@@ -291,12 +291,6 @@ extension RunnerTests {
     after.backButtonLabels != before.backButtonLabels
   }
 
-  /// One read of the bar state, with the time the read started.
-  struct TimedNavigationBarBackState {
-    let state: NavigationBarBackState
-    let startedMs: Double
-  }
-
   /// The pause between two reads of the bar, and how long reads may start, both before the tap
   /// while the bar settles and after it while the pop is confirmed. Only a bar that never holds
   /// still, or a tap that did not navigate, spends the whole budget.
@@ -305,7 +299,7 @@ extension RunnerTests {
 
   static let navigationBarBackUnverified = ErrorPayload(
     code: RunnerWireErrorCode.backSwipeUnverified,
-    message: "back pressed the navigation bar back button, but the navigation bar did not change within 1 s. This is an unknown outcome.",
+    message: "back pressed the navigation bar back button, but the navigation bar's back buttons did not change within 1 s. This is an unknown outcome.",
     hint: "Take a snapshot to see where the app is."
   )
 
@@ -329,16 +323,16 @@ extension RunnerTests {
     case hung
   }
 
-  /// Reads the hittable back buttons, then the bar state until two reads in a row, at least one read
-  /// interval apart, agree and the button's frame is in them, so a push still animating is not read
+  /// Reads the hittable back buttons, then the bar state until two reads in a row, one read interval
+  /// apart, agree and the button's frame is in them, so a push still animating is not read
   /// as the state a pop changes. Each round re-reads the buttons. Reads start only until `deadlineMs`.
   @MainActor
   private func stillNavigationBarBackButton(
     app: XCUIApplication,
     geometry: SurfaceGeometry,
     deadlineMs: Double
   ) -> NavigationBarBackLookup {
-    var previous: TimedNavigationBarBackState?
+    var previous: NavigationBarBackState?
     while true {
       let button: CGRect
       switch navigationBarBackButtonFrames(app: app, deadlineMs: deadlineMs) {
@@ -348,37 +342,21 @@ extension RunnerTests {
       case .read(let frames) where frames.count > 1: return .notFound("ambiguous")
       case .read(let frames): button = frames[0]
       }
-      let startedMs = currentUptimeMs()
-      let current: TimedNavigationBarBackState
+      let current: NavigationBarBackState
       switch readNavigationBarBackState(app: app, phase: .lookup, deadlineMs: deadlineMs) {
       case .hung: return .hung
       case .unreadable: return .notFound("unreadable")
-      case .read(let state): current = TimedNavigationBarBackState(state: state, startedMs: startedMs)
+      case .read(let state): current = state
       }
-      if let previous,
-        Self.navigationBarBackStateHeldStill(from: previous, to: current),
-        Self.navigationBarBackState(current.state, holdsButton: button, geometry: geometry) {
-        return .still(current.state, button: button)
+      if current == previous, Self.navigationBarBackState(current, holdsButton: button, geometry: geometry) {
+        return .still(current, button: button)
       }
       if currentUptimeMs() >= deadlineMs { return .notFound("moving") }
       previous = current
       sleepFor(Self.navigationBarBackReadInterval)
     }
   }
 
-  /// Whether two reads show a still bar: they agree, and they started at least one read interval
-  /// apart, so two reads drawn in one animation frame never pass for a still bar.
-  static func navigationBarBackStateHeldStill(
-    from earlier: TimedNavigationBarBackState,
-    to later: TimedNavigationBarBackState
-  ) -> Bool {
-    later.state == earlier.state && later.startedMs - earlier.startedMs >= navigationBarBackReadInterval * 1000
-  }
-
-  /// How far, in points, each edge of a snapshot frame placed in screen space may sit from the live
-  /// frame, so fractional frame values that XCTest rounds differently still match.
-  static let navigationBarBackFrameTolerance: CGFloat = 0.5
-
   /// Whether `state` holds the live button. A live frame is in screen points, and a snapshot frame
   /// is in the window's own space, which a placed iPad window starts off the screen origin (#3899).
   static func navigationBarBackState(
@@ -388,10 +366,7 @@ extension RunnerTests {
   ) -> Bool {
     state.backButtonFrames.contains { frame in
       let origin = geometry.screenPoint(from: SurfacePoint<WindowContentSpace>(frame.origin)).point
-      let placed = CGRect(origin: origin, size: frame.size)
-      return [
-        (placed.minX, button.minX), (placed.minY, button.minY), (placed.maxX, button.maxX), (placed.maxY, button.maxY),
-      ].allSatisfy { abs($0.0 - $0.1) <= navigationBarBackFrameTolerance }
+      return CGRect(origin: origin, size: frame.size) == button
     }
   }
 
 
@@ -689,49 +689,16 @@ extension RunnerTests {
     XCTAssertTrue(Self.navigationBarBackState(state, holdsButton: snapshotButton, geometry: fullScreen))
   }
 
-  /// A snapshot frame placed in screen space matches a live frame up to half a point per edge, so
-  /// fractional frame values do not defeat the match; a button a point away is another button.
-  func testNavigationBarBackStateHoldsALiveButtonWithinHalfAPointPerEdge() {
-    let state = NavigationBarBackState(
-      backButtonLabels: [["Root"]],
-      backButtonFrames: [CGRect(x: 8.33, y: 54.67, width: 44.33, height: 44)]
-    )
-    let placed = SurfaceGeometry(
-      windowOnScreen: SurfaceRect(CGRect(x: 224.5, y: 128, width: 386, height: 954)),
-      panelNativeSize: nil,
-      orientation: RunnerInterfaceOrientation.portrait
-    )
-
-    XCTAssertTrue(Self.navigationBarBackState(state, holdsButton: CGRect(x: 233, y: 182.5, width: 44, height: 44), geometry: placed))
-    XCTAssertTrue(Self.navigationBarBackState(state, holdsButton: CGRect(x: 232.5, y: 183, width: 44.5, height: 43.5), geometry: placed))
-    XCTAssertFalse(Self.navigationBarBackState(state, holdsButton: CGRect(x: 234, y: 182.5, width: 44, height: 44), geometry: placed))
-    XCTAssertFalse(Self.navigationBarBackState(state, holdsButton: CGRect(x: 233, y: 182.5, width: 45, height: 44), geometry: placed))
-  }
-
-  /// Two agreeing reads of the bar show a still bar only when they started at least one read
-  /// interval apart: two reads drawn in one animation frame of a push agree, but prove nothing.
-  func testNavigationBarBackStateHeldStillOnlyAcrossOneReadInterval() {
-    let bar = NavigationBarBackState(backButtonLabels: [["Root"]], backButtonFrames: [CGRect(x: 8, y: 54, width: 44, height: 44)])
-    let moved = NavigationBarBackState(backButtonLabels: [["Root"]], backButtonFrames: [CGRect(x: 40, y: 54, width: 44, height: 44)])
-    let intervalMs = Self.navigationBarBackReadInterval * 1000
-    let first = TimedNavigationBarBackState(state: bar, startedMs: 1000)
-
-    let sameFrame = TimedNavigationBarBackState(state: bar, startedMs: 1000 + intervalMs / 2)
-    XCTAssertFalse(Self.navigationBarBackStateHeldStill(from: first, to: sameFrame))
-    let oneIntervalLater = TimedNavigationBarBackState(state: bar, startedMs: 1000 + intervalMs)
-    XCTAssertTrue(Self.navigationBarBackStateHeldStill(from: first, to: oneIntervalLater))
-    let movedLater = TimedNavigationBarBackState(state: moved, startedMs: 1000 + intervalMs)
-    XCTAssertFalse(Self.navigationBarBackStateHeldStill(from: first, to: movedLater))
-  }
-
   /// After the tap, only a change of the bar count, the back button count, or a back button label
-  /// shows a pop. A back button that only moved, such as by a large-title collapse, shows none.
+  /// shows a pop. A back button that only moved, such as by a large-title collapse, shows none, but
+  /// it is never a still bar before the tap.
   func testNavigationBarBackPoppedOnlyOnABarOrBackButtonChange() {
     let button = CGRect(x: 8, y: 54, width: 44, height: 44)
     let detail = NavigationBarBackState(backButtonLabels: [["Root"]], backButtonFrames: [button])
 
     let moved = NavigationBarBackState(backButtonLabels: [["Root"]], backButtonFrames: [button.offsetBy(dx: 0, dy: 30)])
     XCTAssertFalse(Self.navigationBarBackPopped(from: detail, to: moved))
+    XCTAssertNotEqual(moved, detail)
     let relabeled = NavigationBarBackState(backButtonLabels: [["Settings"]], backButtonFrames: [button])
     XCTAssertTrue(Self.navigationBarBackPopped(from: detail, to: relabeled))
     let atRoot = NavigationBarBackState(backButtonLabels: [[]], backButtonFrames: [])
 
@@ -137,10 +137,10 @@ than silently applied:
 `backInApp` is the only back command. On iOS the runner first reads the current tree, in the same
 call, for the navigation bar's system back button: a button with the identifier `BackButton` inside a
 navigation bar. It taps that button with a synthesized tap only when exactly one live, hittable
-candidate is found in a readable tree, and two reads in a row of the bar state, started at least
-0.05 s apart, agree and contain that button's frame; each round re-reads the buttons. The match
+candidate is found in a readable tree, and two reads in a row of the bar state, with a 0.05 s pause
+between them, agree and contain that button's frame; each round re-reads the buttons. The match
 places the snapshot frames at the window's screen origin, because a placed iPad window reports them
-from its own top-left, and allows 0.5 pt per edge for fractional frame values. No other button
+from its own top-left. No other button
 counts, whatever its label.
 The bar state is the labels of each navigation bar's `BackButton` children, one list per bar in
 bar order, and the frames of those buttons; one XCTest snapshot per bar. The still check before the
@@ -180,7 +180,7 @@ fills its screen; otherwise it refuses with `APP_SCREEN_UNRESOLVED`. Its failure
 | `APP_SCREEN_WINDOW_UNRESOLVED`, `APP_SCREEN_UNRESOLVED`, `APP_SCREEN_CAPTURE_UNRENDERABLE`, `APP_SCREEN_OFF_LIT_PANEL` | The screen could not be sampled before the swipe. | Nothing |
 | `BACK_SWIPE_NOT_DISPATCHED` | The swipe was refused before any touch went down, an XCTest query on the navigation bar hung before the tap, or the platform has no back command (visionOS; the daemon refuses it first). | Nothing |
 | `BACK_SWIPE_NO_CHANGE` | The swipe was sent and the sampled grid (48×96 grayscale cells, with the top 7 rows always left out; in portrait they hold the status bar and Dynamic Island, and in landscape the iPhone status bar is hidden and the Dynamic Island sits at a side edge, outside those rows) changed in at most 1% of the remaining cells by more than 24 of 256 levels. | The swipe |
-| `BACK_SWIPE_UNVERIFIED` | The swipe may have run, or the back button was tapped and the bar did not change within 1 s or a query on it hung; the outcome is unknown. | Possibly the swipe, or the tap |
+| `BACK_SWIPE_UNVERIFIED` | The swipe may have run, or the back button was tapped and the bar's back buttons did not change within 1 s or a query on it hung; the outcome is unknown. | Possibly the swipe, or the tap |
 
 The swipe is first resolved up to its contact. Then the settle window is a run of samples, with a
 0.05 s pause between captures plus each capture's own time, that agree for as long as the gap the swipe will be credited across: a contact
 
@@ -286,7 +286,7 @@ export const SYSTEM_COMMAND_OUTPUT_SCHEMAS = {
 const appStateCommandDescription =
   'Show foreground app/activity (Android and HarmonyOS; iOS and macOS answer per session)';
 const backCommandDescription =
-  'Navigate back in the app or through system navigation. The in-app mode targets the app navigation stack; system targets platform back behavior. On iOS both modes press the navigation bar system back button (identifier BackButton) only when exactly one hittable one is found in a readable accessibility tree, and succeed only when the number of navigation bars, the number of back buttons, or a back button title then changes (a bar title or a moved back button alone never counts, so a pop that keeps the same back button title and bar count reports back_swipe_unverified); with no such button, two candidates, or an unreadable tree, they swipe from the left edge instead (on an iPad whose app window cannot be resolved, only while the app fills the screen) and succeed only when the app screen changes. Reason back_swipe_no_change: the swipe was sent and the screen did not change; a visible back or close control is an alternative. Reason back_swipe_unverified: the button was pressed but the navigation bar did not change within 1 s, or the swipe may or may not have navigated, because the screen kept changing before it or could not be sampled after it; the resulting screen is unconfirmed. Reason back_swipe_not_dispatched, or a screen that cannot be sampled before the swipe, means nothing was sent. An app with a left-edge drawer may open the drawer instead. A visible back or close control can be targeted directly by its ref.';
+  "Navigate back in the app or through system navigation. The in-app mode targets the app navigation stack; system targets platform back behavior. On iOS both modes press the navigation bar system back button (identifier BackButton) only when exactly one hittable one is found in a readable accessibility tree, and succeed only when the number of navigation bars, the number of back buttons, or a back button title then changes (a bar title or a moved back button alone never counts, so a pop that keeps the same back button title and bar count reports back_swipe_unverified); with no such button, two candidates, or an unreadable tree, they swipe from the left edge instead (on an iPad whose app window cannot be resolved, only while the app fills the screen) and succeed only when the app screen changes. Reason back_swipe_no_change: the swipe was sent and the screen did not change; a visible back or close control is an alternative. Reason back_swipe_unverified: the button was pressed but the navigation bar's back buttons did not change within 1 s, or the swipe may or may not have navigated, because the screen kept changing before it or could not be sampled after it; the resulting screen is unconfirmed. Reason back_swipe_not_dispatched, or a screen that cannot be sampled before the swipe, means nothing was sent. An app with a left-edge drawer may open the drawer instead. A visible back or close control can be targeted directly by its ref.";
 const homeCommandDescription =
   'Send the selected device to its home screen. This leaves the app session open but moves the foreground away from the app.';
 const orientationCommandDescription =