diff --git a/tests/AcDream.App.Tests/UI/Layout/MapHousePanelSlotProbeTests.cs b/tests/AcDream.App.Tests/UI/Layout/MapHousePanelSlotProbeTests.cs
new file mode 100644
index 00000000..9f2850b2
--- /dev/null
+++ b/tests/AcDream.App.Tests/UI/Layout/MapHousePanelSlotProbeTests.cs
@@ -0,0 +1,215 @@
+using System.IO;
+using AcDream.App.UI.Layout;
+using DatReaderWriter;
+using DatReaderWriter.Options;
+
+namespace AcDream.App.Tests.UI.Layout;
+
+/// <summary>
+/// Batch C (overnight hover/UI round, Map/House toolbar panel) discovery
+/// probe. Desk research (docs/research/2026-08-17-map-house-recon.md,
+/// itself built on the FA campaign's already-DAT-verified 16-slot
+/// <c>gmPanelUI::SetupChildren</c> dump) already resolved host
+/// <c>0x2100006E</c> slot <c>0x1000018C</c> / <c>RetailPanelCatalog</c> id
+/// <b>16</b> as the Map/House tab host, and toolbar button
+/// <c>0x1000019A</c> as the (currently ghosted) button that opens it. This
+/// probe RE-CONFIRMS both against the live installed DATs rather than
+/// trusting the committed fixture, and additionally reads the facts the
+/// decomp explains the MEANING of but not the VALUE of: the tab table, the
+/// <c>m_pMap</c> marker-area rect + hotspot template attrs (<c>0x47</c>/
+/// <c>0x48</c>), and the House ListBox's authored default content.
+///
+/// <para>
+/// Kept as a permanent env-gated pin (like <c>FaPanelSlotProbeTests</c>) —
+/// it documents authored truth for future sessions, not a one-shot
+/// throwaway.
+/// </para>
+/// </summary>
+public sealed class MapHousePanelSlotProbeTests
+{
+    private const uint HostLayoutId = 0x2100006Eu;
+    private const uint SlotElementId = 0x1000018Cu;
+    private const uint ToolbarLayoutId = 0x21000016u;
+    private const uint MapHouseToolbarButtonId = 0x1000019Au;
+
+    // gmMapUI PostInit signature children (pc:171993).
+    private const uint MapDateTimeTextId = 0x100001EBu;
+    private const uint MapWidgetId = 0x100001ECu;
+    private const uint MapPlayerIconId = 0x100001EDu;
+    private const uint MapHouseIconId = 0x100001EEu;
+    private const uint MapCoordinateTextId = 0x100001EFu;
+
+    // gmHouseUI PostInit signature child (pc:172581).
+    private const uint HouseTextBoxId = 0x100001E6u;
+
+    [Fact]
+    public void ProbeMapHousePanelSlot()
+    {
+        if (Environment.GetEnvironmentVariable("ACDREAM_PROBE_LIVE_MOUNT") != "1")
+            return;
+
+        var datDir = Environment.GetEnvironmentVariable("ACDREAM_DAT_DIR")
+            ?? Path.Combine(
+                Environment.GetFolderPath(Environment.SpecialFolder.UserProfile),
+                "Documents",
+                "Asheron's Call");
+        using var dats = new DatCollection(datDir, DatAccessType.Read);
+
+        // 1) The slot itself — panel id, type, tab table.
+        ElementInfo? slot = LayoutImporter.ImportInfos(dats, HostLayoutId, SlotElementId);
+        if (slot is null)
+        {
+            Console.WriteLine($"[maphouse] slot 0x{SlotElementId:X8} -> IMPORT NULL");
+            return;
+        }
+
+        string panelId = slot.TryGetEffectiveProperty(0x10000029u, out var p)
+            ? $"{p.UnsignedValue} (kind={p.Kind})"
+            : "ABSENT";
+        Console.WriteLine(
+            $"[maphouse] slot 0x{SlotElementId:X8} panelId={panelId} type={slot.Type} "
+            + $"({slot.X},{slot.Y} {slot.Width}x{slot.Height}) children={slot.Children.Count} "
+            + $"tabTableCount={slot.TabTable.Count}");
+        foreach (var tab in slot.TabTable)
+            Console.WriteLine(
+                $"[maphouse]     tab button=0x{tab.ButtonElementId:X8} page=0x{tab.PageElementId:X8} "
+                + $"default={tab.IsDefault}");
+
+        bool hasMapSignature = FindInfo(slot, MapDateTimeTextId) || FindInfo(slot, MapWidgetId);
+        bool hasHouseSignature = FindInfo(slot, HouseTextBoxId);
+        Console.WriteLine(
+            $"[maphouse] hasMapSignature={hasMapSignature} hasHouseSignature={hasHouseSignature}");
+
+        // Two levels of children so we can see the tab pages' own shape even
+        // if the recovered signature ids above are absent from this install.
+        foreach (ElementInfo c in slot.Children)
+        {
+            Console.WriteLine(
+                $"[maphouse]     child 0x{c.Id:X8} type={c.Type} ({c.X},{c.Y} {c.Width}x{c.Height}) "
+                + $"kids={c.Children.Count}");
+            foreach (ElementInfo g in c.Children)
+                Console.WriteLine(
+                    $"[maphouse]         g 0x{g.Id:X8} type={g.Type} ({g.X},{g.Y} {g.Width}x{g.Height}) "
+                    + $"kids={g.Children.Count}");
+        }
+
+        // 2) The toolbar button that should open panel 16.
+        ElementInfo? button = LayoutImporter.ImportInfos(dats, ToolbarLayoutId, MapHouseToolbarButtonId);
+        string buttonPanelId = button is not null && button.TryGetEffectiveProperty(0x10000029u, out var bp)
+            ? $"{bp.UnsignedValue} (kind={bp.Kind})"
+            : "ABSENT/NULL";
+        Console.WriteLine($"[maphouse] toolbar button 0x{MapHouseToolbarButtonId:X8} panelId={buttonPanelId}");
+
+        // 3) m_pMap's own marker-area rect + hotspot template attrs.
+        ElementInfo? map = FindDescendant(slot, MapWidgetId);
+        if (map is null)
+        {
+            Console.WriteLine($"[maphouse] m_pMap 0x{MapWidgetId:X8} NOT FOUND under slot");
+        }
+        else
+        {
+            string x0 = map.TryGetEffectiveProperty(0x1000004Eu, out var vx0) ? vx0.IntegerValue.ToString() : "ABSENT";
+            string x1 = map.TryGetEffectiveProperty(0x1000004Fu, out var vx1) ? vx1.IntegerValue.ToString() : "ABSENT";
+            string y0 = map.TryGetEffectiveProperty(0x10000050u, out var vy0) ? vy0.IntegerValue.ToString() : "ABSENT";
+            string y1 = map.TryGetEffectiveProperty(0x10000051u, out var vy1) ? vy1.IntegerValue.ToString() : "ABSENT";
+            bool hasTemplateElement = map.TryGetEffectiveProperty(0x47u, out var te);
+            bool hasTemplateLayoutDid = map.TryGetEffectiveProperty(0x48u, out var tl);
+            string templateElement = hasTemplateElement
+                ? $"0x{te.UnsignedValue:X8} (kind={te.Kind})" : "ABSENT";
+            string templateLayoutDid = hasTemplateLayoutDid
+                ? $"0x{tl.UnsignedValue:X8} (kind={tl.Kind})" : "ABSENT";
+            Console.WriteLine(
+                $"[maphouse] m_pMap 0x{MapWidgetId:X8} markerArea=({x0},{y0})-({x1},{y1}) "
+                + $"templateElement(attr 0x47)={templateElement} templateLayoutDid(attr 0x48)={templateLayoutDid} "
+                + $"type={map.Type} children={map.Children.Count}");
+
+            // If both resolved, try importing the actual hotspot template so we
+            // know what widget class AddMapNote instantiates per town.
+            if (hasTemplateElement && hasTemplateLayoutDid && tl.UnsignedValue != 0)
+            {
+                ElementInfo? template = LayoutImporter.ImportInfos(dats, (uint)tl.UnsignedValue, (uint)te.UnsignedValue);
+                Console.WriteLine(template is null
+                    ? "[maphouse] hotspot template IMPORT NULL"
+                    : $"[maphouse] hotspot template type={template.Type} "
+                      + $"({template.Width}x{template.Height}) states={template.States.Count} "
+                      + $"stateMedia={template.StateMedia.Count}");
+            }
+        }
+
+        ElementInfo? playerIcon = FindDescendant(slot, MapPlayerIconId);
+        ElementInfo? houseIcon = FindDescendant(slot, MapHouseIconId);
+        Console.WriteLine(
+            $"[maphouse] playerIcon found={playerIcon is not null} type={playerIcon?.Type} "
+            + $"stateMedia={playerIcon?.StateMedia.Count}");
+        Console.WriteLine(
+            $"[maphouse] houseIcon found={houseIcon is not null} type={houseIcon?.Type} "
+            + $"stateMedia={houseIcon?.StateMedia.Count}");
+
+        // 4) House ListBox default content — dump its own children/text so we
+        // know whether "You do not currently own a house..." is authored
+        // directly in the layout or synthesized at runtime.
+        ElementInfo? houseBox = FindDescendant(slot, HouseTextBoxId);
+        if (houseBox is null)
+        {
+            Console.WriteLine($"[maphouse] house listbox 0x{HouseTextBoxId:X8} NOT FOUND under slot");
+        }
+        else
+        {
+            Console.WriteLine(
+                $"[maphouse] house listbox 0x{HouseTextBoxId:X8} type={houseBox.Type} "
+                + $"children={houseBox.Children.Count} templateListCount={houseBox.TemplateList.Count} "
+                + $"scrollbar=0x{houseBox.ScrollbarElementId:X8}");
+            foreach (var t in houseBox.TemplateList)
+            {
+                Console.WriteLine(
+                    $"[maphouse]     template layoutId=0x{t.TemplateLayoutId:X8} elementId=0x{t.TemplateElementId:X8}");
+                ElementInfo? rowTemplate = LayoutImporter.ImportInfos(dats, t.TemplateLayoutId, t.TemplateElementId);
+                if (rowTemplate is null)
+                {
+                    Console.WriteLine("[maphouse]         row template IMPORT NULL");
+                    continue;
+                }
+                Console.WriteLine(
+                    $"[maphouse]         row template type={rowTemplate.Type} "
+                    + $"({rowTemplate.Width}x{rowTemplate.Height}) kids={rowTemplate.Children.Count}");
+                foreach (ElementInfo rc in rowTemplate.Children)
+                    Console.WriteLine(
+                        $"[maphouse]             rc 0x{rc.Id:X8} type={rc.Type} ({rc.X},{rc.Y} {rc.Width}x{rc.Height})");
+            }
+            foreach (ElementInfo row in houseBox.Children)
+            {
+                string caption = row.TryGetEffectiveProperty(0x17u, out var cap)
+                    ? $"StringInfo(table={cap.StringInfoValue.TableId:X},id={cap.StringInfoValue.StringId:X},lit={cap.StringInfoValue.English != 0})"
+                    : "NO 0x17";
+                Console.WriteLine(
+                    $"[maphouse]     row 0x{row.Id:X8} type={row.Type} caption={caption} kids={row.Children.Count}");
+                foreach (ElementInfo g in row.Children)
+                {
+                    string gcaption = g.TryGetEffectiveProperty(0x17u, out var gcap)
+                        ? $"StringInfo(table={gcap.StringInfoValue.TableId:X},id={gcap.StringInfoValue.StringId:X})"
+                        : "NO 0x17";
+                    Console.WriteLine($"[maphouse]         g 0x{g.Id:X8} type={g.Type} caption={gcaption}");
+                }
+            }
+        }
+    }
+
+    private static bool FindInfo(ElementInfo info, uint id)
+    {
+        if (info.Id == id) return true;
+        foreach (ElementInfo c in info.Children)
+            if (FindInfo(c, id)) return true;
+        return false;
+    }
+
+    private static ElementInfo? FindDescendant(ElementInfo info, uint id)
+    {
+        if (info.Id == id) return info;
+        foreach (ElementInfo c in info.Children)
+        {
+            ElementInfo? found = FindDescendant(c, id);
+            if (found is not null) return found;
+        }
+        return null;
+    }
+}