/src/main/browser/browser-manager-popup-routing.test.ts b/src/main/browser/browser-manager-popup-routing.test.ts
index 89b4d2fe2a8..a3083005016 100644
--- a/src/main/browser/browser-manager-popup-routing.test.ts
+++ b/src/main/browser/browser-manager-popup-routing.test.ts
@@ -40,9 +40,8 @@ vi.mock('./popup-origin-bar-window', () => ({
 }))
 
 import { browserManager } from './browser-manager'
+import { MAX_PAGE_INITIATED_TABS_PER_WINDOW } from './browser-page-initiated-tab-budget'
 import {
-  createDownloadItem,
-  getDownloadItemEventHandler,
   rendererWebContentsId,
   resetBrowserManagerMocks,
   resetBrowserManagerState
@@ -169,11 +168,12 @@ describe('browserManager', () => {
     expect(rendererSendMock).not.toHaveBeenCalled()
   })
 
-  it('keeps featureless window.open popups in-app for every disposition', () => {
+  it('keeps opener-dependent window.open popups in-app for every disposition', () => {
     // Regression guard for the reverted #8332: gating the allow on
     // disposition === 'new-window' silently broke featureless window.open()
-    // OAuth flows (disposition 'foreground-tab'), whose returned handle must
-    // stay live. Disposition is a UX hint, not a trust signal.
+    // OAuth flows, whose returned handle must stay live. A named target, a
+    // features string, and a blank URL each mark such a flow, so all three keep
+    // a real child window no matter which disposition Chromium reports.
     const guest = {
       id: 140,
       isDestroyed: vi.fn(() => false),
@@ -199,14 +199,186 @@ describe('browserManager', () => {
       features: string
       disposition: string
     }) => { action: 'allow' | 'deny' }
+    const openerDependentOpens = [
+      { url: 'https://sso.example.com/auth', frameName: 'ssoWindow', features: '' },
+      { url: 'https://sso.example.com/auth', frameName: '', features: 'width=500,height=600' },
+      { url: 'about:blank', frameName: '', features: '' }
+    ]
     for (const disposition of ['foreground-tab', 'background-tab', 'new-window']) {
-      expect(
-        handler({ url: 'https://sso.example.com/auth', frameName: '', features: '', disposition })
-      ).toMatchObject({ action: 'allow' })
+      for (const open of openerDependentOpens) {
+        expect(handler({ ...open, disposition })).toMatchObject({ action: 'allow' })
+      }
     }
     expect(shellOpenExternalMock).not.toHaveBeenCalled()
   })
 
+  it('routes unnamed featureless window.open safely, including after renderer destruction', () => {
+    const rendererSendMock = vi.fn()
+    let rendererDestroyed = false
+    const guest = {
+      id: 142,
+      isDestroyed: vi.fn(() => false),
+      getType: vi.fn(() => 'webview'),
+      setBackgroundThrottling: guestSetBackgroundThrottlingMock,
+      setWindowOpenHandler: guestSetWindowOpenHandlerMock,
+      on: guestOnMock,
+      off: guestOffMock,
+      openDevTools: guestOpenDevToolsMock
+    }
+    webContentsFromIdMock.mockImplementation((id: number) => {
+      if (id === guest.id) {
+        return guest
+      }
+      if (id === rendererWebContentsId) {
+        return { isDestroyed: vi.fn(() => rendererDestroyed), send: rendererSendMock }
+      }
+      return null
+    })
+
+    browserManager.attachGuestPolicies(guest as never)
+    browserManager.registerGuest({
+      browserPageId: 'browser-1',
+      webContentsId: guest.id,
+      rendererWebContentsId
+    })
+
+    const handler = guestSetWindowOpenHandlerMock.mock.calls[0][0] as (details: {
+      url: string
+      frameName: string
+      features: string
+      disposition: string
+    }) => { action: 'allow' | 'deny' }
+    for (const disposition of ['foreground-tab', 'background-tab']) {
+      expect(
+        handler({
+          url: 'https://docs.example.com/guide',
+          frameName: '',
+          features: '',
+          disposition
+        })
+      ).toEqual({ action: 'deny' })
+    }
+
+    expect(rendererSendMock).toHaveBeenCalledWith('browser:open-link-in-orca-tab', {
+      browserPageId: 'browser-1',
+      url: 'https://docs.example.com/guide'
+    })
+    expect(rendererSendMock).toHaveBeenCalledWith('browser:popup', {
+      browserPageId: 'browser-1',
+      origin: 'https://docs.example.com',
+      action: 'opened-in-orca'
+    })
+    expect(openPopupWithOriginBarMock).not.toHaveBeenCalled()
+    expect(shellOpenExternalMock).not.toHaveBeenCalled()
+    rendererDestroyed = true
+    expect(
+      handler({
+        url: 'https://docs.example.com/guide',
+        frameName: '',
+        features: '',
+        disposition: 'foreground-tab'
+      })
+    ).toEqual({ action: 'deny' })
+    expect(openPopupWithOriginBarMock).not.toHaveBeenCalled()
+    expect(shellOpenExternalMock).not.toHaveBeenCalled()
+  })
+
+  it('shares the page-initiated tab budget across the whole opener popup tree', () => {
+    const rendererSendMock = vi.fn()
+    const guest = {
+      id: 150,
+      isDestroyed: vi.fn(() => false),
+      getType: vi.fn(() => 'webview'),
+      setBackgroundThrottling: guestSetBackgroundThrottlingMock,
+      setWindowOpenHandler: guestSetWindowOpenHandlerMock,
+      on: guestOnMock,
+      once: vi.fn(),
+      off: guestOffMock,
+      openDevTools: guestOpenDevToolsMock
+    }
+    const guestsById = new Map<number, unknown>([[guest.id, guest]])
+    webContentsFromIdMock.mockImplementation((id: number) => {
+      if (id === rendererWebContentsId) {
+        return { isDestroyed: vi.fn(() => false), send: rendererSendMock }
+      }
+      return guestsById.get(id) ?? null
+    })
+
+    browserManager.attachGuestPolicies(guest as never)
+    browserManager.registerGuest({
+      browserPageId: 'browser-1',
+      webContentsId: guest.id,
+      rendererWebContentsId
+    })
+
+    type WindowOpenHandler = (details: {
+      url: string
+      frameName: string
+      features: string
+      disposition: string
+    }) => {
+      action: 'allow' | 'deny'
+      createWindow?: (options: Record<string, never>) => unknown
+    }
+    const handler = guestSetWindowOpenHandlerMock.mock.calls[0][0] as WindowOpenHandler
+
+    // A named child popup keeps a real child window; each one used to start with a fresh budget.
+    const openNamedChild = (index: number): WindowOpenHandler => {
+      const childSetWindowOpenHandlerMock = vi.fn()
+      const child = {
+        id: 1500 + index,
+        isDestroyed: vi.fn(() => false),
+        getType: vi.fn(() => 'webview'),
+        setBackgroundThrottling: vi.fn(),
+        setWindowOpenHandler: childSetWindowOpenHandlerMock,
+        on: vi.fn(),
+        once: vi.fn(),
+        off: vi.fn(),
+        openDevTools: vi.fn()
+      }
+      guestsById.set(child.id, child)
+      openPopupWithOriginBarMock.mockReturnValueOnce({
+        contentWebContents: child,
+        close: vi.fn(),
+        onClosed: vi.fn()
+      })
+      const result = handler({
+        url: `https://sso.example.com/child-${index}`,
+        frameName: `child-${index}`,
+        features: '',
+        disposition: 'new-window'
+      })
+      expect(result).toMatchObject({ action: 'allow' })
+      result.createWindow?.({})
+      return childSetWindowOpenHandlerMock.mock.calls[0][0] as WindowOpenHandler
+    }
+
+    const childHandlers = [openNamedChild(0), openNamedChild(1), openNamedChild(2)]
+    for (const [childIndex, childHandler] of childHandlers.entries()) {
+      for (let openIndex = 0; openIndex < MAX_PAGE_INITIATED_TABS_PER_WINDOW; openIndex++) {
+        expect(
+          childHandler({
+            url: `https://docs.example.com/${childIndex}-${openIndex}`,
+            frameName: '',
+            features: '',
+            disposition: 'foreground-tab'
+          })
+        ).toEqual({ action: 'deny' })
+      }
+    }
+
+    const routedTabs = rendererSendMock.mock.calls.filter(
+      ([channel]) => channel === 'browser:open-link-in-orca-tab'
+    )
+    expect(routedTabs).toHaveLength(MAX_PAGE_INITIATED_TABS_PER_WINDOW)
+    expect(rendererSendMock).toHaveBeenCalledWith('browser:popup', {
+      browserPageId: 'browser-1',
+      origin: 'https://docs.example.com',
+      action: 'blocked'
+    })
+    expect(openPopupWithOriginBarMock).toHaveBeenCalledTimes(childHandlers.length)
+  })
+
   it('keeps plain links current and routes explicit new-tab gestures to Orca tabs', async () => {
     const rendererSendMock = vi.fn()
     const executeJavaScriptInIsolatedWorldMock = vi.fn().mockResolvedValue(undefined)
@@ -589,197 +761,4 @@ describe('browserManager', () => {
       })
     )
   })
-
-  it('attaches guest policies to created popup child windows', () => {
-    const rendererSendMock = vi.fn()
-    const childSetBackgroundThrottlingMock = vi.fn()
-    const childSetWindowOpenHandlerMock = vi.fn()
-    const childOnMock = vi.fn()
-    const childOffMock = vi.fn()
-    const childOpenDevToolsMock = vi.fn()
-    const childGuest = {
-      id: 4040,
-      isDestroyed: vi.fn(() => false),
-      getType: vi.fn(() => 'webview'),
-      setBackgroundThrottling: childSetBackgroundThrottlingMock,
-      setWindowOpenHandler: childSetWindowOpenHandlerMock,
-      on: childOnMock,
-      off: childOffMock,
-      openDevTools: childOpenDevToolsMock
-    }
-    const guest = {
-      id: 404,
-      isDestroyed: vi.fn(() => false),
-      getType: vi.fn(() => 'webview'),
-      setBackgroundThrottling: guestSetBackgroundThrottlingMock,
-      setWindowOpenHandler: guestSetWindowOpenHandlerMock,
-      on: guestOnMock,
-      off: guestOffMock,
-      openDevTools: guestOpenDevToolsMock
-    }
-    webContentsFromIdMock.mockImplementation((id: number) => {
-      if (id === guest.id) {
-        return guest
-      }
-      if (id === rendererWebContentsId) {
-        return { isDestroyed: vi.fn(() => false), send: rendererSendMock }
-      }
-      return null
-    })
-
-    browserManager.attachGuestPolicies(guest as never)
-    browserManager.registerGuest({
-      browserPageId: 'browser-1',
-      webContentsId: guest.id,
-      rendererWebContentsId
-    })
-
-    const didCreateWindowHandler = guestOnMock.mock.calls.find(
-      ([event]) => event === 'did-create-window'
-    )?.[1] as ((window: { webContents: typeof childGuest }) => void) | undefined
-    expect(didCreateWindowHandler).toBeTypeOf('function')
-
-    didCreateWindowHandler?.({ webContents: childGuest })
-
-    expect(childSetBackgroundThrottlingMock).toHaveBeenCalledWith(false)
-    expect(childSetWindowOpenHandlerMock).toHaveBeenCalledTimes(1)
-    expect(childOnMock.mock.calls.filter(([event]) => event === 'did-create-window')).toHaveLength(
-      1
-    )
-    expect(childOnMock.mock.calls.filter(([event]) => event === 'will-navigate')).toHaveLength(1)
-    expect(childOnMock.mock.calls.filter(([event]) => event === 'will-redirect')).toHaveLength(1)
-
-    const childWindowOpenHandler = childSetWindowOpenHandlerMock.mock.calls[0][0] as (details: {
-      url: string
-    }) => { action: 'allow' | 'deny' }
-    expect(childWindowOpenHandler({ url: 'https://identity.example.com/login' })).toMatchObject({
-      action: 'allow'
-    })
-    expect(childWindowOpenHandler({ url: 'file:///etc/passwd' })).toEqual({ action: 'deny' })
-    expect(rendererSendMock).toHaveBeenCalledWith('browser:popup', {
-      browserPageId: 'browser-1',
-      origin: 'null',
-      action: 'blocked'
-    })
-    browserManager.notifyPermissionDenied({
-      guestWebContentsId: childGuest.id,
-      permission: 'notifications',
-      rawUrl: 'https://identity.example.com/login'
-    })
-    expect(rendererSendMock).toHaveBeenCalledWith('browser:permission-denied', {
-      browserPageId: 'browser-1',
-      permission: 'notifications',
-      origin: 'https://identity.example.com'
-    })
-
-    const childDidFailLoadHandler = childOnMock.mock.calls.find(
-      ([event]) => event === 'did-fail-load'
-    )?.[1] as
-      | ((
-          event: Electron.Event,
-          errorCode: number,
-          errorDescription: string,
-          validatedURL: string,
-          isMainFrame: boolean
-        ) => void)
-      | undefined
-    childDidFailLoadHandler?.(
-      {} as Electron.Event,
-      -105,
-      'Name not resolved',
-      'https://identity.example.com/unavailable',
-      true
-    )
-    expect(rendererSendMock).not.toHaveBeenCalledWith(
-      'browser:guest-load-failed',
-      expect.anything()
-    )
-
-    const childDownloadItem = createDownloadItem()
-    browserManager.handleGuestWillDownload({
-      guestWebContentsId: childGuest.id,
-      item: childDownloadItem
-    })
-    expect(rendererSendMock).toHaveBeenCalledWith(
-      'browser:download-requested',
-      expect.objectContaining({ browserPageId: 'browser-1' })
-    )
-    const childDownloadDoneHandler = getDownloadItemEventHandler(childDownloadItem, 'once', 'done')
-    childDownloadDoneHandler?.({} as Electron.Event, 'completed')
-
-    const managerState = browserManager as unknown as {
-      popupOwnerContextByGuestId: Map<number, unknown>
-    }
-    expect(managerState.popupOwnerContextByGuestId.has(childGuest.id)).toBe(true)
-
-    const cleanupChildOnMock = vi.fn()
-    const cleanupChildGuest = {
-      ...childGuest,
-      id: 4041,
-      on: cleanupChildOnMock,
-      off: vi.fn(),
-      setBackgroundThrottling: vi.fn(),
-      setWindowOpenHandler: vi.fn()
-    }
-    const childDidCreateWindowHandler = childOnMock.mock.calls.find(
-      ([event]) => event === 'did-create-window'
-    )?.[1] as ((window: { webContents: typeof cleanupChildGuest }) => void) | undefined
-    childDidCreateWindowHandler?.({ webContents: cleanupChildGuest })
-    expect(managerState.popupOwnerContextByGuestId.has(cleanupChildGuest.id)).toBe(true)
-    const cleanupChildWindowOpenHandler = cleanupChildGuest.setWindowOpenHandler.mock
-      .calls[0][0] as (details: { url: string }) => { action: 'allow' | 'deny' }
-    expect(
-      cleanupChildWindowOpenHandler({ url: 'https://identity.example.com/continue' })
-    ).toMatchObject({ action: 'allow' })
-    const cleanupChildDestroyedHandler = cleanupChildOnMock.mock.calls.find(
-      ([event]) => event === 'destroyed'
-    )?.[1] as (() => void) | undefined
-    cleanupChildDestroyedHandler?.()
-    expect(managerState.popupOwnerContextByGuestId.has(cleanupChildGuest.id)).toBe(false)
-
-    const replacementGuest = {
-      ...guest,
-      id: 405,
-      on: vi.fn(),
-      off: vi.fn(),
-      setBackgroundThrottling: vi.fn(),
-      setWindowOpenHandler: vi.fn()
-    }
-    webContentsFromIdMock.mockImplementation((id: number) => {
-      if (id === guest.id) {
-        return guest
-      }
-      if (id === replacementGuest.id) {
-        return replacementGuest
-      }
-      if (id === rendererWebContentsId) {
-        return { isDestroyed: vi.fn(() => false), send: rendererSendMock }
-      }
-      return null
-    })
-    browserManager.attachGuestPolicies(replacementGuest as never)
-    browserManager.registerGuest({
-      browserPageId: 'browser-1',
-      webContentsId: replacementGuest.id,
-      rendererWebContentsId
-    })
-
-    expect(childWindowOpenHandler({ url: 'https://identity.example.com/next' })).toEqual({
-      action: 'deny'
-    })
-    expect(shellOpenExternalMock).toHaveBeenCalledWith('https://identity.example.com/next')
-    expect(managerState.popupOwnerContextByGuestId.has(childGuest.id)).toBe(false)
-
-    const childDestroyedHandler = childOnMock.mock.calls.find(
-      ([event]) => event === 'destroyed'
-    )?.[1] as (() => void) | undefined
-    childDestroyedHandler?.()
-    expect(managerState.popupOwnerContextByGuestId.has(childGuest.id)).toBe(false)
-
-    browserManager.unregisterAll()
-
-    expect(childOffMock).toHaveBeenCalledWith('did-create-window', expect.any(Function))
-    expect(childOffMock).toHaveBeenCalledWith('will-navigate', expect.any(Function))
-    expect(childOffMock).toHaveBeenCalledWith('will-redirect', expect.any(Function))
-  })
 })
diff --git a/src/main/browser/browser-manager.ts b/src/main/browser/browser-manager.ts
index 1e04cbdf0cc..7ac64b485b9 100644
--- a/src/main/browser/browser-manager.ts
+++ b/src/main/browser/browser-manager.ts
@@ -43,6 +43,11 @@ import {
   buildBrowserClickedLinkRoutingScript,
   buildBrowserIframeClickedLinkRoutingScript
 } from './browser-clicked-link-routing'
+import {
+  createPageInitiatedTabBudget,
+  type PageInitiatedTabBudget
+} from './browser-page-initiated-tab-budget'
+import { isNewBrowserTabPopupIntent } from './browser-popup-new-tab-intent'
 import { cleanElectronUserAgent } from './browser-session-ua'
 import { getBrowserSessionUserAgentMode } from './browser-session-user-agent-mode'
 import { googleAuthUserAgent, isGoogleAuthUrl } from './browser-google-auth-ua'
@@ -233,6 +238,8 @@ export class BrowserManager {
   // Why: reverse map gives O(1) guest→tab lookups on every mouse/load/permission/popup event.
   private readonly tabIdByWebContentsId = new Map<number, string>()
   private readonly popupOwnerContextByGuestId = new Map<number, PopupOwnerContext>()
+  // Why: keyed by the opener tree's root so named child popups can't each mint a fresh tab quota.
+  private readonly pageInitiatedTabBudgetByRootGuestId = new Map<number, PageInitiatedTabBudget>()
   // Why: guests are keyed by page id but renderer visibility by workspace id; bridge the mismatch to activate the right tab before capture.
   private readonly workspaceIdByPageId = new Map<string, string>()
   private readonly sessionProfileIdByPageId = new Map<string, string | null>()
@@ -394,6 +401,16 @@ export class BrowserManager {
     return null
   }
 
+  /** Shared across the whole opener tree, so a chain of popups draws from one budget. */
+  private tryConsumePageInitiatedTab(rootGuestWebContentsId: number): boolean {
+    let budget = this.pageInitiatedTabBudgetByRootGuestId.get(rootGuestWebContentsId)
+    if (!budget) {
+      budget = createPageInitiatedTabBudget()
+      this.pageInitiatedTabBudgetByRootGuestId.set(rootGuestWebContentsId, budget)
+    }
+    return budget.tryConsume(Date.now())
+  }
+
   private resolveRendererForBrowserTab(browserTabId: string): Electron.WebContents | null {
     const rendererWebContentsId = this.rendererWebContentsIdByTabId.get(browserTabId)
     if (!rendererWebContentsId) {
@@ -758,8 +775,9 @@ export class BrowserManager {
       this.attachGuestPolicies(window.webContents, this.resolvePopupOwnerContext(guest.id))
     }
     guest.on('did-create-window', handleDidCreateWindow)
-    guest.setWindowOpenHandler(({ url, frameName }) => {
-      const browserTabId = this.resolveBrowserTabIdForGuestWebContentsId(guest.id)
+    guest.setWindowOpenHandler(({ url, frameName, disposition, features }) => {
+      const ownerContext = this.resolvePopupOwnerContext(guest.id)
+      const browserTabId = ownerContext?.browserTabId ?? null
       const browserUrl = normalizeBrowserNavigationUrl(url)
       const externalUrl = normalizeExternalBrowserUrl(url)
       const expectedClickedLinkFrameName = this.clickedLinkFrameNameByGuestId.get(guest.id)
@@ -784,6 +802,33 @@ export class BrowserManager {
         return { action: 'deny' }
       }
 
+      // Why: an unnamed, featureless window.open() is Chromium's own new-tab shape, so an Orca tab is
+      // the honest presentation; a floating origin-bar window is not. Opener-dependent shapes are
+      // excluded by isNewBrowserTabPopupIntent and still get a real child window below.
+      if (
+        ownerContext &&
+        externalUrl &&
+        isNewBrowserTabPopupIntent({ frameName, disposition, features })
+      ) {
+        // Why: one activation lets a page loop window.open, and each routed tab persists into
+        // workspace session state, so it survives the quit that used to clear popup windows.
+        if (!this.tryConsumePageInitiatedTab(ownerContext.rootGuestWebContentsId)) {
+          this.forwardOrQueuePopupEvent(guest.id, {
+            origin: safeOrigin(externalUrl),
+            action: 'blocked'
+          })
+          return { action: 'deny' }
+        }
+        if (this.openLinkInOrcaTab(ownerContext.browserTabId, externalUrl)) {
+          this.forwardOrQueuePopupEvent(guest.id, {
+            origin: safeOrigin(externalUrl),
+            action: 'opened-in-orca'
+          })
+        }
+        // Why: a recognized new-tab intent must never fall through to a native popup if its renderer vanished mid-open.
+        return { action: 'deny' }
+      }
+
       // Why: file URLs are fine for in-pane previews, but must not spawn native child windows targeting local paths.
       const canOpenAsChild = Boolean(externalUrl || browserUrl === ORCA_BROWSER_BLANK_URL)
       if (browserTabId && canOpenAsChild) {
@@ -1243,6 +1288,7 @@ export class BrowserManager {
     this.clickedLinkFrameNameByGuestId.delete(guestWebContentsId)
     this.offscreenGuestIds.delete(guestWebContentsId)
     this.popupOwnerContextByGuestId.delete(guestWebContentsId)
+    this.pageInitiatedTabBudgetByRootGuestId.delete(guestWebContentsId)
     this.authUserAgentOverrideStateByGuestId.delete(guestWebContentsId)
     this.pendingNavigationByGuestId.delete(guestWebContentsId)
     // Why: a popup must stop inheriting authorization the moment its owner retires, before Chromium destroys the child.
@@ -1444,6 +1490,7 @@ export class BrowserManager {
     this.clickedLinkFrameNameByGuestId.clear()
     this.tabIdByWebContentsId.clear()
     this.popupOwnerContextByGuestId.clear()
+    this.pageInitiatedTabBudgetByRootGuestId.clear()
     this.worktreeIdByTabId.clear()
     this.sessionProfileIdByPageId.clear()
     this.userAgentModeByPageId.clear()
diff --git a/src/main/browser/browser-page-initiated-tab-budget.test.ts b/src/main/browser/browser-page-initiated-tab-budget.test.ts
new file mode 100644
index 00000000000..c2dc7618a7f
--- /dev/null
+++ b/src/main/browser/browser-page-initiated-tab-budget.test.ts
@@ -0,0 +1,34 @@
+import { describe, expect, it } from 'vitest'
+import {
+  createPageInitiatedTabBudget,
+  MAX_PAGE_INITIATED_TABS_PER_WINDOW,
+  PAGE_INITIATED_TAB_WINDOW_MS
+} from './browser-page-initiated-tab-budget'
+
+describe('page-initiated tab budget', () => {
+  it('absorbs a window.open loop fired from a single activation', () => {
+    const budget = createPageInitiatedTabBudget()
+    const granted = Array.from({ length: 12 }, () => budget.tryConsume(1_000)).filter(Boolean)
+
+    expect(granted).toHaveLength(MAX_PAGE_INITIATED_TABS_PER_WINDOW)
+  })
+
+  it('refills once the rolling window has passed, so real browsing is unaffected', () => {
+    const budget = createPageInitiatedTabBudget()
+    for (let i = 0; i < MAX_PAGE_INITIATED_TABS_PER_WINDOW; i++) {
+      expect(budget.tryConsume(1_000)).toBe(true)
+    }
+    expect(budget.tryConsume(1_000 + PAGE_INITIATED_TAB_WINDOW_MS - 1)).toBe(false)
+    expect(budget.tryConsume(1_000 + PAGE_INITIATED_TAB_WINDOW_MS)).toBe(true)
+  })
+
+  it('slides rather than resetting, so a paced flood cannot outrun the cap', () => {
+    const budget = createPageInitiatedTabBudget(2, 1_000)
+
+    expect(budget.tryConsume(0)).toBe(true)
+    expect(budget.tryConsume(900)).toBe(true)
+    // The first grant has aged out by 1_000 but the second has not.
+    expect(budget.tryConsume(1_000)).toBe(true)
+    expect(budget.tryConsume(1_100)).toBe(false)
+  })
+})
diff --git a/src/main/browser/browser-page-initiated-tab-budget.ts b/src/main/browser/browser-page-initiated-tab-budget.ts
new file mode 100644
index 00000000000..d15a5c9ba4c
--- /dev/null
+++ b/src/main/browser/browser-page-initiated-tab-budget.ts
@@ -0,0 +1,26 @@
+/** Bounded so one hostile click cannot plant an unbounded number of tabs. */
+export const MAX_PAGE_INITIATED_TABS_PER_WINDOW = 4
+export const PAGE_INITIATED_TAB_WINDOW_MS = 2_000
+
+export type PageInitiatedTabBudget = {
+  /** Records the grant when it returns true; call only when the tab is actually being opened. */
+  tryConsume: (now: number) => boolean
+}
+
+/** Rolling window, so it absorbs a same-tick `window.open` loop without capping real browsing. */
+export function createPageInitiatedTabBudget(
+  maxPerWindow = MAX_PAGE_INITIATED_TABS_PER_WINDOW,
+  windowMs = PAGE_INITIATED_TAB_WINDOW_MS
+): PageInitiatedTabBudget {
+  let grants: number[] = []
+  return {
+    tryConsume: (now) => {
+      grants = grants.filter((grantedAt) => now - grantedAt < windowMs)
+      if (grants.length >= maxPerWindow) {
+        return false
+      }
+      grants.push(now)
+      return true
+    }
+  }
+}
diff --git a/src/main/browser/browser-popup-new-tab-intent.ts b/src/main/browser/browser-popup-new-tab-intent.ts
new file mode 100644
index 00000000000..316614b4aab
--- /dev/null
+++ b/src/main/browser/browser-popup-new-tab-intent.ts
@@ -0,0 +1,17 @@
+/**
+ * Whether a `window.open()` asks for a new tab rather than a popup window.
+ *
+ * Orca answers a tab by denying, which hands the page `null`, so named and featured opens — whose
+ * flow may use that handle — stay popups.
+ */
+export function isNewBrowserTabPopupIntent(details: {
+  frameName: string
+  disposition: string
+  features: string
+}): boolean {
+  return (
+    details.frameName === '' &&
+    details.features.trim() === '' &&
+    (details.disposition === 'foreground-tab' || details.disposition === 'background-tab')
+  )
+}
diff --git a/src/main/claude/hook-service.test.ts b/src/main/claude/hook-service.test.ts
index 315ee6dd228..531c092e3eb 100644
--- a/src/main/claude/hook-service.test.ts
+++ b/src/main/claude/hook-service.test.ts
@@ -40,9 +40,7 @@ describe('getWindowsManagedLifecycleHook', () => {
     const hook = getWindowsManagedLifecycleHook(scriptPath)
 
     expect(hook.args).toBeUndefined()
-    expect(hook.command).toMatch(
-      /\/powershell\.exe -NoProfile -WindowStyle Hidden -EncodedCommand /
-    )
+    expect(hook.command).toMatch(/\/powershell\.exe -NoProfile -EncodedCommand /)
     expect(hook.command).not.toContain(scriptPath)
     // Why: Git Bash/MSYS mangles backslash paths and slash-prefixed switches.
     expect(hook.command.replace(/-EncodedCommand \S+$/, '')).not.toMatch(/\\| \/[a-zA-Z]+( |$)/)
@@ -384,9 +382,7 @@ describe('ClaudeHookService.install', () => {
         for (const eventName of ['UserPromptSubmit', 'Stop', 'StopFailure']) {
           const hook = settings.hooks[eventName]?.[0]?.hooks?.[0]
           expect(hook?.args).toBeUndefined()
-          expect(hook?.command).toMatch(
-            /\/powershell\.exe -NoProfile -WindowStyle Hidden -EncodedCommand /
-          )
+          expect(hook?.command).toMatch(/\/powershell\.exe -NoProfile -EncodedCommand /)
           expect(hook?.command).not.toContain(scriptPath)
 
           const encoded = hook?.command.match(/-EncodedCommand (\S+)$/)?.[1]
diff --git a/src/main/codex/hook-service-managed-install.test.ts b/src/main/codex/hook-service-managed-install.test.ts
index 5d0021f9499..3e242dc2cf4 100644
--- a/src/main/codex/hook-service-managed-install.test.ts
+++ b/src/main/codex/hook-service-managed-install.test.ts
@@ -31,7 +31,7 @@ import { CodexHookService } from './hook-service'
 import { runExclusivelyForCodexTrustConfig } from './codex-trust-config-mutation-queue'
 
 const WINDOWS_POWERSHELL_LAUNCHER =
-  /^[A-Za-z]:\/[^"]*\/System32\/WindowsPowerShell\/v1\.0\/powershell\.exe -NoProfile -WindowStyle Hidden -EncodedCommand \S+$/
+  /^[A-Za-z]:\/[^"]*\/System32\/WindowsPowerShell\/v1\.0\/powershell\.exe -NoProfile -EncodedCommand \S+$/
 
 const homes = setupCodexHookHomes(homedirMock, getPathMock)
 
diff --git a/src/main/command-code/hook-service.test.ts b/src/main/command-code/hook-service.test.ts
index f5b0f83af62..9765ef5b2f4 100644
--- a/src/main/command-code/hook-service.test.ts
+++ b/src/main/command-code/hook-service.test.ts
@@ -21,7 +21,7 @@ vi.mock('os', async () => {
 import { CommandCodeHookService } from './hook-service'
 
 const WINDOWS_POWERSHELL_LAUNCHER =
-  /^[A-Za-z]:\/[^"]*\/System32\/WindowsPowerShell\/v1\.0\/powershell\.exe -NoProfile -WindowStyle Hidden -EncodedCommand \S+$/
+  /^[A-Za-z]:\/[^"]*\/System32\/WindowsPowerShell\/v1\.0\/powershell\.exe -NoProfile -EncodedCommand \S+$/
 
 describe('CommandCodeHookService', () => {
   let homeDir: string
diff --git a/src/main/cursor/hook-service.test.ts b/src/main/cursor/hook-service.test.ts
index 36f6aa94b48..c6aef9aefc5 100644
--- a/src/main/cursor/hook-service.test.ts
+++ b/src/main/cursor/hook-service.test.ts
@@ -23,7 +23,7 @@ import { CURSOR_EVENTS, type CursorEvent } from './hook-events'
 
 const CURSOR_SCRIPT_FILE_NAME = process.platform === 'win32' ? 'cursor-hook.cmd' : 'cursor-hook.sh'
 const WINDOWS_POWERSHELL_LAUNCHER =
-  /^[A-Za-z]:\/[^"]*\/System32\/WindowsPowerShell\/v1\.0\/powershell\.exe -NoProfile -WindowStyle Hidden -EncodedCommand \S+$/
+  /^[A-Za-z]:\/[^"]*\/System32\/WindowsPowerShell\/v1\.0\/powershell\.exe -NoProfile -EncodedCommand \S+$/
 
 type InstalledCursorHooks = {
   hooks: Record<string, { command?: string }[]>
diff --git a/src/main/daemon/daemon-endpoint-errors.ts b/src/main/daemon/daemon-endpoint-errors.ts
index 663b11ff3fa..b792f0e7044 100644
--- a/src/main/daemon/daemon-endpoint-errors.ts
+++ b/src/main/daemon/daemon-endpoint-errors.ts
@@ -1,4 +1,5 @@
 import { DAEMON_ENDPOINT_LOST_MESSAGE } from './daemon-endpoint-ownership'
+import { DaemonConnectionLostError } from './daemon-errors'
 import { DAEMON_UNAVAILABLE_RECONNECT_MESSAGE } from './types'
 
 /**
@@ -17,6 +18,9 @@ export function isDaemonGoneError(err: unknown): boolean {
   if (!(err instanceof Error)) {
     return false
   }
+  if (err instanceof DaemonConnectionLostError) {
+    return true
+  }
   const errno = err as NodeJS.ErrnoException
   if ((errno.code === 'ENOENT' || errno.code === 'ECONNREFUSED') && errno.syscall === 'connect') {
     return true
diff --git a/src/main/daemon/daemon-pty-adapter-concurrent-recovery.test.ts b/src/main/daemon/daemon-pty-adapter-concurrent-recovery.test.ts
new file mode 100644
index 00000000000..12805c0b3ee
--- /dev/null
+++ b/src/main/daemon/daemon-pty-adapter-concurrent-recovery.test.ts
@@ -0,0 +1,78 @@
+import { expect, it, vi } from 'vitest'
+import { mkdtempSync, rmSync } from 'node:fs'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import { DaemonPtyAdapter } from './daemon-pty-adapter'
+import { DaemonServer } from './daemon-server'
+import { createMockSubprocess } from './daemon-pty-adapter-test-harness'
+import { getDaemonSocketPath } from './daemon-spawner'
+
+it('recovers concurrent spawns rejected by an adapter-initiated disconnect', async () => {
+  const concurrentSpawnCount = 70
+  const dir = mkdtempSync(join(tmpdir(), 'daemon-concurrent-recovery-test-'))
+  const socketPath = getDaemonSocketPath(dir)
+  const tokenPath = join(dir, 'test.token')
+  const allPreparationsEntered = Promise.withResolvers<void>()
+  const releaseHeldPreparations = Promise.withResolvers<void>()
+  const spawnedSessionIds: string[] = []
+  let preparationCount = 0
+
+  const spawnSubprocess: ConstructorParameters<typeof DaemonServer>[0]['spawnSubprocess'] = (
+    options
+  ) => {
+    spawnedSessionIds.push(options.sessionId)
+    return createMockSubprocess()
+  }
+  let server = new DaemonServer({
+    socketPath,
+    tokenPath,
+    spawnSubprocess,
+    // Hold siblings until one retriable reply makes the adapter disconnect their shared socket.
+    preparePtySpawn: async () => {
+      const preparationNumber = ++preparationCount
+      if (preparationCount === concurrentSpawnCount) {
+        allPreparationsEntered.resolve()
+      }
+      await allPreparationsEntered.promise
+      if (preparationNumber === 1) {
+        throw new Error('Connection lost')
+      }
+      await releaseHeldPreparations.promise
+    }
+  })
+  await server.start()
+
+  const respawn = vi.fn(async () => {
+    await server.shutdown()
+    releaseHeldPreparations.resolve()
+    server = new DaemonServer({ socketPath, tokenPath, spawnSubprocess })
+    await server.start()
+  })
+  const adapter = new DaemonPtyAdapter({ socketPath, tokenPath, respawn })
+
+  try {
+    const sessionIds = Array.from(
+      { length: concurrentSpawnCount },
+      (_, index) => `high-volume-${index}`
+    )
+    const results = await Promise.all(
+      sessionIds.map((sessionId) => adapter.spawn({ sessionId, cols: 80, rows: 24 }))
+    )
+
+    expect(preparationCount).toBe(concurrentSpawnCount)
+    expect(respawn).toHaveBeenCalledTimes(1)
+    expect(respawn).toHaveBeenCalledWith('daemon_died')
+    expect(new Set(results.map(({ id }) => id))).toEqual(new Set(sessionIds))
+    expect(new Set(spawnedSessionIds)).toEqual(new Set(sessionIds))
+
+    const later = await adapter.spawn({ sessionId: 'after-recovery', cols: 80, rows: 24 })
+    expect(later.id).toBe('after-recovery')
+    expect(respawn).toHaveBeenCalledTimes(1)
+    expect(spawnedSessionIds).toHaveLength(concurrentSpawnCount + 1)
+  } finally {
+    adapter.dispose()
+    releaseHeldPreparations.resolve()
+    await server.shutdown()
+    rmSync(dir, { recursive: true, force: true })
+  }
+})
diff --git a/src/main/droid/hook-service.test.ts b/src/main/droid/hook-service.test.ts
index bd145fdc1de..7486a12b71b 100644
--- a/src/main/droid/hook-service.test.ts
+++ b/src/main/droid/hook-service.test.ts
@@ -25,7 +25,7 @@ vi.mock('os', async () => {
 import { DroidHookService } from './hook-service'
 
 const WINDOWS_POWERSHELL_LAUNCHER =
-  /^[A-Za-z]:\/[^"]*\/System32\/WindowsPowerShell\/v1\.0\/powershell\.exe -NoProfile -WindowStyle Hidden -EncodedCommand \S+$/
+  /^[A-Za-z]:\/[^"]*\/System32\/WindowsPowerShell\/v1\.0\/powershell\.exe -NoProfile -EncodedCommand \S+$/
 
 describe('DroidHookService', () => {
   let homeDir: string
diff --git a/src/main/gemini/hook-service.test.ts b/src/main/gemini/hook-service.test.ts
index a835a6278f8..551c40bb0b1 100644
--- a/src/main/gemini/hook-service.test.ts
+++ b/src/main/gemini/hook-service.test.ts
@@ -26,7 +26,7 @@ vi.mock('os', async (importOriginal) => {
 import { GeminiHookService } from './hook-service'
 
 const WINDOWS_POWERSHELL_LAUNCHER =
-  /^[A-Za-z]:\/[^"]*\/System32\/WindowsPowerShell\/v1\.0\/powershell\.exe -NoProfile -WindowStyle Hidden -EncodedCommand \S+$/
+  /^[A-Za-z]:\/[^"]*\/System32\/WindowsPowerShell\/v1\.0\/powershell\.exe -NoProfile -EncodedCommand \S+$/
 
 describe('GeminiHookService', () => {
   let homeDir: string
diff --git a/src/main/grok/hook-service.test.ts b/src/main/grok/hook-service.test.ts
index 4b1625614ac..251ae64fa33 100644
--- a/src/main/grok/hook-service.test.ts
+++ b/src/main/grok/hook-service.test.ts
@@ -33,7 +33,7 @@ import { POSIX_HOOK_STDIN_READER } from '../agent-hooks/hook-stdin-contract'
 
 const GROK_SCRIPT_FILE_NAME = process.platform === 'win32' ? 'grok-hook.cmd' : 'grok-hook.sh'
 const WINDOWS_POWERSHELL_LAUNCHER =
-  /^[A-Za-z]:\/[^"]*\/System32\/WindowsPowerShell\/v1\.0\/powershell\.exe -NoProfile -WindowStyle Hidden -EncodedCommand \S+$/
+  /^[A-Za-z]:\/[^"]*\/System32\/WindowsPowerShell\/v1\.0\/powershell\.exe -NoProfile -EncodedCommand \S+$/
 
 // Why (#14828): Windows registers the bare script path when it is cmd-safe and only falls back
 // to the encoded launcher for a profile path that is not (#6078). windows-hook-launcher-chain
diff --git a/src/main/ipc/crash-reporting-renderer-breadcrumbs.test.ts b/src/main/ipc/crash-reporting-renderer-breadcrumbs.test.ts
index 41c108a5cbc..5568030c17a 100644
--- a/src/main/ipc/crash-reporting-renderer-breadcrumbs.test.ts
+++ b/src/main/ipc/crash-reporting-renderer-breadcrumbs.test.ts
@@ -393,6 +393,81 @@ describe('renderer breadcrumb IPC routing', () => {
     ])
   })
 
+  // Why: a #185 crash loop emits a cascade notice per cascade, back to back,
+  // and uncoalesced they would flush the 30-entry ring holding the trail.
+  it('coalesces react commit cascade notices from one driver into one slot', () => {
+    emitRendererBreadcrumb({
+      name: 'react_commit_cascade',
+      data: { commits: 40, rendererSurface: 'main', driverFrame: 'tabs.ts:12:3 bump' }
+    })
+    emitRendererBreadcrumb({
+      name: 'react_commit_cascade',
+      data: { commits: 41, rendererSurface: 'main', driverFrame: 'tabs.ts:12:3 bump' }
+    })
+
+    expect(recordCrashBreadcrumbMock).not.toHaveBeenCalled()
+    expect(
+      recordCoalescedCrashBreadcrumbMock.mock.calls.map(
+        (call) => (call[0] as { coalesceKey: string }).coalesceKey
+      )
+    ).toEqual([
+      'react_commit_cascade:main:tabs.ts:12:3 bump',
+      'react_commit_cascade:main:tabs.ts:12:3 bump'
+    ])
+  })
+
+  // Why keyed and not name-only: coalescing keeps only the newest payload, so
+  // one surface or driver would erase the other's evidence.
+  it('keeps different cascade surfaces and drivers in separate slots', () => {
+    emitRendererBreadcrumb({
+      name: 'react_commit_cascade',
+      data: { commits: 40, rendererSurface: 'main', driverFrame: 'tabs.ts:12:3 bump' }
+    })
+    emitRendererBreadcrumb({
+      name: 'react_commit_cascade',
+      data: { commits: 40, rendererSurface: 'dashboard-popout', driverFrame: 'tabs.ts:12:3 bump' }
+    })
+    emitRendererBreadcrumb({
+      name: 'react_commit_cascade',
+      data: { commits: 40, rendererSurface: 'main', storeWrites: 0 }
+    })
+
+    expect(
+      new Set(
+        recordCoalescedCrashBreadcrumbMock.mock.calls.map(
+          (call) => (call[0] as { coalesceKey: string }).coalesceKey
+        )
+      ).size
+    ).toBe(3)
+  })
+
+  // Why asserted here: the key ends in `stack`, which is what buys the driver
+  // frames the 4000-char budget instead of the 240-char one details get.
+  it('keeps the full driver stack on a react commit cascade notice', () => {
+    const driverStack = `tabs.ts:12:3 bump\n${'tabs.ts:99:1 other\n'.repeat(60)}`
+    emitRendererBreadcrumb({
+      name: 'react_commit_cascade',
+      data: { commits: 40, rendererSurface: 'main', driverFrame: 'tabs.ts:12:3 bump', driverStack }
+    })
+
+    const recorded = recordCoalescedCrashBreadcrumbMock.mock.calls[0]?.[0] as
+      | { data: { driverStack: string } }
+      | undefined
+    expect(recorded?.data.driverStack.length).toBeGreaterThan(240)
+  })
+
+  // Why uncoalesced: it fires at most once per renderer, and it is the signal
+  // that the diagnostic itself never wired up.
+  it('records the uninstalled self-check notice directly', () => {
+    emitRendererBreadcrumb({ name: 'react_commit_cascade_uninstalled' })
+
+    expect(recordCrashBreadcrumbMock).toHaveBeenCalledWith(
+      'react_commit_cascade_uninstalled',
+      undefined
+    )
+    expect(recordCoalescedCrashBreadcrumbMock).not.toHaveBeenCalled()
+  })
+
   it('records non-error renderer breadcrumbs without coalescing', () => {
     emitRendererBreadcrumb({ name: 'renderer_bootstrap_started', data: { dev: true } })
 
diff --git a/src/main/ipc/crash-reporting-renderer-breadcrumbs.ts b/src/main/ipc/crash-reporting-renderer-breadcrumbs.ts
index 2b2129436fb..160cb93dd87 100644
--- a/src/main/ipc/crash-reporting-renderer-breadcrumbs.ts
+++ b/src/main/ipc/crash-reporting-renderer-breadcrumbs.ts
@@ -48,12 +48,14 @@ function recordRendererBreadcrumbTrace(
 // suppressed count instead.
 const DUPLICATE_TAB_OWNER_BREADCRUMB = 'terminal_tab_id_owned_by_multiple_worktrees'
 const PARK_VERDICT_CHURN_BREADCRUMB = 'terminal_park_verdict_churn'
+const REACT_COMMIT_CASCADE_BREADCRUMB = 'react_commit_cascade'
 const COALESCED_RENDERER_BREADCRUMB_NAMES = new Set([
   'renderer_error',
   'renderer_unhandled_rejection',
   'terminal_safe_fit_retry_exhausted',
   DUPLICATE_TAB_OWNER_BREADCRUMB,
   PARK_VERDICT_CHURN_BREADCRUMB,
+  REACT_COMMIT_CASCADE_BREADCRUMB,
   TERMINAL_WEBGL_DIAGNOSTIC_BREADCRUMB
 ])
 const RENDERER_BREADCRUMB_COALESCE_MS = 30_000
@@ -82,6 +84,13 @@ function rendererBreadcrumbCoalesceKey(
   if (name === PARK_VERDICT_CHURN_BREADCRUMB) {
     return `${name}:${String(data?.trigger ?? '')}`
   }
+  // Why keyed on surface and driver frame: the popout and the main window can
+  // cascade independently, and two different driving writes are two different
+  // bugs that last-write coalescing would collapse into one. A driverless crumb
+  // (storeWrites 0, a useState loop) keys separately for the same reason.
+  if (name === REACT_COMMIT_CASCADE_BREADCRUMB) {
+    return `${name}:${String(data?.rendererSurface ?? '')}:${String(data?.driverFrame ?? '')}`
+  }
   // Preserve distinct GPU failures and atlas-reset triggers while coalescing each storm.
   if (name === TERMINAL_WEBGL_DIAGNOSTIC_BREADCRUMB) {
     const kind = String(data?.kind ?? '')
diff --git a/src/main/windows/windows-process-table.test.ts b/src/main/windows/windows-process-table.test.ts
index 919a80deb1c..8bbd0ed7ccb 100644
--- a/src/main/windows/windows-process-table.test.ts
+++ b/src/main/windows/windows-process-table.test.ts
@@ -184,7 +184,7 @@ describe('PowerShell fallback when the native binding is absent', () => {
   })
 })
 
-describe('wedge cooldown', () => {
+describe('sticky wedge', () => {
   let platform: PropertyDescriptor | undefined
 
   beforeEach(() => {
@@ -204,7 +204,7 @@ describe('wedge cooldown', () => {
     // The vendored reader latches a global while a request is in flight and
     // drains its queue only when that request completes. In the wedge this
     // guards against it never does, so every retry would add a closure that is
-    // never called. One probe per cooldown bounds that.
+    // never called.
     vi.useFakeTimers()
     const getAllProcesses = vi.fn(() => {})
     __setWindowsProcessTreeLoaderForTests(() => ({
@@ -218,15 +218,15 @@ describe('wedge cooldown', () => {
     await firstAssertion
     expect(getAllProcesses).toHaveBeenCalledTimes(1)
 
-    await expect(readWindowsProcessTableFresh()).rejects.toThrow(/cooling down/)
+    await expect(readWindowsProcessTableFresh()).rejects.toThrow(/wedged/)
     expect(getAllProcesses).toHaveBeenCalledTimes(1)
   })
 
-  it('lets exactly one caller probe when the cooldown expires', async () => {
-    // Without claiming the recovery slot before probing, every concurrent
-    // caller passes the cooldown check at expiry and each enqueues a callback
-    // into the still-latched native queue -- so each cycle leaks another batch
-    // rather than bounding it to one probe.
+  it('never re-enters the reader while the timed-out read is still out', async () => {
+    // A cooldown bounds the RATE of new callbacks, not the total: one probe per
+    // window still retains one more closure in the still-latched native queue
+    // every window, for the life of the app. Only the outstanding read can
+    // reopen the gate, so a permanent wedge retains exactly one callback.
     vi.useFakeTimers()
     const getAllProcesses = vi.fn(() => {})
     __setWindowsProcessTreeLoaderForTests(() => ({
@@ -240,16 +240,72 @@ describe('wedge cooldown', () => {
     await wedgeAssertion
     expect(getAllProcesses).toHaveBeenCalledTimes(1)
 
-    await vi.advanceTimersByTimeAsync(30_000)
-    const attempts = [
-      readWindowsProcessTableFresh().catch(() => 'rejected'),
-      readWindowsProcessTableFresh().catch(() => 'rejected'),
-      readWindowsProcessTableFresh().catch(() => 'rejected')
-    ]
-    await vi.advanceTimersByTimeAsync(3_000)
-    await Promise.all(attempts)
+    // Four windows of the cooldown this replaced, each with concurrent callers.
+    // Rejection reasons are deliberately not asserted here: the leak this test
+    // pins is the call count, and it must fail on that alone.
+    for (let window = 0; window < 4; window += 1) {
+      await vi.advanceTimersByTimeAsync(30_000)
+      const attempts = [
+        readWindowsProcessTableFresh().catch(() => 'rejected'),
+        readWindowsProcessTableFresh().catch(() => 'rejected'),
+        readWindowsProcessTableFresh().catch(() => 'rejected')
+      ]
+      // Long enough for a probe's own deadline, had one been let through.
+      await vi.advanceTimersByTimeAsync(3_000)
+      expect(await Promise.all(attempts)).toEqual(['rejected', 'rejected', 'rejected'])
+    }
 
-    // One recovery probe, not three.
+    // Still the one callback the wedge is holding -- not one more per window.
+    expect(getAllProcesses).toHaveBeenCalledTimes(1)
+  })
+
+  it('resumes as soon as the timed-out read finally calls back', async () => {
+    // The stuck request completing is what drains the vendored queue, so it is
+    // the only honest evidence the reader recovered. Waiting out a wall clock
+    // afterwards would strand a reader that is already answering.
+    vi.useFakeTimers()
+    let stuck: ((rows: typeof NATIVE | undefined) => void) | undefined
+    const getAllProcesses = vi.fn((cb: (rows: typeof NATIVE | undefined) => void) => {
+      if (stuck) {
+        cb(NATIVE)
+        return
+      }
+      stuck = cb
+    })
+    __setWindowsProcessTreeLoaderForTests(() => ({
+      ProcessDataFlag: { None: 0, Memory: 1, CommandLine: 2 },
+      getAllProcesses
+    }))
+
+    const wedge = readWindowsProcessTableFresh()
+    const wedgeAssertion = expect(wedge).rejects.toThrow(/timed out/)
+    await vi.advanceTimersByTimeAsync(3_000)
+    await wedgeAssertion
+    await expect(readWindowsProcessTableFresh()).rejects.toThrow(/wedged/)
+
+    stuck?.(NATIVE)
+    await expect(readWindowsProcessTableFresh()).resolves.toHaveLength(NATIVE.length)
+    expect(getAllProcesses).toHaveBeenCalledTimes(2)
+  })
+
+  it('ignores a pending timeout from before a test reset', async () => {
+    vi.useFakeTimers()
+    const getAllProcesses = vi.fn((_cb: (rows: typeof NATIVE | undefined) => void) => {})
+    __setWindowsProcessTreeLoaderForTests(() => ({
+      ProcessDataFlag: { None: 0, Memory: 1, CommandLine: 2 },
+      getAllProcesses
+    }))
+
+    const staleRead = readWindowsProcessTableFresh()
+    const staleAssertion = expect(staleRead).rejects.toThrow(/timed out/)
+    await vi.advanceTimersByTimeAsync(0)
+    expect(getAllProcesses).toHaveBeenCalledTimes(1)
+    resetWindowsProcessTableForTests()
+    await vi.advanceTimersByTimeAsync(3_000)
+    await staleAssertion
+
+    getAllProcesses.mockImplementation((cb) => cb(NATIVE))
+    await expect(readWindowsProcessTableFresh()).resolves.toHaveLength(NATIVE.length)
     expect(getAllProcesses).toHaveBeenCalledTimes(2)
   })
 
diff --git a/src/main/windows/windows-process-table.ts b/src/main/windows/windows-process-table.ts
index e03ecee6e29..35dab09d100 100644
--- a/src/main/windows/windows-process-table.ts
+++ b/src/main/windows/windows-process-table.ts
@@ -146,20 +146,18 @@ function loadWindowsProcessTree(): WindowsProcessTreeModule | null {
 const WINDOWS_PROCESS_QUERY_TIMEOUT_MS = 3_000
 
 /**
- * How long to stop calling the reader after it misses its deadline.
- *
- * Why a cooldown and not just the deadline: a timed-out call leaves its
- * callback in the vendored module's queue, and that queue only drains when the
- * latched request finally completes -- which, in the wedge this guards against,
- * never happens. Retrying at the caller's poll rate would then add a closure
- * per tick forever. One probe per cooldown bounds it.
+ * Reads that missed their deadline and have not called back yet.
+ * Refusing re-entry bounds both vendored callbacks and relay addon workers to
+ * one; read ids keep a late callback from clearing a newer wedge.
  */
-const WINDOWS_PROCESS_QUERY_COOLDOWN_MS = 30_000
+const unreturnedReads = new Set<number>()
+let readSequence = 0
+let nativeReaderEpoch = 0
 
-let wedgedUntilMs = 0
-// Why a generation: a request that already lost its deadline must not later
-// clear or re-arm the wedge on behalf of the request that replaced it.
-let readGeneration = 0
+function resetNativeReaderState(): void {
+  nativeReaderEpoch += 1
+  unreturnedReads.clear()
+}
 
 function readNativeRows(): Promise<WindowsProcessRow[]> {
   const native = moduleLoader()
@@ -177,19 +175,13 @@ function readNativeRows(): Promise<WindowsProcessRow[]> {
     // tree dead. "Unavailable" has to stay distinguishable from "empty".
     return Promise.reject(new Error('windows process table unavailable'))
   }
-  const startedAt = Date.now()
-  if (startedAt < wedgedUntilMs) {
-    return Promise.reject(new Error('windows process table is cooling down after a timeout'))
+  if (unreturnedReads.size > 0) {
+    return Promise.reject(
+      new Error('windows process table is wedged: an earlier read has not returned')
+    )
   }
-  if (wedgedUntilMs > 0) {
-    // Coming out of a wedge: re-arm the cooldown BEFORE probing, so exactly one
-    // caller gets through. Without this every concurrent caller passes the
-    // check above at expiry, each enqueues a callback into the still-latched
-    // native queue, and each cooldown cycle leaks another batch rather than
-    // bounding it to one probe.
-    wedgedUntilMs = startedAt + WINDOWS_PROCESS_QUERY_COOLDOWN_MS
-  }
-  const generation = ++readGeneration
+  const readId = ++readSequence
+  const readerEpoch = nativeReaderEpoch
   // Why always both flags: each adds an OpenProcess per process (Memory a
   // GetProcessMemoryInfo, CommandLine a PEB read), so asking for less would be
   // cheaper -- 15.9ms p50 versus 30.6ms at 1050 processes. But every read shares
@@ -204,18 +196,19 @@ function readNativeRows(): Promise<WindowsProcessRow[]> {
     let deadline: ReturnType<typeof setTimeout> | undefined
     try {
       deadline = setTimeout(() => {
-        if (generation === readGeneration) {
-          wedgedUntilMs = Date.now() + WINDOWS_PROCESS_QUERY_COOLDOWN_MS
+        // Test resets invalidate deadlines owned by the prior injected reader.
+        if (readerEpoch === nativeReaderEpoch) {
+          unreturnedReads.add(readId)
         }
         reject(new Error('windows process table timed out'))
       }, WINDOWS_PROCESS_QUERY_TIMEOUT_MS)
       deadline.unref?.()
       native.getAllProcesses((processes) => {
         clearTimeout(deadline)
-        // A callback proves the reader is answering, so stop refusing.
-        if (generation === readGeneration) {
-          wedgedUntilMs = 0
-        }
+        // A callback proves this read drained, so stop refusing. Unconditional:
+        // dropping an id that was never added is a no-op, and only the read
+        // that actually wedged can be holding the gate shut.
+        unreturnedReads.delete(readId)
         if (!processes) {
           reject(new Error('windows process table returned no snapshot'))
           return
@@ -303,7 +296,7 @@ export function __setWindowsProcessTreeLoaderForTests(
 ): void {
   moduleLoader = loader ?? loadWindowsProcessTree
   cachedModule = undefined
-  wedgedUntilMs = 0
+  resetNativeReaderState()
   snapshotReader.reset()
 }
 
@@ -314,7 +307,7 @@ export function __setWindowsProcessTreeRequireForTests(
   requireNative = resolve ?? requireFromMain
   moduleLoader = loadWindowsProcessTree
   cachedModule = undefined
-  wedgedUntilMs = 0
+  resetNativeReaderState()
   snapshotReader.reset()
 }
 
@@ -330,5 +323,5 @@ export function __setWindowsProcessTableCimScanForTests(
 export function resetWindowsProcessTableForTests(): void {
   snapshotReader.reset()
   cachedModule = undefined
-  wedgedUntilMs = 0
+  resetNativeReaderState()
 }
diff --git a/src/renderer/src/components/github-item-dialog/load-item-details/work-item-state-badge.tsx b/src/renderer/src/components/github-item-dialog/load-item-details/work-item-state-badge.tsx
index cd2135b9873..0e05cb0803d 100644
--- a/src/renderer/src/components/github-item-dialog/load-item-details/work-item-state-badge.tsx
+++ b/src/renderer/src/components/github-item-dialog/load-item-details/work-item-state-badge.tsx
@@ -1,26 +1,14 @@
 import React from 'react'
-import { cn } from '@/lib/utils'
+import {
+  getWorkItemStateTone,
+  WorkItemStateBadge as SharedWorkItemStateBadge
+} from '@/components/github/work-item-state-badge'
 import type { GitHubWorkItem } from '../../../../../shared/github/work-item-types'
-import { getStateLabel } from '@/components/github/work-item-state-presentation'
 
+// Why: closed issues stay neutral here (may be completed/resolved); red is reserved
+// for PR closed-without-merge.
 export function getStateTone(item: GitHubWorkItem): string {
-  if (item.type === 'pr') {
-    if (item.state === 'merged') {
-      return 'border-purple-500/30 bg-purple-500/10 text-purple-600 dark:text-purple-300'
-    }
-    if (item.state === 'draft') {
-      return 'border-slate-500/30 bg-slate-500/10 text-slate-600 dark:text-slate-300'
-    }
-    if (item.state === 'closed') {
-      return 'border-rose-500/30 bg-rose-500/10 text-rose-600 dark:text-rose-300'
-    }
-    return 'border-emerald-500/30 bg-emerald-500/10 text-emerald-600 dark:text-emerald-300'
-  }
-  if (item.state === 'closed') {
-    // Why: keep closed issues neutral (may be completed/resolved); red is reserved for PR closed-without-merge.
-    return 'border-ring/50 bg-primary/10 text-foreground'
-  }
-  return 'border-emerald-500/30 bg-emerald-500/10 text-emerald-600 dark:text-emerald-300'
+  return getWorkItemStateTone(item, 'neutral')
 }
 
 export function WorkItemStateBadge({
@@ -30,15 +18,5 @@ export function WorkItemStateBadge({
   item: GitHubWorkItem
   className?: string
 }): React.JSX.Element {
-  return (
-    <span
-      className={cn(
-        'inline-flex h-5 items-center rounded-full border px-2 text-[11px] font-medium',
-        getStateTone(item),
-        className
-      )}
-    >
-      {getStateLabel(item)}
-    </span>
-  )
+  return <SharedWorkItemStateBadge item={item} className={className} closedIssue="neutral" />
 }
diff --git a/src/renderer/src/components/github/review-state-presentation.ts b/src/renderer/src/components/github/review-state-presentation.ts
new file mode 100644
index 00000000000..ac9ef42629e
--- /dev/null
+++ b/src/renderer/src/components/github/review-state-presentation.ts
@@ -0,0 +1,41 @@
+import { GitMerge, GitPullRequestClosed, GitPullRequestDraft, type LucideIcon } from 'lucide-react'
+import type { HostedReviewState } from '../../../../shared/hosted-review'
+
+/** Every review surface renders state from here; `unknown` means we have a number but no fetched state. */
+export type ReviewStateForDisplay = HostedReviewState | 'unknown' | null | undefined
+
+/** Also the tone for an open issue, which reads the same as an open review. */
+export const OPEN_REVIEW_STATE_TONE =
+  'border-emerald-500/30 bg-emerald-500/10 text-emerald-600 dark:text-emerald-300'
+
+/** Outline-pill tone: purple merged, rose closed, slate draft, emerald open, neutral unknown. */
+export function getReviewStateTone(state: ReviewStateForDisplay): string {
+  if (state === 'merged') {
+    return 'border-purple-500/30 bg-purple-500/10 text-purple-600 dark:text-purple-300'
+  }
+  if (state === 'draft') {
+    return 'border-slate-500/30 bg-slate-500/10 text-slate-600 dark:text-slate-300'
+  }
+  if (state === 'closed') {
+    return 'border-rose-500/30 bg-rose-500/10 text-rose-600 dark:text-rose-300'
+  }
+  if (state === 'open') {
+    return OPEN_REVIEW_STATE_TONE
+  }
+  return 'border-border bg-background text-muted-foreground'
+}
+
+// Why: the glyph must carry review state — tone alone made a draft with failing
+// checks render as a red PR icon, which reads as closed.
+export function getReviewStateIcon(state: ReviewStateForDisplay): LucideIcon | null {
+  if (state === 'merged') {
+    return GitMerge
+  }
+  if (state === 'closed') {
+    return GitPullRequestClosed
+  }
+  if (state === 'draft') {
+    return GitPullRequestDraft
+  }
+  return null
+}
diff --git a/src/renderer/src/components/github/work-item-state-badge.tsx b/src/renderer/src/components/github/work-item-state-badge.tsx
new file mode 100644
index 00000000000..4286a7a2c2d
--- /dev/null
+++ b/src/renderer/src/components/github/work-item-state-badge.tsx
@@ -0,0 +1,48 @@
+import React from 'react'
+import { cn } from '@/lib/utils'
+import { getStateLabel } from '@/components/github/work-item-state-presentation'
+import {
+  getReviewStateTone,
+  OPEN_REVIEW_STATE_TONE
+} from '@/components/github/review-state-presentation'
+import type { GitHubWorkItem } from '../../../../shared/github/work-item-types'
+
+/**
+ * Whether a closed ISSUE reads as failure or as neutral completion. PR state tone
+ * never varies — only surfaces disagree on what a closed issue means.
+ */
+export type ClosedIssueTone = 'destructive' | 'neutral'
+
+export function getWorkItemStateTone(item: GitHubWorkItem, closedIssue: ClosedIssueTone): string {
+  if (item.type === 'pr') {
+    return getReviewStateTone(item.state)
+  }
+  if (item.state === 'closed') {
+    return closedIssue === 'neutral'
+      ? 'border-ring/50 bg-primary/10 text-foreground'
+      : 'border-rose-500/30 bg-rose-500/10 text-rose-600 dark:text-rose-300'
+  }
+  return OPEN_REVIEW_STATE_TONE
+}
+
+export function WorkItemStateBadge({
+  item,
+  className,
+  closedIssue
+}: {
+  item: GitHubWorkItem
+  className?: string
+  closedIssue: ClosedIssueTone
+}): React.JSX.Element {
+  return (
+    <span
+      className={cn(
+        'inline-flex h-5 items-center rounded-full border px-2 text-[11px] font-medium',
+        getWorkItemStateTone(item, closedIssue),
+        className
+      )}
+    >
+      {getStateLabel(item)}
+    </span>
+  )
+}
diff --git a/src/renderer/src/components/pull-request-page/presentation/state-badge.tsx b/src/renderer/src/components/pull-request-page/presentation/state-badge.tsx
index 62d38f67806..e50b76344e4 100644
--- a/src/renderer/src/components/pull-request-page/presentation/state-badge.tsx
+++ b/src/renderer/src/components/pull-request-page/presentation/state-badge.tsx
@@ -1,25 +1,12 @@
 import React from 'react'
-import { cn } from '@/lib/utils'
-import { getStateLabel } from '@/components/github/work-item-state-presentation'
+import {
+  getWorkItemStateTone,
+  WorkItemStateBadge as SharedWorkItemStateBadge
+} from '@/components/github/work-item-state-badge'
 import type { GitHubWorkItem } from '../../../../../shared/github/work-item-types'
 
 export function getStateTone(item: GitHubWorkItem): string {
-  if (item.type === 'pr') {
-    if (item.state === 'merged') {
-      return 'border-purple-500/30 bg-purple-500/10 text-purple-600 dark:text-purple-300'
-    }
-    if (item.state === 'draft') {
-      return 'border-slate-500/30 bg-slate-500/10 text-slate-600 dark:text-slate-300'
-    }
-    if (item.state === 'closed') {
-      return 'border-rose-500/30 bg-rose-500/10 text-rose-600 dark:text-rose-300'
-    }
-    return 'border-emerald-500/30 bg-emerald-500/10 text-emerald-600 dark:text-emerald-300'
-  }
-  if (item.state === 'closed') {
-    return 'border-rose-500/30 bg-rose-500/10 text-rose-600 dark:text-rose-300'
-  }
-  return 'border-emerald-500/30 bg-emerald-500/10 text-emerald-600 dark:text-emerald-300'
+  return getWorkItemStateTone(item, 'destructive')
 }
 
 /** Filled counterpart of `getStateTone` for high-emphasis surfaces like the PR page header. */
@@ -42,15 +29,5 @@ export function WorkItemStateBadge({
   item: GitHubWorkItem
   className?: string
 }): React.JSX.Element {
-  return (
-    <span
-      className={cn(
-        'inline-flex h-5 items-center rounded-full border px-2 text-[11px] font-medium',
-        getStateTone(item),
-        className
-      )}
-    >
-      {getStateLabel(item)}
-    </span>
-  )
+  return <SharedWorkItemStateBadge item={item} className={className} closedIssue="destructive" />
 }
diff --git a/src/renderer/src/components/sidebar/worktree-review-helpers.tsx b/src/renderer/src/components/sidebar/worktree-review-helpers.tsx
index 96e64fb4423..26a16c9f629 100644
--- a/src/renderer/src/components/sidebar/worktree-review-helpers.tsx
+++ b/src/renderer/src/components/sidebar/worktree-review-helpers.tsx
@@ -1,5 +1,6 @@
-import { GitMerge, GitPullRequestClosed, GitPullRequestDraft } from 'lucide-react'
+import { GitMerge } from 'lucide-react'
 import { cn } from '@/lib/utils'
+import { getReviewStateIcon } from '@/components/github/review-state-presentation'
 import { PullRequestIcon } from './WorktreeCardHelpers'
 import type { WorktreeCardPrDisplay } from './worktree-card-pr-display'
 
@@ -23,23 +24,6 @@ export function getProviderName(review: WorktreeCardPrDisplay): string {
   return 'GitHub'
 }
 
-// Why: the glyph must carry review state — tone alone made a draft with failing
-// checks render as a red PR icon, which reads as closed.
-function getStateIcon(
-  state: WorktreeCardPrDisplay['state']
-): React.ComponentType<{ className?: string }> | null {
-  if (state === 'merged') {
-    return GitMerge
-  }
-  if (state === 'closed') {
-    return GitPullRequestClosed
-  }
-  if (state === 'draft') {
-    return GitPullRequestDraft
-  }
-  return null
-}
-
 // Why: checks only gate a review that is actually open; draft/closed/merged keep
 // their state tone so the glyph agrees with its tooltip. A stateless row (folder
 // cards render one while a linked review is loading or its details failed) has no
@@ -88,6 +72,6 @@ export function ReviewIcon({
 }): React.JSX.Element {
   const providerIcon =
     variant === 'provider' && review.provider === 'gitlab' ? GitMerge : PullRequestIcon
-  const Icon = getStateIcon(review.state) ?? providerIcon
+  const Icon = getReviewStateIcon(review.state) ?? providerIcon
   return <Icon className={cn(className, getCheckTone(review) ?? getStateTone(review.state))} />
 }
diff --git a/src/renderer/src/components/terminal-pane/terminal-park-verdict-flip-telemetry.ts b/src/renderer/src/components/terminal-pane/terminal-park-verdict-flip-telemetry.ts
index 17b53d53785..13642519029 100644
--- a/src/renderer/src/components/terminal-pane/terminal-park-verdict-flip-telemetry.ts
+++ b/src/renderer/src/components/terminal-pane/terminal-park-verdict-flip-telemetry.ts
@@ -10,13 +10,12 @@
  * one tab as "damping did not reach the oscillating input".
  */
 import { recordRendererCrashBreadcrumb } from '@/lib/crash-breadcrumb-recorder'
+import { REACT_NESTED_UPDATE_LIMIT } from '../../../../shared/react-update-depth-attribution'
 
 export const TERMINAL_TAB_PARK_FLIP_WINDOW_MS = 60_000
 /** Flips per window that no sane park policy should reach. Breadcrumb only. */
 export const TERMINAL_TAB_PARK_FLIP_NOTICE_LIMIT = 12
 
-/** react-dom 19.2.x nested commit limit. */
-const REACT_NESTED_UPDATE_LIMIT = 50
 /** Measured upper bound after the passive-effect pin engages. */
 const PARK_PIN_SETTLE_COMMITS = 6
 /** Worst-case commits from pane, watcher, and store work per verdict flip. */
diff --git a/src/renderer/src/components/workspace-cleanup/workspace-cleanup-candidate-row-data.ts b/src/renderer/src/components/workspace-cleanup/workspace-cleanup-candidate-row-data.ts
index 75103a98d0c..1f9d3d2ce52 100644
--- a/src/renderer/src/components/workspace-cleanup/workspace-cleanup-candidate-row-data.ts
+++ b/src/renderer/src/components/workspace-cleanup/workspace-cleanup-candidate-row-data.ts
@@ -1,9 +1,6 @@
 import { translate } from '@/i18n/i18n'
 import type { WorkspaceCleanupCandidate } from '../../../../shared/workspace-cleanup'
-import {
-  getWorkspaceCleanupGitLabel,
-  type WorkspaceCleanupReviewInfo
-} from './workspace-cleanup-presentation'
+import { getWorkspaceCleanupGitLabel } from './workspace-cleanup-presentation'
 import {
   formatUnpushedCommitCount,
   formatWorkspaceCleanupContextDetail,
@@ -172,13 +169,6 @@ function hasGitStatusPill(candidate: WorkspaceCleanupCandidate): boolean {
   return (candidate.git.upstreamAhead ?? 0) > 0 || candidate.git.clean === false
 }
 
-export function getReviewPillTone(reviewInfo: WorkspaceCleanupReviewInfo): StatusPillTone {
-  if (reviewInfo.state === 'open' || reviewInfo.state === 'draft') {
-    return 'review'
-  }
-  return 'neutral'
-}
-
 export function getContextCount(candidate: WorkspaceCleanupCandidate): number {
   return (
     candidate.localContext.terminalTabCount +
diff --git a/src/renderer/src/components/workspace-cleanup/workspace-cleanup-candidate-row.test.tsx b/src/renderer/src/components/workspace-cleanup/workspace-cleanup-candidate-row.test.tsx
index d9deb16e8e9..9d4ee5a6e2f 100644
--- a/src/renderer/src/components/workspace-cleanup/workspace-cleanup-candidate-row.test.tsx
+++ b/src/renderer/src/components/workspace-cleanup/workspace-cleanup-candidate-row.test.tsx
@@ -247,4 +247,78 @@ describe('CandidateRow', () => {
     expect(container?.querySelector(`[aria-label="Select ${remoteName}"]`)).not.toBeNull()
     expect(container?.querySelector(`[aria-label="Host: builder"]`)).not.toBeNull()
   })
+
+  it('colors the review pill by state the way the PR page and item dialog do', () => {
+    const states = [
+      { state: 'merged' as const, label: 'PR #1', hue: 'purple' },
+      { state: 'closed' as const, label: 'PR #2', hue: 'rose' },
+      { state: 'open' as const, label: 'PR #3', hue: 'emerald' },
+      { state: 'draft' as const, label: 'PR #4', hue: 'slate' }
+    ]
+
+    for (const { state, label, hue } of states) {
+      const candidate = makeCandidate()
+
+      act(() => {
+        root?.render(
+          <CandidateRow
+            identity={getWorkspaceCleanupCandidateIdentity(candidate)}
+            candidate={candidate}
+            expanded={false}
+            last
+            lastActivityLabel="1d ago"
+            reviewInfo={{
+              hasReview: true,
+              label,
+              provider: 'github',
+              state,
+              title: 'Some change'
+            }}
+            selected={false}
+            onIgnore={vi.fn()}
+            onRemove={vi.fn()}
+            onToggleExpanded={vi.fn()}
+            onToggleSelected={vi.fn()}
+            onView={vi.fn()}
+          />
+        )
+      })
+
+      const pill = container?.querySelector(`[aria-label*="${label}"]`)
+      expect(pill?.className).toContain(`text-${hue}-`)
+      expect(pill?.className).not.toContain('text-muted-foreground')
+    }
+  })
+
+  it('leaves a review with an unfetched state neutral', () => {
+    const candidate = makeCandidate()
+
+    act(() => {
+      root?.render(
+        <CandidateRow
+          identity={getWorkspaceCleanupCandidateIdentity(candidate)}
+          candidate={candidate}
+          expanded={false}
+          last
+          lastActivityLabel="1d ago"
+          reviewInfo={{
+            hasReview: true,
+            label: 'PR #9',
+            provider: 'github',
+            state: 'unknown',
+            title: null
+          }}
+          selected={false}
+          onIgnore={vi.fn()}
+          onRemove={vi.fn()}
+          onToggleExpanded={vi.fn()}
+          onToggleSelected={vi.fn()}
+          onView={vi.fn()}
+        />
+      )
+    })
+
+    const pill = container?.querySelector('[aria-label*="PR #9"]')
+    expect(pill?.className).toContain('text-muted-foreground')
+  })
 })
diff --git a/src/renderer/src/components/workspace-cleanup/workspace-cleanup-candidate-row.tsx b/src/renderer/src/components/workspace-cleanup/workspace-cleanup-candidate-row.tsx
index bec347d570d..fd4c442d55b 100644
--- a/src/renderer/src/components/workspace-cleanup/workspace-cleanup-candidate-row.tsx
+++ b/src/renderer/src/components/workspace-cleanup/workspace-cleanup-candidate-row.tsx
@@ -36,10 +36,13 @@ import {
   getCandidateFactStatuses,
   getContextCount,
   getDirtyGitLabel,
-  getReviewPillTone,
   getWorkspaceCleanupBlockerLabels,
   shouldShowGitMetadataChip
 } from './workspace-cleanup-candidate-row-data'
+import {
+  getReviewStateIcon,
+  getReviewStateTone
+} from '@/components/github/review-state-presentation'
 import { StatusPill } from './workspace-cleanup-status-pill'
 import { WorkspaceCleanupMetadataChip } from './workspace-cleanup-metadata-chip'
 import { WorkspaceCleanupForgetLocallyButton } from './workspace-cleanup-forget-locally-button'
@@ -255,10 +258,10 @@ export const CandidateRow = React.memo(function CandidateRow({
             ) : null}
             {reviewInfo.label ? (
               <WorkspaceCleanupMetadataChip
-                icon={GitPullRequest}
+                icon={getReviewStateIcon(reviewInfo.state) ?? GitPullRequest}
                 label={getReviewTooltip(reviewInfo)}
                 value={reviewInfo.label}
-                tone={getReviewPillTone(reviewInfo)}
+                toneClassName={getReviewStateTone(reviewInfo.state)}
               />
             ) : null}
           </div>
diff --git a/src/renderer/src/components/workspace-cleanup/workspace-cleanup-confirm-remove.test.tsx b/src/renderer/src/components/workspace-cleanup/workspace-cleanup-confirm-remove.test.tsx
index dbffc7214e5..379a9d60d10 100644
--- a/src/renderer/src/components/workspace-cleanup/workspace-cleanup-confirm-remove.test.tsx
+++ b/src/renderer/src/components/workspace-cleanup/workspace-cleanup-confirm-remove.test.tsx
@@ -218,4 +218,43 @@ describe('WorkspaceCleanupConfirmRemove', () => {
       '1 workspace currently shows risk and may need a force delete'
     )
   })
+
+  it('gives the review pill a text equivalent for its state color without repeating the number', () => {
+    const candidate = makeFacetCandidate({
+      worktreeId: 'repo-1::/repo/merged-review',
+      displayName: 'Merged review',
+      path: '/repo/merged-review'
+    })
+
+    act(() => {
+      root.render(
+        <WorkspaceCleanupConfirmRemove
+          candidates={[candidate]}
+          now={Date.now()}
+          reviewInfoByWorktreeId={
+            new Map([
+              [
+                candidate.worktreeId,
+                {
+                  hasReview: true,
+                  label: 'PR #15716',
+                  provider: 'github' as const,
+                  state: 'merged' as const,
+                  title: 'keep editor focus'
+                }
+              ]
+            ])
+          }
+          progress={null}
+          onBack={vi.fn()}
+          onCancel={vi.fn()}
+          onConfirm={vi.fn()}
+        />
+      )
+    })
+
+    const srText = container.querySelector('span.sr-only')?.textContent ?? ''
+    expect(srText).toContain('Merged')
+    expect(srText).not.toContain('PR #15716')
+  })
 })
diff --git a/src/renderer/src/components/workspace-cleanup/workspace-cleanup-confirm-remove.tsx b/src/renderer/src/components/workspace-cleanup/workspace-cleanup-confirm-remove.tsx
index c7ccae4a8fe..97a31aedc5c 100644
--- a/src/renderer/src/components/workspace-cleanup/workspace-cleanup-confirm-remove.tsx
+++ b/src/renderer/src/components/workspace-cleanup/workspace-cleanup-confirm-remove.tsx
@@ -15,11 +15,12 @@ import {
   getCandidateFactStatuses,
   formatContextDetailLabels,
   getDirtyGitLabel,
-  getReviewPillTone,
   shouldShowGitMetadataChip
 } from './workspace-cleanup-candidate-row-data'
 import type { WorkspaceCleanupReviewInfo } from './workspace-cleanup-presentation'
 import { formatWorkspaceCleanupRelativeTime } from './workspace-cleanup-relative-time'
+import { getReviewStateTone } from '@/components/github/review-state-presentation'
+import { getReviewStateSrText } from './workspace-cleanup-row-labels'
 import { StatusPill } from './workspace-cleanup-status-pill'
 import { WorkspaceCleanupCandidateList } from './workspace-cleanup-candidate-list'
 import {
@@ -255,7 +256,10 @@ function ConfirmRemoveRow({
           </StatusPill>
         ))}
         {reviewInfo.label ? (
-          <StatusPill tone={getReviewPillTone(reviewInfo)}>{reviewInfo.label}</StatusPill>
+          <StatusPill toneClassName={getReviewStateTone(reviewInfo.state)}>
+            {reviewInfo.label}
+            <span className="sr-only">{getReviewStateSrText(reviewInfo)}</span>
+          </StatusPill>
         ) : null}
         {contextPillLabels.map((label) => (
           <StatusPill key={label}>{label}</StatusPill>
diff --git a/src/renderer/src/components/workspace-cleanup/workspace-cleanup-metadata-chip.tsx b/src/renderer/src/components/workspace-cleanup/workspace-cleanup-metadata-chip.tsx
index 5fea9257680..bae88d8fc03 100644
--- a/src/renderer/src/components/workspace-cleanup/workspace-cleanup-metadata-chip.tsx
+++ b/src/renderer/src/components/workspace-cleanup/workspace-cleanup-metadata-chip.tsx
@@ -8,12 +8,15 @@ export function WorkspaceCleanupMetadataChip({
   icon: Icon,
   label,
   value,
-  tone = 'neutral'
+  tone = 'neutral',
+  toneClassName
 }: {
   icon: LucideIcon
   label: string
   value?: string
   tone?: StatusPillTone
+  /** Overrides `tone` for chips whose color comes from a domain state (e.g. review state). */
+  toneClassName?: string
 }): React.JSX.Element {
   return (
     <Tooltip>
@@ -25,7 +28,8 @@ export function WorkspaceCleanupMetadataChip({
             tone === 'ready' &&
               'border-[color:color-mix(in_srgb,var(--git-decoration-added)_45%,transparent)] bg-[color:color-mix(in_srgb,var(--git-decoration-added)_10%,transparent)] text-[var(--git-decoration-added)]',
             tone === 'review' && 'bg-muted text-foreground',
-            tone === 'destructive' && 'border-destructive/30 text-destructive'
+            tone === 'destructive' && 'border-destructive/30 text-destructive',
+            toneClassName
           )}
           aria-label={label}
         >
diff --git a/src/renderer/src/components/workspace-cleanup/workspace-cleanup-row-labels.ts b/src/renderer/src/components/workspace-cleanup/workspace-cleanup-row-labels.ts
index 887cb1c17d0..b7b897f1a22 100644
--- a/src/renderer/src/components/workspace-cleanup/workspace-cleanup-row-labels.ts
+++ b/src/renderer/src/components/workspace-cleanup/workspace-cleanup-row-labels.ts
@@ -1,9 +1,20 @@
 import type { WorkspaceCleanupReviewInfo } from './workspace-cleanup-presentation'
+import { getWorkspaceCleanupReviewStateLabel } from './workspace-cleanup-facet-labels'
 
 export function formatCompactActivityLabel(label: string): string {
   return label === 'Just now' ? 'now' : label.replace(/ ago$/, '')
 }
 
 export function getReviewTooltip(reviewInfo: WorkspaceCleanupReviewInfo): string {
-  return [reviewInfo.label, reviewInfo.state, reviewInfo.title].filter(Boolean).join(' · ')
+  return [reviewInfo.label, getReviewStateSrText(reviewInfo)].filter(Boolean).join(' · ')
+}
+
+/** Text equivalent for the state color on pills that render the number visibly. */
+export function getReviewStateSrText(reviewInfo: WorkspaceCleanupReviewInfo): string {
+  if (!reviewInfo.state) {
+    return ''
+  }
+  return [getWorkspaceCleanupReviewStateLabel(reviewInfo.state), reviewInfo.title]
+    .filter(Boolean)
+    .join(' · ')
 }
diff --git a/src/renderer/src/components/workspace-cleanup/workspace-cleanup-status-pill.tsx b/src/renderer/src/components/workspace-cleanup/workspace-cleanup-status-pill.tsx
index 1e5786fda49..0a5efdd2bdc 100644
--- a/src/renderer/src/components/workspace-cleanup/workspace-cleanup-status-pill.tsx
+++ b/src/renderer/src/components/workspace-cleanup/workspace-cleanup-status-pill.tsx
@@ -4,10 +4,13 @@ import type { StatusPillTone } from './workspace-cleanup-candidate-row-data'
 
 export function StatusPill({
   children,
-  tone = 'neutral'
+  tone = 'neutral',
+  toneClassName
 }: {
   children: React.ReactNode
   tone?: StatusPillTone
+  /** Overrides `tone` for pills whose color comes from a domain state (e.g. review state). */
+  toneClassName?: string
 }): React.JSX.Element {
   return (
     <span
@@ -17,7 +20,8 @@ export function StatusPill({
         tone === 'ready' &&
           'border-status-success-border bg-status-success-background text-status-success',
         tone === 'review' && 'border-border bg-muted text-foreground',
-        tone === 'destructive' && 'border-destructive/30 text-destructive'
+        tone === 'destructive' && 'border-destructive/30 text-destructive',
+        toneClassName
       )}
     >
       {children}
diff --git a/src/renderer/src/hooks/ipc-events/browser-state-ipc-bridge.ts b/src/renderer/src/hooks/ipc-events/browser-state-ipc-bridge.ts
index 15a632a25e2..4f3450dae85 100644
--- a/src/renderer/src/hooks/ipc-events/browser-state-ipc-bridge.ts
+++ b/src/renderer/src/hooks/ipc-events/browser-state-ipc-bridge.ts
@@ -89,7 +89,20 @@ export function registerBrowserStateIpcBridge(
       if (!sourcePage || getRuntimeEnvironmentIdForWorktree(store, sourcePage.worktreeId)) {
         return
       }
-      store.createBrowserTab(sourcePage.worktreeId, url, { title: url })
+      // Why: the link inherits the opener's cookie jar. Falling back to the default profile would let
+      // a page in an isolated session hand its links to the default one, silently crossing profiles.
+      const sourceTab = (store.browserTabsByWorktree[sourcePage.worktreeId] ?? []).find(
+        (tab) => tab.id === sourcePage.workspaceId
+      )
+      store.createBrowserTab(sourcePage.worktreeId, url, {
+        title: url,
+        ...(sourceTab
+          ? {
+              sessionProfileId: sourceTab.sessionProfileId,
+              sessionPartition: sourceTab.sessionPartition
+            }
+          : {})
+      })
     })
   )
 }
diff --git a/src/renderer/src/hooks/ipc-events/browser-state-open-link-profile.test.ts b/src/renderer/src/hooks/ipc-events/browser-state-open-link-profile.test.ts
new file mode 100644
index 00000000000..b15a5be158c
--- /dev/null
+++ b/src/renderer/src/hooks/ipc-events/browser-state-open-link-profile.test.ts
@@ -0,0 +1,104 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
+const { createBrowserTabMock, storeState } = vi.hoisted(() => ({
+  createBrowserTabMock: vi.fn(),
+  storeState: {
+    value: {} as Record<string, unknown>
+  }
+}))
+
+vi.mock('../../store', () => ({
+  useAppStore: { getState: () => storeState.value }
+}))
+vi.mock('@/lib/worktree-runtime-owner', () => ({
+  getRuntimeEnvironmentIdForWorktree: () => null
+}))
+vi.mock('@/components/browser-pane/describe-page/live-browser-url-registry', () => ({
+  rememberLiveBrowserUrl: vi.fn()
+}))
+vi.mock('./browser-automation-bootstrap-lease', () => ({
+  acquireBrowserAutomationBootstrapLease: vi.fn()
+}))
+
+import { registerBrowserStateIpcBridge } from './browser-state-ipc-bridge'
+
+const noopUnsubscribe = (): void => {}
+
+function captureOpenLinkHandler(): (event: { browserPageId: string; url: string }) => void {
+  let handler: ((event: { browserPageId: string; url: string }) => void) | null = null
+  const browserApi = new Proxy(
+    {
+      onOpenLinkInOrcaTab: (callback: (event: { browserPageId: string; url: string }) => void) => {
+        handler = callback
+        return noopUnsubscribe
+      }
+    } as Record<string, unknown>,
+    {
+      get: (target, property) =>
+        property in target ? target[property as string] : () => noopUnsubscribe
+    }
+  )
+  const api = new Proxy({ browser: browserApi } as Record<string, unknown>, {
+    get: (target, property) =>
+      property in target
+        ? target[property as string]
+        : new Proxy({}, { get: () => () => noopUnsubscribe })
+  })
+  ;(globalThis as { window?: unknown }).window = { api }
+
+  registerBrowserStateIpcBridge([], () => false)
+  if (!handler) {
+    throw new Error('Expected the bridge to subscribe to browser:open-link-in-orca-tab')
+  }
+  return handler
+}
+
+describe('link-opened Orca tabs', () => {
+  beforeEach(() => {
+    createBrowserTabMock.mockReset()
+  })
+
+  it('inherits the opener tab session so an isolated profile cannot leak into the default one', () => {
+    storeState.value = {
+      browserPagesByWorkspace: {
+        'workspace-1': [{ id: 'page-1', workspaceId: 'workspace-1', worktreeId: 'worktree-1' }]
+      },
+      browserTabsByWorktree: {
+        'worktree-1': [
+          {
+            id: 'workspace-1',
+            sessionProfileId: 'profile-client-a',
+            sessionPartition: 'persist:orca-browser-session-client-a'
+          }
+        ]
+      },
+      createBrowserTab: createBrowserTabMock
+    }
+
+    captureOpenLinkHandler()({ browserPageId: 'page-1', url: 'https://docs.example.com/guide' })
+
+    expect(createBrowserTabMock).toHaveBeenCalledWith(
+      'worktree-1',
+      'https://docs.example.com/guide',
+      expect.objectContaining({
+        sessionProfileId: 'profile-client-a',
+        sessionPartition: 'persist:orca-browser-session-client-a'
+      })
+    )
+  })
+
+  it('leaves the profile unset when the opener tab is gone, so the user default still applies', () => {
+    storeState.value = {
+      browserPagesByWorkspace: {
+        'workspace-1': [{ id: 'page-1', workspaceId: 'missing', worktreeId: 'worktree-1' }]
+      },
+      browserTabsByWorktree: {},
+      createBrowserTab: createBrowserTabMock
+    }
+
+    captureOpenLinkHandler()({ browserPageId: 'page-1', url: 'https://docs.example.com/guide' })
+
+    const options = createBrowserTabMock.mock.calls[0][2] as Record<string, unknown>
+    expect('sessionProfileId' in options).toBe(false)
+  })
+})
diff --git a/src/renderer/src/lib/react-commit-cascade-install-order.test.ts b/src/renderer/src/lib/react-commit-cascade-install-order.test.ts
new file mode 100644
index 00000000000..2f5a1227e89
--- /dev/null
+++ b/src/renderer/src/lib/react-commit-cascade-install-order.test.ts
@@ -0,0 +1,137 @@
+import { existsSync, readFileSync } from 'node:fs'
+import { join, resolve, dirname } from 'node:path'
+import { describe, expect, it } from 'vitest'
+
+/**
+ * react-dom reads __REACT_DEVTOOLS_GLOBAL_HOOK__ once, at its own module
+ * evaluation, and enters the graph through several component modules rather
+ * than just the entry's import of react-renderer-root. ES evaluation is
+ * depth-first in source order, so only the FIRST import statement is guaranteed
+ * to beat it — and only if that module's own graph cannot reach react-dom
+ * first, which is why the shim has no imports at all.
+ *
+ * Nothing else fails when either property stops holding: the diagnostic simply
+ * records nothing. These tests are the failure.
+ */
+const RENDERER_ROOT = resolve(__dirname, '..')
+const SHIM_MODULE = 'react-devtools-commit-hook-shim'
+const SHIM_IMPORT = `import './lib/${SHIM_MODULE}'`
+const OBSERVER_IMPORT = "import './lib/react-commit-cascade-observer'"
+
+/** Entries whose crash reports reach the breadcrumb pipe. */
+const INSTRUMENTED_ENTRIES = ['main.tsx', 'popout.tsx']
+/**
+ * The web preload stubs crashReports.recordBreadcrumb to a no-op
+ * (src/renderer/src/web/preload-api/web-diagnostics-api.ts), so instrumenting
+ * the web entry would cost commits and record nothing.
+ */
+const UNINSTRUMENTED_ENTRIES = [join('web', 'main.tsx')]
+
+function firstImportStatement(source: string): string | undefined {
+  return source
+    .split('\n')
+    .map((line) => line.trim())
+    .find((line) => line.startsWith('import '))
+}
+
+function importedSpecifiers(source: string): string[] {
+  return Array.from(source.matchAll(/(?:^|\n)\s*(?:import|export)[^\n]*?from\s*'([^']+)'/g))
+    .map((match) => match[1] as string)
+    .concat(
+      Array.from(source.matchAll(/(?:^|\n)\s*import\s*'([^']+)'/g)).map(
+        (match) => match[1] as string
+      )
+    )
+}
+
+/** Mirrors the alias in config/vitest.config.ts and electron.vite.config.ts. */
+function resolveLocalModule(specifier: string, fromFile: string): string | undefined {
+  const base = specifier.startsWith('@/')
+    ? join(RENDERER_ROOT, specifier.slice(2))
+    : specifier.startsWith('.')
+      ? join(dirname(fromFile), specifier)
+      : undefined
+  if (base === undefined) {
+    return undefined
+  }
+  // Only TS: a .css or asset import cannot pull react-dom into the graph.
+  return [`${base}.ts`, `${base}.tsx`, join(base, 'index.ts')].find((candidate) =>
+    existsSync(candidate)
+  )
+}
+
+/** Bare specifiers stay as-is; local ones are followed so a hop cannot hide react-dom. */
+function transitiveSpecifiers(entryFile: string): Set<string> {
+  const seen = new Set<string>()
+  const specifiers = new Set<string>()
+  const queue = [entryFile]
+  while (queue.length > 0) {
+    const file = queue.pop() as string
+    if (seen.has(file)) {
+      continue
+    }
+    seen.add(file)
+    for (const specifier of importedSpecifiers(readFileSync(file, 'utf8'))) {
+      specifiers.add(specifier)
+      const local = resolveLocalModule(specifier, file)
+      if (local) {
+        queue.push(local)
+      }
+    }
+  }
+  return specifiers
+}
+
+describe('react commit cascade shim install order', () => {
+  for (const entry of INSTRUMENTED_ENTRIES) {
+    it(`keeps the import-free shim as the first import in ${entry}`, () => {
+      const source = readFileSync(join(RENDERER_ROOT, entry), 'utf8')
+
+      expect(source).toContain(SHIM_IMPORT)
+      expect(firstImportStatement(source)).toBe(SHIM_IMPORT)
+    })
+
+    // Why separate: the observer wraps a property react-dom re-reads per commit,
+    // so it only has to be in the graph, not first in it.
+    it(`still installs the observer in ${entry}`, () => {
+      expect(readFileSync(join(RENDERER_ROOT, entry), 'utf8')).toContain(OBSERVER_IMPORT)
+    })
+  }
+
+  for (const entry of UNINSTRUMENTED_ENTRIES) {
+    it(`leaves ${entry} uninstrumented, where breadcrumbs are a no-op`, () => {
+      const source = readFileSync(join(RENDERER_ROOT, entry), 'utf8')
+
+      expect(source).not.toContain('react-commit-cascade-observer')
+    })
+  }
+
+  // Why this is the real ratchet: one import here that transitively reaches
+  // react-dom would let react-dom evaluate first and read no hook, killing the
+  // diagnostic in production with every other test still green.
+  it('keeps the shim free of imports, react-dom above all', () => {
+    const shimFile = join(RENDERER_ROOT, 'lib', `${SHIM_MODULE}.ts`)
+
+    const graph = transitiveSpecifiers(shimFile)
+    expect(Array.from(graph).filter((specifier) => specifier.includes('react-dom'))).toEqual([])
+    expect(Array.from(graph)).toEqual([])
+    // Why a source scan too: the specifier regex only sees an import whose `from`
+    // shares a line with the keyword, and a multi-line import is the common form
+    // here — so the graph check alone would miss the one edit that matters.
+    // Why `from` must be followed by a quote: bare `\bfrom\b` also matched the
+    // word in a comment, and a ratchet that fails on prose gets deleted.
+    // Why the `import(` arm: a top-level `await import(...)` makes this module
+    // async, so react-dom evaluates before the hook is installed.
+    expect(readFileSync(shimFile, 'utf8')).not.toMatch(
+      /^\s*(?:import|export)\b[\s\S]*?\bfrom\s*(?:\/\*[\s\S]*?\*\/\s*)*['"]|^\s*import\s*['"]|\bimport\s*\(/m
+    )
+  })
+
+  it('follows local hops when checking a graph for react-dom', () => {
+    const observerFile = join(RENDERER_ROOT, 'lib', 'react-commit-cascade-observer.ts')
+
+    // The observer's own graph is allowed to be wide; this only proves the walker
+    // above sees past the first hop, so an empty shim graph means something.
+    expect(transitiveSpecifiers(observerFile).size).toBeGreaterThan(3)
+  })
+})
diff --git a/src/renderer/src/lib/react-commit-cascade-observer.react185.test.tsx b/src/renderer/src/lib/react-commit-cascade-observer.react185.test.tsx
new file mode 100644
index 00000000000..a8c4e7c4c58
--- /dev/null
+++ b/src/renderer/src/lib/react-commit-cascade-observer.react185.test.tsx
@@ -0,0 +1,169 @@
+/** @vitest-environment happy-dom */
+// Why first: react-dom below reads __REACT_DEVTOOLS_GLOBAL_HOOK__ at module
+// evaluation. The shim has no imports of its own, so unlike the observer it
+// cannot drag the real breadcrumb recorder in ahead of the vi.mock below.
+import './react-devtools-commit-hook-shim'
+import { act, useLayoutEffect } from 'react'
+import { createRoot, type Root } from 'react-dom/client'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import { create } from 'zustand'
+import { withReactCommitCascadeWriteProbe } from '../store/react-commit-cascade-write-probe'
+import {
+  REACT_CASCADING_LANES,
+  REACT_COMMIT_CASCADE_BREADCRUMB,
+  REACT_COMMIT_CASCADE_NOTICE_LIMIT,
+  resetReactCommitCascadeTelemetryForTests
+} from './react-commit-cascade-telemetry'
+import {
+  installReactCommitCascadeObserver,
+  resetReactCommitCascadeObserverForTests
+} from './react-commit-cascade-observer'
+import type { ReactDevtoolsCommitHook } from './react-devtools-commit-hook-shim'
+
+;(globalThis as { IS_REACT_ACT_ENVIRONMENT?: boolean }).IS_REACT_ACT_ENVIRONMENT = true
+
+const recordBreadcrumb = vi.fn()
+vi.mock('@/lib/crash-breadcrumb-recorder', () => ({
+  recordRendererCrashBreadcrumb: (name: string, data?: unknown) => recordBreadcrumb(name, data)
+}))
+
+/**
+ * A single-driver cascade measures 438 bytes here, where every frame carries this
+ * file's long basename; a production bundle name is shorter. Wide enough to sit
+ * still, narrow enough that a raw stack or an uncapped key list breaks it.
+ */
+const MAX_CASCADE_CRUMB_BYTES = 768
+
+/** Enough to pass the notice limit while staying under React's own 50-commit bail. */
+const CASCADE_TICKS = REACT_COMMIT_CASCADE_NOTICE_LIMIT + 5
+
+type CascadeState = { ticks: number; bump: () => void }
+
+const useCascadeStore = create<CascadeState>()(
+  withReactCommitCascadeWriteProbe((set) => ({
+    ticks: 0,
+    bump: () => {
+      set({ ticks: useCascadeStore.getState().ticks + 1 })
+    }
+  }))
+)
+
+/**
+ * Layout effect, not passive: only the synchronous counter throws #185. A
+ * useEffect loop leaves `pendingLanes: 0` at commit time (measured) because
+ * passive effects flush after the callback, and React only console.errors it.
+ */
+function RunawayLayoutEffectPane(): React.JSX.Element {
+  const ticks = useCascadeStore((state) => state.ticks)
+  useLayoutEffect(() => {
+    if (ticks < CASCADE_TICKS) {
+      useCascadeStore.getState().bump()
+    }
+  })
+  return <div>{ticks}</div>
+}
+
+let host: HTMLDivElement
+let root: Root
+
+const commitHook = (globalThis as { __REACT_DEVTOOLS_GLOBAL_HOOK__?: ReactDevtoolsCommitHook })
+  .__REACT_DEVTOOLS_GLOBAL_HOOK__
+
+beforeEach(() => {
+  recordBreadcrumb.mockReset()
+  resetReactCommitCascadeTelemetryForTests()
+  resetReactCommitCascadeObserverForTests()
+  useCascadeStore.setState({ ticks: 0 })
+  // Why cleared rather than deleting the global: react-dom captured this hook
+  // OBJECT at its own module evaluation, so a replacement object would never be
+  // called — and reinstalling over the last test's wrapper double-counts commits.
+  if (commitHook) {
+    commitHook.onCommitFiberRoot = undefined
+  }
+  installReactCommitCascadeObserver()
+  host = document.createElement('div')
+  document.body.appendChild(host)
+  root = createRoot(host)
+})
+
+afterEach(() => {
+  act(() => {
+    root.unmount()
+  })
+  host.remove()
+})
+
+describe('react commit cascade observer', () => {
+  it('counts a genuine synchronous cascade and names the store write driving it', () => {
+    act(() => {
+      root.render(<RunawayLayoutEffectPane />)
+    })
+
+    const cascadeCalls = recordBreadcrumb.mock.calls.filter(
+      ([name]) => name === REACT_COMMIT_CASCADE_BREADCRUMB
+    )
+    expect(cascadeCalls).toHaveLength(1)
+
+    const payload = (cascadeCalls[0]?.[1] ?? {}) as Record<string, unknown>
+    expect(payload.commits).toBe(REACT_COMMIT_CASCADE_NOTICE_LIMIT)
+    expect(payload.pendingLanes).toBeGreaterThan(0)
+    expect(payload.storeWrites).toBeGreaterThan(0)
+    // The middleware boundary is elided, so this is the code that called `set`.
+    expect(String(payload.driverFrame)).toContain('bump')
+    expect(payload.changedKeys).toBe('ticks')
+    expect(payload.rendererSurface).toBe('main')
+  })
+
+  // Why counted from outside our own wrapper: a bundler change that installs the
+  // observer twice counts every commit twice and fires the crumb at half the real
+  // depth, which no other assertion here can tell from a correct run.
+  it('counts exactly one commit per hook invocation', () => {
+    let cascadingInvocations = 0
+    const observed = commitHook?.onCommitFiberRoot
+    if (commitHook) {
+      // The mount commit holds no cascading lanes, so only these are countable.
+      commitHook.onCommitFiberRoot = (rendererId, fiberRoot, priorityLevel, didError) => {
+        const lanes = (fiberRoot as { pendingLanes?: number } | null)?.pendingLanes ?? 0
+        if ((lanes & REACT_CASCADING_LANES) !== 0) {
+          cascadingInvocations += 1
+        }
+        observed?.call(commitHook, rendererId, fiberRoot, priorityLevel, didError)
+      }
+    }
+    let invocationsAtReport: number | undefined
+    recordBreadcrumb.mockImplementation((name: string) => {
+      if (name === REACT_COMMIT_CASCADE_BREADCRUMB && invocationsAtReport === undefined) {
+        invocationsAtReport = cascadingInvocations
+      }
+    })
+
+    act(() => {
+      root.render(<RunawayLayoutEffectPane />)
+    })
+
+    expect(invocationsAtReport).toBe(REACT_COMMIT_CASCADE_NOTICE_LIMIT)
+  })
+
+  // Why a byte budget: driverStack's key ends in `stack`, which buys 4000 chars,
+  // so a raw stack or an uncapped key list could be added here unnoticed.
+  it('keeps the crumb inside a flat byte budget', () => {
+    act(() => {
+      root.render(<RunawayLayoutEffectPane />)
+    })
+
+    const payload = recordBreadcrumb.mock.calls.find(
+      ([name]) => name === REACT_COMMIT_CASCADE_BREADCRUMB
+    )?.[1]
+    expect(JSON.stringify(payload).length).toBeLessThan(MAX_CASCADE_CRUMB_BYTES)
+  })
+
+  it('stays silent for a render that settles well below the notice limit', () => {
+    useCascadeStore.setState({ ticks: CASCADE_TICKS })
+
+    act(() => {
+      root.render(<RunawayLayoutEffectPane />)
+    })
+
+    expect(recordBreadcrumb).not.toHaveBeenCalled()
+  })
+})
diff --git a/src/renderer/src/lib/react-commit-cascade-observer.test.ts b/src/renderer/src/lib/react-commit-cascade-observer.test.ts
new file mode 100644
index 00000000000..2928afdcebc
--- /dev/null
+++ b/src/renderer/src/lib/react-commit-cascade-observer.test.ts
@@ -0,0 +1,307 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import {
+  REACT_COMMIT_CASCADE_BREADCRUMB,
+  REACT_COMMIT_CASCADE_NOTICE_LIMIT,
+  resetReactCommitCascadeTelemetryForTests
+} from './react-commit-cascade-telemetry'
+import {
+  REACT_COMMIT_CASCADE_INSTALL_CHECK_MS,
+  REACT_COMMIT_CASCADE_UNINSTALLED_BREADCRUMB,
+  installReactCommitCascadeObserver,
+  resetReactCommitCascadeObserverForTests
+} from './react-commit-cascade-observer'
+import {
+  ensureReactDevtoolsCommitHook,
+  type ReactDevtoolsCommitHook
+} from './react-devtools-commit-hook-shim'
+
+const recordBreadcrumb = vi.fn()
+vi.mock('@/lib/crash-breadcrumb-recorder', () => ({
+  recordRendererCrashBreadcrumb: (name: string, data?: unknown) => recordBreadcrumb(name, data)
+}))
+
+const CASCADING_ROOT = { pendingLanes: 2 }
+
+function readHook(): ReactDevtoolsCommitHook {
+  return (globalThis as { __REACT_DEVTOOLS_GLOBAL_HOOK__?: ReactDevtoolsCommitHook })
+    .__REACT_DEVTOOLS_GLOBAL_HOOK__ as ReactDevtoolsCommitHook
+}
+
+beforeEach(() => {
+  recordBreadcrumb.mockClear()
+  resetReactCommitCascadeTelemetryForTests()
+  resetReactCommitCascadeObserverForTests()
+  // Why the delete: install wraps whatever is there, so a hook left over from
+  // the previous test would stack a second counter onto the same callback.
+  delete (globalThis as { __REACT_DEVTOOLS_GLOBAL_HOOK__?: unknown }).__REACT_DEVTOOLS_GLOBAL_HOOK__
+  installReactCommitCascadeObserver()
+})
+
+afterEach(() => {
+  vi.useRealTimers()
+})
+
+describe('react devtools commit hook shim', () => {
+  // Why asserted: without a pre-existing hook react-dom injects nothing, so a
+  // packaged build only gets commit callbacks if the shim installs its own.
+  it('exposes what react-dom requires to inject', () => {
+    const hook = readHook()
+
+    expect(hook.supportsFiber).toBe(true)
+    expect(hook.isDisabled).toBe(false)
+    expect(hook.inject?.({})).toBeGreaterThan(0)
+    expect(typeof hook.onCommitFiberRoot).toBe('function')
+  })
+
+  // Why asserted: react-dom calls this once per DELETED FIBER, guarded only by
+  // a typeof check. Defining it would put our shim on every unmount path.
+  it('leaves the per-deleted-fiber callbacks undefined', () => {
+    const hook = readHook() as Record<string, unknown>
+
+    expect(hook.onCommitFiberUnmount).toBeUndefined()
+    expect(hook.onPostCommitFiberRoot).toBeUndefined()
+    expect(hook.setStrictMode).toBeUndefined()
+  })
+
+  // Why asserted: react-refresh captures this property and calls
+  // oldOnCommitFiberRoot.apply(this, arguments) with no typeof guard, unlike the
+  // fallback it gives onScheduleFiberRoot.
+  it('ships a callable onCommitFiberRoot before anything wraps it', () => {
+    delete (globalThis as { __REACT_DEVTOOLS_GLOBAL_HOOK__?: unknown })
+      .__REACT_DEVTOOLS_GLOBAL_HOOK__
+    const hook = ensureReactDevtoolsCommitHook()
+
+    expect(typeof hook?.onCommitFiberRoot).toBe('function')
+    expect(() => hook?.onCommitFiberRoot?.(1, null, undefined, false)).not.toThrow()
+  })
+})
+
+describe('installReactCommitCascadeObserver', () => {
+  it('breadcrumbs once the commit callback reaches the notice limit', () => {
+    const hook = readHook()
+    for (let commit = 0; commit < REACT_COMMIT_CASCADE_NOTICE_LIMIT; commit += 1) {
+      hook.onCommitFiberRoot?.(1, CASCADING_ROOT, undefined, false)
+    }
+
+    expect(recordBreadcrumb).toHaveBeenCalledTimes(1)
+    expect(recordBreadcrumb.mock.calls[0]?.[0]).toBe(REACT_COMMIT_CASCADE_BREADCRUMB)
+  })
+
+  it('ignores a commit whose root reports no cascading lanes', () => {
+    const hook = readHook()
+    for (let commit = 0; commit < REACT_COMMIT_CASCADE_NOTICE_LIMIT * 2; commit += 1) {
+      hook.onCommitFiberRoot?.(1, { pendingLanes: 0 }, undefined, false)
+    }
+
+    expect(recordBreadcrumb).not.toHaveBeenCalled()
+  })
+
+  // Why asserted: a future React that stops exposing pendingLanes must make the
+  // diagnostic go quiet, not fire on a depth it can no longer evaluate.
+  it('ends the cascade when pendingLanes is not readable', () => {
+    const hook = readHook()
+    for (let commit = 0; commit < REACT_COMMIT_CASCADE_NOTICE_LIMIT - 1; commit += 1) {
+      hook.onCommitFiberRoot?.(1, CASCADING_ROOT, undefined, false)
+    }
+
+    hook.onCommitFiberRoot?.(1, { renamedLanes: 2 }, undefined, false)
+    for (let commit = 0; commit < REACT_COMMIT_CASCADE_NOTICE_LIMIT - 1; commit += 1) {
+      hook.onCommitFiberRoot?.(1, CASCADING_ROOT, undefined, false)
+    }
+
+    expect(recordBreadcrumb).not.toHaveBeenCalled()
+  })
+
+  // Why a string and not undefined: '2' & 42 is 2, so a bitmask-only guard would
+  // keep the cascade alive on a value React never meant as a lane.
+  it('ends the cascade when pendingLanes is not a number', () => {
+    const hook = readHook()
+    for (let commit = 0; commit < REACT_COMMIT_CASCADE_NOTICE_LIMIT - 1; commit += 1) {
+      hook.onCommitFiberRoot?.(1, CASCADING_ROOT, undefined, false)
+    }
+
+    hook.onCommitFiberRoot?.(1, { pendingLanes: '2' }, undefined, false)
+    for (let commit = 0; commit < REACT_COMMIT_CASCADE_NOTICE_LIMIT - 1; commit += 1) {
+      hook.onCommitFiberRoot?.(1, CASCADING_ROOT, undefined, false)
+    }
+
+    expect(recordBreadcrumb).not.toHaveBeenCalled()
+  })
+
+  it('chains onto an existing callback instead of replacing it', () => {
+    const previous = vi.fn()
+    const hook = readHook()
+    hook.onCommitFiberRoot = previous
+    resetReactCommitCascadeObserverForTests()
+    installReactCommitCascadeObserver()
+
+    hook.onCommitFiberRoot?.(7, CASCADING_ROOT, undefined, true)
+
+    expect(previous).toHaveBeenCalledWith(7, CASCADING_ROOT, undefined, true)
+  })
+
+  // Why asserted: our throw would otherwise land in react-dom's own catch and
+  // silently unhook DevTools and Fast Refresh from the rest of the chain.
+  it('still calls the chained hook when our own work throws', () => {
+    const previous = vi.fn()
+    const hook = readHook()
+    hook.onCommitFiberRoot = previous
+    resetReactCommitCascadeObserverForTests()
+    installReactCommitCascadeObserver()
+
+    const hostile = {
+      get pendingLanes(): number {
+        throw new Error('hostile root')
+      }
+    }
+    expect(() => hook.onCommitFiberRoot?.(1, hostile, undefined, false)).not.toThrow()
+    expect(previous).toHaveBeenCalledTimes(1)
+  })
+
+  it('is idempotent, so a second install cannot double-count commits', () => {
+    installReactCommitCascadeObserver()
+    const hook = readHook()
+    for (let commit = 0; commit < REACT_COMMIT_CASCADE_NOTICE_LIMIT - 1; commit += 1) {
+      hook.onCommitFiberRoot?.(1, CASCADING_ROOT, undefined, false)
+    }
+
+    expect(recordBreadcrumb).not.toHaveBeenCalled()
+  })
+})
+
+// Why: a reshuffled import or a bundler hoist disables the diagnostic with no
+// test failure. This is what makes that visible in the field instead.
+describe('install self-check', () => {
+  it('breadcrumbs when no commit ever reached the hook', () => {
+    vi.useFakeTimers()
+    resetReactCommitCascadeObserverForTests()
+    installReactCommitCascadeObserver()
+
+    vi.advanceTimersByTime(REACT_COMMIT_CASCADE_INSTALL_CHECK_MS)
+
+    expect(recordBreadcrumb).toHaveBeenCalledWith(
+      REACT_COMMIT_CASCADE_UNINSTALLED_BREADCRUMB,
+      undefined
+    )
+  })
+
+  it('stays silent once any commit has been seen', () => {
+    vi.useFakeTimers()
+    resetReactCommitCascadeObserverForTests()
+    installReactCommitCascadeObserver()
+    readHook().onCommitFiberRoot?.(1, { pendingLanes: 0 }, undefined, false)
+
+    vi.advanceTimersByTime(REACT_COMMIT_CASCADE_INSTALL_CHECK_MS)
+
+    expect(recordBreadcrumb).not.toHaveBeenCalled()
+  })
+
+  // Why asserted: a hook that refuses the assignment is exactly the case the
+  // self-check exists for, so it must arm on the failure path too.
+  it('breadcrumbs when the hook refuses the callback assignment', () => {
+    vi.useFakeTimers()
+    resetReactCommitCascadeObserverForTests()
+    const frozenHook = Object.freeze({ isDisabled: false, supportsFiber: true })
+    ;(globalThis as { __REACT_DEVTOOLS_GLOBAL_HOOK__?: unknown }).__REACT_DEVTOOLS_GLOBAL_HOOK__ =
+      frozenHook
+
+    expect(() => installReactCommitCascadeObserver()).not.toThrow()
+    vi.advanceTimersByTime(REACT_COMMIT_CASCADE_INSTALL_CHECK_MS)
+
+    expect((frozenHook as { onCommitFiberRoot?: unknown }).onCommitFiberRoot).toBeUndefined()
+    expect(recordBreadcrumb).toHaveBeenCalledWith(
+      REACT_COMMIT_CASCADE_UNINSTALLED_BREADCRUMB,
+      undefined
+    )
+  })
+
+  it('breadcrumbs when no hook can be reached at all', () => {
+    vi.useFakeTimers()
+    resetReactCommitCascadeObserverForTests()
+    Object.defineProperty(globalThis, '__REACT_DEVTOOLS_GLOBAL_HOOK__', {
+      configurable: true,
+      get() {
+        throw new Error('no devtools global')
+      }
+    })
+
+    expect(() => installReactCommitCascadeObserver()).not.toThrow()
+    vi.advanceTimersByTime(REACT_COMMIT_CASCADE_INSTALL_CHECK_MS)
+
+    expect(recordBreadcrumb).toHaveBeenCalledWith(
+      REACT_COMMIT_CASCADE_UNINSTALLED_BREADCRUMB,
+      undefined
+    )
+  })
+})
+
+/**
+ * Why an allocation assertion and not a timing one: this callback runs on every
+ * commit the app makes, so the cost that matters is garbage. Measured on this
+ * loop, an escaping object literal, a template string and a per-call closure
+ * each cost more than 3.8 MB where the current code costs tens of KB.
+ */
+describe('commit hook cost', () => {
+  const HOT_COMMITS = 1_000_000
+  /** ~30x the measured zero-allocation baseline, ~4x under the cheapest regression. */
+  const MAX_HEAP_GROWTH_BYTES = 1_000_000
+
+  function measureHeapGrowth(commit: () => void): number {
+    const collectGarbage = (globalThis as { gc?: () => void }).gc
+    // --expose-gc is pinned in config/vitest.config.ts execArgv.
+    expect(typeof collectGarbage).toBe('function')
+    for (let warmup = 0; warmup < 50_000; warmup += 1) {
+      commit()
+    }
+    collectGarbage?.()
+    const before = process.memoryUsage().heapUsed
+    for (let iteration = 0; iteration < HOT_COMMITS; iteration += 1) {
+      commit()
+    }
+    return process.memoryUsage().heapUsed - before
+  }
+
+  it('allocates nothing on an ordinary commit', () => {
+    const hook = readHook()
+    const quietRoot = { pendingLanes: 0 }
+
+    const growth = measureHeapGrowth(() => hook.onCommitFiberRoot?.(1, quietRoot, undefined, false))
+
+    expect(growth).toBeLessThan(MAX_HEAP_GROWTH_BYTES)
+  })
+
+  // Why separately: the cascading branch runs the counter, the arm check and the
+  // report guard, none of which may start allocating once a cascade is deep.
+  it('allocates nothing while a cascade is being counted', () => {
+    const hook = readHook()
+
+    const growth = measureHeapGrowth(() =>
+      hook.onCommitFiberRoot?.(1, CASCADING_ROOT, undefined, false)
+    )
+
+    expect(growth).toBeLessThan(MAX_HEAP_GROWTH_BYTES)
+  })
+})
+
+// Why asserted: main.tsx imports this module for its side effect alone, so
+// deleting the bare install call would disable the diagnostic in production.
+describe('module self-install', () => {
+  it('counts commits after nothing but an import', async () => {
+    vi.useFakeTimers()
+    delete (globalThis as { __REACT_DEVTOOLS_GLOBAL_HOOK__?: unknown })
+      .__REACT_DEVTOOLS_GLOBAL_HOOK__
+    vi.resetModules()
+
+    await import('./react-commit-cascade-observer')
+
+    const hook = readHook()
+    for (let commit = 0; commit < REACT_COMMIT_CASCADE_NOTICE_LIMIT; commit += 1) {
+      hook.onCommitFiberRoot?.(1, CASCADING_ROOT, undefined, false)
+    }
+
+    expect(recordBreadcrumb).toHaveBeenCalledWith(
+      REACT_COMMIT_CASCADE_BREADCRUMB,
+      expect.objectContaining({ commits: REACT_COMMIT_CASCADE_NOTICE_LIMIT })
+    )
+  })
+})
diff --git a/src/renderer/src/lib/react-commit-cascade-observer.ts b/src/renderer/src/lib/react-commit-cascade-observer.ts
new file mode 100644
index 00000000000..bfac75898bd
--- /dev/null
+++ b/src/renderer/src/lib/react-commit-cascade-observer.ts
@@ -0,0 +1,101 @@
+/**
+ * Installs the per-commit hook that feeds the cascade telemetry.
+ *
+ * Why the devtools callback and not <Profiler> or a root effect: Profiler is
+ * stripped from production react-dom, and a dependency-less useLayoutEffect
+ * fires per render of its OWN component, not per commit — measured, a root
+ * effect saw 1 of 11 commits a leaf drove. react-dom calls onCommitFiberRoot
+ * once per commit per root in both bundles, inside its own try/catch, and hands
+ * us the FiberRoot whose `pendingLanes` drive the reset rule.
+ *
+ * Ordering: this module only WRAPS `onCommitFiberRoot`, which react-dom re-reads
+ * at every commit, so it may be imported anywhere. The deadline belongs to
+ * react-devtools-commit-hook-shim, which must merely exist before react-dom's
+ * module evaluation and is therefore the entries' first import.
+ */
+import { observeReactCommit } from '@/lib/react-commit-cascade-telemetry'
+import { recordRendererCrashBreadcrumb } from '@/lib/crash-breadcrumb-recorder'
+import {
+  ensureReactDevtoolsCommitHook,
+  type ReactDevtoolsCommitHook
+} from '@/lib/react-devtools-commit-hook-shim'
+
+export const REACT_COMMIT_CASCADE_UNINSTALLED_BREADCRUMB = 'react_commit_cascade_uninstalled'
+
+/** Long enough that any live renderer has committed; short enough to reach a crash report. */
+export const REACT_COMMIT_CASCADE_INSTALL_CHECK_MS = 10_000
+
+type FiberRootLike = { pendingLanes?: unknown }
+
+let installed = false
+let commitsSeen = 0
+let installCheckTimer: ReturnType<typeof setTimeout> | undefined
+
+/**
+ * A reshuffled import or a bundler hoist would disable the diagnostic with no
+ * test failure. Make that visible in the field instead of silent.
+ */
+function scheduleInstallSelfCheck(): void {
+  if (installCheckTimer !== undefined || typeof setTimeout !== 'function') {
+    return
+  }
+  installCheckTimer = setTimeout(() => {
+    if (commitsSeen === 0) {
+      recordRendererCrashBreadcrumb(REACT_COMMIT_CASCADE_UNINSTALLED_BREADCRUMB)
+    }
+  }, REACT_COMMIT_CASCADE_INSTALL_CHECK_MS)
+  // Why unref where available: the check must never hold a renderer teardown open.
+  ;(installCheckTimer as { unref?: () => void })?.unref?.()
+}
+
+export function installReactCommitCascadeObserver(): void {
+  if (installed) {
+    return
+  }
+  try {
+    const hook = ensureReactDevtoolsCommitHook()
+    if (hook) {
+      installObserverOnHook(hook)
+      // Why only after the assignment: a hook that refuses it stays uninstalled,
+      // so a later call can retry rather than being gated out.
+      installed = true
+    }
+  } catch {
+    // A renderer without a patchable global still has to boot.
+  }
+  // Why outside the try: a failed install is exactly when the crumb matters.
+  scheduleInstallSelfCheck()
+}
+
+function installObserverOnHook(hook: ReactDevtoolsCommitHook): void {
+  const previous = hook.onCommitFiberRoot
+  // Fixed arity, not rest args: this runs on every commit and must not allocate.
+  hook.onCommitFiberRoot = (rendererId, root, priorityLevel, didError) => {
+    // Why our own try/catch when react-dom already has one: theirs would
+    // swallow the rest of this callback, silently unhooking DevTools and
+    // Fast Refresh from the chain below.
+    try {
+      commitsSeen += 1
+      const pendingLanes = (root as FiberRootLike | null)?.pendingLanes
+      // Why 0 and not a skip: a React shape change that hides pendingLanes must
+      // end the cascade, not freeze a stale depth that later commits push over
+      // the limit. 0 is the lane value that means "nothing pending", so it
+      // takes the same reset path and this fails safe to no crumb.
+      observeReactCommit(root, typeof pendingLanes === 'number' ? pendingLanes : 0)
+    } catch {
+      // Best-effort crash evidence only.
+    }
+    previous?.call(hook, rendererId, root, priorityLevel, didError)
+  }
+}
+
+export function resetReactCommitCascadeObserverForTests(): void {
+  installed = false
+  commitsSeen = 0
+  if (installCheckTimer !== undefined) {
+    clearTimeout(installCheckTimer)
+    installCheckTimer = undefined
+  }
+}
+
+installReactCommitCascadeObserver()
diff --git a/src/renderer/src/lib/react-commit-cascade-store-write-samples.test.ts b/src/renderer/src/lib/react-commit-cascade-store-write-samples.test.ts
new file mode 100644
index 00000000000..17489399883
--- /dev/null
+++ b/src/renderer/src/lib/react-commit-cascade-store-write-samples.test.ts
@@ -0,0 +1,144 @@
+import { afterEach, beforeEach, describe, expect, it } from 'vitest'
+import { create } from 'zustand'
+import { withReactCommitCascadeWriteProbe } from '../store/react-commit-cascade-write-probe'
+import {
+  MAX_REPORTED_CHANGED_KEYS,
+  MAX_SAMPLED_WRITES,
+  armReactCommitCascadeWriteSampling,
+  noteReactCommitCascadeStoreWrite,
+  readReactCommitCascadeWriteSummary,
+  resetReactCommitCascadeWriteSamples
+} from './react-commit-cascade-store-write-samples'
+
+// Not an intersection with ErrorConstructor: both fields have to stay optional
+// so the absent-captureStackTrace platform can be simulated.
+type ErrorWithCapture = {
+  captureStackTrace?: (target: object, constructorOpt?: unknown) => void
+  stackTraceLimit?: number
+}
+const errorWithCapture = Error as unknown as ErrorWithCapture
+const originalCapture = errorWithCapture.captureStackTrace
+const originalLimit = errorWithCapture.stackTraceLimit
+
+/** Stands in for the zustand slice action that calls `set`. */
+function storeAction(): void {
+  noteReactCommitCascadeStoreWrite(storeAction, { ticks: 1 })
+}
+function runawayEffect(): void {
+  storeAction()
+}
+function paneRender(): void {
+  runawayEffect()
+}
+
+beforeEach(() => {
+  resetReactCommitCascadeWriteSamples()
+})
+
+afterEach(() => {
+  resetReactCommitCascadeWriteSamples()
+  errorWithCapture.captureStackTrace = originalCapture
+  errorWithCapture.stackTraceLimit = originalLimit
+})
+
+describe('driver stack frames', () => {
+  // Why more than one frame: frame 0 is the slice action every cascade shares.
+  // The caller above it is the loop we are actually hunting.
+  it('names callers above the frame the write came from', () => {
+    armReactCommitCascadeWriteSampling()
+    paneRender()
+
+    const summary = readReactCommitCascadeWriteSummary()
+    const frames = summary.driverStack?.split('\n') ?? []
+    expect(summary.driverFrame).toContain('runawayEffect')
+    expect(frames[0]).toBe(summary.driverFrame)
+    expect(frames.length).toBeGreaterThan(1)
+    expect(summary.driverStack).toContain('paneRender')
+    expect(summary.driverFrame).not.toContain('paneRender')
+  })
+
+  // Why: the redaction that strips paths is keyed on the detail NAME, so a path
+  // inside this value would ship a developer's home directory.
+  it('keeps every reported frame path-free', () => {
+    armReactCommitCascadeWriteSampling()
+    paneRender()
+
+    expect(readReactCommitCascadeWriteSummary().driverStack).not.toContain('/')
+  })
+})
+
+describe('capture failures', () => {
+  // Why asserted: the limit is process-global, so leaking a raised value would
+  // make every unrelated throw in the app capture eight frames forever.
+  it('restores Error.stackTraceLimit when the capture throws', () => {
+    errorWithCapture.stackTraceLimit = 3
+    errorWithCapture.captureStackTrace = () => {
+      throw new Error('capture refused')
+    }
+    armReactCommitCascadeWriteSampling()
+
+    expect(() => storeAction()).not.toThrow()
+    expect(errorWithCapture.stackTraceLimit).toBe(3)
+    expect(readReactCommitCascadeWriteSummary().storeWrites).toBe(1)
+  })
+
+  // Why asserted: no sample is ever pushed without captureStackTrace, so a cap
+  // bound to samples.length would leave key collection running for the whole
+  // cascade on any engine that lacks the API.
+  it('stops collecting after the sample cap when captureStackTrace is unavailable', () => {
+    delete errorWithCapture.captureStackTrace
+    armReactCommitCascadeWriteSampling()
+    for (let write = 0; write < 100; write += 1) {
+      noteReactCommitCascadeStoreWrite(storeAction, { [`key${write}`]: write })
+    }
+    // Restored before asserting: vitest builds its own failure stacks with it.
+    errorWithCapture.captureStackTrace = originalCapture
+
+    const summary = readReactCommitCascadeWriteSummary()
+    expect(summary.storeWrites).toBe(100)
+    expect(summary.driverFrame).toBeUndefined()
+    expect(summary.storeWriteSites).toBe(0)
+    expect(summary.changedKeys?.split(',')).toHaveLength(MAX_SAMPLED_WRITES)
+    expect(summary.changedKeys).not.toContain('key99')
+    expect(summary.changedKeys?.length).toBeLessThan(240)
+  })
+
+  // Why still asserted: one write can change many keys, so the report cap is
+  // what keeps the detail inside its 240-char budget.
+  it('caps reported changed keys from a single wide write', () => {
+    const wide = Object.fromEntries(
+      Array.from({ length: 40 }, (_, index) => [`key${index}`, index])
+    )
+    armReactCommitCascadeWriteSampling()
+    noteReactCommitCascadeStoreWrite(storeAction, wide)
+
+    const summary = readReactCommitCascadeWriteSummary()
+    expect(summary.changedKeys?.split(',')).toHaveLength(MAX_REPORTED_CHANGED_KEYS)
+    expect(summary.changedKeys?.length).toBeLessThan(240)
+  })
+})
+
+// Why measured through the real middleware: the arming condition is what keeps
+// an ordinary write down to one boolean read, and nothing else asserts it end to end.
+describe('disarmed cost', () => {
+  const WRITE_FLOOD = 10_000
+
+  it('captures no stack across a write flood with no cascade', () => {
+    const useFloodStore = create<{ ticks: number }>()(
+      withReactCommitCascadeWriteProbe(() => ({ ticks: 0 }))
+    )
+    let captures = 0
+    errorWithCapture.captureStackTrace = (target, boundary) => {
+      captures += 1
+      originalCapture?.(target, boundary)
+    }
+
+    for (let write = 0; write < WRITE_FLOOD; write += 1) {
+      useFloodStore.setState({ ticks: write })
+    }
+
+    expect(captures).toBe(0)
+    expect(useFloodStore.getState().ticks).toBe(WRITE_FLOOD - 1)
+    expect(readReactCommitCascadeWriteSummary().storeWrites).toBe(0)
+  })
+})
diff --git a/src/renderer/src/lib/react-commit-cascade-store-write-samples.ts b/src/renderer/src/lib/react-commit-cascade-store-write-samples.ts
new file mode 100644
index 00000000000..ef8565255a8
--- /dev/null
+++ b/src/renderer/src/lib/react-commit-cascade-store-write-samples.ts
@@ -0,0 +1,157 @@
+/**
+ * Samples the store writes made during a suspected React commit cascade.
+ *
+ * Why sampling writes and not the throw site: React #185 lands on whichever
+ * fiber dispatched after a root-global counter tripped, so the reported
+ * component is a bystander (see shared/react-update-depth-attribution.ts). The
+ * writes that kept scheduling are the only frames that identify the loop.
+ *
+ * Cost discipline: the armed flag is the only thing the store-write path reads
+ * when no cascade is suspected, capture is capped per cascade, and frames are
+ * formatted at report time so a sampled write pays for nothing it may not use.
+ */
+
+/**
+ * Read on every store write, so it is a plain field load on a shared object
+ * rather than a cross-module call.
+ */
+export const reactCommitCascadeWriteProbe = { armed: false }
+
+/** Frame 0 is the store action; the rest reach up into whatever loops over it. */
+const CAPTURE_STACK_FRAME_LIMIT = 8
+/**
+ * Frame 0 alone names a slice action, which every cascade shares. Two frames of
+ * caller is what distinguishes the effect driving the loop from its neighbours.
+ */
+const REPORTED_FRAMES_PER_SITE = 3
+/** Whole frames only, inside the 4000-char budget a `stack`-suffixed detail gets. */
+const MAX_DRIVER_STACK_CHARS = 3_800
+/** A loop repeats; six samples name every distinct participant worth naming. */
+export const MAX_SAMPLED_WRITES = 6
+/** Keeps `changedKeys` inside the 240-char detail cap without truncating mid-key. */
+export const MAX_REPORTED_CHANGED_KEYS = 12
+
+type SampledWrite = { stack?: string }
+
+let storeWrites = 0
+let samples: SampledWrite[] = []
+let changedKeys: Set<string> | null = null
+
+export type ReactCommitCascadeWriteSummary = {
+  storeWrites: number
+  storeWriteSites: number
+  driverFrame: string | undefined
+  driverStack: string | undefined
+  changedKeys: string | undefined
+}
+
+export function armReactCommitCascadeWriteSampling(): void {
+  reactCommitCascadeWriteProbe.armed = true
+}
+
+export function resetReactCommitCascadeWriteSamples(): void {
+  reactCommitCascadeWriteProbe.armed = false
+  storeWrites = 0
+  samples = []
+  changedKeys = null
+}
+
+/**
+ * Call only while armed. `boundary` is the wrapping `set` function, so V8 elides
+ * our own frames and the first captured frame is the real caller. Typed as
+ * `object` because zustand's `set` is an overload set, not a plain signature.
+ */
+export function noteReactCommitCascadeStoreWrite(boundary: object, partial: unknown): void {
+  storeWrites += 1
+  // Why the write count and not samples.length: samples only grows where
+  // Error.captureStackTrace exists, so that cap would never engage without it and
+  // key collection would run for the whole cascade.
+  if (storeWrites > MAX_SAMPLED_WRITES) {
+    return
+  }
+  // Why object-only: a functional updater's keys are unknowable without running it.
+  if (partial && typeof partial === 'object') {
+    changedKeys ??= new Set<string>()
+    for (const key of Object.keys(partial)) {
+      changedKeys.add(key)
+    }
+  }
+  const capture = Error as ErrorConstructor & {
+    captureStackTrace?: (target: object, constructorOpt?: unknown) => void
+    stackTraceLimit?: number
+  }
+  if (typeof capture.captureStackTrace !== 'function') {
+    return
+  }
+  const previousLimit = capture.stackTraceLimit
+  const sample: SampledWrite = {}
+  try {
+    capture.stackTraceLimit = CAPTURE_STACK_FRAME_LIMIT
+    capture.captureStackTrace(sample, boundary)
+    samples.push(sample)
+  } catch {
+    // Best-effort crash evidence only.
+  } finally {
+    capture.stackTraceLimit = previousLimit
+  }
+}
+
+/** `at fn (/Users/me/app/src/x.ts:1:2)` becomes `x.ts:1:2 fn`. */
+function reduceFrame(frame: string): string | undefined {
+  const match = /^\s*at\s+(?:(.+?)\s+\()?(.+?):(\d+):(\d+)\)?\s*$/.exec(frame)
+  if (!match) {
+    return undefined
+  }
+  const [, fn, location, line, column] = match
+  // Why basename only: the redaction that strips paths is keyed on the detail
+  // NAME, so a full path inside this value would ship a developer's home dir.
+  const basename = location?.split(/[/\\]/).pop() ?? ''
+  return fn ? `${basename}:${line}:${column} ${fn}` : `${basename}:${line}:${column}`
+}
+
+/** One reduced frame group per distinct call site, deepest frame first. */
+function sampledSiteFrames(): string[][] {
+  const sites: string[][] = []
+  const seen = new Set<string>()
+  for (const sample of samples) {
+    const frames = (sample.stack?.split('\n') ?? [])
+      .map(reduceFrame)
+      .filter((frame): frame is string => frame !== undefined)
+      .slice(0, REPORTED_FRAMES_PER_SITE)
+    const site = frames[0]
+    if (site === undefined || seen.has(site)) {
+      continue
+    }
+    seen.add(site)
+    sites.push(frames)
+  }
+  return sites
+}
+
+/** Drops whole frames, so a truncated stack never ends mid-frame. */
+function joinWithinBudget(frames: string[]): string | undefined {
+  const kept: string[] = []
+  let remaining = MAX_DRIVER_STACK_CHARS
+  for (const frame of frames) {
+    if (frame.length + 1 > remaining) {
+      break
+    }
+    kept.push(frame)
+    remaining -= frame.length + 1
+  }
+  return kept.length > 0 ? kept.join('\n') : undefined
+}
+
+/** Formats only here, so an unreported cascade pays nothing for its samples. */
+export function readReactCommitCascadeWriteSummary(): ReactCommitCascadeWriteSummary {
+  const sites = sampledSiteFrames()
+  const keys = changedKeys ? Array.from(changedKeys).slice(0, MAX_REPORTED_CHANGED_KEYS) : []
+  return {
+    storeWrites,
+    storeWriteSites: sites.length,
+    // Why frame 0 stays alone: the main-side coalesce key clusters on it.
+    driverFrame: sites[0]?.[0],
+    driverStack: joinWithinBudget(sites.flat()),
+    changedKeys: keys.length > 0 ? keys.join(',') : undefined
+  }
+}
diff --git a/src/renderer/src/lib/react-commit-cascade-telemetry.test.ts b/src/renderer/src/lib/react-commit-cascade-telemetry.test.ts
new file mode 100644
index 00000000000..89e0456c2ce
--- /dev/null
+++ b/src/renderer/src/lib/react-commit-cascade-telemetry.test.ts
@@ -0,0 +1,339 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+import { sanitizeCrashReportDetails } from '../../../shared/crash-report-redaction'
+import { REACT_NESTED_UPDATE_LIMIT } from '../../../shared/react-update-depth-attribution'
+import {
+  REACT_CASCADING_LANES,
+  setReactCommitCascadeRendererSurface,
+  REACT_COMMIT_CASCADE_ARM_COMMITS,
+  REACT_COMMIT_CASCADE_BREADCRUMB,
+  REACT_COMMIT_CASCADE_MIN_REPORT_INTERVAL_MS,
+  REACT_COMMIT_CASCADE_NOTICE_LIMIT,
+  createReactCommitCascadeState,
+  recordReactCommit,
+  resetReactCommitCascadeTelemetryForTests,
+  type ReactCommitCascadeState
+} from './react-commit-cascade-telemetry'
+import {
+  noteReactCommitCascadeStoreWrite,
+  reactCommitCascadeWriteProbe,
+  readReactCommitCascadeWriteSummary
+} from './react-commit-cascade-store-write-samples'
+
+const recordBreadcrumb = vi.fn()
+vi.mock('@/lib/crash-breadcrumb-recorder', () => ({
+  recordRendererCrashBreadcrumb: (name: string, data?: unknown) => recordBreadcrumb(name, data)
+}))
+
+const ROOT = { pendingLanes: 2 }
+const OTHER_ROOT = { pendingLanes: 2 }
+/** SyncLane; what react-dom leaves pending on a cascading commit. */
+const SYNC_LANE = 2
+/** Any lane outside React's nested-update mask ends the cascade. */
+const IDLE_LANE = 1_073_741_824
+
+function cascadePayload(callIndex = 0): Record<string, unknown> {
+  const call = recordBreadcrumb.mock.calls[callIndex]
+  return (call?.[1] ?? {}) as Record<string, unknown>
+}
+
+function driveCommits(args: {
+  state: ReactCommitCascadeState
+  count: number
+  root?: unknown
+  lanes?: number
+  nowMs?: number
+  onCommit?: () => void
+}): void {
+  const readNowMs = (): number => args.nowMs ?? 1_000
+  for (let index = 0; index < args.count; index += 1) {
+    recordReactCommit({
+      state: args.state,
+      root: args.root ?? ROOT,
+      pendingLanes: args.lanes ?? SYNC_LANE,
+      readNowMs
+    })
+    args.onCommit?.()
+  }
+}
+
+beforeEach(() => {
+  recordBreadcrumb.mockClear()
+  resetReactCommitCascadeTelemetryForTests()
+})
+
+// Why asserted: both thresholds only mean anything relative to React's own bail.
+// If the notice limit ever meets it, the crumb stops beating the throw.
+describe('cascade thresholds', () => {
+  it('derives arm and notice limits from React commit budget', () => {
+    expect(REACT_COMMIT_CASCADE_NOTICE_LIMIT).toBeLessThan(REACT_NESTED_UPDATE_LIMIT)
+    expect(REACT_COMMIT_CASCADE_ARM_COMMITS).toBeLessThan(REACT_COMMIT_CASCADE_NOTICE_LIMIT)
+    expect(REACT_CASCADING_LANES).toBe(42)
+  })
+})
+
+describe('recordReactCommit', () => {
+  it('stays silent below the notice limit', () => {
+    const state = createReactCommitCascadeState()
+    driveCommits({ state, count: REACT_COMMIT_CASCADE_NOTICE_LIMIT - 1 })
+
+    expect(recordBreadcrumb).not.toHaveBeenCalled()
+    expect(state.commits).toBe(REACT_COMMIT_CASCADE_NOTICE_LIMIT - 1)
+  })
+
+  it('fires exactly once at the notice limit and not again in the same cascade', () => {
+    const state = createReactCommitCascadeState()
+    driveCommits({ state, count: REACT_COMMIT_CASCADE_NOTICE_LIMIT * 3 })
+
+    expect(recordBreadcrumb).toHaveBeenCalledTimes(1)
+    expect(recordBreadcrumb.mock.calls[0]?.[0]).toBe(REACT_COMMIT_CASCADE_BREADCRUMB)
+    expect(cascadePayload().commits).toBe(REACT_COMMIT_CASCADE_NOTICE_LIMIT)
+  })
+
+  it('emits flat primitives only', () => {
+    const state = createReactCommitCascadeState()
+    driveCommits({ state, count: REACT_COMMIT_CASCADE_NOTICE_LIMIT })
+
+    const payload = cascadePayload()
+    expect(
+      Object.values(payload).every((value) => value === null || typeof value !== 'object')
+    ).toBe(true)
+    expect(payload).toMatchObject({
+      commits: REACT_COMMIT_CASCADE_NOTICE_LIMIT,
+      commitBudget: REACT_NESTED_UPDATE_LIMIT,
+      pendingLanes: SYNC_LANE,
+      storeWrites: 0,
+      storeWriteSites: 0,
+      rendererSurface: 'main'
+    })
+  })
+
+  // Why this is the whole reset rule: React zeroes its counter the moment a
+  // commit leaves no sync lanes pending, so a lull must not accumulate.
+  it('ends the cascade when the root stops holding cascading lanes', () => {
+    const state = createReactCommitCascadeState()
+    driveCommits({ state, count: REACT_COMMIT_CASCADE_NOTICE_LIMIT - 1 })
+
+    driveCommits({ state, count: 1, lanes: 0 })
+
+    expect(state.commits).toBe(0)
+    expect(state.cascadeRoot).toBeNull()
+    driveCommits({ state, count: REACT_COMMIT_CASCADE_NOTICE_LIMIT - 1 })
+    expect(recordBreadcrumb).not.toHaveBeenCalled()
+  })
+
+  it('ignores lanes outside React nested-update mask', () => {
+    const state = createReactCommitCascadeState()
+    driveCommits({ state, count: REACT_COMMIT_CASCADE_NOTICE_LIMIT * 2, lanes: IDLE_LANE })
+
+    expect(state.commits).toBe(0)
+    expect(recordBreadcrumb).not.toHaveBeenCalled()
+  })
+
+  // Why per root: React's counter is root-global but not cross-root, so two
+  // roots alternating commits are not one cascade.
+  it('restarts the count when a different root commits', () => {
+    const state = createReactCommitCascadeState()
+    driveCommits({ state, count: REACT_COMMIT_CASCADE_NOTICE_LIMIT - 1 })
+
+    driveCommits({ state, count: 1, root: OTHER_ROOT })
+
+    expect(state.commits).toBe(1)
+    expect(state.cascadeRoot).toBe(OTHER_ROOT)
+    expect(recordBreadcrumb).not.toHaveBeenCalled()
+  })
+
+  it('honours explicit limit overrides', () => {
+    const state = createReactCommitCascadeState()
+    for (let index = 0; index < 4; index += 1) {
+      recordReactCommit({
+        state,
+        root: ROOT,
+        pendingLanes: SYNC_LANE,
+        readNowMs: () => 1_000,
+        noticeLimit: 4,
+        armCommits: 2
+      })
+    }
+
+    expect(cascadePayload().commits).toBe(4)
+  })
+
+  // Why asserted: a clock read per commit is the one cost this design refuses.
+  it('reads the clock only at arm and at report', () => {
+    const state = createReactCommitCascadeState()
+    const readNowMs = vi.fn(() => 1_000)
+    for (let index = 0; index < REACT_COMMIT_CASCADE_NOTICE_LIMIT; index += 1) {
+      recordReactCommit({ state, root: ROOT, pendingLanes: SYNC_LANE, readNowMs })
+    }
+
+    expect(readNowMs).toHaveBeenCalledTimes(2)
+  })
+})
+
+// Why asserted: the popout is a separate BrowserWindow with its own module
+// state, so the payload is the only thing that says which window cascaded.
+describe('renderer surface', () => {
+  it('reports the surface the cascade happened on', () => {
+    setReactCommitCascadeRendererSurface('dashboard-popout')
+    const state = createReactCommitCascadeState()
+    driveCommits({ state, count: REACT_COMMIT_CASCADE_NOTICE_LIMIT })
+
+    expect(cascadePayload().rendererSurface).toBe('dashboard-popout')
+  })
+})
+
+describe('driver attribution', () => {
+  it('arms write sampling at the arm floor, not before', () => {
+    const state = createReactCommitCascadeState()
+    driveCommits({ state, count: REACT_COMMIT_CASCADE_ARM_COMMITS - 1 })
+    expect(reactCommitCascadeWriteProbe.armed).toBe(false)
+
+    driveCommits({ state, count: 1 })
+    expect(reactCommitCascadeWriteProbe.armed).toBe(true)
+  })
+
+  it('names the driving write with a path-free frame', () => {
+    const state = createReactCommitCascadeState()
+    function drivingWrite(): void {
+      noteReactCommitCascadeStoreWrite(drivingWrite, { tabs: [] })
+    }
+    driveCommits({
+      state,
+      count: REACT_COMMIT_CASCADE_NOTICE_LIMIT,
+      onCommit: () => {
+        if (reactCommitCascadeWriteProbe.armed) {
+          drivingWrite()
+        }
+      }
+    })
+
+    const payload = cascadePayload()
+    expect(payload.storeWrites).toBeGreaterThan(0)
+    // Why the caller and not drivingWrite itself: captureStackTrace elides the
+    // boundary frame, so in production the first frame is whoever called `set`.
+    expect(String(payload.driverFrame)).toContain('onCommit')
+    expect(payload.changedKeys).toBe('tabs')
+    // Why: the path redaction is keyed on the detail NAME, so a path inside the
+    // value would ship a developer's home directory.
+    expect(String(payload.driverStack)).not.toContain('/')
+    // Why sanitize instead of matching the key name: the 4000-char budget is
+    // decided by a camel-split rule in crash-report-redaction, so a hand-copied
+    // regex here can pass while the real rule drops the frames to 240.
+    // Why resolve the key from the payload: hard-coding it here is the same
+    // drift this assertion exists to catch.
+    const stackKey = Object.keys(payload).find(
+      (key) => key !== 'driverFrame' && String(payload[key]).includes(String(payload.driverFrame))
+    )
+    expect(stackKey).toBeDefined()
+    const longFrames = 'a'.repeat(600)
+    const sanitized = sanitizeCrashReportDetails({ ...payload, [stackKey as string]: longFrames })
+    expect(String(sanitized[stackKey as string])).toHaveLength(longFrames.length)
+  })
+
+  it('clears samples when a cascade ends', () => {
+    const state = createReactCommitCascadeState()
+    function drivingWrite(): void {
+      noteReactCommitCascadeStoreWrite(drivingWrite, { tabs: [] })
+    }
+    driveCommits({
+      state,
+      count: REACT_COMMIT_CASCADE_NOTICE_LIMIT,
+      onCommit: () => {
+        if (reactCommitCascadeWriteProbe.armed) {
+          drivingWrite()
+        }
+      }
+    })
+    recordBreadcrumb.mockClear()
+
+    driveCommits({ state, count: 1, lanes: 0 })
+    driveCommits({
+      state,
+      count: REACT_COMMIT_CASCADE_NOTICE_LIMIT,
+      nowMs: 1_000 + REACT_COMMIT_CASCADE_MIN_REPORT_INTERVAL_MS + 1
+    })
+
+    expect(cascadePayload().storeWrites).toBe(0)
+    expect(cascadePayload().driverFrame).toBeUndefined()
+  })
+})
+
+describe('report throttle', () => {
+  it('suppresses cascades inside the interval and carries the count forward', () => {
+    const state = createReactCommitCascadeState()
+    for (let cascade = 0; cascade < 3; cascade += 1) {
+      driveCommits({ state, count: 1, lanes: 0 })
+      driveCommits({ state, count: REACT_COMMIT_CASCADE_NOTICE_LIMIT })
+    }
+
+    expect(recordBreadcrumb).toHaveBeenCalledTimes(1)
+    expect(state.suppressed).toBe(2)
+
+    driveCommits({ state, count: 1, lanes: 0 })
+    driveCommits({
+      state,
+      count: REACT_COMMIT_CASCADE_NOTICE_LIMIT,
+      nowMs: 1_000 + REACT_COMMIT_CASCADE_MIN_REPORT_INTERVAL_MS + 1
+    })
+
+    expect(recordBreadcrumb).toHaveBeenCalledTimes(2)
+    expect(cascadePayload(1).suppressed).toBe(2)
+    expect(state.suppressed).toBe(0)
+  })
+})
+
+/**
+ * Why dimensional and not just functional: a cascade that ends releases its
+ * samples, but a renderer that oscillates for minutes runs that arm/end cycle
+ * thousands of times, and anything the reset misses accumulates there.
+ */
+describe('repeated arm and end cycles', () => {
+  const CYCLES = 1_000
+  /** The steady state is a few KB of live objects; a per-cycle leak is megabytes. */
+  const MAX_HEAP_GROWTH_BYTES = 1_000_000
+
+  function drivingWrite(): void {
+    noteReactCommitCascadeStoreWrite(drivingWrite, { tabs: [], panes: [] })
+  }
+
+  function runCascadeCycle(state: ReactCommitCascadeState): void {
+    driveCommits({
+      state,
+      count: REACT_COMMIT_CASCADE_NOTICE_LIMIT,
+      onCommit: () => {
+        if (reactCommitCascadeWriteProbe.armed) {
+          drivingWrite()
+        }
+      }
+    })
+    driveCommits({ state, count: 1, lanes: 0 })
+  }
+
+  it('leaves nothing behind across a thousand cascades', () => {
+    const collectGarbage = (globalThis as { gc?: () => void }).gc
+    // --expose-gc is pinned in config/vitest.config.ts execArgv.
+    expect(typeof collectGarbage).toBe('function')
+    const state = createReactCommitCascadeState()
+    for (let warmup = 0; warmup < 20; warmup += 1) {
+      runCascadeCycle(state)
+    }
+    collectGarbage?.()
+    const before = process.memoryUsage().heapUsed
+
+    for (let cycle = 0; cycle < CYCLES; cycle += 1) {
+      runCascadeCycle(state)
+    }
+    collectGarbage?.()
+
+    expect(process.memoryUsage().heapUsed - before).toBeLessThan(MAX_HEAP_GROWTH_BYTES)
+    expect(reactCommitCascadeWriteProbe.armed).toBe(false)
+    expect(readReactCommitCascadeWriteSummary()).toMatchObject({
+      storeWrites: 0,
+      storeWriteSites: 0,
+      driverFrame: undefined,
+      driverStack: undefined,
+      changedKeys: undefined
+    })
+    expect(state.cascadeRoot).toBeNull()
+  })
+})
diff --git a/src/renderer/src/lib/react-commit-cascade-telemetry.ts b/src/renderer/src/lib/react-commit-cascade-telemetry.ts
new file mode 100644
index 00000000000..73051d21599
--- /dev/null
+++ b/src/renderer/src/lib/react-commit-cascade-telemetry.ts
@@ -0,0 +1,205 @@
+/**
+ * Counts consecutive same-root commits that keep scheduling synchronous work,
+ * and breadcrumbs the cascade before React #185 throws.
+ *
+ * This mirrors React's own accounting rather than approximating it with a time
+ * window: react-dom resets its nested-update counter the moment a commit leaves
+ * no sync lanes pending, and increments it otherwise. Reading `root.pendingLanes`
+ * at commit time reproduces that reset exactly.
+ *
+ * Known over-count: React also requires the committed lanes to intersect its own
+ * mask, which we cannot read from the devtools callback. Dropping that term can
+ * only make us count a commit React would have skipped, so we fire early, never
+ * late — the safe direction for a diagnostic that must beat the throw.
+ *
+ * Out of scope by construction: a passive-effect (useEffect) loop reports
+ * pendingLanes 0 here, because passive effects flush after the commit callback.
+ * That is correct — React tracks those in nestedPassiveUpdateCount, which only
+ * console.errors in development and never throws #185.
+ */
+import { compactBreadcrumbData } from '@/lib/crash-breadcrumb-data'
+import { recordRendererCrashBreadcrumb } from '@/lib/crash-breadcrumb-recorder'
+import {
+  armReactCommitCascadeWriteSampling,
+  readReactCommitCascadeWriteSummary,
+  resetReactCommitCascadeWriteSamples
+} from '@/lib/react-commit-cascade-store-write-samples'
+import { readStoreListenerCount } from '@/store/store-listener-census'
+import type { RendererSurface } from '@/lib/renderer-memory-sampling'
+import { REACT_NESTED_UPDATE_LIMIT } from '../../../shared/react-update-depth-attribution'
+
+export const REACT_COMMIT_CASCADE_BREADCRUMB = 'react_commit_cascade'
+
+/**
+ * SyncLane | InputContinuousLane | DefaultLane. A root still holding any of
+ * these after a commit is what React counts as a nested update.
+ */
+export const REACT_CASCADING_LANES = 42
+
+/** Headroom for the crumb to be built and sent before React throws above 50. */
+const REACT_COMMIT_CASCADE_NOTICE_HEADROOM = 10
+export const REACT_COMMIT_CASCADE_NOTICE_LIMIT =
+  REACT_NESTED_UPDATE_LIMIT - REACT_COMMIT_CASCADE_NOTICE_HEADROOM
+/**
+ * Nothing in the app legitimately reaches 20 consecutive same-root cascading
+ * commits — the two deliberate oscillation loops are capped at 8 and 3 — and it
+ * leaves 20 commits for the sampled writes to land inside the loop.
+ */
+export const REACT_COMMIT_CASCADE_ARM_COMMITS = 20
+/** Matches RENDERER_BREADCRUMB_COALESCE_MS; main drops anything faster anyway. */
+export const REACT_COMMIT_CASCADE_MIN_REPORT_INTERVAL_MS = 30_000
+
+export type ReactCommitCascadeState = {
+  /**
+   * Held strongly, and never dereferenced. The next commit that leaves no
+   * cascading lanes clears the slot — milliseconds away in a live renderer —
+   * so the only tree this pins is a React root unmounted mid-cascade, such as
+   * the per-decoration roots in useDiffCommentDecorator.
+   */
+  cascadeRoot: unknown
+  commits: number
+  reported: boolean
+  armedAtMs: number | null
+  lastReportedAtMs: number | null
+  /** Cascades that reached the notice limit while the report interval was live. */
+  suppressed: number
+}
+
+export function createReactCommitCascadeState(): ReactCommitCascadeState {
+  return {
+    cascadeRoot: null,
+    commits: 0,
+    reported: false,
+    armedAtMs: null,
+    lastReportedAtMs: null,
+    suppressed: 0
+  }
+}
+
+const sharedState = createReactCommitCascadeState()
+let rendererSurface: RendererSurface = 'main'
+
+export function setReactCommitCascadeRendererSurface(surface: RendererSurface): void {
+  rendererSurface = surface
+}
+
+export function resetReactCommitCascadeTelemetryForTests(): void {
+  Object.assign(sharedState, createReactCommitCascadeState())
+  rendererSurface = 'main'
+  resetReactCommitCascadeWriteSamples()
+}
+
+function endCascade(state: ReactCommitCascadeState): void {
+  state.cascadeRoot = null
+  state.commits = 0
+  state.reported = false
+  state.armedAtMs = null
+  resetReactCommitCascadeWriteSamples()
+}
+
+function reportCascade(state: ReactCommitCascadeState, pendingLanes: number, nowMs: number): void {
+  const suppressed = state.suppressed
+  state.suppressed = 0
+  state.lastReportedAtMs = nowMs
+  const writes = readReactCommitCascadeWriteSummary()
+  recordRendererCrashBreadcrumb(
+    REACT_COMMIT_CASCADE_BREADCRUMB,
+    compactBreadcrumbData({
+      commits: state.commits,
+      commitBudget: REACT_NESTED_UPDATE_LIMIT,
+      elapsedMs: state.armedAtMs === null ? undefined : nowMs - state.armedAtMs,
+      pendingLanes,
+      // Why 0 is worth shipping: it says the loop is useState-driven, not store-driven.
+      storeWrites: writes.storeWrites,
+      storeWriteSites: writes.storeWriteSites,
+      driverFrame: writes.driverFrame,
+      driverStack: writes.driverStack,
+      changedKeys: writes.changedKeys,
+      storeListeners: readStoreListenerCount() ?? undefined,
+      rendererSurface,
+      suppressed: suppressed > 0 ? suppressed : undefined
+    })
+  )
+}
+
+function recordCommit(
+  state: ReactCommitCascadeState,
+  root: unknown,
+  pendingLanes: number,
+  readNowMs: () => number,
+  noticeLimit: number,
+  armCommits: number,
+  minReportIntervalMs: number
+): void {
+  if ((pendingLanes & REACT_CASCADING_LANES) === 0) {
+    if (state.cascadeRoot !== null) {
+      endCascade(state)
+    }
+    return
+  }
+  if (root !== state.cascadeRoot) {
+    endCascade(state)
+    state.cascadeRoot = root
+  }
+
+  state.commits += 1
+  if (state.commits < armCommits) {
+    return
+  }
+  if (state.commits === armCommits) {
+    state.armedAtMs = readNowMs()
+    armReactCommitCascadeWriteSampling()
+    return
+  }
+  if (state.reported || state.commits < noticeLimit) {
+    return
+  }
+
+  state.reported = true
+  const nowMs = readNowMs()
+  // Why the renderer throttles too: nothing rate-limits this pipe, and every
+  // call is a structured clone plus an ipcRenderer.send.
+  const sinceReportMs = state.lastReportedAtMs === null ? null : nowMs - state.lastReportedAtMs
+  if (sinceReportMs !== null && sinceReportMs >= 0 && sinceReportMs < minReportIntervalMs) {
+    state.suppressed += 1
+    return
+  }
+  reportCascade(state, pendingLanes, nowMs)
+}
+
+/** Injectable entry point; production uses observeReactCommit. */
+export function recordReactCommit(args: {
+  state: ReactCommitCascadeState
+  root: unknown
+  pendingLanes: number
+  readNowMs: () => number
+  noticeLimit?: number
+  armCommits?: number
+  minReportIntervalMs?: number
+}): void {
+  recordCommit(
+    args.state,
+    args.root,
+    args.pendingLanes,
+    args.readNowMs,
+    args.noticeLimit ?? REACT_COMMIT_CASCADE_NOTICE_LIMIT,
+    args.armCommits ?? REACT_COMMIT_CASCADE_ARM_COMMITS,
+    args.minReportIntervalMs ?? REACT_COMMIT_CASCADE_MIN_REPORT_INTERVAL_MS
+  )
+}
+
+/**
+ * Per-commit hot path: one property read, one mask, two compares, one
+ * increment. No clock read and no allocation until a cascade arms.
+ */
+export function observeReactCommit(root: unknown, pendingLanes: number): void {
+  recordCommit(
+    sharedState,
+    root,
+    pendingLanes,
+    Date.now,
+    REACT_COMMIT_CASCADE_NOTICE_LIMIT,
+    REACT_COMMIT_CASCADE_ARM_COMMITS,
+    REACT_COMMIT_CASCADE_MIN_REPORT_INTERVAL_MS
+  )
+}
diff --git a/src/renderer/src/lib/react-devtools-commit-hook-shim.ts b/src/renderer/src/lib/react-devtools-commit-hook-shim.ts
new file mode 100644
index 00000000000..7afde839020
--- /dev/null
+++ b/src/renderer/src/lib/react-devtools-commit-hook-shim.ts
@@ -0,0 +1,70 @@
+/**
+ * Guarantees __REACT_DEVTOOLS_GLOBAL_HOOK__ exists, and nothing else.
+ *
+ * Split out from the observer because the two halves have different deadlines:
+ * react-dom reads this global ONCE, at its own module evaluation, so a fresh
+ * shim must beat that import — but wrapping `onCommitFiberRoot` can happen at
+ * any time, since react-dom re-reads the property at every commit. This module
+ * therefore installs itself on import and has NO imports of its own, so a bare
+ * side-effect import cannot be outrun by a transitive graph that reaches
+ * react-dom, and cannot drag the breadcrumb recorder in ahead of any vi.mock.
+ */
+
+/**
+ * Only what react-dom and react-refresh require. onCommitFiberUnmount,
+ * onPostCommitFiberRoot and setStrictMode are deliberately absent: react-dom
+ * guards each with a typeof check, and calls onCommitFiberUnmount once per
+ * DELETED FIBER, which is genuinely hot when terminal panes unmount.
+ */
+export type ReactDevtoolsCommitHook = {
+  isDisabled?: boolean
+  supportsFiber?: boolean
+  renderers?: Map<number, unknown>
+  inject?: (renderer: unknown) => number
+  onCommitFiberRoot?: (
+    rendererId: number,
+    root: unknown,
+    priorityLevel: unknown,
+    didError: boolean
+  ) => void
+}
+
+// Indexed, not a global augmentation: bippy (a react-grab dependency) already
+// declares this global with a narrower callback signature.
+type GlobalWithReactDevtoolsHook = Record<string, ReactDevtoolsCommitHook | undefined>
+
+function createCommitHookShim(): ReactDevtoolsCommitHook {
+  const renderers = new Map<number, unknown>()
+  return {
+    isDisabled: false,
+    supportsFiber: true,
+    renderers,
+    inject: (renderer) => {
+      const rendererId = renderers.size + 1
+      renderers.set(rendererId, renderer)
+      return rendererId
+    },
+    // Why a noop and not undefined: react-refresh captures this property and
+    // calls oldOnCommitFiberRoot.apply(this, arguments) with no typeof guard.
+    onCommitFiberRoot: () => {}
+  }
+}
+
+/** Returns the existing hook untouched, or installs a minimal one. */
+export function ensureReactDevtoolsCommitHook(): ReactDevtoolsCommitHook | undefined {
+  try {
+    const globalWithHook = globalThis as unknown as GlobalWithReactDevtoolsHook
+    const existing = globalWithHook.__REACT_DEVTOOLS_GLOBAL_HOOK__
+    if (existing) {
+      return existing
+    }
+    const hook = createCommitHookShim()
+    globalWithHook.__REACT_DEVTOOLS_GLOBAL_HOOK__ = hook
+    return hook
+  } catch {
+    // A renderer without a patchable global still has to boot.
+    return undefined
+  }
+}
+
+ensureReactDevtoolsCommitHook()
diff --git a/src/renderer/src/main.tsx b/src/renderer/src/main.tsx
index cff89bd6b38..825ff536b6f 100644
--- a/src/renderer/src/main.tsx
+++ b/src/renderer/src/main.tsx
@@ -1,3 +1,9 @@
+// Why first, and why the import-free shim: react-dom reads
+// __REACT_DEVTOOLS_GLOBAL_HOOK__ once at module evaluation, so the global has to
+// exist before it. The observer below only wraps a property react-dom re-reads
+// per commit, so its own import graph can evaluate whenever it likes.
+import './lib/react-devtools-commit-hook-shim'
+import './lib/react-commit-cascade-observer'
 import './assets/main.css'
 
 import { StrictMode } from 'react'
diff --git a/src/renderer/src/popout.tsx b/src/renderer/src/popout.tsx
index 00470df1374..3c84112d1a3 100644
--- a/src/renderer/src/popout.tsx
+++ b/src/renderer/src/popout.tsx
@@ -1,3 +1,9 @@
+// Why first, and why the import-free shim: react-dom reads
+// __REACT_DEVTOOLS_GLOBAL_HOOK__ once at module evaluation, so the global has to
+// exist before it. The observer below only wraps a property react-dom re-reads
+// per commit, so its own import graph can evaluate whenever it likes.
+import './lib/react-devtools-commit-hook-shim'
+import './lib/react-commit-cascade-observer'
 import './assets/main.css'
 
 import { StrictMode, useEffect } from 'react'
@@ -15,6 +21,7 @@ import { translate } from './i18n/i18n'
 import { useAppStore } from './store'
 import type { GlobalSettings } from '../../shared/global-settings-types'
 import { getOrCreateRendererRoot } from './lib/react-renderer-root'
+import { setReactCommitCascadeRendererSurface } from './lib/react-commit-cascade-telemetry'
 
 // Why: the pop-out window is a separate BrowserWindow with its own React root,
 // so it must run the same renderer bootstrap as main.tsx (crash diagnostics,
@@ -22,6 +29,7 @@ import { getOrCreateRendererRoot } from './lib/react-renderer-root'
 // window. It shares the preload/window.api but not the DOM or JS context.
 recordRendererCrashBreadcrumb('popout_bootstrap_started', { dev: import.meta.env.DEV })
 installRendererCrashDiagnostics('dashboard-popout')
+setReactCommitCascadeRendererSurface('dashboard-popout')
 
 function applyPopoutAppearance(settings: GlobalSettings | null): void {
   applyDocumentTheme(settings?.theme ?? 'system', { disableTransitions: false })
diff --git a/src/renderer/src/store/index.ts b/src/renderer/src/store/index.ts
index 3fd5b308585..35bc1845736 100644
--- a/src/renderer/src/store/index.ts
+++ b/src/renderer/src/store/index.ts
@@ -52,61 +52,64 @@ import {
   registerRuntimeHttpLinkBrowserOpener
 } from '@/lib/http-link-routing'
 import { installStoreListenerCensus } from './store-listener-census'
+import { withReactCommitCascadeWriteProbe } from './react-commit-cascade-write-probe'
 import {
   registerRendererMemoryProfileContributor,
   summarizeStateCollectionSizes
 } from '@/lib/renderer-memory-profile'
 import { estimateStateCollectionKB } from '@/lib/state-collection-byte-estimate'
 
-export const useAppStore = create<AppState>()((...a) => {
-  // Why: the inner api is only reachable here, before create() copies subscribe onto the hook.
-  installStoreListenerCensus(a[2])
-  return {
-    ...createRepoSlice(...a),
-    ...createSparsePresetsSlice(...a),
-    ...createWorktreeSlice(...a),
-    ...createTerminalSlice(...a),
-    ...createTabsSlice(...a),
-    ...createUISlice(...a),
-    ...createSettingsSlice(...a),
-    ...createKeybindingsSlice(...a),
-    ...createGitHubSlice(...a),
-    ...createHostedReviewSlice(...a),
-    ...createLinearSlice(...a),
-    ...createPreflightSlice(...a),
-    ...createJiraSlice(...a),
-    ...createEditorSlice(...a),
-    ...createStatsSlice(...a),
-    ...createMemorySlice(...a),
-    ...createWorkspaceSpaceSlice(...a),
-    ...createClaudeUsageSlice(...a),
-    ...createCodexUsageSlice(...a),
-    ...createOpenCodeUsageSlice(...a),
-    ...createBrowserSlice(...a),
-    ...createRateLimitSlice(...a),
-    ...createSshSlice(...a),
-    ...createRuntimeEnvironmentSshSlice(...a),
-    ...createAgentStatusSlice(...a),
-    ...createPaneForegroundAgentSlice(...a),
-    ...createDiffCommentsSlice(...a),
-    ...createDetectedAgentsSlice(...a),
-    ...createRuntimeDetectedAgentsSlice(...a),
-    ...createWorktreeNavHistorySlice(...a),
-    ...createDictationSlice(...a),
-    ...createWorkspaceCleanupSlice(...a),
-    ...createWorkspaceCleanupBrowseSlice(...a),
-    ...createRuntimeStatusSlice(...a),
-    ...createPullRequestGenerationSlice(...a),
-    ...createCommitMessageGenerationSlice(...a),
-    ...createPinnedTabCloseConfirmSlice(...a),
-    ...createRecentlyClosedTabsSlice(...a),
-    ...createOrcaProfilesSlice(...a),
-    ...createNewIssueDraftSlice(...a),
-    ...createTaskCreationDraftsSlice(...a),
-    ...createRemoteServerUpdatesSlice(...a),
-    ...createTerminalQuickCommandHostsSlice(...a)
-  }
-})
+export const useAppStore = create<AppState>()(
+  withReactCommitCascadeWriteProbe((...a) => {
+    // Why: the inner api is only reachable here, before create() copies subscribe onto the hook.
+    installStoreListenerCensus(a[2])
+    return {
+      ...createRepoSlice(...a),
+      ...createSparsePresetsSlice(...a),
+      ...createWorktreeSlice(...a),
+      ...createTerminalSlice(...a),
+      ...createTabsSlice(...a),
+      ...createUISlice(...a),
+      ...createSettingsSlice(...a),
+      ...createKeybindingsSlice(...a),
+      ...createGitHubSlice(...a),
+      ...createHostedReviewSlice(...a),
+      ...createLinearSlice(...a),
+      ...createPreflightSlice(...a),
+      ...createJiraSlice(...a),
+      ...createEditorSlice(...a),
+      ...createStatsSlice(...a),
+      ...createMemorySlice(...a),
+      ...createWorkspaceSpaceSlice(...a),
+      ...createClaudeUsageSlice(...a),
+      ...createCodexUsageSlice(...a),
+      ...createOpenCodeUsageSlice(...a),
+      ...createBrowserSlice(...a),
+      ...createRateLimitSlice(...a),
+      ...createSshSlice(...a),
+      ...createRuntimeEnvironmentSshSlice(...a),
+      ...createAgentStatusSlice(...a),
+      ...createPaneForegroundAgentSlice(...a),
+      ...createDiffCommentsSlice(...a),
+      ...createDetectedAgentsSlice(...a),
+      ...createRuntimeDetectedAgentsSlice(...a),
+      ...createWorktreeNavHistorySlice(...a),
+      ...createDictationSlice(...a),
+      ...createWorkspaceCleanupSlice(...a),
+      ...createWorkspaceCleanupBrowseSlice(...a),
+      ...createRuntimeStatusSlice(...a),
+      ...createPullRequestGenerationSlice(...a),
+      ...createCommitMessageGenerationSlice(...a),
+      ...createPinnedTabCloseConfirmSlice(...a),
+      ...createRecentlyClosedTabsSlice(...a),
+      ...createOrcaProfilesSlice(...a),
+      ...createNewIssueDraftSlice(...a),
+      ...createTaskCreationDraftsSlice(...a),
+      ...createRemoteServerUpdatesSlice(...a),
+      ...createTerminalQuickCommandHostsSlice(...a)
+    }
+  })
+)
 
 registerHttpLinkStoreAccessor(() => useAppStore.getState())
 registerRuntimeHttpLinkBrowserOpener(async (request) => {
diff --git a/src/renderer/src/store/react-commit-cascade-write-probe.test.ts b/src/renderer/src/store/react-commit-cascade-write-probe.test.ts
new file mode 100644
index 00000000000..0c18706e976
--- /dev/null
+++ b/src/renderer/src/store/react-commit-cascade-write-probe.test.ts
@@ -0,0 +1,73 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+import { create, type StoreApi, type UseBoundStore } from 'zustand'
+import { withReactCommitCascadeWriteProbe } from './react-commit-cascade-write-probe'
+
+const { probe, noteWrite } = vi.hoisted(() => ({
+  probe: { armed: false },
+  noteWrite: vi.fn()
+}))
+vi.mock('@/lib/react-commit-cascade-store-write-samples', () => ({
+  reactCommitCascadeWriteProbe: probe,
+  noteReactCommitCascadeStoreWrite: (boundary: object, partial: unknown) =>
+    noteWrite(boundary, partial)
+}))
+
+type ProbedState = { ticks: number; label?: string }
+
+function createProbedStore(): UseBoundStore<StoreApi<ProbedState>> {
+  return create<ProbedState>()(
+    withReactCommitCascadeWriteProbe<ProbedState>(() => ({ ticks: 0, label: 'initial' }))
+  )
+}
+
+beforeEach(() => {
+  probe.armed = false
+  noteWrite.mockReset()
+})
+
+describe('withReactCommitCascadeWriteProbe', () => {
+  // Why this matters most: this wraps every write the app makes. A diagnostic
+  // that throws here would drop the write and take app state with it.
+  it('lands the write even when the sampler throws', () => {
+    noteWrite.mockImplementation(() => {
+      throw new Error('sampler exploded')
+    })
+    const useProbedStore = createProbedStore()
+    probe.armed = true
+
+    expect(() => useProbedStore.setState({ ticks: 3 })).not.toThrow()
+    expect(useProbedStore.getState().ticks).toBe(3)
+  })
+
+  // Why asserted: create() copies api.setState onto the hook AFTER the creator
+  // runs, so a middleware that forgets this line leaves store.setState unprobed.
+  it('routes the api setState through the probe', () => {
+    const useProbedStore = createProbedStore()
+    probe.armed = true
+
+    useProbedStore.setState({ ticks: 1 })
+
+    expect(noteWrite).toHaveBeenCalledTimes(1)
+    // The boundary must be the wrapper itself, so V8 elides it from the sample.
+    expect(noteWrite.mock.calls[0]?.[0]).toBe(useProbedStore.setState)
+    expect(noteWrite.mock.calls[0]?.[1]).toEqual({ ticks: 1 })
+  })
+
+  it('passes the replace flag through', () => {
+    const useProbedStore = createProbedStore()
+    probe.armed = true
+
+    useProbedStore.setState({ ticks: 2 }, true)
+
+    expect(useProbedStore.getState()).toEqual({ ticks: 2 })
+  })
+
+  it('costs nothing but a flag read while unarmed', () => {
+    const useProbedStore = createProbedStore()
+
+    useProbedStore.setState({ ticks: 4 })
+
+    expect(noteWrite).not.toHaveBeenCalled()
+    expect(useProbedStore.getState().ticks).toBe(4)
+  })
+})
diff --git a/src/renderer/src/store/react-commit-cascade-write-probe.ts b/src/renderer/src/store/react-commit-cascade-write-probe.ts
new file mode 100644
index 00000000000..229c46dcb0c
--- /dev/null
+++ b/src/renderer/src/store/react-commit-cascade-write-probe.ts
@@ -0,0 +1,37 @@
+/**
+ * zustand middleware that samples store writes during a suspected React commit
+ * cascade, so the crash report names the code driving it.
+ *
+ * Why middleware and not a setState patch: create() hands slices the `set`
+ * closure built before `api` exists (zustand/esm/vanilla.mjs), so patching
+ * useAppStore.setState afterwards misses every slice-internal set() — and the
+ * slices are where the writes are. Wrapping the creator catches both, the same
+ * way store-listener-census has to reach the inner api to see hook subscribers.
+ *
+ * Cost when no cascade is suspected: one boolean field load per write.
+ */
+import {
+  noteReactCommitCascadeStoreWrite,
+  reactCommitCascadeWriteProbe
+} from '@/lib/react-commit-cascade-store-write-samples'
+import type { StateCreator } from 'zustand'
+
+export function withReactCommitCascadeWriteProbe<TState>(
+  createState: StateCreator<TState, [], []>
+): StateCreator<TState, [], []> {
+  return (set, get, api) => {
+    const wrapped = ((partial: unknown, replace?: unknown): void => {
+      if (reactCommitCascadeWriteProbe.armed) {
+        try {
+          noteReactCommitCascadeStoreWrite(wrapped, partial)
+        } catch {
+          // This is the app's universal write path: a diagnostic that throws here
+          // would drop the write itself.
+        }
+      }
+      ;(set as (nextPartial: unknown, nextReplace?: unknown) => void)(partial, replace)
+    }) as typeof set
+    api.setState = wrapped as typeof api.setState
+    return createState(wrapped, get, api)
+  }
+}
diff --git a/src/shared/react-update-depth-attribution.ts b/src/shared/react-update-depth-attribution.ts
index 7d79a1d36ad..98b45d478bd 100644
--- a/src/shared/react-update-depth-attribution.ts
+++ b/src/shared/react-update-depth-attribution.ts
@@ -4,6 +4,13 @@
  * next after the counter trips. The catching boundary is a bystander picked by commit order.
  */
 
+/**
+ * react-dom 19.2.x NESTED_UPDATE_LIMIT. getRootForUpdatedFiber throws once the
+ * root-global nested-update counter passes it. Every diagnostic that budgets
+ * commits against React's bail must derive its threshold from this one number.
+ */
+export const REACT_NESTED_UPDATE_LIMIT = 50
+
 export const UNRELIABLE_BOUNDARY_ATTRIBUTION = 'unreliable'
 export type CrashReportAttribution = typeof UNRELIABLE_BOUNDARY_ATTRIBUTION
 
diff --git a/src/shared/runtime-client-export-parity.test.ts b/src/shared/runtime-client-export-parity.test.ts
index ad3d9708eec..2b86d2e6e99 100644
--- a/src/shared/runtime-client-export-parity.test.ts
+++ b/src/shared/runtime-client-export-parity.test.ts
@@ -158,6 +158,7 @@ type RuntimeTypeInventory = [
   Runtime.RuntimeTerminalSplit,
   Runtime.RuntimeTerminalState,
   Runtime.RuntimeTerminalSummary,
+  Runtime.RuntimeTerminalUnavailableReason,
   Runtime.RuntimeTerminalVisualGroupNode,
   Runtime.RuntimeTerminalVisualLayout,
   Runtime.RuntimeTerminalVisualLayoutNode,
@@ -225,8 +226,11 @@ describe('runtime client public export parity', () => {
       'BROWSER_UNAVAILABLE_ERROR_CODE',
       'COMPUTER_ERROR_CODES',
       'HEADLESS_RUNTIME_WINDOW_ID',
+      'TERMINAL_PTY_DEGRADATION_CAPABILITY',
+      'TERMINAL_UNAVAILABLE_ERROR_CODE',
       'UNPUBLISHED_WORKTREE_PUBLICATION_EPOCH',
-      'browserUnavailableMessage'
+      'browserUnavailableMessage',
+      'terminalUnavailableMessage'
     ])
     expect(Object.keys(RemoteClient).sort()).toEqual([
       'RemoteRuntimeClientError',
diff --git a/tests/e2e/browser-tab.spec.ts b/tests/e2e/browser-tab.spec.ts
index 4988b76ccc2..00075b4af19 100644
--- a/tests/e2e/browser-tab.spec.ts
+++ b/tests/e2e/browser-tab.spec.ts
@@ -680,7 +680,7 @@ test.describe('Browser Tab', () => {
     }
   })
 
-  test('plain links stay current while explicit new-tab gestures activate Orca tabs', async ({
+  test('every new-tab link gesture activates an Orca tab and never a native window', async ({
     electronApp,
     orcaPage
   }) => {
@@ -698,23 +698,20 @@ test.describe('Browser Tab', () => {
       const baseWindowCount = await electronApp.evaluate(
         ({ BaseWindow }) => BaseWindow.getAllWindows().length
       )
-      const baseTabCount = await orcaPage.locator('[data-tab-id]').count()
-      await clickBrowserLink(orcaPage, sourceTab!.id, '#external-link')
-
+      // A plain target=_blank click is a new-tab request, in the main frame and in an iframe;
+      // the source tab must stay put rather than navigate away under it.
       const sourceTabLocator = orcaPage.locator(`[data-tab-id="${sourceTab!.id}"]`)
-      await expect(sourceTabLocator).toContainText('Linked destination', { timeout: 10_000 })
-      await expect(orcaPage.locator('[data-tab-id]')).toHaveCount(baseTabCount)
+      await clickBrowserLink(orcaPage, sourceTab!.id, '#external-link')
+      await expectBrowserTabActive(orcaPage, 'Linked destination')
+      await expect(sourceTabLocator).toContainText('Source page')
+      await switchToBrowserTab(orcaPage, worktreeId, sourceTab!.id)
 
-      await clickBrowserLink(orcaPage, sourceTab!.id, '#return-link')
-      await expect(sourceTabLocator).toContainText('Source page', { timeout: 10_000 })
       await clickBrowserLink(orcaPage, sourceTab!.id, '#frame-link', {
         frameSelector: '#link-frame'
       })
-      await expect(sourceTabLocator).toContainText('Frame destination', { timeout: 10_000 })
-      await expect(orcaPage.locator('[data-tab-id]')).toHaveCount(baseTabCount)
-
-      await clickBrowserLink(orcaPage, sourceTab!.id, '#return-link')
-      await expect(sourceTabLocator).toContainText('Source page', { timeout: 10_000 })
+      await expectBrowserTabActive(orcaPage, 'Frame destination')
+      await expect(sourceTabLocator).toContainText('Source page')
+      await switchToBrowserTab(orcaPage, worktreeId, sourceTab!.id)
 
       await clickBrowserLink(orcaPage, sourceTab!.id, '#frame-modifier-link', {
         frameSelector: '#link-frame',