diff --git a/config/scripts/mobile-web-page-routes.mjs b/config/scripts/mobile-web-page-routes.mjs
index 9d2f5a0a0d0..fb37c534cc1 100644
--- a/config/scripts/mobile-web-page-routes.mjs
+++ b/config/scripts/mobile-web-page-routes.mjs
@@ -1,14 +1,14 @@
 /**
  * The screens this desktop asks a phone's shell to render from the app bundle instead of natively.
  *
- * One entry per route proved on the web, and the list is deliberately short: a route that is not
- * here renders the native screen, which is the state every phone is already in. Adding one is a
- * product decision with a device proof behind it, not a consequence of the bundle happening to
- * contain the module.
+ * One entry per route proved on the web. A route that is not here is not served: older phone builds
+ * render their native screen, and current ones show the update screen. Adding one is a product
+ * decision with a device proof behind it, not a consequence of the bundle happening to contain the
+ * module; dropping one walls current phones on that screen.
  *
  * `grants` names what the screen needs the shell to do for it. A shell that implements fewer than
- * an entry names renders the native screen for that route, so writing a grant here before the app
- * that implements it ships costs nothing and breaks nothing.
+ * an entry names does not serve that route (older builds go native, current ones ask for an app
+ * update), so write a grant here only once the app that implements it ships.
  *
  * Declared here rather than in src/shared because the builder is the only thing that reads it: the
  * shape it must satisfy is MobileWebBundleRouteSchema, which the manifest write is checked against.
@@ -19,7 +19,7 @@
  * on a route that imports the seam and declares nothing.
  *
  * `optionalGrants` names what a screen is better with and complete without (ruling 37). A shell that
- * implements fewer than an entry's `grants` renders the native screen; a shell that implements fewer
+ * implements fewer than an entry's `grants` does not serve the route; a shell that implements fewer
  * than its `optionalGrants` renders the page and the page hides that one affordance. So the two
  * lanes are a product decision about the screen: a capability the screen cannot be shown without
  * goes above, and one an author can point at a complete screen without goes below.
diff --git a/mobile/app/h/[hostId]/agent-history/[worktreeId].tsx b/mobile/app/h/[hostId]/agent-history/[worktreeId].tsx
index 0288cbb393c..fe36c18f846 100644
--- a/mobile/app/h/[hostId]/agent-history/[worktreeId].tsx
+++ b/mobile/app/h/[hostId]/agent-history/[worktreeId].tsx
@@ -14,8 +14,7 @@ import { firstParam } from '../../../../src/navigation/route-param-reader'
  * Agent session history, from the desktop's bundle or from this app.
  *
  * The switch is `index.tsx`'s, for its reasons: the shell renders the page only for a route the
- * bundle lists with grants this app implements, and `fallback` is what a negotiation that said no
- * falls back to.
+ * bundle lists with grants this app implements, and walls the host otherwise.
  *
  * Two dynamic segments rather than one, so both are encoded: `useLocalSearchParams` answers the
  * decoded value, and a worktree id or a deep-linked host id carrying `/`, `?`, `#` or whitespace
@@ -70,11 +69,6 @@ export default withWorkspaceRoute(function MobileAgentSessionHistoryScreen() {
   // page has left. The key is what makes the change a remount, which disposes that bridge in the
   // commit, and the new session starts with no grants until its own `init`.
   return (
-    <MobileWebShellScreen
-      key={decision.route.pathname}
-      hostId={hostId}
-      route={decision.route}
-      fallback={panel}
-    />
+    <MobileWebShellScreen key={decision.route.pathname} hostId={hostId} route={decision.route} />
   )
 })
diff --git a/mobile/app/h/[hostId]/files/[worktreeId].tsx b/mobile/app/h/[hostId]/files/[worktreeId].tsx
index e4746dd6cc4..1bf2ded62dd 100644
--- a/mobile/app/h/[hostId]/files/[worktreeId].tsx
+++ b/mobile/app/h/[hostId]/files/[worktreeId].tsx
@@ -17,7 +17,7 @@ import { shellSwitchDecision } from '../../../../src/mobile-web-shell/shell-swit
  * The file explorer, from the desktop's bundle or from this app.
  *
  * The shell decides, not this switch: it renders the page only for a route the bundle lists with
- * grants this app implements, and answers `native-route` otherwise, which is what `fallback` is.
+ * grants this app implements, and walls the host otherwise.
  *
  * Encoded, not interpolated raw, for the reason `web.tsx` states: an id carrying `?`, `#` or
  * whitespace would build a pathname the page refuses and mount nothing.
@@ -67,7 +67,6 @@ export default withWorkspaceRoute(function MobileFileExplorerScreen() {
       key={shellScreenRouteKey(decision.route)}
       hostId={hostId}
       route={decision.route}
-      fallback={native}
     />
   )
 })
diff --git a/mobile/app/h/[hostId]/files/preview/[worktreeId].tsx b/mobile/app/h/[hostId]/files/preview/[worktreeId].tsx
index 8b3b6a8e872..5d1c804879d 100644
--- a/mobile/app/h/[hostId]/files/preview/[worktreeId].tsx
+++ b/mobile/app/h/[hostId]/files/preview/[worktreeId].tsx
@@ -78,7 +78,6 @@ export default withWorkspaceRoute(function MobileFilePreviewRoute() {
       key={shellScreenRouteKey(decision.route)}
       hostId={route.params.hostId}
       route={decision.route}
-      fallback={native}
     />
   )
 })
diff --git a/mobile/app/h/[hostId]/index.tsx b/mobile/app/h/[hostId]/index.tsx
index fa480192c72..1c47796a408 100644
--- a/mobile/app/h/[hostId]/index.tsx
+++ b/mobile/app/h/[hostId]/index.tsx
@@ -11,9 +11,8 @@ import { shellSwitchDecision } from '../../../src/mobile-web-shell/shell-switch-
  * The worktree list, from the desktop's bundle or from this app.
  *
  * The shell decides, not this switch: it renders the page only for a route the bundle lists with
- * grants this app implements, and answers `native-route` otherwise, which is what `fallback` is.
- * So the two ways to stay native are a build without the shell and a negotiation that said no, and
- * the second one covers every host whose desktop is older than the page.
+ * grants this app implements, and walls the host otherwise. So the one way to stay native is a build
+ * without the shell.
  *
  * Encoded, not interpolated raw, for the reason `web.tsx` states: a deep-linked host id carrying
  * `?`, `#` or whitespace would build a pathname the page refuses, and a refusal here is a failure
@@ -50,7 +49,6 @@ function HostListScreen() {
       key={hostId}
       hostId={hostId}
       route={decision.route}
-      fallback={native}
     />
   )
 }
diff --git a/mobile/app/h/[hostId]/review/[worktreeId].tsx b/mobile/app/h/[hostId]/review/[worktreeId].tsx
index 4372653e770..55c8cd8897d 100644
--- a/mobile/app/h/[hostId]/review/[worktreeId].tsx
+++ b/mobile/app/h/[hostId]/review/[worktreeId].tsx
@@ -19,7 +19,7 @@ import { shellSwitchDecision } from '../../../../src/mobile-web-shell/shell-swit
  * The files switch's shape. What is different here is that the native screen is a component rather
  * than the body of this file: `MobileDiffReviewRouteScreen` calls the review controller, and a
  * controller at this file's top level would subscribe behind the page as well as in front of it.
- * As an element it is built and not mounted, and only `fallback` ever mounts it.
+ * As an element it is built and not mounted, and only a native-shell build mounts it.
  *
  * `matchesRoutePattern` is segment-count exact with literal equality on the static segments, so
  * these five segments collide with nothing: the explorer's five carry `files`.
@@ -73,7 +73,6 @@ export default withWorkspaceRoute(function MobileDiffReviewScreen() {
       key={shellScreenRouteKey(decision.route)}
       hostId={hostId}
       route={decision.route}
-      fallback={native}
     />
   )
 })
diff --git a/mobile/app/h/[hostId]/session/[worktreeId].tsx b/mobile/app/h/[hostId]/session/[worktreeId].tsx
index 9d22d087519..903636e1550 100644
--- a/mobile/app/h/[hostId]/session/[worktreeId].tsx
+++ b/mobile/app/h/[hostId]/session/[worktreeId].tsx
@@ -20,7 +20,7 @@ import { shellSwitchDecision } from '../../../../src/mobile-web-shell/shell-swit
  * The review switch's shape, for its reasons: the native screen is `MobileSessionRouteScreen`
  * rather than the body of this file, because `useMobileSessionController` at this file's top level
  * would open the terminal, chat and tab subscriptions behind the page as well as in front of it.
- * As an element it is built and not mounted, and only `fallback` ever mounts it.
+ * As an element it is built and not mounted, and only a native-shell build mounts it.
  *
  * Four query params rather than the review's four, and one of them is not part of this screen's
  * identity: `paneKey`. A notification tap for a pane of the session already on screen is a tab
@@ -103,7 +103,6 @@ export default withWorkspaceRoute(function MobileSessionScreen() {
       key={shellScreenRouteKey({ pathname: decision.route.pathname, params: identity })}
       hostId={hostId}
       route={decision.route}
-      fallback={native}
       onRouteParamClear={erasePaneKey}
     />
   )
diff --git a/mobile/app/h/[hostId]/source-control/[worktreeId].tsx b/mobile/app/h/[hostId]/source-control/[worktreeId].tsx
index c8575a56b41..dca50eae101 100644
--- a/mobile/app/h/[hostId]/source-control/[worktreeId].tsx
+++ b/mobile/app/h/[hostId]/source-control/[worktreeId].tsx
@@ -17,8 +17,8 @@ import { shellSwitchDecision } from '../../../../src/mobile-web-shell/shell-swit
 /**
  * The source-control hub, from the desktop's bundle or from this app.
  *
- * The files switch's shape, for its reasons: the shell answers `native-route` for a route the
- * bundle does not list or this app's grants do not cover, and `fallback` is what that renders.
+ * The files switch's shape, for its reasons: the shell walls a route the bundle does not list or
+ * this app's grants do not cover.
  *
  * `pr` and `history` are not switched and never will be. Both are `Redirect`s into this route, and
  * a redirect inside the page would leave the session bound to a pathname the page has left; left
@@ -83,7 +83,6 @@ export default withWorkspaceRoute(function MobileSourceControlScreen() {
       key={shellScreenRouteKey(decision.route)}
       hostId={hostId}
       route={decision.route}
-      fallback={native}
     />
   )
 })
diff --git a/mobile/app/h/[hostId]/tasks.tsx b/mobile/app/h/[hostId]/tasks.tsx
index ce63e24405e..84ca55f8f8d 100644
--- a/mobile/app/h/[hostId]/tasks.tsx
+++ b/mobile/app/h/[hostId]/tasks.tsx
@@ -43,7 +43,6 @@ export default function MobileTasksRoute() {
       key={hostId}
       hostId={hostId}
       route={decision.route}
-      fallback={native}
     />
   )
 }
diff --git a/mobile/app/h/[hostId]/web.tsx b/mobile/app/h/[hostId]/web.tsx
index c805b823d0d..3e319ef3e50 100644
--- a/mobile/app/h/[hostId]/web.tsx
+++ b/mobile/app/h/[hostId]/web.tsx
@@ -25,10 +25,6 @@ export default function MobileWebShellRoute() {
   }
   // The screen the page stands in for. The document is served at `/`, which matches no route in
   // the tree the page carries, so this is the only thing that tells it which one to open.
-  //
-  // The fallback is a redirect rather than the native screen: this route exists only to open the
-  // page deliberately, so a bundle that does not list the worktree list has nothing to show here
-  // and the host route is where the list actually lives.
   return (
     <MobileWebShellScreen
       // Same reason as the agent-history route: a host holds the grants its session opened with,
@@ -36,7 +32,6 @@ export default function MobileWebShellRoute() {
       key={hostId}
       hostId={hostId}
       route={decision.route}
-      fallback={<Redirect href={`/h/${hostId}`} />}
     />
   )
 }
diff --git a/mobile/src/components/ProtocolBlockScreen.test.ts b/mobile/src/components/ProtocolBlockScreen.test.ts
index 7a33bfa28c8..6c88b085f32 100644
--- a/mobile/src/components/ProtocolBlockScreen.test.ts
+++ b/mobile/src/components/ProtocolBlockScreen.test.ts
@@ -101,13 +101,22 @@ describe('ProtocolBlockScreen', () => {
     expect(desktop).toContain('Open GitHub Releases')
   })
 
-  it('sends a host without a bundle to the desktop update', () => {
-    const output = render({ kind: 'blocked', reason: 'bundle-unavailable' })
-    expect(output).toContain('Update Orca on your computer')
-    expect(output).toContain(
-      'This paired desktop app does not include the mobile workspace yet. Update Orca on your computer, then try this host again.'
-    )
-    expect(primaryActionUrl()).toBe(RELEASES_URL)
+  it('tells a host without a bundle, or without this screen, the desktop is too old', () => {
+    for (const reason of ['bundle-unavailable', 'page-route-unlisted'] as const) {
+      const output = render({ kind: 'blocked', reason })
+      expect(output).toContain('Update Orca on your computer')
+      expect(output).toContain(
+        'This paired desktop app is too old for your current Orca Mobile app. Update Orca on your computer, then try this host again.'
+      )
+      expect(output).not.toContain('does not include the mobile workspace')
+      expect(primaryActionUrl()).toBe(RELEASES_URL)
+    }
+  })
+
+  it('sends a screen that needs a grant this app lacks to the mobile update', () => {
+    const output = render({ kind: 'blocked', reason: 'page-route-grant-missing' })
+    expect(output).toContain('Update Orca Mobile')
+    expect(output).toContain("This desktop's mobile workspace needs a newer Orca Mobile app.")
   })
 
   it('sends an unknown manifest schema to the mobile update', () => {
diff --git a/mobile/src/components/ProtocolBlockScreen.tsx b/mobile/src/components/ProtocolBlockScreen.tsx
index c6d7eba1e22..0de1bec3786 100644
--- a/mobile/src/components/ProtocolBlockScreen.tsx
+++ b/mobile/src/components/ProtocolBlockScreen.tsx
@@ -5,15 +5,18 @@ import { Platform, Pressable, StyleSheet, Text, View } from 'react-native'
 import { colors, radii, spacing, typography } from '../theme/mobile-theme'
 import type { CompatVerdict } from '../transport/protocol-compat'
 import type { MobileWebBundleCompatVerdict } from '../transport/mobile-web-bundle-compat'
+import type { PageRouteRefusalVerdict } from '../mobile-web-shell/page-route-policy'
 
 const RELEASES_URL = 'https://github.com/stablyai/orca/releases'
 const IOS_APP_STORE_URL = 'itms-apps://apps.apple.com/app/orca-ide/id6766130217'
 
-/** Every wall this screen renders: the protocol one and the bundle one. Both are terminal — there
- *  is no native workspace to fall back to, so the only way out is updating one of the two apps. */
+/** Every wall this screen renders: the protocol one, the bundle one and the page route one. All are
+ *  terminal — there is no native workspace to fall back to, so the only way out is updating one of
+ *  the two apps. */
 export type BlockedVerdict =
   | Extract<CompatVerdict, { kind: 'blocked' }>
   | Extract<MobileWebBundleCompatVerdict, { kind: 'blocked' }>
+  | PageRouteRefusalVerdict
 
 type Props = {
   verdict: BlockedVerdict
@@ -30,9 +33,11 @@ function blockRemedy(verdict: BlockedVerdict): BlockRemedy {
   switch (verdict.reason) {
     case 'mobile-too-old':
     case 'bundle-shell-too-old':
+    case 'page-route-grant-missing':
       return 'update-mobile'
     case 'desktop-too-old':
     case 'bundle-unavailable':
+    case 'page-route-unlisted':
       return 'update-desktop'
     case 'bundle-incompatible':
       return verdict.side === 'desktop' ? 'update-desktop' : 'refresh-bundle'
@@ -57,9 +62,6 @@ function blockBody(verdict: BlockedVerdict, remedy: BlockRemedy, storeName: stri
   if (verdict.reason === 'mobile-too-old') {
     return `This desktop needs a newer Orca Mobile app. Update Orca Mobile from ${storeName}, then try this host again.`
   }
-  if (verdict.reason === 'bundle-unavailable') {
-    return 'This paired desktop app does not include the mobile workspace yet. Update Orca on your computer, then try this host again.'
-  }
   if (remedy === 'update-mobile') {
     return `This desktop's mobile workspace needs a newer Orca Mobile app. Update Orca Mobile from ${storeName}, then try this host again.`
   }
diff --git a/mobile/src/diagnostics/mobile-web-shell-update-failure-copy.ts b/mobile/src/diagnostics/mobile-web-shell-update-failure-copy.ts
index 8894727013b..44d0f3d1a30 100644
--- a/mobile/src/diagnostics/mobile-web-shell-update-failure-copy.ts
+++ b/mobile/src/diagnostics/mobile-web-shell-update-failure-copy.ts
@@ -41,7 +41,9 @@ const WALL_COPY: Record<MobileWebShellUpdateFailureWall, string> = {
   'bundle-unavailable': 'the host has no workspace bundle',
   'bundle-shell-too-old': 'this app is too old for the saved bundle',
   'host-too-old-for-bundle': 'the host is too old for the saved bundle',
-  'bundle-too-old-for-host': 'the saved bundle is too old for the host'
+  'bundle-too-old-for-host': 'the saved bundle is too old for the host',
+  'page-route-unlisted': "the host's workspace does not include this screen",
+  'page-route-grant-missing': 'this screen needs a newer app'
 }
 
 function generation(buildId: string): string {
@@ -61,6 +63,8 @@ function outcomeCopy(failure: MobileWebShellUpdateFailure): string {
         : `Blocked: ${WALL_COPY[failure.wall]}.`
     case 'native-route':
       return 'Showed the native screen.'
+    case 'route-unavailable':
+      return 'Showed that the screen is not available.'
     case 'failed':
       return 'Showed the failure screen.'
     case 'waiting':
diff --git a/mobile/src/mobile-web-shell/MobileWebShellScreen.test.tsx b/mobile/src/mobile-web-shell/MobileWebShellScreen.test.tsx
index 69fa1bbaceb..1b7976259ed 100644
--- a/mobile/src/mobile-web-shell/MobileWebShellScreen.test.tsx
+++ b/mobile/src/mobile-web-shell/MobileWebShellScreen.test.tsx
@@ -30,7 +30,6 @@ import { bridgeId, clientFrame, createFakeRpcClient } from './bridge-host-test-f
 import {
   byName,
   trackRenderedScreen,
-  NativeFallback,
   SCREEN_BUILD_ID as BUILD_ID,
   SCREEN_DIRECTORY as DIRECTORY,
   hostParentOf,
@@ -282,8 +281,7 @@ describe('the hybrid shell screen', () => {
     const element = (next: Record<string, string>) =>
       createElement(MobileWebShellScreen, {
         hostId: 'host-1',
-        route: { pathname: '/h/host-1', params: next },
-        fallback: createElement(NativeFallback)
+        route: { pathname: '/h/host-1', params: next }
       })
     dependencies.state = readyState('session-one')
     const rendered: { tree: ReactTestRenderer | null } = { tree: null }
@@ -528,10 +526,10 @@ describe('the hybrid shell screen', () => {
   })
 })
 
-describe('the route the shell was not asked to render', () => {
-  it('hands the screen back to the caller rather than painting anything of its own', async () => {
-    const tree = await renderScreen({ kind: 'native-route' })
-    expect(tree.root.findAllByType(NativeFallback)).toHaveLength(1)
+describe('a route the page does not serve and no side can be blamed for', () => {
+  it('paints the unavailable screen itself, with no view and no spinner', async () => {
+    const tree = await renderScreen({ kind: 'route-unavailable' })
+    expect(textOf(tree)).toContain('This workspace screen is not available on this host.')
     expect(byName(tree, 'ShellViewProbe')).toEqual([])
     expect(byName(tree, 'ActivityIndicator')).toEqual([])
   })
diff --git a/mobile/src/mobile-web-shell/MobileWebShellScreen.tsx b/mobile/src/mobile-web-shell/MobileWebShellScreen.tsx
index ea58f9876e3..c5e6d1209d2 100644
--- a/mobile/src/mobile-web-shell/MobileWebShellScreen.tsx
+++ b/mobile/src/mobile-web-shell/MobileWebShellScreen.tsx
@@ -33,6 +33,7 @@ import { useMobileWebShellSession } from './use-mobile-web-shell-session'
 import { usePageHostSnapshot } from './use-page-host-snapshot'
 import { useReportedHostAreaServing } from './host-area-serving'
 import { isHostRouteOf } from './page-route-policy'
+import { PageRouteUnavailableScreen } from './PageRouteUnavailableScreen'
 import { useResponsiveLayout } from '../layout/responsive-layout'
 import { storageReadParamsSchema, type BridgeNativeVerb } from './bridge/bridge-native-verbs'
 import { SHELL_OPENING_LABEL, ShellPageCover, ShellWaitingFrame } from './ShellWaitingFrame'
@@ -134,12 +135,8 @@ export type MobileWebShellScreenProps = {
   hostId: string
   /** The screen this shell stands in for, which the page cannot derive from a document served at `/`. */
   route: BridgeInitRoute
-  /**
-   * What to render when the bundle does not list this route, or lists it needing a grant this app
-   * does not implement. Required, because every caller has a native screen behind it: that is what
-   * the negotiation falls back to, and a shell with nothing behind it would paint a blank instead.
-   */
-  fallback: ReactNode
+  /** False for the catch-all, whose pathnames have no screen in this app. */
+  appNamesRoute?: boolean
   /**
    * The page applied a one-shot route param and asks for it to be erased (ruling 34), naming what
    * it applied. Only a caller that put one on the route ever hears this, and the comparison is
@@ -159,7 +156,7 @@ export type MobileWebShellScreenProps = {
 export function MobileWebShellScreen({
   hostId,
   route,
-  fallback,
+  appNamesRoute,
   onRouteParamClear,
   runtime
 }: MobileWebShellScreenProps) {
@@ -190,6 +187,7 @@ export function MobileWebShellScreen({
     hostId,
     routePathname: route.pathname,
     wide: isWideLayout,
+    appNamesRoute,
     runtime
   })
   // Full screen from the download on, as on a phone; while checking, nobody knows the page owns it.
@@ -352,8 +350,8 @@ export function MobileWebShellScreen({
     }
   }, [hostId, unreadable])
 
-  if (state.kind === 'native-route') {
-    return fallback
+  if (state.kind === 'route-unavailable') {
+    return <PageRouteUnavailableScreen hostId={hostId} />
   }
   if (state.kind === 'wall') {
     return <ProtocolBlockScreen verdict={state.verdict} />
diff --git a/mobile/src/mobile-web-shell/PageRouteUnavailableScreen.tsx b/mobile/src/mobile-web-shell/PageRouteUnavailableScreen.tsx
index 615435ae3e1..e42ad777b00 100644
--- a/mobile/src/mobile-web-shell/PageRouteUnavailableScreen.tsx
+++ b/mobile/src/mobile-web-shell/PageRouteUnavailableScreen.tsx
@@ -6,9 +6,9 @@ import { colors, radii, spacing, typography } from '../theme/mobile-theme'
 /**
  * What a host-scoped pathname nothing can paint lands on.
  *
- * The catch-all route is the one switch with no native screen behind it, so its `fallback` cannot
- * be a panel: a pathname the bundle does not list, or lists needing a grant this app lacks, has no
- * renderer on either side. This replaces expo-router's Unmatched there, which says "Unmatched
+ * The catch-all route is the one switch with no native screen behind it, so its refusal cannot be
+ * a panel: a pathname the bundle does not serve has no renderer on either side. The shell shows it
+ * too when it cannot say which app is behind (`route-unavailable`). This replaces expo-router's Unmatched there, which says "Unmatched
  * Route" and offers a sitemap link that means nothing to someone holding a stale app.
  *
  * `replace` and not `push`: this screen is a dead end, so leaving it must not leave it behind to
diff --git a/mobile/src/mobile-web-shell/catch-all-page-route-states.test.tsx b/mobile/src/mobile-web-shell/catch-all-page-route-states.test.tsx
index 91d3add4383..f0d2bc967e2 100644
--- a/mobile/src/mobile-web-shell/catch-all-page-route-states.test.tsx
+++ b/mobile/src/mobile-web-shell/catch-all-page-route-states.test.tsx
@@ -4,7 +4,7 @@
  *
  * `catch-all-page-route.test.tsx` mocks both and reads what the switch hands over; this drives the
  * other half — the session reducer is the only thing stubbed, so the screen the user sees for
- * `native-route`, `offline`, `checking` and the wall is the one this app ships.
+ * `route-unavailable`, `offline`, `checking` and the wall is the one this app ships.
  */
 import { createElement } from 'react'
 import { act, create, type ReactTestInstance, type ReactTestRenderer } from 'react-test-renderer'
@@ -26,7 +26,7 @@ const SNAPSHOT = vi.hoisted(() => ({
 const dependencies = vi.hoisted((): Dependencies => {
   Object.assign(globalThis, { __DEV__: true })
   return {
-    state: { kind: 'native-route' },
+    state: { kind: 'route-unavailable' },
     params: {},
     replace: vi.fn(),
     push: vi.fn()
@@ -192,16 +192,22 @@ afterEach(() => {
 })
 
 describe('the screen the catch-all paints for each shell state', () => {
-  it('renders the refusal through the shell fallback, not beside it', async () => {
-    // `native-route` is the only state that reaches `fallback`, so this is what pins that binding:
-    // with `fallback={null}` the shell paints nothing and the control below is gone.
-    const tree = await renderRoute({ kind: 'native-route' })
+  it('shows the refusal when the shell finds the page does not serve the pathname', async () => {
+    const tree = await renderRoute({ kind: 'route-unavailable' })
+    expect(textOf(tree)).toContain('This workspace screen is not available on this host.')
+    expect(textOf(tree)).not.toContain('too old')
+    expect(backControl(tree)).toBeDefined()
+  })
+
+  it('shows the same refusal on a native-shell build, with no shell mounted', async () => {
+    vi.stubEnv('EXPO_PUBLIC_MOBILE_SHELL', '')
+    const tree = await renderRoute({ kind: 'checking' })
     expect(textOf(tree)).toContain('This workspace screen is not available on this host.')
     expect(backControl(tree)).toBeDefined()
   })
 
   it('leaves the dead end rather than stacking it, on the encoded host route', async () => {
-    const tree = await renderRoute({ kind: 'native-route' })
+    const tree = await renderRoute({ kind: 'route-unavailable' })
     await act(async () => {
       backControl(tree).props.onPress()
     })
@@ -219,7 +225,7 @@ describe('the screen the catch-all paints for each shell state', () => {
     for (const hostId of ['a?b', 'a#b', 'a b', 'a/b', 'a\\b']) {
       dependencies.params = { hostId, page: ['settings'] }
       dependencies.replace.mockClear()
-      const tree = await renderRoute({ kind: 'native-route' })
+      const tree = await renderRoute({ kind: 'route-unavailable' })
       await act(async () => {
         backControl(tree).props.onPress()
       })
@@ -240,7 +246,7 @@ describe('the screen the catch-all paints for each shell state', () => {
    */
   it('goes to the app root when there is no host to go back to', async () => {
     dependencies.params = { page: ['settings'] }
-    const tree = await renderRoute({ kind: 'native-route' })
+    const tree = await renderRoute({ kind: 'route-unavailable' })
     await act(async () => {
       backControl(tree, ROOT_LABEL).props.onPress()
     })
diff --git a/mobile/src/mobile-web-shell/catch-all-page-route.test.tsx b/mobile/src/mobile-web-shell/catch-all-page-route.test.tsx
index 773d6784031..7354fff0f30 100644
--- a/mobile/src/mobile-web-shell/catch-all-page-route.test.tsx
+++ b/mobile/src/mobile-web-shell/catch-all-page-route.test.tsx
@@ -50,10 +50,17 @@ vi.mock('./MobileWebShellScreen', () => ({
 }))
 
 import { BRIDGE_MAX_ROUTE_PARAMS, BRIDGE_ROUTE_PATHNAME_PATTERN } from './bridge/bridge-caps'
-import { grantsForRoute, pageRendersRoute, routeViewOf } from './page-route-policy'
+import { grantsForRoute, matchesRoutePattern, routeViewOf } from './page-route-policy'
 import { shellScreenRouteKey } from './shell-screen-route'
 import MobileWebPageCatchAllScreen from './catch-all-page-route'
 
+/** Whether a narrow session on `pathname` would be served the page under `routes`. */
+function servesRoute(routes: Parameters<typeof routeViewOf>[0], pathname: string): boolean {
+  return routeViewOf(routes, pathname).pageRoutes.some((pattern) =>
+    matchesRoutePattern(pathname, pattern)
+  )
+}
+
 async function render(): Promise<void> {
   await act(async () => {
     create(createElement(MobileWebPageCatchAllScreen))
@@ -209,8 +216,8 @@ const FUTURE_MANIFEST = [
 
 describe('the gate a catch-all pathname meets', () => {
   it('renders a manifest route this app has no route file for', () => {
-    expect(pageRendersRoute(FUTURE_MANIFEST, '/h/H1/insights')).toBe(true)
-    expect(pageRendersRoute(FUTURE_MANIFEST, '/h/H1/insights/W1')).toBe(true)
+    expect(servesRoute(FUTURE_MANIFEST, '/h/H1/insights')).toBe(true)
+    expect(servesRoute(FUTURE_MANIFEST, '/h/H1/insights/W1')).toBe(true)
     expect(grantsForRoute(FUTURE_MANIFEST, '/h/H1/insights/W1')).toEqual([
       'navigate',
       'storage',
@@ -220,12 +227,12 @@ describe('the gate a catch-all pathname meets', () => {
   })
 
   it('refuses a pathname the manifest does not list', () => {
-    expect(pageRendersRoute(FUTURE_MANIFEST, '/h/H1/settings')).toBe(false)
+    expect(servesRoute(FUTURE_MANIFEST, '/h/H1/settings')).toBe(false)
     expect(grantsForRoute(FUTURE_MANIFEST, '/h/H1/settings')).toEqual([])
   })
 
   it('refuses a listed route needing a grant this app does not implement', () => {
-    expect(pageRendersRoute(FUTURE_MANIFEST, '/h/H1/future')).toBe(false)
+    expect(servesRoute(FUTURE_MANIFEST, '/h/H1/future')).toBe(false)
     expect(routeViewOf(FUTURE_MANIFEST, '/h/H1/future').pageRoutes).toEqual([
       '/h/[hostId]/insights',
       '/h/[hostId]/insights/[worktreeId]'
diff --git a/mobile/src/mobile-web-shell/catch-all-page-route.tsx b/mobile/src/mobile-web-shell/catch-all-page-route.tsx
index bfc56eee68a..8118f1aa3c1 100644
--- a/mobile/src/mobile-web-shell/catch-all-page-route.tsx
+++ b/mobile/src/mobile-web-shell/catch-all-page-route.tsx
@@ -9,9 +9,10 @@ import { shellSwitchDecision } from './shell-switch-decision'
  * Any host-scoped pathname this app has no route file for, handed to the shell.
  *
  * The only switch with no native screen behind it: a screen registered after this app shipped is in
- * the desktop's bundle and nowhere else, so `fallback` is a refusal rather than a panel. The
- * manifest still decides — the session reducer answers `native-route` for a pathname the bundle
- * does not list, and that answer lands on the same refusal.
+ * the desktop's bundle and nowhere else, so a native-shell build gets a refusal rather than a panel.
+ * `appNamesRoute={false}` gives a pathname the bundle does not serve that same refusal from the
+ * shell: with no screen for it here, nothing says the desktop is the one behind (a stale deep link
+ * looks the same).
  *
  * Least specific of everything in its directory, so it takes only what expo-router would otherwise
  * send to Unmatched; every route that has a file keeps it, on both platforms.
@@ -69,18 +70,16 @@ export default function MobileWebPageCatchAllScreen() {
   // with, so a screen reused across a route change would authorise frames under grants the page has
   // left behind.
   //
-  // `fallback` is the refusal and only the refusal. `native-route` is the shell saying this build
-  // cannot serve this pathname, which is the one question the refusal answers; the states it does
-  // not reach answer different ones, and each is true for a screen only the page has. Offline means
-  // the bundle that would serve it cannot be fetched, `checking` means the answer is not in yet,
-  // and the wall means no page can be served at all. Absorbing those would tell someone with no
-  // connection that the screen does not exist. `catch-all-page-route-states.test.tsx` drives them.
+  // The shell's own states, not the refusal: offline means the bundle that would serve it cannot be
+  // fetched, `checking` means the answer is not in yet, and a wall means no page can be served at
+  // all. Absorbing those would tell someone with no connection that the screen does not exist.
+  // `catch-all-page-route-states.test.tsx` drives them.
   return (
     <MobileWebShellScreen
       key={shellScreenRouteKey(decision.route)}
       hostId={hostId}
       route={decision.route}
-      fallback={refusal}
+      appNamesRoute={false}
     />
   )
 }
diff --git a/mobile/src/mobile-web-shell/host-area-layout-class-change.test.tsx b/mobile/src/mobile-web-shell/host-area-layout-class-change.test.tsx
index ab2ad9c8021..964a06d88c5 100644
--- a/mobile/src/mobile-web-shell/host-area-layout-class-change.test.tsx
+++ b/mobile/src/mobile-web-shell/host-area-layout-class-change.test.tsx
@@ -3,7 +3,8 @@
  *
  * Off a wide layout a detail route is served as before; on one it is served only by a page that
  * declares `canOwnHostArea`, because an older page would draw its own sidebar beside the native
- * one. The session rebuilds on the change, so the page's in-page stack does not survive it.
+ * one, so an older one is walled. The session rebuilds on the change, so the page's in-page stack
+ * does not survive it.
  */
 import { act, create, type ReactTestRenderer } from 'react-test-renderer'
 import { describe, expect, it, vi } from 'vitest'
@@ -156,9 +157,9 @@ describe('a detail session across a layout-class change', () => {
     })
   })
 
-  it('goes native on a wide layout under a page without the declaration, and back', async () => {
+  it('walls on a wide layout under a page without the declaration, and serves again after', async () => {
     expect(await settledKinds(false, [false, true, false])).toEqual({
-      kinds: ['ready session-1', 'native-route', 'ready session-2'],
+      kinds: ['ready session-1', 'wall', 'ready session-2'],
       manifestReads: 3
     })
   })
diff --git a/mobile/src/mobile-web-shell/host-area-leave-session.test.tsx b/mobile/src/mobile-web-shell/host-area-leave-session.test.tsx
index 06b0814025a..eddf863c588 100644
--- a/mobile/src/mobile-web-shell/host-area-leave-session.test.tsx
+++ b/mobile/src/mobile-web-shell/host-area-leave-session.test.tsx
@@ -89,8 +89,7 @@ async function hopFromSession(viewport: { width: number; height: number }, href:
     mounted.tree = create(
       createElement(MobileWebShellScreen, {
         hostId: 'host-1',
-        route: { pathname: DETAIL },
-        fallback: null
+        route: { pathname: DETAIL }
       })
     )
   })
diff --git a/mobile/src/mobile-web-shell/host-area-session.test.ts b/mobile/src/mobile-web-shell/host-area-session.test.ts
index 34d613a93dc..c4a8a08e465 100644
--- a/mobile/src/mobile-web-shell/host-area-session.test.ts
+++ b/mobile/src/mobile-web-shell/host-area-session.test.ts
@@ -131,11 +131,16 @@ describe('the wide host-area session', () => {
     })
   })
 
-  it('stays native for no page and for a page without the declaration, host route or detail', () => {
+  it('walls the desktop for no page and for a page without the declaration, host route or detail', () => {
     for (const pathname of [HOST_ROUTE, '/h/host-1/session/wt-1']) {
-      for (const routes of [null, desktopRoutes(false)]) {
-        expect(wideStateFor(routes, pathname).state.kind).toBe('native-route')
-      }
+      expect(wideStateFor(null, pathname).state).toEqual({
+        kind: 'wall',
+        verdict: { kind: 'blocked', reason: 'bundle-unavailable' }
+      })
+      expect(wideStateFor(desktopRoutes(false), pathname).state).toEqual({
+        kind: 'wall',
+        verdict: { kind: 'blocked', reason: 'page-route-unlisted' }
+      })
     }
   })
 
diff --git a/mobile/src/mobile-web-shell/host-area-sidebar-matrix.test.tsx b/mobile/src/mobile-web-shell/host-area-sidebar-matrix.test.tsx
index 77c0eb6573f..ef3211e5889 100644
--- a/mobile/src/mobile-web-shell/host-area-sidebar-matrix.test.tsx
+++ b/mobile/src/mobile-web-shell/host-area-sidebar-matrix.test.tsx
@@ -118,7 +118,7 @@ vi.mock('../navigation/host-stack', async () => {
       return (
         <serving.HostAreaServingContext.Provider value={recorded}>
           {env.hostSession === null ? null : (
-            <MobileWebShellScreen hostId="host-1" route={{ pathname: HOST }} fallback={null} />
+            <MobileWebShellScreen hostId="host-1" route={{ pathname: HOST }} />
           )}
         </serving.HostAreaServingContext.Provider>
       )
diff --git a/mobile/src/mobile-web-shell/host-area-two-hosts.test.tsx b/mobile/src/mobile-web-shell/host-area-two-hosts.test.tsx
index b2a281153eb..ab3b64de09e 100644
--- a/mobile/src/mobile-web-shell/host-area-two-hosts.test.tsx
+++ b/mobile/src/mobile-web-shell/host-area-two-hosts.test.tsx
@@ -84,11 +84,7 @@ vi.mock('../navigation/host-stack', async () => {
     HostStack: () =>
       stack.hosts.map((hostId, index) => (
         <stack.Focused.Provider key={hostId} value={index === stack.hosts.length - 1}>
-          <MobileWebShellScreen
-            hostId={hostId}
-            route={{ pathname: `/h/${hostId}` }}
-            fallback={null}
-          />
+          <MobileWebShellScreen hostId={hostId} route={{ pathname: `/h/${hostId}` }} />
         </stack.Focused.Provider>
       ))
   }
diff --git a/mobile/src/mobile-web-shell/mobile-web-shell-cached-generation.ts b/mobile/src/mobile-web-shell/mobile-web-shell-cached-generation.ts
index 1902f594d91..bde3485b6c8 100644
--- a/mobile/src/mobile-web-shell/mobile-web-shell-cached-generation.ts
+++ b/mobile/src/mobile-web-shell/mobile-web-shell-cached-generation.ts
@@ -2,9 +2,9 @@ import type {
   CachedGeneration,
   MobileWebShellBlockedVerdict,
   MobileWebShellSession,
+  MobileWebShellSessionState,
   MobileWebShellStep
 } from './mobile-web-shell-session-contract'
-import { NATIVE_ROUTE } from './mobile-web-shell-gates'
 import { matchesRoutePattern, routeViewOf } from './page-route-policy'
 import { step } from './mobile-web-shell-session-step'
 
@@ -34,32 +34,32 @@ export function openCached(
 }
 
 /**
- * Opens a generation already on disk under its own route list, or leaves the route native when that
- * list does not carry it. The only judge available when the newer manifest is absent or refused:
+ * Opens a generation already on disk under its own route list, or answers `unclaimed` when that list
+ * does not carry it. The only judge available when the newer manifest is absent or refused:
  * opening under a bundle this shell is not running would grant the page what other bytes declared.
  *
- * The route question comes first and `wall` is asked only on the served branch, the order
- * `onManifestRead` takes: a route this bundle never claimed is not a screen to refuse, and a
- * generation cached before routes were listed claims none at all. `patch` belongs to either answer;
- * `served` is what only an opened page gets, so the native one carries no notice about an update
- * for a screen it is not showing.
+ * `unclaimed` is the caller's because these bytes say nothing about what the host serves now: the
+ * screen the newer manifest would have answered with, never a version wall. `wall` is asked only on
+ * the served branch, since it judges bytes that are about to be shown. `patch` belongs to either
+ * answer; `served` is what only an opened page gets.
  */
 export function openByOwnRoutes(
   session: MobileWebShellSession,
   generation: CachedGeneration,
   options: {
+    unclaimed: MobileWebShellSessionState
     patch?: Partial<MobileWebShellSession>
     served?: Partial<MobileWebShellSession>
     wall?: MobileWebShellBlockedVerdict | null
-  } = {}
+  }
 ): MobileWebShellStep {
-  const { patch = {}, served = {}, wall = null } = options
+  const { unclaimed, patch = {}, served = {}, wall = null } = options
   const view = {
     ...routeViewOf(generation.routes, session.routePathname, session.wide),
     routes: generation.routes
   }
   if (!rendersRoute(view.pageRoutes, session.routePathname)) {
-    return step(session, { ...patch, ...view, state: NATIVE_ROUTE })
+    return step(session, { ...patch, ...view, state: unclaimed })
   }
   if (wall !== null) {
     return step(session, { ...patch, ...view, state: { kind: 'wall', verdict: wall } })
diff --git a/mobile/src/mobile-web-shell/mobile-web-shell-gates.ts b/mobile/src/mobile-web-shell/mobile-web-shell-gates.ts
index 26e50574309..63a90d4d939 100644
--- a/mobile/src/mobile-web-shell/mobile-web-shell-gates.ts
+++ b/mobile/src/mobile-web-shell/mobile-web-shell-gates.ts
@@ -11,7 +11,7 @@ import type {
 /** Shared because several transitions reach each of them, and two objects that are equal but not
  *  identical are two renders where the reducer meant one. */
 export const CHECKING: MobileWebShellSessionState = { kind: 'checking' }
-export const NATIVE_ROUTE: MobileWebShellSessionState = { kind: 'native-route' }
+export const ROUTE_UNAVAILABLE: MobileWebShellSessionState = { kind: 'route-unavailable' }
 
 /**
  * Whether a gates change may start or restart the flow.
@@ -47,9 +47,6 @@ export type MobileWebShellGateVerdict =
   | { readonly kind: 'pending' }
   | { readonly kind: 'offline' }
   | { readonly kind: 'status-unreadable' }
-  /** The desktop ships no bundle, so it lists no page route and this one is the native screen's.
-   *  Not a wall: a wall says the workspace cannot be opened, and here there is none to open. */
-  | { readonly kind: 'native-route' }
   | { readonly kind: 'wall'; readonly verdict: MobileWebShellBlockedVerdict }
   | { readonly kind: 'open' }
 
@@ -75,14 +72,7 @@ export function gateVerdict(gates: MobileWebShellGates): MobileWebShellGateVerdi
     hostStatus: gates.hostStatus,
     manifest: null
   })
-  if (verdict.kind !== 'blocked') {
-    return { kind: 'open' }
-  }
-  // `bundle-unavailable` is the only verdict reachable with no manifest, and it is the one block
-  // that is not a wall: a desktop with no bundle declares no page route, so every route is native.
-  return verdict.reason === 'bundle-unavailable'
-    ? { kind: 'native-route' }
-    : { kind: 'wall', verdict }
+  return verdict.kind === 'blocked' ? { kind: 'wall', verdict } : { kind: 'open' }
 }
 
 /**
@@ -101,8 +91,6 @@ export function gateState(
   retriedOnce: boolean
 ): MobileWebShellSessionState | null {
   switch (verdict.kind) {
-    case 'native-route':
-      return NATIVE_ROUTE
     case 'wall':
       return { kind: 'wall', verdict: verdict.verdict }
     case 'status-unreadable':
diff --git a/mobile/src/mobile-web-shell/mobile-web-shell-page-route-wall.test.ts b/mobile/src/mobile-web-shell/mobile-web-shell-page-route-wall.test.ts
new file mode 100644
index 00000000000..0dcbc016aac
--- /dev/null
+++ b/mobile/src/mobile-web-shell/mobile-web-shell-page-route-wall.test.ts
@@ -0,0 +1,96 @@
+import { describe, expect, it } from 'vitest'
+import {
+  MANIFEST,
+  afterCacheRead,
+  createMobileWebShellSession,
+  gates,
+  run
+} from './mobile-web-shell-session-test-fixtures'
+
+const UNLISTED_WALL = { kind: 'wall', verdict: { kind: 'blocked', reason: 'page-route-unlisted' } }
+
+describe('a manifest whose page does not serve this route walls instead of going native', () => {
+  it('walls the desktop as too old for a route the bundle does not list', () => {
+    const step = run(afterCacheRead(null).session, {
+      type: 'manifest-read',
+      manifest: { ...MANIFEST, routes: [{ pathname: '/h/[hostId]/tasks', grants: [] }] }
+    })
+    expect(step.session.state).toEqual(UNLISTED_WALL)
+    expect(step.effects).toEqual([])
+  })
+
+  it('walls this app as too old for a route listed with a grant it does not implement', () => {
+    const step = run(afterCacheRead(null).session, {
+      type: 'manifest-read',
+      manifest: {
+        ...MANIFEST,
+        routes: [{ pathname: '/h/[hostId]', grants: ['navigate', 'teleport'] }]
+      }
+    })
+    expect(step.session.state).toEqual({
+      kind: 'wall',
+      verdict: { kind: 'blocked', reason: 'page-route-grant-missing' }
+    })
+    expect(step.effects).toEqual([])
+  })
+
+  it('walls the desktop as too old when it predates the routes field itself', () => {
+    const step = run(afterCacheRead(null).session, {
+      type: 'manifest-read',
+      manifest: { ...MANIFEST, routes: undefined }
+    })
+    expect(step.session.state).toEqual(UNLISTED_WALL)
+  })
+
+  it('answers the compat wall before the route, since an unreadable schema hides the route list', () => {
+    const step = run(afterCacheRead(null).session, {
+      type: 'manifest-read',
+      manifest: { ...MANIFEST, schemaVersion: 99, routes: [] }
+    })
+    expect(step.session.state).toEqual({
+      kind: 'wall',
+      verdict: { kind: 'blocked', reason: 'bundle-shell-too-old', schemaVersion: 99 }
+    })
+  })
+
+  it('walls a page below the floor as it is, whatever routes it lists', () => {
+    const step = run(afterCacheRead(null).session, {
+      type: 'manifest-read',
+      manifest: { ...MANIFEST, pageVersion: 0, routes: [] }
+    })
+    expect(step.session.state).toMatchObject({
+      kind: 'wall',
+      verdict: { reason: 'bundle-incompatible', side: 'desktop', pageVersion: 0 }
+    })
+  })
+
+  it('says the screen is unavailable, not the desktop too old, for a pathname this app has no screen for', () => {
+    const opened = run(
+      createMobileWebShellSession('/h/host-1/insights', false, false),
+      { type: 'gates-changed', gates: gates() },
+      { type: 'cache-read', generation: null }
+    )
+    const step = run(opened.session, { type: 'manifest-read', manifest: MANIFEST })
+    expect(step.session.state).toEqual({ kind: 'route-unavailable' })
+  })
+
+  it('says the screen is unavailable when the manifest carries a pattern this shell cannot read', () => {
+    const step = run(afterCacheRead(null).session, {
+      type: 'manifest-read',
+      manifest: { ...MANIFEST, routes: [{ pathname: '/h/[...a]/[...b]', grants: [] }] }
+    })
+    expect(step.session.state).toEqual({ kind: 'route-unavailable' })
+  })
+
+  it('keeps that answer across a layout flip, which rebuilds the session', () => {
+    const opened = run(
+      createMobileWebShellSession('/h/host-1/insights', false, false),
+      { type: 'gates-changed', gates: gates() },
+      { type: 'cache-read', generation: null },
+      { type: 'manifest-read', manifest: MANIFEST }
+    )
+    expect(run(opened.session, { type: 'layout-changed', wide: true }).session.appNamesRoute).toBe(
+      false
+    )
+  })
+})
diff --git a/mobile/src/mobile-web-shell/mobile-web-shell-refused-update-decision.test.ts b/mobile/src/mobile-web-shell/mobile-web-shell-refused-update-decision.test.ts
index fddcb2962ac..46787c52261 100644
--- a/mobile/src/mobile-web-shell/mobile-web-shell-refused-update-decision.test.ts
+++ b/mobile/src/mobile-web-shell/mobile-web-shell-refused-update-decision.test.ts
@@ -11,6 +11,8 @@ import {
   withoutRecord
 } from './mobile-web-shell-session-test-fixtures'
 
+const DOWNLOAD_FAILED = { kind: 'failed', reason: 'download-failed', retriedOnce: false }
+
 /**
  * The host is up, it serves a generation this shell could not take, and one that works is on disk.
  *
@@ -126,21 +128,20 @@ describe('an update this shell refused falls back to the generation that already
     expect(refused().session.updateNotice).toBe('update-failed')
   })
 
-  it('leaves the route native when the cached bundle never carried it, before any wall', () => {
-    // The order `onManifestRead` takes, and the one the compat wall broke: a route this bundle
-    // does not serve is not a screen to refuse. Below the host's floor as well, so the only thing
-    // that can produce `native-route` here is the route question being asked first.
+  it('shows the download failure when the cached bundle never carried the route, before any wall', () => {
+    // The newer manifest claimed the route, so the cache lacking it is this download's failure.
+    // Below the host's floor as well: the wall judges bytes about to be shown, and these are not.
     const fetching = run(afterCacheRead({ ...CACHED_BELOW_HOST_FLOOR, routes: [] }).session, {
       type: 'manifest-read',
       manifest: NEWER
     })
     const step = run(fetching.session, { type: 'download-failed', cause: BUNDLE_REFUSED })
-    expect(step.session.state).toEqual({ kind: 'native-route' })
+    expect(step.session.state).toEqual(DOWNLOAD_FAILED)
     expect(step.session.updateNotice).toBeNull()
     expect(withoutRecord(step.effects)).toEqual([])
   })
 
-  it('leaves it native for a generation from before routes were listed at all', () => {
+  it('shows the download failure for a generation from before routes were listed at all', () => {
     // `routes: undefined` is every generation cached by a desktop older than the field. It claims
     // no route, so it cannot claim this one, and it must not be walled for that.
     const fetching = run(
@@ -148,7 +149,7 @@ describe('an update this shell refused falls back to the generation that already
       { type: 'manifest-read', manifest: NEWER }
     )
     const step = run(fetching.session, { type: 'download-failed', cause: BUNDLE_REFUSED })
-    expect(step.session.state).toEqual({ kind: 'native-route' })
+    expect(step.session.state).toEqual(DOWNLOAD_FAILED)
   })
 })
 
@@ -171,11 +172,13 @@ describe('the fallback answers each gate verdict the way the rest of the shell d
     return run(moved.session, { type: 'download-failed', cause: BUNDLE_REFUSED })
   }
 
-  it('answers native-route when the host has stopped serving a bundle at all', () => {
-    // Not a wall and not the cached page: a desktop that ships no bundle declares no page route,
-    // so this route is the native screen's, which is what `gateVerdict` answers everywhere else.
+  it('walls the host when it has stopped serving a bundle at all', () => {
+    // Not the cached page: the gate's own answer, which is what `gateVerdict` answers elsewhere.
     const step = refusedUnder({ hostCapabilities: [] })
-    expect(step.session.state).toEqual({ kind: 'native-route' })
+    expect(step.session.state).toEqual({
+      kind: 'wall',
+      verdict: { kind: 'blocked', reason: 'bundle-unavailable' }
+    })
     expect(step.session.updateNotice).toBeNull()
     expect(withoutRecord(step.effects)).toEqual([])
   })
diff --git a/mobile/src/mobile-web-shell/mobile-web-shell-screen-test-harness.tsx b/mobile/src/mobile-web-shell/mobile-web-shell-screen-test-harness.tsx
index a1b81f1bdc4..49eb01840a6 100644
--- a/mobile/src/mobile-web-shell/mobile-web-shell-screen-test-harness.tsx
+++ b/mobile/src/mobile-web-shell/mobile-web-shell-screen-test-harness.tsx
@@ -156,11 +156,6 @@ export function resetScreenDependencies(dependencies: ScreenDependencies): void
   dependencies.backSends = 0
 }
 
-/** The caller's native screen, as a component so `findAllByType` can name it without a host string. */
-export function NativeFallback(): null {
-  return null
-}
-
 export function readyState(sessionId: string): MobileWebShellSessionState {
   return {
     kind: 'ready',
@@ -196,14 +191,12 @@ export function unmountRenderedScreens(): void {
 export type ScreenComponent = ComponentType<{
   hostId: string
   route: { pathname: string }
-  fallback: ReactElement
 }>
 
 function element(Screen: ScreenComponent): ReactElement {
   return createElement(Screen, {
     hostId: 'host-1',
-    route: { pathname: '/h/host-1' },
-    fallback: createElement(NativeFallback)
+    route: { pathname: '/h/host-1' }
   })
 }
 
diff --git a/mobile/src/mobile-web-shell/mobile-web-shell-session-contract.ts b/mobile/src/mobile-web-shell/mobile-web-shell-session-contract.ts
index c70bdb866d2..a39fd7361b8 100644
--- a/mobile/src/mobile-web-shell/mobile-web-shell-session-contract.ts
+++ b/mobile/src/mobile-web-shell/mobile-web-shell-session-contract.ts
@@ -1,5 +1,5 @@
 import type { MobileWebShellFailureReason } from '../../modules/orca-mobile-web-shell/src/load-state'
-import type { MobileWebPageRoute } from './page-route-policy'
+import type { MobileWebPageRoute, PageRouteRefusalVerdict } from './page-route-policy'
 import type {
   MobileWebBundleCompatManifest,
   MobileWebBundleCompatVerdict,
@@ -39,7 +39,7 @@ export type MobileWebShellManifestFacts = MobileWebBundleCompatManifest & {
   readonly buildId: string
   readonly totalBytes: number
   readonly totalAssets: number
-  /** Undefined for a desktop older than the field, which is every route staying native. */
+  /** Undefined for a desktop older than the field, which serves no route. */
   readonly routes: readonly MobileWebPageRoute[] | undefined
 }
 
@@ -57,10 +57,9 @@ export type CachedGeneration = {
   readonly compat: MobileWebBundleCompatManifest
 }
 
-export type MobileWebShellBlockedVerdict = Extract<
-  MobileWebBundleCompatVerdict,
-  { kind: 'blocked' }
->
+export type MobileWebShellBlockedVerdict =
+  | Extract<MobileWebBundleCompatVerdict, { kind: 'blocked' }>
+  | PageRouteRefusalVerdict
 
 /** The shell's own failures plus the one the view cannot report: a download or a cache write that
  *  never produced a generation to hand it. */
@@ -105,14 +104,9 @@ export type MobileWebShellSessionState =
       readonly totalBytes: number
       readonly elapsedMs: number
     }
-  /**
-   * This route is the native screen's, and the caller renders it.
-   *
-   * Either the bundle does not list the route, or it lists it needing a grant this shell does not
-   * implement, or the desktop ships no bundle at all. Not a failure and not a wall: every route
-   * starts native, and the negotiation saying no leaves it where it was.
-   */
-  | { readonly kind: 'native-route' }
+  /** The page does not serve this screen and neither app can be named as the one to update: a
+   *  pathname this app has no screen for, or a manifest pattern this shell cannot read. */
+  | { readonly kind: 'route-unavailable' }
   | { readonly kind: 'wall'; readonly verdict: MobileWebShellBlockedVerdict }
   | {
       readonly kind: 'failed'
@@ -224,6 +218,9 @@ export type MobileWebShellSessionEvent =
 export type MobileWebShellSession = {
   /** The concrete route this session was opened for, matched against what the bundle lists. */
   readonly routePathname: string
+  /** False for the catch-all's pathnames: with no screen of its own here, an unserved one is not
+   *  evidence of an older desktop. */
+  readonly appNamesRoute: boolean
   /** A wide layout: served only under `canOwnHostArea`; the host route gets every route's grants. */
   readonly wide: boolean
   /** The route list the view below was built from, so a layout-class change can rebuild it. */
diff --git a/mobile/src/mobile-web-shell/mobile-web-shell-session.test.ts b/mobile/src/mobile-web-shell/mobile-web-shell-session.test.ts
index efc2192559e..4cb3a63d12e 100644
--- a/mobile/src/mobile-web-shell/mobile-web-shell-session.test.ts
+++ b/mobile/src/mobile-web-shell/mobile-web-shell-session.test.ts
@@ -16,6 +16,8 @@ import {
 } from './mobile-web-shell-session-test-fixtures'
 import { shellPageFrame } from './shell-page-frame'
 
+const NO_BUNDLE_WALL = { kind: 'wall', verdict: { kind: 'blocked', reason: 'bundle-unavailable' } }
+
 describe('the gates decide whether a step is taken at all', () => {
   it('waits while a connection is still being made', () => {
     const step = started({ reachability: 'connecting' })
@@ -46,11 +48,9 @@ describe('the gates decide whether a step is taken at all', () => {
     expect(step.effects).toEqual([{ kind: 'open-cache' }])
   })
 
-  it('leaves the route native for a readable host that serves no bundle', () => {
-    // Not a wall: a wall says the workspace cannot be opened, and a desktop with no bundle declares
-    // no page route, so there is nothing to open and the native screen is where this already was.
+  it('walls a readable host that serves no bundle rather than falling back to a native screen', () => {
     const step = started({ hostCapabilities: [] })
-    expect(step.session.state).toEqual({ kind: 'native-route' })
+    expect(step.session.state).toEqual(NO_BUNDLE_WALL)
     expect(step.effects).toEqual([])
   })
 
@@ -64,13 +64,13 @@ describe('the gates decide whether a step is taken at all', () => {
 })
 
 describe('the offline rule', () => {
-  it('leaves an unreachable host native when its cached bundle lists no such route', () => {
+  it("shows offline, not a wall, when an unreachable host's cached bundle lists no such route", () => {
     const offline = started({ reachability: 'unreachable' })
     const step = run(offline.session, {
       type: 'cache-read',
       generation: { ...CACHED, routes: [] }
     })
-    expect(step.session.state).toEqual({ kind: 'native-route' })
+    expect(step.session.state).toEqual({ kind: 'offline' })
     expect(step.effects).toEqual([])
   })
 
@@ -171,45 +171,6 @@ describe('the connected flow', () => {
     expect(step.effects).toEqual([{ kind: 'download' }])
   })
 
-  it('downloads nothing for a route the bundle does not list', () => {
-    const step = run(afterCacheRead(null).session, {
-      type: 'manifest-read',
-      manifest: { ...MANIFEST, routes: [{ pathname: '/h/[hostId]/tasks', grants: [] }] }
-    })
-    expect(step.session.state).toEqual({ kind: 'native-route' })
-    expect(step.effects).toEqual([])
-  })
-
-  it('downloads nothing for a route listed with a grant this shell does not implement', () => {
-    const step = run(afterCacheRead(null).session, {
-      type: 'manifest-read',
-      manifest: {
-        ...MANIFEST,
-        routes: [{ pathname: '/h/[hostId]', grants: ['navigate', 'teleport'] }]
-      }
-    })
-    expect(step.session.state).toEqual({ kind: 'native-route' })
-    expect(step.effects).toEqual([])
-  })
-
-  it('leaves the route native for a desktop older than the field itself', () => {
-    const step = run(afterCacheRead(null).session, {
-      type: 'manifest-read',
-      manifest: { ...MANIFEST, routes: undefined }
-    })
-    expect(step.session.state).toEqual({ kind: 'native-route' })
-  })
-
-  it('answers the route before it answers the wall, since a native route has none to show', () => {
-    // A bundle this shell cannot open is not a reason to refuse a screen it was never going to
-    // open: the wall belongs to the page, and this route is the native screen's.
-    const step = run(afterCacheRead(null).session, {
-      type: 'manifest-read',
-      manifest: { ...MANIFEST, schemaVersion: 99, routes: [] }
-    })
-    expect(step.session.state).toEqual({ kind: 'native-route' })
-  })
-
   it('still walls a listed route whose bundle this shell cannot read', () => {
     const step = run(afterCacheRead(null).session, {
       type: 'manifest-read',
@@ -408,13 +369,13 @@ describe('recovery follows the shell view contract', () => {
     expect(rearmed.effects).toEqual([{ kind: 'open-cache' }])
   })
 
-  it('hands a recovery back to the native screen when the host serves no bundle', () => {
+  it('walls a recovery when the host no longer serves a bundle', () => {
     const stale = run(readySession().session, {
       type: 'gates-changed',
       gates: gates({ hostCapabilities: [] })
     })
     const step = run(stale.session, { type: 'shell-failed', reason: 'document-load-failed' })
-    expect(step.session.state).toEqual({ kind: 'native-route' })
+    expect(step.session.state).toEqual(NO_BUNDLE_WALL)
     // The cache still goes: the bytes that failed are suspect whatever screen follows them.
     expect(step.effects).toEqual([{ kind: 'delete-cache' }])
   })
@@ -520,10 +481,10 @@ describe('try again', () => {
     expect(again.effects).toEqual([{ kind: 'delete-cache' }, { kind: 'open-cache' }])
   })
 
-  it('stays native rather than looping when the host still serves no bundle', () => {
-    const native = started({ hostCapabilities: [] })
-    const retried = run(native.session, { type: 'retry-pressed' })
-    expect(retried.session.state).toEqual({ kind: 'native-route' })
+  it('stays walled rather than looping when the host still serves no bundle', () => {
+    const walled = started({ hostCapabilities: [] })
+    const retried = run(walled.session, { type: 'retry-pressed' })
+    expect(retried.session.state).toEqual(NO_BUNDLE_WALL)
     expect(retried.effects).toEqual([])
   })
 
@@ -684,13 +645,13 @@ describe('a gates change that says nothing new starts nothing', () => {
     expect(settled.effects).toEqual([{ kind: 'open-cache' }])
   })
 
-  it('drops a check in flight to the native screen when the host stops serving a bundle', () => {
+  it('walls a check in flight when the host stops serving a bundle', () => {
     const checking = started()
     const step = run(checking.session, {
       type: 'gates-changed',
       gates: gates({ hostCapabilities: [] })
     })
-    expect(step.session.state).toEqual({ kind: 'native-route' })
+    expect(step.session.state).toEqual(NO_BUNDLE_WALL)
   })
 })
 
diff --git a/mobile/src/mobile-web-shell/mobile-web-shell-session.ts b/mobile/src/mobile-web-shell/mobile-web-shell-session.ts
index c14c04e36e2..31ad7612946 100644
--- a/mobile/src/mobile-web-shell/mobile-web-shell-session.ts
+++ b/mobile/src/mobile-web-shell/mobile-web-shell-session.ts
@@ -22,9 +22,9 @@ import {
   gateKey,
   gateState,
   gateVerdict,
-  NATIVE_ROUTE
+  ROUTE_UNAVAILABLE
 } from './mobile-web-shell-gates'
-import { routeViewOf, sameRouteView } from './page-route-policy'
+import { pageRouteRefusalVerdict, routeViewOf, sameRouteView } from './page-route-policy'
 import { CLEAR_PAGE_DOCUMENT_STATE, pageDocumentStatePatch } from './page-document-state'
 import { openByOwnRoutes, openCached, rendersRoute } from './mobile-web-shell-cached-generation'
 import { step } from './mobile-web-shell-session-step'
@@ -32,10 +32,12 @@ import { AWAIT_DOCUMENT_LOAD, reducePageDocumentLifecycle } from './page-documen
 
 export function createMobileWebShellSession(
   routePathname: string,
-  wide = false
+  wide = false,
+  appNamesRoute = true
 ): MobileWebShellSession {
   return {
     routePathname,
+    appNamesRoute,
     wide,
     pageRoutes: [],
     pageRouteGrants: [],
@@ -105,8 +107,13 @@ function onCacheRead(
     if (generation === null) {
       return step(session, { cached: null, state: { kind: 'offline' } })
     }
-    // The cached bundle's own list, which is the only one an unreachable host can be judged by.
-    return openByOwnRoutes(session, generation, { patch: { cached: generation } })
+    // The cached bundle's own list, which is the only one an unreachable host can be judged by. A
+    // route it lacks is the offline screen, as with nothing cached: an unreachable host cannot be
+    // told too old, and connecting is what fetches the bundle that may carry the route.
+    return openByOwnRoutes(session, generation, {
+      unclaimed: { kind: 'offline' },
+      patch: { cached: generation }
+    })
   }
   return step(session, { cached: generation, state: CHECKING }, [{ kind: 'read-manifest' }])
 }
@@ -119,15 +126,8 @@ function onManifestRead(
   if (gates === null) {
     return step(session, {})
   }
-  // Before the compat verdict, because a route that stays native has nothing to wall about: a
-  // bundle this shell could not open is not a reason to refuse a screen it was never going to open.
-  const view = {
-    ...routeViewOf(manifest.routes, session.routePathname, session.wide),
-    routes: manifest.routes
-  }
-  if (!rendersRoute(view.pageRoutes, session.routePathname)) {
-    return step(session, { ...view, state: NATIVE_ROUTE })
-  }
+  // Before the route question: a page below the floor is a desktop too old whatever it lists, and
+  // a schema this shell cannot read leaves the route list unreadable too.
   const verdict = evaluateMobileWebBundleCompat({
     hostCapabilities: gates.hostCapabilities,
     hostStatus: gates.hostStatus,
@@ -136,6 +136,19 @@ function onManifestRead(
   if (verdict.kind === 'blocked') {
     return step(session, { state: { kind: 'wall', verdict } })
   }
+  const view = {
+    ...routeViewOf(manifest.routes, session.routePathname, session.wide),
+    routes: manifest.routes
+  }
+  if (!rendersRoute(view.pageRoutes, session.routePathname)) {
+    // The view is kept so a layout flip that would serve the route restarts the session.
+    const refusal = session.appNamesRoute
+      ? pageRouteRefusalVerdict(manifest.routes, session.routePathname, session.wide)
+      : null
+    const state =
+      refusal === null ? ROUTE_UNAVAILABLE : ({ kind: 'wall', verdict: refusal } as const)
+    return step(session, { ...view, state })
+  }
   // Same build id is the same bytes (the id is their digest), so the generation on disk opens as is.
   const cached = session.cached
   if (cached?.buildId === manifest.buildId) {
@@ -253,6 +266,9 @@ function decideDownloadFailed(
     return step(session, { state: gated })
   }
   return openByOwnRoutes(session, cached, {
+    // The newer manifest claimed this route or never arrived, so the cache lacking it is this
+    // download's failure, with its retry.
+    unclaimed: { kind: 'failed', reason: 'download-failed', retriedOnce: session.retriedOnce },
     served: { updateNotice: readFailureSide(cause.reason) === 'bundle' ? 'update-failed' : null },
     wall: cachedGenerationWall(verdict, gates, cached.compat)
   })
@@ -266,7 +282,10 @@ function onLayoutChanged(session: MobileWebShellSession, wide: boolean): MobileW
     return step(session, { wide })
   }
   // Still counting flows, so nothing the old session has in flight lands on this one.
-  const fresh = { ...createMobileWebShellSession(session.routePathname, wide), flow: session.flow }
+  const fresh = {
+    ...createMobileWebShellSession(session.routePathname, wide, session.appNamesRoute),
+    flow: session.flow
+  }
   return startFlow(fresh, session.gates)
 }
 
diff --git a/mobile/src/mobile-web-shell/mobile-web-shell-update-failure-outcome.ts b/mobile/src/mobile-web-shell/mobile-web-shell-update-failure-outcome.ts
index dd3a89e4daf..7a552806349 100644
--- a/mobile/src/mobile-web-shell/mobile-web-shell-update-failure-outcome.ts
+++ b/mobile/src/mobile-web-shell/mobile-web-shell-update-failure-outcome.ts
@@ -12,8 +12,8 @@ export function updateFailureOutcomeOf(
     case 'activating':
     case 'ready':
       return { outcome: 'opened-cached', wall: null }
-    case 'native-route':
-      return { outcome: 'native-route', wall: null }
+    case 'route-unavailable':
+      return { outcome: 'route-unavailable', wall: null }
     case 'wall':
       return { outcome: 'wall', wall: updateFailureWallOf(state.verdict) }
     case 'failed':
diff --git a/mobile/src/mobile-web-shell/mobile-web-shell-update-failure-record.test.ts b/mobile/src/mobile-web-shell/mobile-web-shell-update-failure-record.test.ts
index 0843e7ab553..f545267e785 100644
--- a/mobile/src/mobile-web-shell/mobile-web-shell-update-failure-record.test.ts
+++ b/mobile/src/mobile-web-shell/mobile-web-shell-update-failure-record.test.ts
@@ -106,10 +106,10 @@ describe('every exit from a failed update read leaves one record', () => {
     ])
   })
 
-  it('a cached generation that never carried this route leaves it native', () => {
+  it('a cached generation that never carried this route shows the download failure', () => {
     const step = refusedUnder({}, { ...CACHED, routes: [] })
-    expect(step.session.state).toEqual({ kind: 'native-route' })
-    expect(recorded(step)).toMatchObject([{ outcome: 'native-route', wall: null }])
+    expect(step.session.state).toMatchObject({ kind: 'failed', reason: 'download-failed' })
+    expect(recorded(step)).toMatchObject([{ outcome: 'failed', wall: null }])
   })
 
   it('gates gone offline under the fetch open the cache unjudged', () => {
@@ -124,10 +124,10 @@ describe('every exit from a failed update read leaves one record', () => {
     expect(recorded(step)).toMatchObject([{ outcome: 'failed' }])
   })
 
-  it('gates that dropped the bundle capability leave the route native', () => {
+  it('gates that dropped the bundle capability wall the host', () => {
     const step = refusedUnder({ hostCapabilities: [] })
-    expect(step.session.state).toEqual({ kind: 'native-route' })
-    expect(recorded(step)).toMatchObject([{ outcome: 'native-route' }])
+    expect(step.session.state).toMatchObject({ kind: 'wall' })
+    expect(recorded(step)).toMatchObject([{ outcome: 'wall', wall: 'bundle-unavailable' }])
   })
 
   it('gates still dialling or pending leave the session waiting', () => {
diff --git a/mobile/src/mobile-web-shell/mobile-web-shell-update-failure.ts b/mobile/src/mobile-web-shell/mobile-web-shell-update-failure.ts
index c34ca181efe..79e7fa96595 100644
--- a/mobile/src/mobile-web-shell/mobile-web-shell-update-failure.ts
+++ b/mobile/src/mobile-web-shell/mobile-web-shell-update-failure.ts
@@ -3,7 +3,7 @@ import {
   isMobileWebBundleTransportFailure,
   readMobileWebBundleErrorCode
 } from '../transport/mobile-web-bundle-operations'
-import type { MobileWebBundleCompatVerdict } from '../transport/mobile-web-bundle-compat'
+import type { MobileWebShellBlockedVerdict } from './mobile-web-shell-session-contract'
 import {
   MOBILE_WEB_BUNDLE_FETCH_REFUSALS,
   MobileWebBundleFetchError
@@ -69,7 +69,9 @@ export function updateFailureCauseOf(error: unknown): MobileWebShellUpdateFailur
 /** What the shell put on screen instead of the generation it could not take. */
 export const MOBILE_WEB_SHELL_UPDATE_FAILURE_OUTCOMES = [
   'opened-cached',
+  // Written by builds that still fell back to native screens; kept so their records still read.
   'native-route',
+  'route-unavailable',
   'wall',
   'failed',
   'waiting'
@@ -83,13 +85,15 @@ export const MOBILE_WEB_SHELL_UPDATE_FAILURE_WALLS = [
   'bundle-unavailable',
   'bundle-shell-too-old',
   'host-too-old-for-bundle',
-  'bundle-too-old-for-host'
+  'bundle-too-old-for-host',
+  'page-route-unlisted',
+  'page-route-grant-missing'
 ] as const
 
 export type MobileWebShellUpdateFailureWall = (typeof MOBILE_WEB_SHELL_UPDATE_FAILURE_WALLS)[number]
 
 export function updateFailureWallOf(
-  verdict: Extract<MobileWebBundleCompatVerdict, { kind: 'blocked' }>
+  verdict: MobileWebShellBlockedVerdict
 ): MobileWebShellUpdateFailureWall {
   if (verdict.reason !== 'bundle-incompatible') {
     return verdict.reason
diff --git a/mobile/src/mobile-web-shell/page-route-policy.test.ts b/mobile/src/mobile-web-shell/page-route-policy.test.ts
index 4215a855bb9..10fbeba14e2 100644
--- a/mobile/src/mobile-web-shell/page-route-policy.test.ts
+++ b/mobile/src/mobile-web-shell/page-route-policy.test.ts
@@ -3,9 +3,9 @@ import { z } from 'zod'
 import { MobileWebBundleRouteSchema } from '../../../src/shared/mobile-web-bundle/manifest-contract'
 import {
   matchesRoutePattern,
-  pageRendersRoute,
   MOBILE_WEB_SHELL_GRANTS,
   grantsForRoute,
+  pageRouteRefusalVerdict,
   routePatternRefusal,
   routeViewOf
 } from './page-route-policy'
@@ -19,6 +19,13 @@ import {
 } from './bridge/bridge-native-verbs'
 import { BRIDGE_SCREENCAST_BINARY_GRANT } from './bridge/bridge-screencast-grant'
 
+/** Whether a narrow session on `pathname` would be served the page under `routes`. */
+function servesRoute(routes: Parameters<typeof routeViewOf>[0], pathname: string): boolean {
+  return routeViewOf(routes, pathname).pageRoutes.some((pattern) =>
+    matchesRoutePattern(pathname, pattern)
+  )
+}
+
 /**
  * The patterns a session would be told it may keep, read through the view the reducer builds.
  *
@@ -126,7 +133,7 @@ describe('a pattern with a rest segment', () => {
 
   it('serves such a route and grants it what it declared', () => {
     const routes = [{ pathname: PATTERN, grants: ['navigate', 'storage'] }]
-    expect(pageRendersRoute(routes, '/h/a/insights/deep/er')).toBe(true)
+    expect(servesRoute(routes, '/h/a/insights/deep/er')).toBe(true)
     expect(grantsForRoute(routes, '/h/a/insights/deep/er')).toEqual(['navigate', 'storage'])
   })
 
@@ -170,14 +177,14 @@ describe('the routes this shell will render from the page', () => {
 
   it('answers nothing for a desktop older than the field', () => {
     expect(pageRoutesOf(undefined)).toEqual([])
-    expect(pageRendersRoute(undefined, '/h/host-1')).toBe(false)
+    expect(servesRoute(undefined, '/h/host-1')).toBe(false)
   })
 
   it('answers the two halves of the negotiation together', () => {
     const routes = [{ pathname: '/h/[hostId]', grants: ['navigate'] }]
-    expect(pageRendersRoute(routes, '/h/host-1')).toBe(true)
-    expect(pageRendersRoute(routes, '/h/host-1/tasks')).toBe(false)
-    expect(pageRendersRoute([], '/h/host-1')).toBe(false)
+    expect(servesRoute(routes, '/h/host-1')).toBe(true)
+    expect(servesRoute(routes, '/h/host-1/tasks')).toBe(false)
+    expect(servesRoute([], '/h/host-1')).toBe(false)
   })
 })
 
@@ -592,3 +599,16 @@ describe('a shell whose policy has never heard of the optional lane', () => {
     expect(grantsForRoute(written, opened)).toEqual(['navigate', 'storage', 'screencastBinary'])
   })
 })
+
+describe('why the page does not serve a route', () => {
+  const reasonFor = (...args: Parameters<typeof pageRouteRefusalVerdict>) =>
+    pageRouteRefusalVerdict(...args)?.reason
+
+  it('blames the desktop on a wide layout when its page cannot own the host area', () => {
+    const routes = [{ pathname: '/h/[hostId]', grants: [] }]
+    expect(reasonFor(routes, '/h/a', true)).toBe('page-route-unlisted')
+    expect(
+      reasonFor([{ ...routes[0]!, grants: ['teleport'], canOwnHostArea: true }], '/h/a', true)
+    ).toBe('page-route-grant-missing')
+  })
+})
diff --git a/mobile/src/mobile-web-shell/page-route-policy.ts b/mobile/src/mobile-web-shell/page-route-policy.ts
index 6aeeed92ace..3de345d1bd5 100644
--- a/mobile/src/mobile-web-shell/page-route-policy.ts
+++ b/mobile/src/mobile-web-shell/page-route-policy.ts
@@ -11,9 +11,8 @@ export type MobileWebPageRoute = NonNullable<MobileWebBundleManifestRead['routes
  * What this app build does on a page's behalf.
  *
  * Every name here is a capability the shell implements and will honour over the bridge, and it is
- * the same list `init.grants.native` tells the page it has. A bundle naming a grant absent from
- * here renders its native screen instead: an old app against a new bundle lands on a screen that
- * works rather than on a tap that does nothing.
+ * the same list `init.grants.native` tells the page it has. A route naming a grant absent from
+ * here is not served: this app asks to be updated rather than landing on a tap that does nothing.
  */
 export const MOBILE_WEB_SHELL_GRANTS = [
   'navigate',
@@ -65,7 +64,7 @@ export type RoutePatternRefusal = (typeof ROUTE_PATTERN_REFUSALS)[number]
  * Whether a manifest pattern is one this matcher can read, and what is wrong with it if not.
  *
  * One rest segment, trailing, is the shape expo-router's own file system can produce and the only
- * one this reads. Anything else is refused by name and matches nothing, so its route stays native
+ * one this reads. Anything else is refused by name and matches nothing, so its route is not served
  * — the same answer a phone too old to have heard of rest segments gives, and the answer a shell
  * should give for a pattern whose tail it cannot say it understood.
  *
@@ -124,8 +123,8 @@ export function matchesRoutePattern(pathname: string, pattern: string): boolean
 /**
  * The routes this shell will render from the page: listed, and needing nothing it lacks.
  *
- * `every` and not `some`: one grant this build lacks takes the whole route native, so a token every
- * page route declares couples the whole set to a shell that carries it — `haptics` is the first,
+ * `every` and not `some`: one grant this build lacks leaves the whole route unserved, so a token
+ * every page route declares couples the whole set to a shell that carries it — `haptics` is the first,
  * and against a shell without it no page route is served at all.
  */
 function implementedPageRouteEntries(
@@ -151,25 +150,6 @@ function effectiveRouteGrants(route: MobileWebPageRoute): string[] {
   return [...route.grants, ...(route.optionalGrants ?? [])].filter(implementsGrant)
 }
 
-/** The patterns alone, for the readers in this module that only name routes. */
-function implementedPageRoutes(routes: readonly MobileWebPageRoute[] | undefined): string[] {
-  return implementedPageRouteEntries(routes).map((route) => route.pathname)
-}
-
-/**
- * Whether the page renders this route, rather than the native screen.
- *
- * Both halves are the negotiation: the desktop lists what it has proved on the web, and the shell
- * answers for what it can do. Either side saying no leaves the route native, which is where every
- * route starts and what every phone already ships.
- */
-export function pageRendersRoute(
-  routes: readonly MobileWebPageRoute[] | undefined,
-  pathname: string
-): boolean {
-  return implementedPageRoutes(routes).some((pattern) => matchesRoutePattern(pathname, pattern))
-}
-
 /**
  * The grants one page session gets: what this shell implements, narrowed to what the route it was
  * opened for declared.
@@ -220,8 +200,7 @@ export function routeViewOf(
 ) {
   const entries = implementedPageRouteEntries(routes)
   const root = hostAreaRoot(pathname)
-  // Native unless the page declares it: an older page draws its own sidebar beside the native one.
-  if (wide && (root === null || !pageCanOwnHostArea(entries, root))) {
+  if (!servesWideLayout(entries, pathname, wide)) {
     return { pageRoutes: [], pageRouteGrants: [], routeGrants: [], ownsHostArea: false }
   }
   const ownsHostArea = wide && pathname === root
@@ -281,6 +260,46 @@ function pageCanOwnHostArea(entries: readonly MobileWebPageRoute[], root: string
   )
 }
 
+/** Wide sessions need a page that draws the host area: an older page draws its own sidebar beside
+ *  the native one. */
+function servesWideLayout(
+  entries: readonly MobileWebPageRoute[],
+  pathname: string,
+  wide: boolean
+): boolean {
+  const root = hostAreaRoot(pathname)
+  return !wide || (root !== null && pageCanOwnHostArea(entries, root))
+}
+
+/**
+ * Why the page will not serve a route `routeViewOf` left out, as a wall the shell shows, or null
+ * when a declared pattern this shell cannot read might have covered it and no side can be blamed.
+ *
+ * Split on whether a shell implementing every grant would serve it: if so the page is ahead of this
+ * app, and otherwise the desktop's page predates the screen.
+ */
+export type PageRouteRefusalVerdict =
+  | { readonly kind: 'blocked'; readonly reason: 'page-route-unlisted' }
+  | { readonly kind: 'blocked'; readonly reason: 'page-route-grant-missing' }
+
+export function pageRouteRefusalVerdict(
+  routes: readonly MobileWebPageRoute[] | undefined,
+  pathname: string,
+  wide: boolean
+): PageRouteRefusalVerdict | null {
+  const declared = routes ?? []
+  if (declared.some((route) => routePatternRefusal(route.pathname) !== null)) {
+    return null
+  }
+  const servedWithEveryGrant =
+    servesWideLayout(declared, pathname, wide) &&
+    declared.some((route) => matchesRoutePattern(pathname, route.pathname))
+  return {
+    kind: 'blocked',
+    reason: servedWithEveryGrant ? 'page-route-grant-missing' : 'page-route-unlisted'
+  }
+}
+
 /** Every served route's grants, so `route-handoff.web.ts` keeps each hop in the page, plus the read
  *  of a workspace key that page opens in-page. */
 function hostAreaGrants(entries: readonly MobileWebPageRoute[]): string[] {
diff --git a/mobile/src/mobile-web-shell/shell-lifecycle-log.test.ts b/mobile/src/mobile-web-shell/shell-lifecycle-log.test.ts
index c0bf3e52ffd..f533e345443 100644
--- a/mobile/src/mobile-web-shell/shell-lifecycle-log.test.ts
+++ b/mobile/src/mobile-web-shell/shell-lifecycle-log.test.ts
@@ -141,12 +141,14 @@ describe('shell lifecycle log lines', () => {
     expect(JSON.stringify(lines)).not.toContain('/Users/someone')
   })
 
-  it('logs nothing for a route that stays native, the normal case for native screens', () => {
+  it('logs the wall a host with no page earns', () => {
     const { session, lines } = replay([
       { type: 'gates-changed', gates: gates({ hostCapabilities: [] }) }
     ])
-    expect(session.state.kind).toBe('native-route')
-    expect(lines).toEqual([])
+    expect(session.state.kind).toBe('wall')
+    expect(summary(lines)).toEqual([
+      'web-shell-flow Web shell: blocked by version check | reason=bundle-unavailable'
+    ])
   })
 
   it('logs a missed ready deadline, the failure it causes and the recovery flow', () => {
diff --git a/mobile/src/mobile-web-shell/shell-lifecycle-log.ts b/mobile/src/mobile-web-shell/shell-lifecycle-log.ts
index 718c997a3b7..0b92e7ff10d 100644
--- a/mobile/src/mobile-web-shell/shell-lifecycle-log.ts
+++ b/mobile/src/mobile-web-shell/shell-lifecycle-log.ts
@@ -127,7 +127,7 @@ export function shellStallLine(
             `Web shell: page has not drawn after ${seconds}`,
             `build=${buildPrefix(state.buildId)} page ready=${yesNo(session.pageReady)} readyAsks=${trace.readyAsks} documentLoaded=${yesNo(trace.documentLoaded)}`
           )
-    case 'native-route':
+    case 'route-unavailable':
     case 'wall':
     case 'failed':
     case 'offline':
@@ -228,9 +228,10 @@ function transitionLine(
         ? flowLine('info', 'Web shell: activating app', 'source=download')
         : null
     case 'ready':
-    case 'native-route':
-      // `ready` is logged at paint; native is every native screen's normal outcome.
+      // Logged at paint.
       return null
+    case 'route-unavailable':
+      return flowLine('warn', 'Web shell: page does not serve this route')
     case 'wall': {
       const side = 'side' in after.verdict ? ` side=${after.verdict.side}` : ''
       return flowLine(
diff --git a/mobile/src/mobile-web-shell/shell-page-frame.test.ts b/mobile/src/mobile-web-shell/shell-page-frame.test.ts
index 8c4d7b5b6d8..f682aea0e04 100644
--- a/mobile/src/mobile-web-shell/shell-page-frame.test.ts
+++ b/mobile/src/mobile-web-shell/shell-page-frame.test.ts
@@ -21,7 +21,7 @@ describe('how long the shell keeps its own frame up', () => {
       { kind: 'checking' },
       { kind: 'activating', source: 'download' },
       { kind: 'offline' },
-      { kind: 'native-route' }
+      { kind: 'route-unavailable' }
     ] as const satisfies readonly MobileWebShellSessionState[]) {
       expect(frame({ state }), state.kind).toBe('pending')
     }
diff --git a/mobile/src/mobile-web-shell/use-mobile-web-shell-session.test.ts b/mobile/src/mobile-web-shell/use-mobile-web-shell-session.test.ts
index a2be9c8b0d8..2e915d7f9d2 100644
--- a/mobile/src/mobile-web-shell/use-mobile-web-shell-session.test.ts
+++ b/mobile/src/mobile-web-shell/use-mobile-web-shell-session.test.ts
@@ -593,8 +593,11 @@ describe('the wait for the page to speak', () => {
     })
     await flush()
     // Pinned, not merely "moved on": `/h/host-1/tasks` is not the route the bundle lists, so a
-    // re-armed session settles on the native screen. A failure would also leave `checking`.
-    expect(seen.at(-1)?.kind).toBe('native-route')
+    // re-armed session settles on the desktop wall. A failure would also leave `checking`.
+    expect(seen.at(-1)).toEqual({
+      kind: 'wall',
+      verdict: { kind: 'blocked', reason: 'page-route-unlisted' }
+    })
     await act(async () => {
       tree.unmount()
     })
diff --git a/mobile/src/mobile-web-shell/use-mobile-web-shell-session.ts b/mobile/src/mobile-web-shell/use-mobile-web-shell-session.ts
index f511a46c9eb..05cfba5dd53 100644
--- a/mobile/src/mobile-web-shell/use-mobile-web-shell-session.ts
+++ b/mobile/src/mobile-web-shell/use-mobile-web-shell-session.ts
@@ -84,10 +84,13 @@ export function useMobileWebShellSession(args: {
   routePathname: string
   /** A wide layout; a change restarts the session only where it changes the answer. */
   wide?: boolean
+  /** False when this app has no screen of its own for the route. */
+  appNamesRoute?: boolean
   runtime?: MobileWebShellRuntime
 }): MobileWebShellSessionView {
   const { hostId, routePathname } = args
   const wide = args.wide === true
+  const appNamesRoute = args.appNamesRoute !== false
   const gates = useHostProtocolGates()
   const { client, state: connState } = useHostClient(hostId)
 
@@ -97,7 +100,7 @@ export function useMobileWebShellSession(args: {
   const storeRef = useRef<GenerationStore | null>(null)
   storeRef.current ??= runtime.createStore()
 
-  const sessionRef = useRef(createMobileWebShellSession(routePathname, wide))
+  const sessionRef = useRef(createMobileWebShellSession(routePathname, wide, appNamesRoute))
   const [state, setState] = useState(sessionRef.current.state)
   const [pageReady, setPageReady] = useState(sessionRef.current.pageReady)
   const [pageFrame, setPageFrame] = useState(() => shellPageFrame(sessionRef.current))
@@ -235,13 +238,13 @@ export function useMobileWebShellSession(args: {
     invalidate()
     hostIdRef.current = hostId
     logTraceRef.current = EMPTY_SHELL_LOG_TRACE
-    sessionRef.current = createMobileWebShellSession(routePathname, wide)
+    sessionRef.current = createMobileWebShellSession(routePathname, wide, appNamesRoute)
     startedAtRef.current = runtime.now()
     setState(sessionRef.current.state)
     setPageReady(sessionRef.current.pageReady)
     setPageFrame(shellPageFrame(sessionRef.current))
     return invalidate
-  }, [hostId, invalidate, routePathname, runtime])
+  }, [appNamesRoute, hostId, invalidate, routePathname, runtime])
 
   // Log-only: one warning per parked state object, cancelled by any state, paint, host or route change.
   // `CHECKING` is one shared object, so checking-to-checking steps keep the first open's timer.
diff --git a/mobile/src/session/MobileDiffReviewRouteScreen.tsx b/mobile/src/session/MobileDiffReviewRouteScreen.tsx
index a2424003912..819c3b0e31f 100644
--- a/mobile/src/session/MobileDiffReviewRouteScreen.tsx
+++ b/mobile/src/session/MobileDiffReviewRouteScreen.tsx
@@ -14,8 +14,8 @@ import { useWorkspaceRouteHandoff } from '../navigation/workspace-route-handoff'
  *
  * A route file that both reads the flag and calls `useMobileDiffReviewController` runs the whole
  * controller — its client subscriptions included — behind the page, because hooks cannot be
- * conditional. As an element passed for `fallback` it is created and not mounted, so the
- * controller runs only when the shell answers `native-route`. Same reason the explorer switch
+ * conditional. As an element it is created and not mounted, so the controller runs only when a
+ * native-shell build renders it. Same reason the explorer switch
  * builds its panel as an element.
  *
  * The params are read here rather than handed down, so this is the route body and the two route
diff --git a/mobile/src/transport/mobile-web-bundle-reply-schemas.ts b/mobile/src/transport/mobile-web-bundle-reply-schemas.ts
index 9f028c57967..6944d441db9 100644
--- a/mobile/src/transport/mobile-web-bundle-reply-schemas.ts
+++ b/mobile/src/transport/mobile-web-bundle-reply-schemas.ts
@@ -28,9 +28,9 @@ import {
 const MAX_DATA_BASE64_LENGTH = Math.ceil(MOBILE_WEB_BUNDLE_CHUNK_BYTES / 3) * 4 + 8
 
 /** A screen the desktop asks this shell to render from the bundle. Optional, because a desktop
- *  older than the field sends none and every route then stays native, which is where they all
- *  start. Loose for the same reason the manifest is: a grant name this build does not know is not a
- *  reason to refuse a bundle, it is a reason to leave that one route native.
+ *  older than the field sends none, and then no route is served. Loose for the same reason the
+ *  manifest is: a grant name this build does not know is not a reason to refuse a bundle, only that
+ *  one route.
  *
  *  `optionalGrants` is read so this build can honour it, and typed here only — the host's own
  *  schema is where its grammar and the ceiling over the union live. A shell without this line still