diff --git a/util/forge/config.py b/util/forge/config.py
index e260d60..c28c7e6 100644
--- a/util/forge/config.py
+++ b/util/forge/config.py
@@ -1,4 +1,8 @@
-"""Forge plugin build — hotkey injection at install/apply time."""
+"""Forge plugin build — install-time hotkey and UI scale injection.
+
+Vanilla Forge_MV.js / Forge_MZ.js from len's repo stay untouched on disk.
+Patches are applied in memory when installing or applying settings to a game.
+"""
 
 from __future__ import annotations
 
@@ -7,6 +11,7 @@ import re
 from pathlib import Path
 
 from util.playtest.config import load_config
+from util.forge.scale_patches import apply_ui_scale_patches
 
 _PKG_ROOT = Path(__file__).resolve().parent
 
@@ -34,21 +39,21 @@ def _js_literal(value) -> str:
 
 
 def plugin_entry(engine: str, hotkey: str, ui_scale: str = "auto") -> str:
-    _ = ui_scale  # reserved; vanilla Forge has no UI scale param yet
     hk = _js_literal(hotkey.strip() or "F10")
+    scale = _js_literal(ui_scale.strip() or "auto")
     name = PLUGIN_BY_ENGINE[engine]
     if engine == "MZ":
         return (
             f'        {{ "name": "{name}", "status": true, '
             f'"description": "Forge — in-game cheat & editor overlay", '
             f'"parameters": {{ "hotkey": {hk}, "speedKey": "Control", '
-            f'"startOpen": "false", "itemMaxOverride": "0" }} }}'
+            f'"startOpen": "false", "itemMaxOverride": "0", "uiScale": {scale} }} }}'
         )
     return (
         f'        {{ "name": "{name}", "status": true, '
         f'"description": "Forge — in-game cheat & editor overlay", '
         f'"parameters": {{ "Hotkey": {hk}, "SpeedKey": "Control", '
-        f'"StartOpen": "false", "ItemMaxOverride": "0" }} }}'
+        f'"StartOpen": "false", "ItemMaxOverride": "0", "UiScale": {scale} }} }}'
     )
 
 
@@ -76,38 +81,77 @@ def _patch_forge_hotkey(forge_text: str, hotkey: str, engine: str) -> str:
     return forge_text
 
 
-def _patch_forge_runtime_hotkey(forge_text: str, hotkey: str, engine: str) -> str:
-    hk = json.dumps(hotkey.strip() or "F10")
+def _patch_forge_ui_scale_default(forge_text: str, ui_scale: str, engine: str) -> str:
+    scale = ui_scale.strip() or "auto"
     if engine == "MZ":
-        forge_text, n = re.subn(
+        pattern = r"(\* @param uiScale\s*\n(?:\s*\*[^\n]*\n)*?\s*\* @default )auto"
+        if scale != "auto":
+            forge_text, n = re.subn(pattern, rf"\g<1>{scale}", forge_text, count=1)
+            if n == 0:
+                raise ValueError("Could not patch @default uiScale in Forge_MZ.js")
+        return forge_text
+
+    pattern = r"(\* @param UiScale\s*\n(?:\s*\*[^\n]*\n)*?\s*\* @default )auto"
+    if scale != "auto":
+        forge_text, n = re.subn(pattern, rf"\g<1>{scale}", forge_text, count=1)
+        if n == 0:
+            raise ValueError("Could not patch @default UiScale in Forge_MV.js")
+    return forge_text
+
+
+def _patch_forge_mtc_defaults(forge_text: str, hotkey: str, ui_scale: str) -> str:
+    hk = json.dumps(hotkey.strip() or "F10")
+    scale = json.dumps(str(ui_scale or "auto").strip() or "auto")
+    forge_text = re.sub(r"_hotkey: 'F10'", f"_hotkey: {hk}", forge_text, count=1)
+    forge_text = re.sub(r"_uiScale: 'auto'", f"_uiScale: {scale}", forge_text, count=1)
+    return forge_text
+
+
+def _patch_forge_runtime(forge_text: str, hotkey: str, ui_scale: str, engine: str) -> str:
+    hk = json.dumps(hotkey.strip() or "F10")
+    scale = json.dumps(str(ui_scale or "auto").strip() or "auto")
+    if engine == "MZ":
+        forge_text = re.sub(
             r"window\.Forge\._hotkey = \(P\.hotkey \|\| '[^']*'\)\.trim\(\);",
             f"window.Forge._hotkey = {hk};",
             forge_text,
             count=1,
         )
-        if n == 0:
-            raise ValueError("Could not patch runtime hotkey in Forge_MZ.js")
+        forge_text = re.sub(
+            r"window\.Forge\._uiScale = \(P\.uiScale \|\| '[^']*'\)\.trim\(\);",
+            f"window.Forge._uiScale = {scale};",
+            forge_text,
+            count=1,
+        )
         return forge_text
 
-    forge_text, n = re.subn(
+    forge_text = re.sub(
         r"window\.Forge\._hotkey = \(P\.Hotkey \|\| '[^']*'\)\.trim\(\);",
         f"window.Forge._hotkey = {hk};",
         forge_text,
         count=1,
     )
-    if n == 0:
-        raise ValueError("Could not patch runtime hotkey in Forge_MV.js")
+    forge_text = re.sub(
+        r"window\.Forge\._uiScale = \(P\.UiScale \|\| '[^']*'\)\.trim\(\);",
+        f"window.Forge._uiScale = {scale};",
+        forge_text,
+        count=1,
+    )
     return forge_text
 
 
 def prepare_forge_js(engine: str, source: Path | None = None, cfg: dict | None = None) -> str:
-    """Build Forge_MV.js or Forge_MZ.js with configured hotkey."""
+    """Build the Forge plugin written into a game folder (vanilla source + Dazed patches)."""
     src = source or bundled_plugin_path(engine)
     effective = {**load_config(), **(cfg or {})}
     hotkey = effective.get("forgeHotkey", "F10")
-    text = src.read_text(encoding="utf-8")
+    ui_scale = effective.get("uiScale", "auto")
+
+    text = apply_ui_scale_patches(src.read_text(encoding="utf-8"), engine)
     text = _patch_forge_hotkey(text, hotkey, engine)
-    text = _patch_forge_runtime_hotkey(text, hotkey, engine)
+    text = _patch_forge_ui_scale_default(text, str(ui_scale), engine)
+    text = _patch_forge_mtc_defaults(text, hotkey, str(ui_scale))
+    text = _patch_forge_runtime(text, hotkey, str(ui_scale), engine)
     return text
 
 
diff --git a/util/forge/scale_patches.py b/util/forge/scale_patches.py
new file mode 100644
index 0000000..a727ad2
--- /dev/null
+++ b/util/forge/scale_patches.py
@@ -0,0 +1,186 @@
+"""UI scale patches applied at Forge install/apply time only.
+
+Vanilla Forge_MZ.js / Forge_MV.js from len's repo are never modified on disk.
+prepare_forge_js() reads the bundled upstream copy and applies these patches
+in memory before writing the result into the game folder.
+"""
+
+from __future__ import annotations
+
+import re
+
+_UI_SCALE_HELP_MZ = (
+    " *\n"
+    " * @param uiScale\n"
+    " * @text UI Scale\n"
+    " * @desc Overlay size. Use auto to match game width, or a number like 1.5 or 2.\n"
+    " * @type string\n"
+    " * @default auto\n"
+)
+
+_UI_SCALE_HELP_MV = (
+    " *\n"
+    " * @param UiScale\n"
+    " * @desc Overlay size. Use auto to match the window, or a number like 1.5 or 2.\n"
+    " * @default auto\n"
+)
+
+_SCALE_BLOCK = """\
+    function resolveUiScale(v) {
+      if (v !== 'auto' && v != null && String(v).trim() !== '') {
+        var n = parseFloat(v);
+        if (!isNaN(n) && n > 0) return Math.max(0.75, Math.min(3, n));
+      }
+      var base = 816;
+      var gameW = (typeof Graphics !== 'undefined' && Graphics.width) ? Graphics.width : 0;
+      var viewW = window.innerWidth || document.documentElement.clientWidth || base;
+      var w = Math.max(gameW || base, viewW);
+      var scale = w / base;
+      var dpr = window.devicePixelRatio || 1;
+      if (dpr > 1.15) scale *= Math.min(2, 0.75 + dpr * 0.35);
+      return Math.max(1, Math.min(2.75, scale));
+    }
+    function scalePx(n, fx) {
+      if (!fx || fx === 1) return n;
+      return Math.round(n * fx);
+    }
+    function scalePxCss(css, fx) {
+      if (!fx || fx === 1) return css;
+      return css.replace(/(\\d+(?:\\.\\d+)?)px/g, function (_, n) {
+        return scalePx(parseFloat(n), fx) + 'px';
+      });
+    }
+    function scaleStyle(style, fx) {
+      if (!style || !fx || fx === 1) return style;
+      return style.replace(/(\\d+(?:\\.\\d+)?)px/g, function (_, n) {
+        return scalePx(parseFloat(n), fx) + 'px';
+      });
+    }
+    var uiFx = resolveUiScale(API._uiScale || 'auto');
+"""
+
+_SCROLLBAR_OLD = (
+    "::-webkit-scrollbar{width:9px;height:9px}\\\n"
+    "::-webkit-scrollbar-track{background:transparent}\\\n"
+    "::-webkit-scrollbar-thumb{background:var(--fg-border-strong);border-radius:5px}\\\n"
+    "::-webkit-scrollbar-thumb:hover{background:var(--fg-text-faint)}\";"
+)
+
+_SCROLLBAR_NEW = (
+    ".fg-list::-webkit-scrollbar,.fg-rail::-webkit-scrollbar,.fg-detail::-webkit-scrollbar{width:9px}\\\n"
+    ".fg-list::-webkit-scrollbar-thumb,.fg-detail::-webkit-scrollbar-thumb{background:var(--fg-border-strong);border-radius:5px}\";"
+)
+
+
+def _sub(text: str, pattern: str, repl, *, label: str, count: int = 1) -> str:
+    new_text, n = re.subn(pattern, repl, text, count=count)
+    if n != count:
+        raise ValueError(f"Forge UI scale patch failed ({label}): expected {count} replacement(s), got {n}")
+    return new_text
+
+
+def apply_ui_scale_patches(text: str, engine: str) -> str:
+    """Return upstream Forge JS with Dazed overlay scaling (install-time only)."""
+    if engine == "MZ":
+        text = _sub(
+            text,
+            r"( \* @default 0\n)( \*\n \* @command open)",
+            rf"\1{_UI_SCALE_HELP_MZ}\2",
+            label="MZ uiScale param",
+        )
+        scaffold_scale = "    window.Forge._uiScale = (P.uiScale || 'auto').trim();\n"
+        scaffold_pattern = (
+            r"(    window\.Forge\._itemMaxOverride = Number\(P\.itemMaxOverride\) \|\| 0;\n)"
+        )
+    else:
+        text = _sub(
+            text,
+            r"( \* @default 0\n)( \*\n \* @help)",
+            rf"\1{_UI_SCALE_HELP_MV}\2",
+            label="MV UiScale param",
+        )
+        scaffold_scale = "    window.Forge._uiScale = (P.UiScale || 'auto').trim();\n"
+        scaffold_pattern = (
+            r"(    window\.Forge\._itemMaxOverride = Number\(P\.ItemMaxOverride\) \|\| 0;\n)"
+        )
+
+    text = _sub(
+        text,
+        r"(_speedBoost: 2) \};",
+        r"\1, _uiScale: 'auto' };",
+        label="MTC _uiScale default",
+    )
+
+    text = _sub(
+        text,
+        r"(    function load\(k, d\) \{ try \{ var s = localStorage\.getItem\(LS \+ k\); return s == null \? d : JSON\.parse\(s\); \} catch \(e\) \{ return d; \} \}\n)"
+        r"(    // persisted speed settings)",
+        lambda m: m.group(1) + _SCALE_BLOCK + m.group(2),
+        label="UI scale helpers",
+    )
+
+    text = _sub(
+        text,
+        r"else if \(k === 'style'\) n\.setAttribute\('style', props\[k\]\);",
+        "else if (k === 'style') n.setAttribute('style', scaleStyle(props[k], uiFx));",
+        label="el() style scaling",
+    )
+
+    text = text.replace(_SCROLLBAR_OLD, _SCROLLBAR_NEW)
+
+    text = _sub(
+        text,
+        "pointer-events:none!important';",
+        "pointer-events:none!important;overflow:visible!important';",
+        label="host overflow",
+    )
+
+    text = _sub(
+        text,
+        r"shadow\.appendChild\(el\('style', \{ text: CSS \}\)\);",
+        "shadow.appendChild(el('style', { text: scalePxCss(CSS, uiFx) }));",
+        label="scaled stylesheet",
+    )
+
+    replacements = [
+        (
+            r"var st = load\('panel', \{ x: 16, y: 16, w: Math\.min\(880, vw - 32\), h: Math\.min\(560, vh - 32\) \}\);",
+            "var st = load('panel', { x: scalePx(16, uiFx), y: scalePx(16, uiFx), w: Math.min(scalePx(880, uiFx), vw - scalePx(32, uiFx)), h: Math.min(scalePx(560, uiFx), vh - scalePx(32, uiFx)) });",
+            "panel defaults",
+        ),
+        (
+            r"st\.w = Math\.max\(420, Math\.min\(st\.w, vw - 8\)\); st\.h = Math\.max\(320, Math\.min\(st\.h, vh - 8\)\);",
+            "st.w = Math.max(scalePx(420, uiFx), Math.min(st.w, vw - scalePx(8, uiFx))); st.h = Math.max(scalePx(320, uiFx), Math.min(st.h, vh - scalePx(8, uiFx)));",
+            "panel bounds",
+        ),
+        (
+            r"var lp = load\('launcherPos', \{ x: vw - 56, y: vh - 56 \}\);",
+            "var lp = load('launcherPos', { x: vw - scalePx(56, uiFx), y: vh - scalePx(56, uiFx) });",
+            "launcher defaults",
+        ),
+        (
+            r"lp\.x = Math\.max\(4, Math\.min\(lp\.x, vw - 46\)\); lp\.y = Math\.max\(4, Math\.min\(lp\.y, vh - 46\)\);",
+            "lp.x = Math.max(scalePx(4, uiFx), Math.min(lp.x, vw - scalePx(46, uiFx))); lp.y = Math.max(scalePx(4, uiFx), Math.min(lp.y, vh - scalePx(46, uiFx)));",
+            "launcher bounds",
+        ),
+        (
+            r"Math\.min\(window\.innerHeight - 30, oy \+ dy\)",
+            "Math.min(window.innerHeight - scalePx(30, uiFx), oy + dy)",
+            "drag height clamp",
+        ),
+        (
+            r"var w = Math\.max\(480, ow \+ ev\.clientX - sx\), h = Math\.max\(360, oh \+ ev\.clientY - sy\);",
+            "var w = Math.max(scalePx(480, uiFx), ow + ev.clientX - sx), h = Math.max(scalePx(360, uiFx), oh + ev.clientY - sy);",
+            "resize minimums",
+        ),
+        (
+            r"var rowH = opts\.rowH \|\| 30, pool = \[\], model = \[\], view = \[\], query = '';",
+            "var rowH = opts.rowH || scalePx(30, uiFx), pool = [], model = [], view = [], query = '';",
+            "virtual list row height",
+        ),
+    ]
+    for pattern, repl, label in replacements:
+        text = _sub(text, pattern, repl, label=label)
+
+    text = _sub(text, scaffold_pattern, lambda m: m.group(1) + scaffold_scale, label="scaffolding uiScale")
+    return text