diff --git a/goodwe_controller/DECISIONS/UX-13-one-layout-table.md b/goodwe_controller/DECISIONS/UX-13-one-layout-table.md
index b23019f..540cbb0 100644
--- a/goodwe_controller/DECISIONS/UX-13-one-layout-table.md
+++ b/goodwe_controller/DECISIONS/UX-13-one-layout-table.md
@@ -60,6 +60,12 @@ What UX-02 made authoritative stays authoritative:
   new validator. At P0: 261 calls, 158 refused, no refusal changed.
 - test_selfconfig.py part 5 still checks the old page script; P1 moves the page
   into `app/static/` and the same check applies there.
+- P2: the Installer view (`app/static/settings.js`) draws from
+  `app/uipage.py`, which serialises the table and names no key itself
+  (test_uilayout part 5, test_settings part 2). The view posts its page model
+  to the existing `/config/validate` and `/config/save`, which turn it into
+  options with `ui_to_options()` before the shipped validator runs. No route
+  was added.
 
 ## 4. What this costs
 
diff --git a/goodwe_controller/app/hass.py b/goodwe_controller/app/hass.py
index 3835e1d..a2546c1 100644
--- a/goodwe_controller/app/hass.py
+++ b/goodwe_controller/app/hass.py
@@ -132,8 +132,15 @@ class HomeAssistant:
         except aiohttp.ClientConnectionError as err:
             OUTAGE.down("api", "no connection", f"read all states: {err}")
             return None
-        except (aiohttp.ClientError, TimeoutError, ValueError) as err:
-            self._moan("read:*", "Reading the entity list failed: %s", err)
+        # A timeout's own text is empty, so the line names the wait instead
+        # (UX-13 P1 test, c).
+        except TimeoutError:
+            self._moan("read:*", "Reading the entity list failed: no answer "
+                       "within %s seconds.", STATES_TIMEOUT_S)
+            return None
+        except (aiohttp.ClientError, ValueError) as err:
+            self._moan("read:*", "Reading the entity list failed: %s",
+                       str(err) or type(err).__name__)
             return None
         if not isinstance(obj, list):
             self._moan("shape:*", "The entity list is not a list: %.80r", obj)
diff --git a/goodwe_controller/app/homeview.py b/goodwe_controller/app/homeview.py
index 4e58505..250720d 100644
--- a/goodwe_controller/app/homeview.py
+++ b/goodwe_controller/app/homeview.py
@@ -82,7 +82,7 @@ def flow(w, *, shadow=False):
     return "resting"
 
 
-def now_block(*, grid_w, pv_w, batt_w, has_solar, shadow):
+def now_block(*, grid_w, pv_w, batt_w, has_solar, shadow, settled=True):
     """The four tiles. `house_w` needs all three readings, so without a solar
     reading it is None rather than a number that leaves the sun out."""
     house, disagree = None, False
@@ -105,7 +105,7 @@ def now_block(*, grid_w, pv_w, batt_w, has_solar, shadow):
             "solar": tile_solar(pv_w, has_solar),
             "house": tile_house(house, has_solar, disagree),
             "grid": tile_grid(grid_w),
-            "batt": tile_batt(batt_w, shadow),
+            "batt": tile_batt(batt_w, shadow, settled),
         },
     }
 
@@ -174,7 +174,7 @@ def hour_bars(points, day0, day1):
         price = (sum(p.eur_per_kwh for p in inside) / len(inside)
                  if inside else None)
         bars.append({"h": k, "start": a.isoformat(), "label": hhmm(a),
-                     "end_label": hhmm(b),
+                     "end_label": hhmm(b), "points": len(inside),
                      "eur_kwh": None if price is None else round(price, 4),
                      "estimate": bool(inside) and any(p.provisional
                                                       for p in inside),
@@ -196,6 +196,19 @@ def hour_bars(points, day0, day1):
     return bars
 
 
+def day_range(points):
+    """(lowest, highest) of today's published points, as {eur_kwh, label},
+    or (None, None). The feed's own points, like the trade legs, not the
+    chart's hour averages."""
+    firm = [p for p in points if not p.provisional]
+    if not firm:
+        return None, None
+    lo = min(firm, key=lambda p: p.eur_per_kwh)
+    hi = max(firm, key=lambda p: p.eur_per_kwh)
+    return ({"eur_kwh": round(lo.eur_per_kwh, 4), "label": hhmm(lo.start)},
+            {"eur_kwh": round(hi.eur_per_kwh, 4), "label": hhmm(hi.start)})
+
+
 # --------------------------------------------------------------------------- #
 # The plan, per battery
 # --------------------------------------------------------------------------- #
@@ -407,7 +420,7 @@ def region_of(opts):
             if rid in REGION_PRESETS else None}
 
 
-def build_plan(c, now, shadow, running, held=False):
+def build_plan(c, now, shadow, running, held=False, settled=True):
     day0, day1 = local_day(now)
     fresh = c.fresh_tariff_plan(now)
     plan = fresh
@@ -477,17 +490,15 @@ def build_plan(c, now, shadow, running, held=False):
         "day": brussels(now).date().isoformat(),
         "now_h": round(_hours(now, day0), 3),
         "hours": int(round(_hours(day1, day0))),
-        "verdict": VERDICT[verdict_key],
+        "verdict": (VERDICT[verdict_key] if settled or verdict_key != "held"
+                    else ZERO_GOING),
         "verdict_key": verdict_key,
-        "head": plan_head(verdict_key, shadow),
+        "head": plan_head(verdict_key, shadow, settled),
         "prices": bars,
         "runs": runs,
         "lines": lines,
         "why": c.why_words,
-        "price_line": line_prices(
-            price_now,
-            min(known, key=lambda b: b["eur_kwh"]) if known else None,
-            max(known, key=lambda b: b["eur_kwh"]) if known else None),
+        "price_line": line_prices(price_now, *day_range(seen)),
         "tomorrow_line": line_tomorrow(tomorrow) if feed else "",
         "region": region,
         "region_line": (line_region(region["id"], region["year"])
@@ -499,6 +510,13 @@ def build_plan(c, now, shadow, running, held=False):
 # --------------------------------------------------------------------------- #
 # Batteries, attention, month peak, control
 # --------------------------------------------------------------------------- #
+def at_zero(inv) -> bool:
+    """Has this inverter's last accepted power request reached 0 W? A stop or
+    an alarm asks for 0 W at once, but the inverter gets it with the next
+    write, so until then the page says "Going to 0 W" (UX-13 P1 test, a)."""
+    return abs(inv.standing_w()) < 1.0
+
+
 def battery_rows(c, shadow, running, held=False):
     shares = {}
     alloc = getattr(c, "allocation", None)
@@ -521,7 +539,8 @@ def battery_rows(c, shadow, running, held=False):
             "maintenance": phase,
             "now": battery_now(inv.soc, inv.batt, phase=phase, shadow=shadow,
                                running=running, held=held,
-                               would_w=shares.get(inv.name)),
+                               would_w=shares.get(inv.name),
+                               settled=at_zero(inv)),
             # Per-battery reasons arrive with battery modes (OPT-11).
             "why": None,
         })
@@ -633,15 +652,18 @@ def build(c, *, level: str, checks: list, now: datetime | None = None) -> dict:
     # what the add-on would do.
     held = level == "bad" and not shadow
     running = (bool(c.auto) or shadow) and not held
+    settled = all(at_zero(inv) for inv in c.inverters)
     ctl = next((r for r in checks if r.get("id") == "controller"), None)
     return {
         "state": {"kind": kind, "pill": pill(kind),
                   "ran": ctl.get("text", "") if ctl else "",
                   "sub": banner_sub(kind)},
         "now": now_block(grid_w=c.grid, pv_w=c.pv_w, batt_w=c.site_batt_w,
-                         has_solar=bool(c.pv_roster), shadow=shadow),
+                         has_solar=bool(c.pv_roster), shadow=shadow,
+                         settled=settled),
         "batteries": battery_rows(c, shadow, running, held),
-        "plan": build_plan(c, now, shadow, running, held=held),
+        "plan": build_plan(c, now, shadow, running, held=held,
+                           settled=settled),
         "attention": ([{"severity": INFO, "id": "shadow",
                          "title": ATTN_SHADOW, "body": attn_shadow_body(),
                          "docs": None}] if shadow else []) + attention(checks),
@@ -673,8 +695,9 @@ ATTN_SHADOW = "Shadow mode is on"
 def attn_shadow_body() -> str:
     return "The add-on decides everything, but every inverter stays at 0 W."
 
+ZERO_HELD, ZERO_GOING = "Held at 0 W", "Going to 0 W"
 VERDICT = {
-    "held": "Held at 0 W",
+    "held": ZERO_HELD,
     "stopped": "Stopped",
     "cycle": "Monthly cycle today",
     "trade": "Trading on price",
@@ -728,26 +751,31 @@ def tile_grid(grid_w) -> str:
     return "Balanced"
 
 
-def tile_batt(batt_w, shadow) -> str:
+def _zero(settled) -> str:
+    return ZERO_HELD if settled else ZERO_GOING
+
+
+def tile_batt(batt_w, shadow, settled=True) -> str:
     if shadow:
-        return "Held at 0 W"
+        return _zero(settled)
     return {"giving": "Giving power", "charging": "Charging",
             "resting": "Resting", None: "No reading"}[flow(batt_w)]
 
 
 def battery_now(soc, batt_w, *, phase, shadow, running, held=False,
-                would_w=None) -> str:
+                would_w=None, settled=True) -> str:
     if soc is None or batt_w is None:
         return "No reading from this battery."
+    zero = _zero(settled)
     if shadow:
         if would_w is None or abs(would_w) <= IDLE_W:
-            return "Held at 0 W. Would rest now."
+            return f"{zero}. Would rest now."
         verb = "give" if would_w > 0 else "charge"
-        return f"Held at 0 W. Would {verb} {_kw(would_w)} now."
+        return f"{zero}. Would {verb} {_kw(would_w)} now."
     if held:
-        return "Held at 0 W until the alarm clears."
+        return f"{zero} until the alarm clears."
     if not running:
-        return "Held at 0 W while control is stopped."
+        return f"{zero} while control is stopped."
     if phase != M_IDLE:
         return {M_DRAIN: "Monthly cycle: emptying.",
                 M_CHARGE: "Monthly cycle: refilling.",
@@ -761,9 +789,10 @@ def battery_now(soc, batt_w, *, phase, shadow, running, held=False,
     return "Resting now."
 
 
-def plan_head(key, shadow) -> str:
+def plan_head(key, shadow, settled=True) -> str:
     if key == "held":
-        return "Every inverter is at 0 W until the alarm clears."
+        return ("Every inverter is at 0 W until the alarm clears." if settled
+                else "Every inverter goes to 0 W until the alarm clears.")
     if key == "stopped":
         return "Control is stopped, so nothing is planned."
     if not shadow:
@@ -784,8 +813,10 @@ def run_grid_what(kwh, shadow) -> str:
         f" up to {_kwh(kwh)} from the grid."
 
 
+# The trade legs and the price line use the feed's own points (a 15-minute
+# period on a quarter-hourly feed), so both name the same price and time.
 def run_grid_why(price) -> str:
-    return f"Cheapest price in the list, {_eur(price)} per kWh."
+    return f"Lowest published price, {_eur(price)} per kWh."
 
 
 def run_grid_amount(eur) -> str:
@@ -798,7 +829,7 @@ def run_give_what(kwh, shadow) -> str:
 
 
 def run_give_why(price) -> str:
-    return f"Dearest price in the list, {_eur(price)} per kWh."
+    return f"Highest published price, {_eur(price)} per kWh."
 
 
 def run_give_amount(eur) -> str:
@@ -880,8 +911,8 @@ def line_prices(now_eur, lo, hi) -> str:
     if now_eur is not None:
         parts.append(f"Price now {_eur(now_eur)} per kWh, all in.")
     if lo is not None and hi is not None:
-        parts.append(f"Today: cheapest {_eur(lo['eur_kwh'])} at "
-                     f"{lo['label']}, dearest {_eur(hi['eur_kwh'])} at "
+        parts.append(f"Today: lowest {_eur(lo['eur_kwh'])} at "
+                     f"{lo['label']}, highest {_eur(hi['eur_kwh'])} at "
                      f"{hi['label']}.")
     return " ".join(parts) or "No prices for today."
 
@@ -924,7 +955,7 @@ def text_samples() -> list:
     """`(kind, text)` for every sentence above, rendered with real values, so
     test_messages.py can hold each to its STYLE limit. Kinds: title, plan
     (2 sentences of 12 words), line (1 sentence of 25 words)."""
-    out = [("title", t) for t in VERDICT.values()]
+    out = [("title", t) for t in VERDICT.values()] + [("title", ZERO_GOING)]
     out += [("title", t) for t in ATTN_TITLES.values()]
     out += [("title", MODE_HOUSE), ("title", ATTN_SHADOW),
             ("line", attn_shadow_body())]
@@ -938,6 +969,7 @@ def text_samples() -> list:
         out.append(("title", tile_house(None, True, True)))
         out += [("title", tile_grid(v)) for v in (None, 1200, -800, 5)]
         out += [("title", tile_batt(v, sh)) for v in (None, 2500, -2500, 0)]
+        out.append(("title", tile_batt(0, sh, settled=False)))
         for phase in (M_IDLE, M_DRAIN, M_CHARGE, M_HOLD):
             for w in (2500, -2500, 0):
                 out.append(("plan", battery_now(62, w, phase=phase,
@@ -945,8 +977,14 @@ def text_samples() -> list:
                                                 would_w=-2400)))
         out.append(("plan", battery_now(62, 0, phase=M_IDLE, shadow=sh,
                                         running=False)))
-        out.append(("plan", battery_now(62, 0, phase=M_IDLE, shadow=False,
-                                        running=False, held=True)))
+        for settled in (True, False):
+            out.append(("plan", battery_now(62, 0, phase=M_IDLE, shadow=False,
+                                            running=False, held=True,
+                                            settled=settled)))
+            out.append(("plan", battery_now(62, 0, phase=M_IDLE, shadow=sh,
+                                            running=False, would_w=-2400,
+                                            settled=settled)))
+        out.append(("plan", plan_head("held", sh, settled=False)))
         out.append(("plan", battery_now(None, None, phase=M_IDLE, shadow=sh,
                                         running=True)))
         for k in VERDICT:
diff --git a/goodwe_controller/app/static/app.css b/goodwe_controller/app/static/app.css
index 826b35d..ad582d7 100644
--- a/goodwe_controller/app/static/app.css
+++ b/goodwe_controller/app/static/app.css
@@ -135,3 +135,84 @@ dialog::backdrop{background:rgba(0,0,0,.45)}
 .chart [data-tip]{cursor:default}
 .chart [data-tip]:hover,.chart [data-tip]:focus,.chart .hot{outline:2px solid var(--ink);outline-offset:-1px}
 .sr{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
+/* UX-13 P2: Settings, the Installer view (mockup version 2) */
+.btn.link{border:0;background:none;color:var(--accent);padding:6px 0;min-height:0}
+.search{width:100%;border:1px solid var(--line);background:var(--card);border-radius:10px;padding:10px 12px;min-height:44px;margin-bottom:10px}
+.key{font:11px/1.3 ui-monospace,SFMono-Regular,Menlo,monospace;color:var(--faint);overflow-wrap:anywhere}
+.chip{display:inline-flex;align-items:center;gap:4px;font-size:12px;border-radius:999px;padding:1px 8px;background:var(--info-bg);color:var(--muted);white-space:nowrap}
+.chip.now{background:var(--ok-bg);color:var(--ok)} .chip.rs{background:var(--warn-bg);color:var(--warn)}
+.chip.bad{background:var(--bad-bg);color:var(--bad)} .chip.changed{background:var(--accent-soft);color:var(--accent)}
+details.grp{background:var(--card);border:1px solid var(--line);border-radius:12px;margin-bottom:10px;box-shadow:var(--shadow)}
+details.grp>summary{list-style:none;cursor:pointer;padding:14px;display:flex;gap:10px;align-items:center;min-height:56px;flex-wrap:wrap}
+details.grp>summary::-webkit-details-marker{display:none}
+details.grp>summary .grow{flex:1 1 200px}
+details.grp>summary .gdesc{display:block}
+details.grp>summary .chev{transition:transform .15s;flex:none;font-size:22px;line-height:1;width:18px;text-align:center;color:var(--muted)}
+details.grp[open]>summary .chev{transform:rotate(90deg)}
+.gchips,.gbadge{display:inline-flex;flex-wrap:wrap;gap:4px}
+details.grp .body{padding:0 14px 8px}
+details.sub{border-top:1px solid var(--line);margin-top:4px}
+details.sub>summary{cursor:pointer;padding:10px 0;color:var(--accent);font-size:14px;min-height:44px;display:flex;align-items:center}
+.subhead{font-size:12px;text-transform:uppercase;letter-spacing:.04em;color:var(--faint);margin:14px 0 0;font-weight:700}
+.f{padding:12px 0;border-top:1px solid var(--line);min-width:0}
+.part>.f:first-child,.subhead+.f{border-top:0}
+.f .lbl{font-weight:600;font-size:14px}
+.f .help{font-size:13px;color:var(--muted);margin-top:4px}
+.f .ctl{margin-top:8px;min-width:0}
+.f.inline{display:grid;grid-template-columns:minmax(0,1fr) auto;gap:4px 12px;align-items:start}
+.f.inline .ctl{margin-top:0;grid-row:1;grid-column:2}
+.f.inline .help,.f.inline .msgs{grid-column:1/-1}
+.f.changed>.head .lbl::after{content:" •";color:var(--accent)}
+.msg{font-size:13px;margin-top:6px;display:flex;gap:6px;align-items:flex-start;border-radius:8px;padding:6px 8px;overflow-wrap:anywhere}
+.msg .mi{font-weight:800;flex:none}
+.msg.bad{background:var(--bad-bg);color:var(--bad)} .msg.warn{background:var(--warn-bg);color:var(--warn)} .msg.info{background:var(--info-bg);color:var(--info)}
+.f.has-bad .ctl select,.f.has-bad .ctl input,.f.has-bad .ent-btn{border-color:var(--bad)}
+.switch{position:relative;width:52px;height:44px;border:0;background:none;cursor:pointer;flex:none;padding:0}
+.switch::before{content:"";position:absolute;left:2px;top:8px;width:48px;height:28px;border-radius:14px;background:var(--track);transition:background .15s}
+.switch::after{content:"";position:absolute;top:11px;left:5px;width:22px;height:22px;border-radius:50%;background:#fff;box-shadow:0 1px 2px rgba(0,0,0,.3);transition:left .15s}
+.switch[aria-checked="true"]::before{background:var(--accent)}
+.switch[aria-checked="true"]::after{left:25px}
+.swrap{display:inline-flex;align-items:center;gap:8px;min-height:44px}
+.swtext{font-size:13px;color:var(--muted)}
+select.sel,input.txt,input.num{border:1px solid var(--line);background:var(--card);border-radius:10px;padding:9px 10px;min-height:44px;max-width:100%}
+select.sel{width:100%}
+.row>select.sel{width:auto;flex:1 1 200px}
+input.num{width:110px;text-align:right;font-variant-numeric:tabular-nums}
+input.txt{width:100%}
+input:disabled{opacity:.6}
+.seg{display:inline-flex;border:1px solid var(--line);border-radius:10px;overflow:hidden;max-width:100%;flex-wrap:wrap}
+.seg button{border:0;background:var(--card);padding:8px 12px;min-height:44px;cursor:pointer;border-left:1px solid var(--line)}
+.seg button:first-child{border-left:0}
+.seg button[aria-checked="true"]{background:var(--accent-soft);color:var(--accent);font-weight:600}
+.choice{display:flex;gap:10px;align-items:flex-start;border:1px solid var(--line);border-radius:10px;padding:10px 12px;margin-top:8px;cursor:pointer;width:100%;text-align:left;background:var(--card);min-height:44px}
+.choice[aria-checked="true"]{border-color:var(--accent);background:var(--accent-soft)}
+.choice .rad{flex:none;width:18px;height:18px;border-radius:50%;border:2px solid var(--faint);margin-top:2px}
+.choice[aria-checked="true"] .rad{border:5px solid var(--accent)}
+.slider{display:flex;align-items:center;gap:10px;width:100%}
+.slider input[type=range]{flex:1;min-width:0;accent-color:var(--accent);height:28px}
+.unit{color:var(--muted);font-size:13px;white-space:nowrap}
+.ent-btn{width:100%;text-align:left;border:1px solid var(--line);background:var(--card);border-radius:10px;padding:8px 10px;min-height:44px;cursor:pointer;display:flex;gap:8px;align-items:center}
+.ent-btn .grow{min-width:0}
+.ent-btn .grow>div{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
+.ent-pop{border:1px solid var(--line);border-radius:10px;margin-top:6px;background:var(--card);overflow:hidden}
+.ent-pop input[type=search]{border:0;border-bottom:1px solid var(--line);width:100%;padding:10px;background:var(--card);min-height:44px}
+.ent-note{padding:6px 10px}
+.ent-list{max-height:240px;overflow:auto}
+.ent-opt{display:flex;gap:8px;align-items:center;width:100%;border:0;border-bottom:1px solid var(--line);background:none;text-align:left;padding:8px 10px;cursor:pointer;min-height:44px}
+.ent-opt:hover,.ent-opt:focus{background:var(--accent-soft)}
+.ent-opt .grow{min-width:0}
+.ent-opt .grow>div{overflow-wrap:anywhere}
+.ent-opt .v{font-variant-numeric:tabular-nums;font-size:13px;color:var(--muted);white-space:nowrap}
+.ent-all{display:flex;gap:6px;padding:6px 10px;align-items:center;min-height:44px}
+.elist .erow{padding:6px 0;border-bottom:1px dashed var(--line)}
+.elist>.btn{margin-top:8px}
+.inv{border:1px solid var(--line);border-radius:10px;padding:0 12px;margin:10px 0}
+.inv>.hd{display:flex;align-items:center;gap:8px;padding:10px 0;border-bottom:1px solid var(--line);font-weight:600;flex-wrap:wrap}
+.inv>.f:nth-child(2){border-top:0}
+.invs>.btn{margin:4px 0 8px}
+#savebar{position:fixed;left:0;right:0;bottom:0;z-index:15}
+#savebar .in{max-width:820px;margin:0 auto 10px;padding:10px 12px;background:var(--ink);color:var(--bg);border-radius:12px;display:flex;flex-wrap:wrap;gap:8px;align-items:center;box-shadow:0 4px 16px rgba(0,0,0,.25);width:calc(100% - 32px)}
+#savebar .btn{min-height:44px;padding:6px 12px;background:transparent;color:var(--bg);border-color:rgba(127,127,127,.6)}
+#savebar .btn.primary{background:var(--accent);border-color:var(--accent);color:var(--on-accent)}
+@media (max-width:640px){#savebar{bottom:62px}}
+#s-set{padding-bottom:80px}
diff --git a/goodwe_controller/app/static/app.js b/goodwe_controller/app/static/app.js
index fb9810a..0153c55 100644
--- a/goodwe_controller/app/static/app.js
+++ b/goodwe_controller/app/static/app.js
@@ -40,10 +40,12 @@
     clearTimeout(toast.timer); toast.timer = setTimeout(() => e.classList.remove("show"), 2600);
   }
   let onYes = null;
+  // `key` names Home's words in ui_text, or is {name, description, yes}.
   function ask(key, fn) {
-    $("#dlg-t").textContent = t("dialog." + key + ".name");
-    $("#dlg-b").textContent = t("dialog." + key + ".description");
-    $("#dlg-yes").textContent = t("dialog." + key + ".yes");
+    const w = typeof key === "string" ? t("dialog." + key) : key;
+    $("#dlg-t").textContent = w.name;
+    $("#dlg-b").textContent = w.description;
+    $("#dlg-yes").textContent = w.yes;
     onYes = fn;
     const d = $("#dlg");
     if (typeof d.showModal === "function") d.showModal(); else if (window.confirm($("#dlg-t").textContent)) fn();
@@ -98,7 +100,6 @@
     renderControl(structured);
     renderDetails(!structured);
     renderBatteries();
-    renderSettings();
   }
 
   /* ---------------- Home: now ---------------- */
@@ -162,7 +163,7 @@
       const title = b.label + " " + t("plan.time_to") + " " + b.end_label;
       if (b.eur_kwh == null) return chartItem("i", "none", "", title, [t("plan.none_tip") + "."]);
       const kind = b.kind === "cheap" ? ", " + t("plan.cheap_tip") : b.kind === "dear" ? ", " + t("plan.dear_tip") : "";
-      const est = b.estimate ? ", " + t("plan.estimate_tip") : "";
+      const est = (b.points > 1 ? ", " + t("plan.average_tip") : "") + (b.estimate ? ", " + t("plan.estimate_tip") : "");
       return chartItem("i", (b.kind || "mid") + (b.estimate ? " est" : ""),
                        "height:" + Math.max(4, Math.round(Math.abs(b.eur_kwh) / mx * 100)) + "%",
                        title, [eur(b.eur_kwh) + " " + t("plan.per_kwh") + kind + est + "."]);
@@ -289,7 +290,7 @@
     if (open) $("#c-details").open = true;
   }
 
-  /* ---------------- Batteries and Settings (placeholders until P2/P3) ---------------- */
+  /* ---------------- Batteries (placeholder until P3) ---------------- */
   function renderBatteries() {
     if (!S.batteries) { $("#bcards").replaceChildren(); return; }
     $("#bcards").replaceChildren(...S.batteries.map((b) => h("div", { class: "card" },
@@ -301,10 +302,6 @@
         h("dt", {}, t("batteries.now")), h("dd", {}, b.now),
         h("dt", {}, t("batteries.mode")), h("dd", {}, b.mode)))));
   }
-  function renderSettings() {
-    const line = S.plan && S.plan.region_line;
-    $("#set-region").textContent = line || ""; $("#set-region").hidden = !line;
-  }
 
   /* ---------------- control buttons ---------------- */
   // The action is a toggle, so the page reads the live state first and sends
@@ -334,6 +331,9 @@
   $("#btn-maint").addEventListener("click", () => ask("maint_start", () => simple("maint_start")));
   $("#btn-abort").addEventListener("click", () => ask("maint_abort", () => simple("maint_abort")));
 
+  // Shared with settings.js, which loads after this file.
+  window.UX13 = { h, ask, toast, t, maint: (what) => ask(what, () => simple(what)) };
+
   /* ---------------- tabs: hash routes, arrow keys ---------------- */
   const TABS = [...document.querySelectorAll(".tab")];
   function select(tab, focus) {
@@ -345,6 +345,7 @@
     if (focus) tab.focus();
     if (location.hash !== "#" + tab.dataset.hash) history.replaceState(null, "", "#" + tab.dataset.hash);
     schedule();
+    document.dispatchEvent(new CustomEvent("ux13:tab", { detail: tab.dataset.hash }));
   }
   TABS.forEach((x, i) => {
     x.addEventListener("click", () => select(x, false));
diff --git a/goodwe_controller/app/static/index.html b/goodwe_controller/app/static/index.html
index cecb7a2..ad2b649 100644
--- a/goodwe_controller/app/static/index.html
+++ b/goodwe_controller/app/static/index.html
@@ -96,16 +96,23 @@
   <div id="bcards"></div>
   <div class="card">
     <p class="small muted" style="margin:0 0 10px" data-t="batteries.description"></p>
-    <a class="btn" href="config" data-t="batteries.settings"></a>
+    <a class="btn" href="#settings" data-t="batteries.settings"></a>
   </div>
 </section>
 
 <section class="screen" id="s-set" role="tabpanel" aria-labelledby="t-set" hidden>
-  <div class="card">
-    <h2 data-t="settings.name"></h2>
-    <p class="small muted" data-t="settings.description"></p>
-    <p class="small" id="set-region" hidden></p>
-    <a class="btn primary" href="config" data-t="settings.open"></a>
+  <div class="row spread" style="margin-bottom:6px">
+    <h2 style="margin:0" data-s="name"></h2>
+    <a class="small" href="config" id="set-classic" data-s="classic"></a>
+  </div>
+  <p class="small muted" style="margin:0 0 10px" data-s="description"></p>
+  <div id="set-banner" aria-live="polite"></div>
+  <div id="set-body">
+    <input class="search" id="set-search" type="search" autocomplete="off" spellcheck="false" data-s-ph="search.description" data-s-label="search.name">
+    <div class="card" id="set-other" hidden><h2 data-s="other"></h2><ul class="plain small" id="set-other-list"></ul></div>
+    <div id="groups"><p class="small muted" data-s="loading"></p></div>
+    <p class="small muted" id="set-nomatch" hidden data-s="no_match.description"></p>
+    <p class="tiny muted" data-s="footer.description"></p>
   </div>
 </section>
 
@@ -126,10 +133,16 @@
     <button class="btn primary" id="dlg-yes" type="button"></button>
   </div>
 </dialog>
+<div id="savebar" role="region" hidden><div class="in">
+  <span class="grow" id="sb-text" aria-live="polite"></span>
+  <button class="btn" id="sb-discard" type="button" data-s="savebar.discard"></button>
+  <button class="btn primary" id="sb-save" type="button" data-s="savebar.save"></button>
+</div></div>
 <div id="toast" role="status" aria-live="polite"></div>
 <div id="tip" class="tip" aria-hidden="true"></div>
 
 <script type="application/json" id="ui-text">/*UI_TEXT*/</script>
 <script>/*APP_JS*/</script>
+<script>/*SETTINGS_JS*/</script>
 </body>
 </html>
diff --git a/goodwe_controller/app/static/settings.js b/goodwe_controller/app/static/settings.js
new file mode 100644
index 0000000..074ad3e
--- /dev/null
+++ b/goodwe_controller/app/static/settings.js
@@ -0,0 +1,555 @@
+"use strict";
+/* UX-13 P2: Settings, the Installer view. It draws from /config/model's
+   `layout` (app/uilayout.py through app/uipage.py) and `ui` (the page model
+   from app/uimodel.py), so this file names no option key: keys, labels,
+   ranges and choices all arrive as data. It posts the page model back; the
+   add-on turns it into options and runs its own start checks, and nothing
+   they refuse is saved. Every word is from app/ui_text or the add-on, and
+   data is set as text, never as HTML. */
+(function () {
+  const ROOT = JSON.parse(document.getElementById("ui-text").textContent);
+  const W = ROOT.settings;
+  const { h, ask, toast, maint } = window.UX13;
+  const $ = (s) => document.querySelector(s);
+  const ws = (path) => path.split(".").reduce((o, k) => (o == null ? o : o[k]), W);
+  const clone = (x) => (x === undefined ? undefined : JSON.parse(JSON.stringify(x)));
+  const same = (a, b) => JSON.stringify(a ?? null) === JSON.stringify(b ?? null);
+
+  document.querySelectorAll("[data-s]").forEach((e) => { e.textContent = ws(e.dataset.s) || ""; });
+  document.querySelectorAll("[data-s-ph]").forEach((e) => { e.placeholder = ws(e.dataset.sPh) || ""; });
+  document.querySelectorAll("[data-s-label]").forEach((e) => { e.setAttribute("aria-label", ws(e.dataset.sLabel) || ""); });
+  $("#savebar").setAttribute("aria-label", W.savebar.label);
+
+  let M = null;              // the last /config/model
+  let V = null;              // the page model being edited
+  let ORIG = null;           // the page model as stored
+  let FP = "";               // the stored blob's fingerprint (compare-and-swap)
+  let MSG = [];              // [{field, card, tier, text}] from the add-on
+  let DEVICE = "";
+  let LIST = null;           // the inverter list field
+  let FILLED = {};           // field key -> the preset field that fills it
+  let active = false;
+  let uid = 0;
+  const ROWS = [];
+  const OPEN = new Set();
+  const UNLOCKED = new Set();
+
+  /* ---------------- the page model ---------------- */
+  const sub = (f) => f.key.slice(LIST.key.length + 1);
+  function valueIn(model, f, card) {
+    if (card == null) return model[f.key];
+    const c = (model[LIST.key] || [])[card];
+    return c ? c[sub(f)] : undefined;
+  }
+  const get = (f, card) => valueIn(V, f, card);
+  function visible(f) {
+    return (f.show || []).every(([name, op, want]) => {
+      const have = V[name];
+      if (op === "==") return same(have, want);
+      if (op === "!=") return !same(have, want);
+      if (op === "in") return want.some((x) => same(x, have));
+      if (have == null || have === "" || isNaN(+have)) return false;
+      return op === ">" ? +have > want : +have < want;
+    });
+  }
+  function put(f, card, v, redraw) {
+    if (card == null) V[f.key] = v;
+    else V[LIST.key][card][sub(f)] = v;
+    if (f.mirror) {
+      const m = findField(f.mirror);
+      if (m && (m.choices || []).some((c) => same(c[0], v))) V[f.mirror] = v;
+    }
+    if (f.fills && f.presets && f.presets[v]) V[f.fills] = f.presets[v].value;
+    if (redraw || f.fills) render(); else paint();
+    queueValidate();
+  }
+  function findField(key) {
+    for (const g of M.layout.groups) for (const p of g.parts) for (const f of p.fields) {
+      if (f.key === key) return f;
+      for (const s of f.fields || []) if (s.key === key) return s;
+    }
+    return null;
+  }
+
+  /* ---------------- numbers: stored units <-> shown units ---------------- */
+  const decimals = (x) => { const s = String(x); return s.includes(".") ? s.split(".")[1].length : 0; };
+  function shown(f, v) {
+    if (v == null || v === "") return "";
+    return String(+(Number(v) / (f.scale || 1)).toFixed(6));
+  }
+  function stored(f, x) {
+    const st = f.step || (f.type === "integer" ? 1 : 0);
+    let v = x * (f.scale || 1);
+    if (st) v = Math.round(v / st) * st;
+    if (f.min != null) v = Math.max(f.min, v);
+    if (f.max != null) v = Math.min(f.max, v);
+    return f.type === "integer" ? Math.round(v) : +v.toFixed(Math.min(10, decimals(st) + 2));
+  }
+
+  /* ---------------- controls ---------------- */
+  function choicesOf(f, cur) {
+    const out = (f.choices || []).filter((c) => !c[2] || same(c[0], cur));
+    if (cur != null && cur !== "" && !out.some((c) => same(c[0], cur))) out.push([cur, String(cur)]);
+    return out;
+  }
+  function toggle(f, card, lid) {
+    const on = !!get(f, card);
+    const b = h("button", { type: "button", class: "switch", role: "switch", "aria-checked": String(on), "aria-labelledby": lid });
+    const txt = h("span", { class: "swtext", "aria-hidden": "true" }, on ? W.on : W.off);
+    b.addEventListener("click", () => {
+      const n = b.getAttribute("aria-checked") !== "true";
+      b.setAttribute("aria-checked", String(n)); txt.textContent = n ? W.on : W.off;
+      put(f, card, n);
+    });
+    return h("span", { class: "swrap" }, b, txt);
+  }
+  function radios(f, card, lid, cards) {
+    const cur = get(f, card);
+    const g = h("div", { class: cards ? "choices" : "seg", role: "radiogroup", "aria-labelledby": lid });
+    const items = choicesOf(f, cur);
+    const buttons = items.map(([v, label], i) => {
+      const on = same(v, cur);
+      const hint = cards && f.hints ? f.hints[v] : "";
+      const b = h("button", { type: "button", role: "radio", class: cards ? "choice" : null, "aria-checked": String(on),
+                              tabindex: on || (!items.some((c) => same(c[0], cur)) && i === 0) ? "0" : "-1" },
+        cards ? [h("span", { class: "rad", "aria-hidden": "true" }), h("span", {}, h("div", {}, label), hint ? h("div", { class: "tiny muted" }, hint) : null)] : label);
+      b.addEventListener("click", () => put(f, card, v, true));
+      b.addEventListener("keydown", (e) => {
+        const d = { ArrowRight: 1, ArrowDown: 1, ArrowLeft: -1, ArrowUp: -1 }[e.key];
+        if (!d) return;
+        e.preventDefault();
+        const j = (i + d + items.length) % items.length;
+        put(f, card, items[j][0], true);
+        const again = document.querySelector(`[data-rk="${CSS.escape(g.dataset.rk)}"] [role=radio]:nth-child(${j + 1})`);
+        if (again) again.focus();
+      });
+      return b;
+    });
+    g.dataset.rk = f.key + "|" + card;
+    g.append(...buttons);
+    return g;
+  }
+  function select(f, card, lid) {
+    const cur = get(f, card);
+    const s = h("select", { class: "sel", "aria-labelledby": lid });
+    for (const [v, label] of choicesOf(f, cur)) s.append(h("option", { value: JSON.stringify(v), selected: same(v, cur) }, label));
+    for (const [v, label] of f.later || []) s.append(h("option", { value: JSON.stringify(v), disabled: true }, label));
+    s.addEventListener("change", () => put(f, card, JSON.parse(s.value), true));
+    const preset = f.presets && f.presets[cur];
+    return preset ? h("div", { class: "row" }, s, h("span", { class: "chip" }, W.region_year.replace("{year}", preset.year))) : s;
+  }
+  function slider(f, card, lid) {
+    if (f.min == null || f.max == null) return number(f, card, lid);
+    const sc = f.scale || 1;
+    const st = f.step || (f.type === "integer" ? 1 : 0.01);
+    const v = get(f, card);
+    const r = h("input", { type: "range", min: f.min, max: f.max, step: st, value: v == null ? f.min : v, "aria-labelledby": lid });
+    const n = h("input", { class: "num", type: "number", inputmode: "decimal", min: f.min / sc, max: f.max / sc, step: st / sc, value: shown(f, v), "aria-labelledby": lid });
+    r.addEventListener("input", () => { const x = stored(f, +r.value / sc); n.value = shown(f, x); put(f, card, x); });
+    n.addEventListener("change", () => {
+      if (n.value === "" || isNaN(+n.value)) { n.value = shown(f, get(f, card)); return; }
+      const x = stored(f, +n.value); r.value = x; n.value = shown(f, x); put(f, card, x);
+    });
+    return h("div", { class: "slider" }, r, n, f.unit ? h("span", { class: "unit" }, f.unit) : null);
+  }
+  function number(f, card, lid) {
+    const sc = f.scale || 1;
+    const by = FILLED[f.key];
+    const preset = by && by.presets[V[by.key]];
+    const n = h("input", { class: "num", type: "number", inputmode: "decimal", step: f.step ? f.step / sc : "any",
+                           min: f.min == null ? null : f.min / sc, max: f.max == null ? null : f.max / sc,
+                           value: shown(f, get(f, card)), disabled: !!preset, "aria-labelledby": lid });
+    n.addEventListener("input", () => {
+      if (n.value === "") { if (f.optional) put(f, card, null); return; }
+      if (!isNaN(+n.value)) put(f, card, stored(f, +n.value));
+    });
+    n.addEventListener("change", () => { n.value = shown(f, get(f, card)); });
+    return h("div", {}, h("div", { class: "row" }, n, f.unit ? h("span", { class: "unit" }, f.unit) : null),
+             preset ? h("div", { class: "tiny muted" }, W.preset.description) : null);
+  }
+  function text(f, card, lid) {
+    const v = get(f, card);
+    const t = h("input", { class: "txt", type: "text", value: v == null ? "" : v, autocapitalize: "none", spellcheck: "false", "aria-labelledby": lid });
+    t.addEventListener("input", () => put(f, card, t.value));
+    return t;
+  }
+  function locked(f, card, lid) {
+    const box = h("div", {});
+    const id = f.key + "#" + card;
+    const open = () => { UNLOCKED.add(id); box.replaceChildren(slider(f, card, lid)); };
+    if (UNLOCKED.has(id)) { open(); return box; }
+    const v = get(f, card);
+    box.append(h("div", { class: "row" },
+      h("strong", {}, v == null ? W.not_set : shown(f, v) + (f.unit ? " " + f.unit : "")),
+      h("span", { class: "chip" }, W.locked),
+      h("button", { type: "button", class: "btn link", "aria-label": W.change + ": " + f.label, onclick: open }, W.change)));
+    return box;
+  }
+
+  /* entity picker: search, the matching kind first, the live reading */
+  const ENT = {};
+  function entities(kind) {
+    const now = Date.now();
+    const e = ENT[kind];
+    if (e && now - e.at < 30000) return e.p;
+    const p = fetch("ha/entities?kind=" + encodeURIComponent(kind || ""), { cache: "no-store" })
+      .then((r) => (r.ok ? r.json() : { available: false, entities: [] }))
+      .catch(() => ({ available: false, entities: [] }));
+    ENT[kind] = { at: now, p };
+    return p;
+  }
+  const reading = (e) => (e && e.state != null && e.state !== "" ? String(e.state) + (e.unit ? " " + e.unit : "") : "–");
+  function picker(f, lid, value, pick) {
+    let data = null, all = false;
+    const btn = h("button", { type: "button", class: "ent-btn", "aria-expanded": "false", "aria-haspopup": "listbox", "aria-labelledby": lid });
+    const pop = h("div", { class: "ent-pop", hidden: true });
+    const q = h("input", { type: "search", placeholder: W.picker.search.description, "aria-label": W.picker.search.description, autocomplete: "off", spellcheck: "false" });
+    const note = h("div", { class: "tiny muted ent-note" });
+    const list = h("div", { class: "ent-list", role: "listbox", "aria-labelledby": lid });
+    const allBox = h("label", { class: "tiny muted ent-all" },
+      h("input", { type: "checkbox", onchange: (e) => { all = e.target.checked; fill(); } }), W.picker.all);
+    function drawBtn() {
+      const id = value();
+      const e = data && data.entities.find((x) => x.entity_id === id);
+      btn.replaceChildren();
+      if (id) btn.append(h("span", { class: "grow" }, h("div", {}, e ? e.name : id), h("div", { class: "key" }, id)),
+                         data && data.available ? h("span", { class: "chip " + (e ? "now" : "rs") }, e ? reading(e) : W.picker.missing) : null);
+      else btn.append(h("span", { class: "grow muted" }, W.picker.choose));
+      btn.append(h("span", { class: "muted", "aria-hidden": "true" }, "▾"));
+    }
+    function opt(id, name, val) {
+      return h("button", { type: "button", class: "ent-opt", role: "option", "aria-selected": String(id === value()),
+                           onclick: () => { pick(id); close(); drawBtn(); btn.focus(); } },
+        h("span", { class: "grow" }, h("div", {}, name), h("div", { class: "key" }, id)), val ? h("span", { class: "v" }, val) : null);
+    }
+    function fill() {
+      const typed = q.value.trim();
+      const t = typed.toLowerCase();
+      const rows = (data ? data.entities : []).filter((e) => (all || e.match) && (e.entity_id + " " + e.name).toLowerCase().includes(t)).slice(0, 200);
+      list.replaceChildren(...rows.map((e) => opt(e.entity_id, e.name, reading(e))));
+      if (typed.includes(".") && !rows.some((e) => e.entity_id === typed)) list.append(opt(typed, W.picker.use, ""));
+      if (!list.children.length) list.append(h("div", { class: "small muted", style: "padding:10px" }, W.picker.none.description));
+      note.textContent = data && data.text ? data.text : "";
+      note.hidden = !note.textContent;
+    }
+    function close() { pop.hidden = true; btn.setAttribute("aria-expanded", "false"); }
+    btn.addEventListener("click", () => {
+      if (!pop.hidden) { close(); return; }
+      pop.hidden = false; btn.setAttribute("aria-expanded", "true"); q.value = ""; fill();
+      setTimeout(() => q.focus(), 0);
+    });
+    q.addEventListener("input", fill);
+    pop.addEventListener("keydown", (e) => {
+      if (e.key === "Escape") { e.preventDefault(); close(); btn.focus(); return; }
+      if (e.key !== "ArrowDown" && e.key !== "ArrowUp") return;
+      e.preventDefault();
+      const opts = [...list.querySelectorAll(".ent-opt")];
+      const i = opts.indexOf(document.activeElement);
+      const j = e.key === "ArrowDown" ? Math.min(opts.length - 1, i + 1) : i - 1;
+      if (j < 0) q.focus(); else if (opts[j]) opts[j].focus();
+    });
+    pop.append(q, note, list, allBox);
+    drawBtn();
+    entities(f.kind).then((d) => { data = d; drawBtn(); if (!pop.hidden) fill(); });
+    return h("div", { class: "ent" }, btn, pop,
+      f.optional ? h("button", { type: "button", class: "btn link tiny", onclick: () => { pick(""); drawBtn(); } }, W.picker.clear) : null);
+  }
+  function entity(f, card, lid) {
+    return picker(f, lid, () => get(f, card) || "", (v) => put(f, card, v));
+  }
+  function entityList(f, card, lid) {
+    const arr = () => (Array.isArray(get(f, card)) ? get(f, card) : []);
+    const box = h("div", { class: "elist" });
+    arr().forEach((_id, i) => {
+      box.append(h("div", { class: "erow" },
+        h("div", { class: "tiny muted" }, W.phase + " " + (i + 1)),
+        picker(f, lid, () => arr()[i] || "", (v) => { const a = arr().slice(); a[i] = v; put(f, card, a); }),
+        h("button", { type: "button", class: "btn link tiny", onclick: () => { const a = arr().slice(); a.splice(i, 1); put(f, card, a, true); } }, W.remove)));
+    });
+    box.append(h("button", { type: "button", class: "btn", onclick: () => put(f, card, arr().concat([""]), true) }, "+ " + W.add_row));
+    return box;
+  }
+  function solarList(f, card, lid) {
+    const arr = () => (Array.isArray(get(f, card)) ? get(f, card) : []);
+    const box = h("div", { class: "elist" });
+    arr().forEach((row, i) => {
+      const flip = h("button", { type: "button", class: "switch", role: "switch", "aria-checked": String(!!row.reversed), "aria-label": W.reversed });
+      flip.addEventListener("click", () => { const a = clone(arr()); a[i].reversed = !a[i].reversed; put(f, card, a, true); });
+      box.append(h("div", { class: "erow" },
+        picker(f, lid, () => arr()[i].entity || "", (v) => { const a = clone(arr()); a[i].entity = v; put(f, card, a); }),
+        h("div", { class: "row" }, h("span", { class: "swrap" }, flip, h("span", { class: "swtext" }, W.reversed)),
+          h("button", { type: "button", class: "btn link tiny", onclick: () => { const a = clone(arr()); a.splice(i, 1); put(f, card, a, true); } }, W.remove))));
+    });
+    box.append(h("button", { type: "button", class: "btn", onclick: () => put(f, card, arr().concat([{ entity: "", reversed: false }]), true) }, "+ " + W.add_solar));
+    return box;
+  }
+  const CONTROLS = { toggle, segmented: (f, c, l) => radios(f, c, l, false), choice: (f, c, l) => radios(f, c, l, true),
+                     select, slider, number, text, locked, entity, entity_list: entityList, solar_list: solarList };
+
+  /* ---------------- rows, cards and groups ---------------- */
+  function keyText(f, card) {
+    if (card != null) return V[LIST.shape] === "flat" && f.flat ? f.flat : LIST.key + "[" + card + "]." + sub(f);
+    return f.key.startsWith("ui.") ? (f.writes || []).join(", ") : f.key;
+  }
+  function fieldRow(f, card, gid) {
+    if (f.control === "inverter_list") return cardList(f, gid);
+    const lid = "sf" + (++uid);
+    const keys = keyText(f, card);
+    const msg = h("div", { class: "msgs" });
+    const make = CONTROLS[f.control] || text;
+    const row = h("div", { class: "f" + (f.control === "toggle" ? " inline" : ""), "data-key": f.key, "data-card": card },
+      h("div", { class: "head" }, h("div", { class: "lbl", id: lid }, f.label, f.unit && f.control !== "slider" && f.control !== "number" && f.control !== "locked" ? " (" + f.unit + ")" : ""),
+        keys ? h("div", { class: "key" }, keys) : null),
+      h("div", { class: "ctl" }, make(f, card, lid)),
+      f.help ? h("div", { class: "help" }, f.help) : null, msg);
+    ROWS.push({ f, card, el: row, msg, gid, search: (f.label + " " + keys + " " + f.key + " " + (f.help || "")).toLowerCase() });
+    return row;
+  }
+  function blankCard(f, first) {
+    const out = {};
+    for (const s of f.fields) {
+      const k = sub(s);
+      out[k] = s.control === "slider" && first && first[k] != null ? first[k] : s.type === "boolean" ? false : s.control === "number" ? null : "";
+    }
+    return out;
+  }
+  function cardList(f, gid) {
+    const wrap = h("div", { class: "invs", "data-key": f.key });
+    const msg = h("div", { class: "msgs" });
+    const cards = V[f.key];
+    if (!Array.isArray(cards)) {
+      wrap.append(h("div", { class: "msg info" }, W.raw_roster.description), msg);
+    } else {
+      cards.forEach((c, i) => {
+        const box = h("div", { class: "inv" }, h("div", { class: "hd" },
+          h("span", { class: "grow" }, c.name || W.inverter + " " + (i + 1)), h("span", { class: "key" }, f.key + "[" + i + "]"),
+          cards.length > 1 ? h("button", { type: "button", class: "btn link tiny", onclick: () => {
+            V[f.key].splice(i, 1); V[f.count] = V[f.key].length; put(f, null, V[f.key], true);
+          } }, W.remove) : null));
+        for (const s of f.fields) box.append(fieldRow(s, i, gid));
+        wrap.append(box);
+      });
+      wrap.append(msg, h("button", { type: "button", class: "btn", onclick: () => {
+        V[f.key].push(blankCard(f, V[f.key][0])); Object.assign(V, f.grow); V[f.count] = V[f.key].length;
+        put(f, null, V[f.key], true);
+      } }, "+ " + W.add_inverter));
+    }
+    ROWS.push({ f, card: null, el: wrap, msg, gid, list: true, search: (f.label + " " + f.key + " " + (f.help || "")).toLowerCase() });
+    return wrap;
+  }
+  const chev = () => h("span", { class: "chev", "aria-hidden": "true" }, "›");
+  function render() {
+    const host = $("#groups");
+    const y = window.scrollY;
+    host.replaceChildren();
+    ROWS.length = 0;
+    for (const g of M.layout.groups) {
+      const d = h("details", { class: "grp", "data-g": g.id },
+        h("summary", {}, h("span", { class: "grow" }, h("strong", {}, g.name), h("span", { class: "small muted gdesc" }, g.description)),
+          h("span", { class: "gchips" }, h("span", { class: "gbadge" }), ...g.applies.map((a) => h("span", { class: "chip applies" }, a))), chev()));
+      d.open = OPEN.has(g.id);
+      d.addEventListener("toggle", () => { if (!$("#set-search").value) (d.open ? OPEN.add(g.id) : OPEN.delete(g.id)); });
+      const body = h("div", { class: "body" });
+      if (g.support_only) body.append(h("div", { class: "msg warn", role: "note" }, W.support.description));
+      for (const p of g.parts) {
+        const pid = g.id + "." + p.id;
+        let box;
+        if (p.collapsed) {
+          box = h("details", { class: "sub part" }, h("summary", {}, p.name));
+          box.open = OPEN.has(pid);
+          box.addEventListener("toggle", () => { if (!$("#set-search").value) (box.open ? OPEN.add(pid) : OPEN.delete(pid)); });
+        } else {
+          box = h("div", { class: "part" }, p.name ? h("div", { class: "subhead" }, p.name) : null);
+        }
+        if (p.description) box.append(h("p", { class: "small muted", style: "margin:4px 0" }, p.description));
+        for (const f of p.fields) box.append(fieldRow(f, null, g.id));
+        body.append(box);
+      }
+      if (g.id === "maintenance") {
+        body.append(h("div", { class: "part" }, h("div", { class: "subhead" }, W.cycle.name),
+          h("p", { class: "small muted", style: "margin:4px 0" }, W.cycle.description),
+          h("div", { class: "row" },
+            h("button", { type: "button", class: "btn", onclick: () => maint("maint_start") }, ROOT.home.control.maint_start),
+            h("button", { type: "button", class: "btn danger", onclick: () => maint("maint_abort") }, ROOT.home.control.maint_abort))));
+      }
+      d.append(body);
+      host.append(d);
+    }
+    paint();
+    window.scrollTo(0, y);
+  }
+
+  /* ---------------- messages, visibility, search, badges ---------------- */
+  const ICON = { bad: "×", warn: "!", info: "i" };
+  const RANK = { bad: 0, warn: 1, info: 2 };
+  function mine(r, m) {
+    if (m.field !== r.f.key) return false;
+    if (r.list || r.card == null) return true;
+    return m.card == null ? r.card === 0 : m.card === r.card;
+  }
+  function paint() {
+    const q = $("#set-search").value.trim().toLowerCase();
+    const placed = new Set();
+    for (const r of ROWS) {
+      r.visible = visible(r.f);
+      const msgs = MSG.filter((m, i) => { const hit = mine(r, m); if (hit && r.visible) placed.add(i); return hit; })
+        .sort((a, z) => RANK[a.tier] - RANK[z.tier]);
+      r.tiers = new Set(msgs.map((m) => m.tier));
+      r.msg.replaceChildren(...msgs.map((m) => h("div", { class: "msg " + m.tier },
+        h("span", { class: "mi", "aria-hidden": "true" }, ICON[m.tier] || "i"),
+        h("span", {}, h("span", { class: "sr" }, W.tier[m.tier] + ": "), m.text))));
+      r.el.classList.toggle("has-bad", r.tiers.has("bad"));
+      // A card list counts as one change when cards were added or removed;
+      // an edit inside a card counts on its own row.
+      r.changed = r.list ? !same((get(r.f) || []).length, (valueIn(ORIG, r.f) || []).length)
+                         : !same(get(r.f, r.card), valueIn(ORIG, r.f, r.card));
+      r.el.classList.toggle("changed", r.changed && !r.list);
+    }
+    // Search: a row shows when it is visible and matches. A card list shows
+    // while any of its rows does.
+    for (const r of ROWS) if (!r.list) r.el.hidden = !(r.visible && (!q || r.search.includes(q)));
+    for (const r of ROWS) if (r.list) r.el.hidden = !!q && !r.search.includes(q) && !ROWS.some((s) => !s.list && s.card != null && !s.el.hidden);
+    let any = false;
+    document.querySelectorAll("#groups details.grp").forEach((d) => {
+      const rows = ROWS.filter((r) => r.gid === d.dataset.g);
+      d.querySelectorAll(".part").forEach((p) => {
+        const inside = rows.filter((r) => p.contains(r.el));
+        if (inside.length) p.hidden = inside.every((r) => r.el.hidden);
+      });
+      const hit = rows.some((r) => !r.el.hidden);
+      any = any || hit;
+      d.hidden = !!q && !hit;
+      if (q && hit) { d.open = true; d.querySelectorAll("details.sub").forEach((s) => { s.open = true; }); }
+      const shownRows = rows.filter((r) => r.visible && !r.list);
+      const bad = shownRows.filter((r) => r.tiers.has("bad")).length + rows.filter((r) => r.list && r.tiers.has("bad")).length;
+      const warn = shownRows.filter((r) => !r.tiers.has("bad") && r.tiers.has("warn")).length;
+      const changed = rows.filter((r) => r.changed).length;
+      d.querySelector(".gbadge").replaceChildren(...[
+        bad ? h("span", { class: "chip bad" }, bad + " " + W.to_fix) : null,
+        warn ? h("span", { class: "chip rs" }, warn + " " + W.to_check) : null,
+        changed ? h("span", { class: "chip changed" }, changed + " " + W.changed) : null].filter(Boolean));
+    });
+    $("#set-nomatch").hidden = !q || any;
+    // A sentence shown beside any field is not repeated here.
+    const shownText = new Set(MSG.filter((m, i) => placed.has(i)).map((m) => m.text));
+    const other = MSG.filter((m, i) => !shownText.has(m.text) && MSG.findIndex((x) => x.text === m.text) === i);
+    if (DEVICE) other.push({ tier: "info", text: DEVICE });
+    $("#set-other").hidden = !other.length;
+    $("#set-other-list").replaceChildren(...other.map((m) => h("li", { class: "c-" + ({ bad: "bad", warn: "warn" }[m.tier] || "info") },
+      h("span", { class: "sr" }, W.tier[m.tier] + ": "), (ICON[m.tier] || "i") + " " + m.text)));
+    savebar();
+  }
+  function dirtyCount() {
+    const seen = new Set();
+    for (const r of ROWS) if (r.changed) seen.add(r.f.key + "#" + r.card);
+    return seen.size;
+  }
+  function savebar() {
+    const n = V ? dirtyCount() : 0;
+    $("#savebar").hidden = !(active && n);
+    $("#sb-text").textContent = n + " " + (n === 1 ? W.savebar.one : W.savebar.many);
+  }
+  $("#set-search").addEventListener("input", () => { if (V) paint(); });
+
+  /* ---------------- talking to the add-on ---------------- */
+  let vtimer = null, vseq = 0;
+  function queueValidate() { clearTimeout(vtimer); vtimer = setTimeout(validate, 400); }
+  async function validate() {
+    const seq = ++vseq;
+    try {
+      const r = await fetch("config/validate", { method: "POST", headers: { "Content-Type": "application/json" },
+                                                 body: JSON.stringify({ model: V }) });
+      const b = await r.json();
+      if (seq !== vseq) return;
+      MSG = b.messages || [];
+      DEVICE = b.device_note || "";
+      paint();
+    } catch (e) { /* the next change tries again */ }
+  }
+  function banner(level, title, sub, button, onClick) {
+    const host = $("#set-banner");
+    if (!title) { host.replaceChildren(); return; }
+    host.replaceChildren(h("div", { class: "banner " + ({ ok: "b-ok", bad: "b-bad" }[level] || "b-warn") },
+      h("span", { class: "ic", "aria-hidden": "true" }, { ok: "✓", bad: "×" }[level] || "!"),
+      h("span", {}, title, h("small", {}, sub, button ? [" ", h("button", { type: "button", class: "btn link", onclick: onClick }, button)] : null))));
+  }
+  function restart() {
+    ask(W.dialog, async () => {
+      try {
+        await fetch("config/restart", { method: "POST", headers: { "Content-Type": "application/json" },
+                                        body: JSON.stringify({ confirm: "restart" }) });
+      } catch (e) { /* the add-on stops answering while it restarts */ }
+      toast(W.toast.restarting.description);
+    });
+  }
+  async function load(after) {
+    let m;
+    try {
+      const r = await fetch("config/model?lang=en", { cache: "no-store" });
+      if (!r.ok) throw new Error("model " + r.status);
+      m = await r.json();
+      if (!m.layout || !m.ui) throw new Error("no layout");
+    } catch (e) {
+      $("#groups").replaceChildren();
+      $("#set-search").hidden = true;
+      banner("bad", W.load_failed.name, W.load_failed.description);
+      return;
+    }
+    M = m; V = clone(m.ui); ORIG = clone(m.ui); FP = m.fingerprint; MSG = []; DEVICE = "";
+    $("#set-search").hidden = false;
+    FILLED = {};
+    LIST = null;
+    for (const g of M.layout.groups) for (const p of g.parts) for (const f of p.fields) {
+      if (f.fills) FILLED[f.fills] = f;
+      if (f.control === "inverter_list") LIST = f;
+    }
+    if (!OPEN.size && M.layout.groups.length) OPEN.add(M.layout.groups[0].id);
+    if (after === "saved") banner("ok", W.saved.name, W.saved.description, W.restart, restart);
+    else if ((m.running_differs || []).length) banner("warn", W.differs.name, W.differs.description, W.restart, restart);
+    else banner();
+    render();
+    validate();
+  }
+  function firstBad() {
+    const r = ROWS.find((x) => x.tiers && x.tiers.has("bad") && x.visible);
+    if (!r) { if (!$("#set-other").hidden) $("#set-other").scrollIntoView({ block: "center" }); return; }
+    for (let p = r.el.parentElement; p; p = p.parentElement) if (p.tagName === "DETAILS") p.open = true;
+    r.el.scrollIntoView({ block: "center" });
+    const input = r.el.querySelector("input,select,button");
+    if (input) input.focus({ preventScroll: true });
+  }
+  async function save() {
+    const btn = $("#sb-save");
+    btn.disabled = true; btn.textContent = W.savebar.saving;
+    try {
+      clearTimeout(vtimer);
+      await validate();
+      if (MSG.some((m) => m.tier === "bad")) { toast(W.toast.blocked.description); firstBad(); return; }
+      const r = await fetch("config/save", { method: "POST", headers: { "Content-Type": "application/json" },
+                                             body: JSON.stringify({ model: V, fingerprint: FP }) });
+      const b = await r.json().catch(() => ({}));
+      if (r.ok) { toast(W.toast.saved); await load("saved"); return; }
+      if (r.status === 409 && b.kind === "stale") {
+        FP = b.fingerprint || FP;
+        const names = (b.changed_fields || []).map((k) => { const f = findField(k); return f ? f.label : k; });
+        banner("bad", W.stale.name, W.stale.description + (names.length ? " " + names.join(", ") + "." : ""));
+        return;
+      }
+      if (r.status === 422) { MSG = b.messages || []; paint(); toast(W.toast.blocked.description); firstBad(); return; }
+      toast(W.toast.failed);
+    } catch (e) { toast(W.toast.failed); }
+    finally { btn.disabled = false; btn.textContent = W.savebar.save; }
+  }
+  $("#sb-save").addEventListener("click", save);
+  $("#sb-discard").addEventListener("click", () => {
+    V = clone(ORIG); UNLOCKED.clear(); render(); validate(); toast(W.toast.discarded);
+    if ($("#set-banner .b-bad")) banner();
+  });
+  addEventListener("beforeunload", (e) => { if (V && dirtyCount()) { e.preventDefault(); e.returnValue = ""; } });
+  document.addEventListener("ux13:tab", (e) => {
+    active = e.detail === "settings";
+    if (active && !M) load(); else savebar();
+  });
+  // app.js chose the first tab before this file ran.
+  if ($("#t-set").getAttribute("aria-selected") === "true") { active = true; load(); }
+})();
diff --git a/goodwe_controller/app/ui_text/en.json b/goodwe_controller/app/ui_text/en.json
index 6170326..dbb87a0 100644
--- a/goodwe_controller/app/ui_text/en.json
+++ b/goodwe_controller/app/ui_text/en.json
@@ -29,7 +29,12 @@
   "choices": {
     "contract": {"none": "No prices", "fixed": "Fixed price", "daynight": "Day and night", "dynamic": "Dynamic, hourly", "custom": "Other time windows"},
     "fallback": {"none": "None", "fixed": "One price", "daynight": "Day and night", "custom": "Other time windows"},
-    "region": {"flanders": "Flanders, Fluvius Antwerpen", "own": "I enter my own figure"}
+    "region": {"flanders": "Flanders, Fluvius Antwerpen", "own": "I enter my own figure"},
+    "meter_source": {"off": "One grid power entity", "ha_dsmr": "Import and export entities", "mqtt_p1": "Meter over MQTT", "ha_signed": "One net power entity", "homewizard_local": "HomeWizard meter on the network"},
+    "meter_phases": {"1": "1 phase", "3": "3 phases"},
+    "shadow_mode": {"auto": "Automatic", "on": "Always on", "off": "Off"},
+    "price_provider": {"generic_dayahead": "Day-ahead market price", "custom_formula": "Your own price formula", "manual_csv": "A price file"},
+    "log_level": {"trace": "Everything, for support", "debug": "Detailed, to find a problem", "info": "Normal", "warning": "Warnings and errors", "error": "Errors only"}
   },
   "applies": {
     "restart": {"name": "Applies after a restart"},
@@ -58,7 +63,8 @@
       "estimate_tip": "estimate from yesterday",
       "none_tip": "No price known",
       "no_prices": {"description": "No prices for today, so the chart shows only the plan."},
-      "list": "The plan in words"
+      "list": "The plan in words",
+      "average_tip": "hour average"
     },
     "peak": {"name": "Peak limit", "this_month": "This month's peak", "limit": "Limit", "none": "None recorded yet", "unreadable": "Cannot be read now"},
     "attention": {"name": "Needs attention", "nothing": "Nothing to look at", "to_look": "to look at", "details": "Details", "alarm": "Alarm", "warning": "Warning", "info": "Info"},
@@ -74,7 +80,83 @@
     "toast": {"started": "Control started.", "stopped": "Control stopped.", "done": "Done.", "failed": "That did not work. Try again."},
     "offline": {"name": "Cannot reach the add-on", "description": "The page tries again every 3 seconds."},
     "batteries": {"name": "Batteries", "description": "Battery modes and on and off switches arrive in a later update.", "level": "Level", "now": "Now", "stored": "Stored", "mode": "Mode", "settings": "Change inverter settings"},
-    "settings": {"name": "Settings", "description": "The new settings screens arrive in a later update, so use the settings page for now.", "open": "Open the settings page"},
+    "settings": {"name": "Settings", "description": "The settings are grouped by task below.", "open": "Open the settings page"},
     "setup": {"name": "Setup", "description": "The setup steps arrive in a later update, so use the settings page for now."}
+  },
+  "choices_later": {
+    "region": {"wallonia": "Wallonia, no preset yet", "brussels": "Brussels, no preset yet"}
+  },
+  "choice_help": {
+    "meter_source": {
+      "off": {"description": "A Home Assistant entity that reads grid power in W, positive when you take from the grid."},
+      "ha_dsmr": {"description": "Two Home Assistant entities from the DSMR integration, one for import and one for export."},
+      "mqtt_p1": {"description": "The meter's readings arrive over MQTT on a topic you name."},
+      "ha_signed": {"description": "One Home Assistant entity that reads net grid power, positive for import."},
+      "homewizard_local": {"description": "The add-on reads a HomeWizard meter on your network, and can spot a stuck meter."}
+    }
+  },
+  "settings": {
+    "name": "Settings",
+    "description": "Every setting, grouped by task, and the simple view follows in a later update.",
+    "classic": "Classic settings",
+    "search": {"name": "Find a setting", "description": "Find a setting, for example peak or meter."},
+    "no_match": {"description": "No setting matches your search."},
+    "loading": "Loading the settings",
+    "load_failed": {"name": "Cannot read the settings", "description": "The add-on could not read its stored settings, so use Classic settings or the Configuration tab."},
+    "footer": {"description": "Every change is checked by the add-on's own start checks before it is saved."},
+    "to_fix": "to fix",
+    "to_check": "to check",
+    "changed": "changed",
+    "on": "On",
+    "off": "Off",
+    "not_set": "Not set",
+    "locked": "Locked",
+    "change": "Change",
+    "support": {"description": "These were measured on real hardware, so change them only when support asks."},
+    "picker": {
+      "choose": "Choose an entity",
+      "search": {"description": "Search by name or entity id."},
+      "all": "Show every entity",
+      "use": "Use this entity id",
+      "clear": "Clear",
+      "missing": "Not in Home Assistant",
+      "none": {"description": "Nothing matches, so check the entity in Developer Tools."}
+    },
+    "add_inverter": "Add an inverter",
+    "inverter": "Inverter",
+    "remove": "Remove",
+    "add_row": "Add a row",
+    "add_solar": "Add a solar inverter",
+    "reversed": "Reads negative",
+    "phase": "Phase",
+    "raw_roster": {"description": "This inverter list can only be changed in the Configuration tab."},
+    "region_year": "{year} figures",
+    "hour": "{hour}:00 UTC",
+    "preset": {"description": "Filled in by the region above, so choose your own figure to change it."},
+    "cycle": {"name": "Run a cycle by hand", "description": "The same actions as on Home, each asking first."},
+    "savebar": {"label": "Unsaved changes", "one": "change not saved", "many": "changes not saved", "discard": "Discard", "save": "Save", "saving": "Saving"},
+    "saved": {"name": "Saved, not running yet", "description": "The add-on runs the settings it started with until you restart it."},
+    "differs": {"name": "Stored settings are not running", "description": "Some stored settings differ from what runs now, so restart the add-on to apply them."},
+    "stale": {"name": "Changed somewhere else", "description": "These settings changed elsewhere while you edited, so save again to keep yours or discard to load theirs."},
+    "other": "Other messages",
+    "restart": "Restart now",
+    "dialog": {"name": "Restart the add-on?", "description": "Every inverter is set to 0 W while the add-on restarts, and then the new settings apply.", "yes": "Restart now"},
+    "toast": {
+      "saved": "Saved. Restart to apply.",
+      "discarded": "Changes discarded.",
+      "failed": "That did not work. Try again.",
+      "blocked": {"description": "Fix the settings marked in red, then save again."},
+      "restarting": {"description": "Restart requested, so this page stops answering for a moment."}
+    },
+    "tier": {"bad": "Must fix", "warn": "Check this", "info": "Note"},
+    "derive": {
+      "raw_roster": {"description": "This inverter list can only be changed in the Configuration tab."},
+      "no_inverter": {"description": "Add at least one inverter."},
+      "flat_named": {"description": "Add a second inverter before naming this one."},
+      "no_source": {"description": "Choose where the dynamic prices come from."},
+      "custom_profile": {"description": "Other time windows can only be changed in the Configuration tab."},
+      "no_price": {"description": "Enter a price per kWh."},
+      "unknown": {"description": "The page cannot store this choice, so reload the page."}
+    }
   }
 }
diff --git a/goodwe_controller/app/uilayout.py b/goodwe_controller/app/uilayout.py
index 23fec4d..b0288e4 100644
--- a/goodwe_controller/app/uilayout.py
+++ b/goodwe_controller/app/uilayout.py
@@ -43,6 +43,8 @@ class Field:
     applies: str = RESTART
     simple: bool = False        # also on Settings, Simple
     wizard: int = 0             # setup wizard step 1-6, 0 = not in the wizard
+    mirror: str = ""            # a choice also copied to this field, if offered
+    fills: str = ""             # a preset choice fills this field (uimodel)
 
     @property
     def text(self) -> str:
@@ -73,17 +75,20 @@ _MAINT = (("maintenance_enabled", "==", True),)
 _ONE = (("inverter_count", "==", 1),)
 _SEVERAL = (("inverter_count", ">", 1),)
 _PHASES = (("meter_phases", ">", 1),)
+# One inverter stored flat has no name or capacity (uimodel._roster_encode).
+_LISTED = (("inverter_shape", "!=", "flat"),)
 
 # The per-inverter card. Its keys are `inverters.<field>` in config.yaml.
 ROSTER_FIELDS = (
-    Field("inverters.name", TEXT, wizard=2),
+    Field("inverters.name", TEXT, show=_LISTED, wizard=2),
     Field("inverters.setpoint_entity", ENTITY, kind="number", wizard=2),
     Field("inverters.max_w", SLIDER, "W", step=100, wizard=2),
     Field("inverters.bms_soc_floor", SLIDER, "%", wizard=2),
     Field("inverters.soc_entity", ENTITY, kind="pct", wizard=2),
     Field("inverters.batt_entity", ENTITY, kind="power_w", wizard=2),
     Field("inverters.batt_invert", TOGGLE, wizard=2),
-    Field("inverters.capacity_kwh", NUMBER, "kWh", step=0.1, wizard=2),
+    Field("inverters.capacity_kwh", NUMBER, "kWh", step=0.1, show=_LISTED,
+          wizard=2),
 )
 
 GROUPS = (
@@ -123,7 +128,9 @@ GROUPS = (
     )),
     Group("tariff", (
         Part("", (
-            Field("ui.contract", SEGMENTED, wizard=4),
+            # A contract without a feed is also the price used when a feed
+            # is down, so the fallback follows it (uimodel._tariff_encode).
+            Field("ui.contract", SEGMENTED, wizard=4, mirror="ui.fallback"),
             Field("price_provider", SELECT, show=_DYNAMIC, wizard=4),
             Field("price_formula", TEXT,
                   show=_DYNAMIC + (("price_provider", "==", "custom_formula"),),
@@ -131,7 +138,8 @@ GROUPS = (
             Field("price_csv_path", TEXT,
                   show=_DYNAMIC + (("price_provider", "==", "manual_csv"),),
                   wizard=4),
-            Field("ui.region", SELECT, wizard=4),
+            Field("ui.region", SELECT, wizard=4,
+                  fills="price_taxes_eur_kwh"),
             Field("price_taxes_eur_kwh", NUMBER, "€/kWh", step=0.00001,
                   wizard=4),
             Field("price_markup_eur_kwh", NUMBER, "€/kWh", step=0.001,
diff --git a/goodwe_controller/app/uimodel.py b/goodwe_controller/app/uimodel.py
index fddf36e..08523ed 100644
--- a/goodwe_controller/app/uimodel.py
+++ b/goodwe_controller/app/uimodel.py
@@ -21,11 +21,23 @@ from .price import FLEMISH_TAXES_COMPONENTS_EUR_KWH
 from .static_tariff import ProfileInvalid, parse_static_profile
 
 __all__ = ["options_to_ui", "ui_to_options", "REGION_PRESETS",
-           "arbitrage_from_batteries", "DeriveError"]
+           "arbitrage_from_batteries", "DeriveError", "COUNT", "GROWN"]
 
 
 class DeriveError(ValueError):
-    """The page model asks for something no options blob can say."""
+    """The page model asks for something no options blob can say. `code` names
+    the sentence the page shows (app/ui_text `derive.<code>`), and `field` the
+    page field it is shown beside."""
+
+    def __init__(self, text, code="", field=""):
+        super().__init__(text)
+        self.code, self.field = code, field
+
+
+# The page model's inverter count, which show conditions read, and what adding
+# a card sets: a second inverter turns the one flat inverter into a list.
+COUNT = "inverter_count"
+GROWN = {"inverter_shape": "list"}
 
 
 # --------------------------------------------------------------------------- #
@@ -80,13 +92,16 @@ def _roster_encode(m, keep):
     out = {}
     shape, cards = m.get("inverter_shape"), m.get("inverters")
     if shape == "raw":
-        raise DeriveError("the inverter list is edited in the Configuration tab")
+        raise DeriveError("the inverter list is edited in the Configuration tab",
+                          "raw_roster", "inverters")
     if not cards:
-        raise DeriveError("at least one inverter is needed")
+        raise DeriveError("at least one inverter is needed", "no_inverter",
+                          "inverters")
     if shape == "flat" and len(cards) == 1:
         card = cards[0]
         if not _blank(card.get("name")) or not _blank(card.get("capacity_kwh")):
-            raise DeriveError("one inverter stored flat has no name or capacity")
+            raise DeriveError("one inverter stored flat has no name or "
+                              "capacity", "flat_named", "inverters")
         for k in _ROSTER_FLAT:
             if card.get(k) is not None or k in keep:
                 out[k] = card.get(k)
@@ -96,8 +111,9 @@ def _roster_encode(m, keep):
                         for c in cards]
     # The flat keys beside a list are not read: they stay as stored.
     out.update({k: copy.deepcopy(keep[k]) for k in _ROSTER_FLAT if k in keep})
-    if shape == "flat":
-        # CFG-04 rule 9e: a flat power request entity beside a list is refused.
+    if shape == "flat" or _roster_decode(keep)["inverter_shape"] == "flat":
+        # CFG-04 rule 9e: a flat power request entity beside a list is refused,
+        # so a list that replaces the flat inverter clears it.
         out["setpoint_entity"] = ""
     return out
 
@@ -210,7 +226,8 @@ def _tariff_encode(m, keep):
     contract = m.get("ui.contract")
     if contract == "dynamic":
         if _blank(m.get("price_provider")) or m.get("price_provider") == "off":
-            raise DeriveError("a dynamic contract needs a price source")
+            raise DeriveError("a dynamic contract needs a price source",
+                              "no_source", "price_provider")
         out["price_provider"] = m["price_provider"]
         kind = m.get("ui.fallback")
     else:
@@ -226,17 +243,19 @@ def _tariff_encode(m, keep):
     elif kind == "custom":
         if "static_profile" not in keep:
             raise DeriveError("odd tariff windows are edited in the "
-                              "Configuration tab")
+                              "Configuration tab", "custom_profile",
+                              "ui.contract")
         out["static_profile"] = keep["static_profile"]
     else:
-        raise DeriveError(f"unknown contract {kind!r}")
+        raise DeriveError(f"unknown contract {kind!r}", "unknown",
+                          "ui.contract")
     return out
 
 
 def _price_of(m, name):
     value = _num(m.get(name))
     if value is None:
-        raise DeriveError(f"{name} needs a price")
+        raise DeriveError(f"{name} needs a price", "no_price", name)
     return value
 
 
@@ -259,7 +278,7 @@ def _region_encode(m, keep):
             out["price_taxes_profile"] = keep["price_taxes_profile"]
         return out
     if region not in REGION_PRESETS:
-        raise DeriveError(f"unknown region {region!r}")
+        raise DeriveError(f"unknown region {region!r}", "unknown", "ui.region")
     p = REGION_PRESETS[region]
     out = {"price_taxes_eur_kwh": p["taxes_eur_kwh"]}
     if p["taxes_profile"] or "price_taxes_profile" in keep:
diff --git a/goodwe_controller/app/uipage.py b/goodwe_controller/app/uipage.py
new file mode 100644
index 0000000..9a84e4b
--- /dev/null
+++ b/goodwe_controller/app/uipage.py
@@ -0,0 +1,275 @@
+"""UX-13 P2: the settings view's server half. It names no option key.
+
+It turns app/uilayout.py's table into the JSON the page draws from (labels
+from the Supervisor's translations, ranges and choices from its schema, page
+words from app/ui_text), turns a posted page model into options through
+app/uimodel.py, and says beside which page field each validator sentence
+goes. The rules stay in validate.py and the sentences are passed on as they
+are (DECISIONS/UX-13-one-layout-table.md).
+"""
+
+import copy
+import io
+import json
+import os
+import re
+
+from . import uilayout as L
+from . import uimodel as U
+from .configui import help_of, label_of, problems_by_field, split_group
+
+UI_TEXT = os.path.join(os.path.dirname(os.path.abspath(__file__)), "ui_text",
+                       "en.json")
+# A choice the page cannot make, only keep: odd tariff windows (P5 editor).
+ONLY_IF_HELD = ("custom",)
+_TIERS = ("bad", "warn", "info")
+
+
+def ui_text() -> dict:
+    with io.open(UI_TEXT, encoding="utf-8") as f:
+        return json.load(f)
+
+
+def _roster():
+    """The inverter list field's key, read off the table."""
+    return next(f.key for _g, _p, f in L.fields()
+                if f.control == L.INVERTER_LIST)
+
+
+def _node(schema_ui, key):
+    """The Supervisor's schema entry for `key` (`list.sub` too), or {}."""
+    nodes, path = schema_ui or [], key.split(".")
+    for step in path[:-1]:
+        parent = next((n for n in nodes if n.get("name") == step), None)
+        nodes = (parent or {}).get("schema") or []
+    return next((n for n in nodes if n.get("name") == path[-1]), None) or {}
+
+
+def _words(translations, lang, key, T):
+    """(label, help) for a field: ui_text for `ui.` fields, else the
+    translation without its `Group · ` prefix, and the raw key last."""
+    if key.startswith("ui."):
+        entry = T["fields"].get(key[3:], {})
+        return entry.get("name", key), entry.get("description", "")
+    path = tuple(key.split(".")[:-1])
+    name = key.split(".")[-1]
+    label, _lang = label_of(translations, lang, name, path)
+    text, _lang = help_of(translations, lang, name, path)
+    return split_group(label)[1], text
+
+
+def _choices(fld, node, T, value_type):
+    """[[value, label, only_if_held], ...] for a choice control, or None."""
+    if fld.control not in (L.SEGMENTED, L.SELECT, L.CHOICE):
+        return None
+    name = fld.key[3:] if fld.key.startswith("ui.") else fld.key
+    words = T["choices"].get(name) or {}
+    if fld.key.startswith("ui."):
+        values = list(words)
+    elif node.get("options"):
+        values = [v for v in node["options"] if not words or v in words]
+    elif value_type == "integer" and node.get("lengthMax") is not None:
+        values = list(range(int(node["lengthMin"]), int(node["lengthMax"]) + 1))
+        if words:
+            values = [v for v in values if str(v) in words]
+    else:
+        return []
+    out = []
+    for v in values:
+        label = words.get(str(v))
+        if label is None:
+            label = (T["settings"]["hour"].replace("{hour}", f"{v:02d}")
+                     if isinstance(v, int) else str(v))
+        preset = U.REGION_PRESETS.get(v) if fld.fills else None
+        if preset:
+            label = f"{label}, " + T["settings"]["region_year"].replace(
+                "{year}", str(preset["year"]))
+        out.append([v, label, v in ONLY_IF_HELD])
+    return out
+
+
+def _field(fld, schema_ui, translations, lang, T):
+    node = _node(schema_ui, fld.key)
+    label, text = _words(translations, lang, fld.key, T)
+    value_type = ("float" if fld.control == L.NUMBER and fld.key.startswith("ui.")
+                  else node.get("type") or "")
+    out = {"key": fld.key, "control": fld.control, "label": label,
+           "help": text, "unit": fld.unit, "scale": fld.scale,
+           "step": fld.step, "kind": fld.kind,
+           "show": [list(c) for c in fld.show], "applies": fld.applies,
+           "type": value_type, "optional": not node.get("required", False),
+           "writes": sorted(k for k, how in L.DERIVED.items()
+                            if how == fld.key)}
+    if node.get("lengthMin") is not None:
+        out["min"] = node["lengthMin"]
+    if node.get("lengthMax") is not None:
+        out["max"] = node["lengthMax"]
+    choices = _choices(fld, node, T, value_type)
+    if choices is not None:
+        out["choices"] = choices
+        name = fld.key[3:] if fld.key.startswith("ui.") else fld.key
+        later = T.get("choices_later", {}).get(name)
+        if later:
+            out["later"] = [[v, words] for v, words in later.items()]
+        hints = T.get("choice_help", {}).get(name)
+        if hints:
+            out["hints"] = {v: e.get("description", "")
+                            for v, e in hints.items()}
+    if fld.mirror:
+        out["mirror"] = fld.mirror
+    if fld.fills:
+        out["fills"] = fld.fills
+        out["presets"] = {rid: {"year": p["year"], "value": p["taxes_eur_kwh"]}
+                          for rid, p in U.REGION_PRESETS.items()}
+    roster = _roster()
+    if fld.key.startswith(roster + "."):
+        sub = fld.key[len(roster) + 1:]
+        if L.DERIVED.get(sub) == roster:
+            out["flat"] = sub           # how the one flat inverter stores it
+    if fld.control == L.INVERTER_LIST:
+        out["fields"] = [_field(sub, schema_ui, translations, lang, T)
+                         for sub in L.ROSTER_FIELDS]
+        out["count"] = U.COUNT
+        out["grow"] = dict(U.GROWN)
+        out["shape"] = next(iter(U.GROWN))
+    return out
+
+
+def layout(schema_ui, translations, lang="en") -> dict:
+    """Every group, part and field of the Installer view, as the page draws
+    it. Built from the table only: a field the table places is on the page."""
+    T = ui_text()
+    groups = []
+    for g in L.GROUPS:
+        parts = []
+        for p in g.parts:
+            words = T["parts"].get(f"{g.id}.{p.id}", {}) if p.id else {}
+            parts.append({"id": p.id, "name": words.get("name", ""),
+                          "description": words.get("description", ""),
+                          "collapsed": p.collapsed,
+                          "fields": [_field(f, schema_ui, translations, lang, T)
+                                     for f in p.fields]})
+        words = T["groups"].get(g.id, {})
+        applies = sorted({f.applies for p in g.parts for f in p.fields})
+        groups.append({"id": g.id, "name": words.get("name", g.id),
+                       "description": words.get("description", ""),
+                       "support_only": g.support_only,
+                       "applies": [T["applies"][a]["name"] for a in applies],
+                       "parts": parts})
+    return {"groups": groups}
+
+
+# --------------------------------------------------------------------------- #
+# The page model -> options, for the validator and the save
+# --------------------------------------------------------------------------- #
+def _same(a, b) -> bool:
+    """Equal as the Supervisor stores it: 3 and 3.0 alike, True and 1 not."""
+    if isinstance(a, bool) or isinstance(b, bool):
+        return type(a) is type(b) and a == b
+    if isinstance(a, (int, float)) and isinstance(b, (int, float)):
+        return a == b
+    if isinstance(a, list) and isinstance(b, list):
+        return len(a) == len(b) and all(_same(x, y) for x, y in zip(a, b))
+    if isinstance(a, dict) and isinstance(b, dict):
+        return a.keys() == b.keys() and all(_same(a[k], b[k]) for k in a)
+    return type(a) is type(b) and a == b
+
+
+def to_options(model: dict, stored: dict | None = None) -> dict:
+    """The options blob for a posted page model. A value equal to the stored
+    one is written as stored, in the stored key order, so a save that changed
+    nothing writes an identical blob (the browser reads 3.0 as 3)."""
+    out = U.ui_to_options(model)
+    stored = stored or {}
+    for k, v in out.items():
+        if k in stored and _same(v, stored[k]):
+            out[k] = copy.deepcopy(stored[k])
+    return ({k: out[k] for k in stored if k in out}
+            | {k: v for k, v in out.items() if k not in stored})
+
+
+def derive_message(err: U.DeriveError) -> dict:
+    words = ui_text()["settings"]["derive"]
+    text = words.get(err.code, words["unknown"])["description"]
+    return {"field": err.field or None, "card": None, "tier": "bad",
+            "text": text}
+
+
+# --------------------------------------------------------------------------- #
+# Where a sentence goes on the page
+# --------------------------------------------------------------------------- #
+# `inverters.max_w`, or `inverters[1].setpoint_entity` for one card.
+_SUB = re.compile(r"(?<![A-Za-z0-9_])([a-z_0-9]+)(?:\[(\d+)\])?\.([a-z_0-9]+)")
+
+
+def _mirror_of(key):
+    return next((f.key for _g, _p, f in L.fields() if f.mirror == key), None)
+
+
+def targets(key: str, text: str, model: dict) -> list:
+    """[(page field, card)] for a sentence that names option `key`. `card` is
+    the inverter card's index, or None."""
+    roster = _roster()
+    cards = model.get(roster) if isinstance(model.get(roster), list) else []
+    names = [c.get("name") for c in cards if isinstance(c, dict)]
+    # messages.setting(): “Inverter rating” for inverter-b (inverters.max_w),
+    # or a roster rule's own `inverters[1] (inverter-b)`.
+    card = next((i for i, n in enumerate(names)
+                 if n and f"for {n} ({roster}." in text), None)
+    index = re.search(re.escape(roster) + r"\[(\d+)\]", text)
+    if card is None and index and int(index.group(1)) < len(cards):
+        card = int(index.group(1))
+    if key == roster:
+        subs = [(f"{roster}.{s}", int(i) if i and int(i) < len(cards) else card)
+                for r, i, s in _SUB.findall(text) if r == roster]
+        subs = [x for x in dict.fromkeys(subs) if L.field(x[0])]
+        return subs or [(roster, card)]
+    if key in L.DERIVED:
+        how = L.DERIVED[key]
+        if how == roster:
+            return [(f"{roster}.{key}", 0 if card is None else card)]
+        fld = L.field(how)
+        if fld is not None and not L.visible(fld, model) and _mirror_of(how):
+            return [(_mirror_of(how), None)]
+        return [(how, None)]
+    if L.field(key) is not None:
+        return [(key, None)]
+    return [(None, None)]
+
+
+def anchors(problems, notes, model, keys) -> list:
+    """[{field, card, tier, text}] for the refusals and notes. `field` is
+    None for a sentence that names no setting on the page."""
+    out, seen = [], set()
+
+    def add(field, card, tier, text):
+        if (field, card, text) not in seen:
+            seen.add((field, card, text))
+            out.append({"field": field, "card": card, "tier": tier,
+                        "text": text})
+
+    by_key, unanchored = problems_by_field(problems, keys)
+    for key, texts in by_key.items():
+        for text in texts:
+            for field, card in targets(key, text, model):
+                add(field, card, "bad", text)
+    for text in unanchored:
+        add(None, None, "bad", text)
+    for note in notes:
+        tier = note.tier if note.tier in _TIERS else "info"
+        for key in note.keys or (None,):
+            for field, card in (targets(key, note.text, model) if key
+                                else [(None, None)]):
+                add(field, card, tier, note.text)
+    # A sentence placed on one inverter's field is not also put on the list.
+    roster = _roster()
+    placed = {m["text"] for m in out
+              if (m["field"] or "").startswith(roster + ".")}
+    return [m for m in out if not (m["field"] == roster
+                                   and m["text"] in placed)]
+
+
+def fields_of(keys, model) -> list:
+    """The page fields that show these option keys (a stale save's list)."""
+    return list(dict.fromkeys(f for k in keys for f, _c in targets(k, "", model)
+                              if f))
diff --git a/goodwe_controller/app/web.py b/goodwe_controller/app/web.py
index 648b7ca..e599ce0 100644
--- a/goodwe_controller/app/web.py
+++ b/goodwe_controller/app/web.py
@@ -37,12 +37,13 @@ import os
 
 from aiohttp import web
 
-from . import messages, selfconfig
+from . import messages, selfconfig, uipage
 from .haentities import EntityCache
 from .homeview import region_of
 from .validate import config_notes
 from .config_page import CONFIG_PAGE
 from .configui import changed_keys, field_model, problems_by_field
+from .uimodel import DeriveError, options_to_ui
 
 _LOG = logging.getLogger("goodwe.web")
 
@@ -65,13 +66,16 @@ def page() -> str:
     """The assembled index page. `</` is escaped inside the two inline
     scripts, so no text in them can close the tag early."""
     ui_text = json.dumps(json.loads(_read(UI_TEXT)), ensure_ascii=False)
-    script = _read(os.path.join(STATIC, "app.js"))
-    if "</script" in script.lower():
-        raise ValueError("app.js may not contain a closing script tag")
+    scripts = {}
+    for name in ("app.js", "settings.js"):
+        scripts[name] = _read(os.path.join(STATIC, name))
+        if "</script" in scripts[name].lower():
+            raise ValueError(f"{name} may not contain a closing script tag")
     return (_read(os.path.join(STATIC, "index.html"))
             .replace("/*APP_CSS*/", _read(os.path.join(STATIC, "app.css")))
             .replace("/*UI_TEXT*/", ui_text.replace("</", "<\\/"))
-            .replace("/*APP_JS*/", script))
+            .replace("/*APP_JS*/", scripts["app.js"])
+            .replace("/*SETTINGS_JS*/", scripts["settings.js"]))
 
 
 # ⚠️ WHAT THE PANEL SAYS WHEN IT COULD NOT READ A DEVICE RANGE. Two of
@@ -121,15 +125,22 @@ def build_app(controller, selfcfg=None) -> web.Application:
     async def config_index(_request):
         return web.Response(text=CONFIG_PAGE, content_type="text/html")
 
-    async def _proposed(request):
+    async def _proposed(request, stored=None):
+        """(body, options, model). UX-13's settings view posts its page
+        `model`, which app/uimodel.py turns into the options blob here, so the
+        validator and the Supervisor only ever see a real blob. The classic
+        page posts `options`. Raises DeriveError for a model no blob can say."""
         try:
             body = await request.json()
         except ValueError:
             raise web.HTTPBadRequest(text="expected JSON")
+        model = body.get("model")
+        if isinstance(model, dict):
+            return body, uipage.to_options(model, stored), model
         options = body.get("options")
         if not isinstance(options, dict):
             raise web.HTTPBadRequest(text="expected an options object")
-        return body, options
+        return body, options, None
 
     async def config_model(request):
         """Everything the page needs to draw itself, from ONE Supervisor call.
@@ -161,6 +172,10 @@ def build_app(controller, selfcfg=None) -> web.Application:
             # UX-13 P1: the levies preset and its year, for the P2 Settings
             # screens, which show the year beside the region choice.
             "region": region_of(options),
+            # UX-13 P2: the Installer view draws from these two.
+            "layout": uipage.layout(info.get("schema") or [],
+                                    info.get("translations") or {}, lang),
+            "ui": options_to_ui(options),
         })
         return web.json_response(model)
 
@@ -177,7 +192,12 @@ def build_app(controller, selfcfg=None) -> web.Application:
         product this card is delivering; anything this layer did to them would
         be a second opinion about a rule it does not own.
         """
-        _body, options = await _proposed(request)
+        try:
+            _body, options, model = await _proposed(request)
+        except DeriveError as err:
+            return web.json_response({"problems": [], "by_key": {},
+                                      "unanchored": [], "notes": [],
+                                      "messages": [uipage.derive_message(err)]})
         notes = []
         problems, unread = await selfconfig.problems_and_ranges(
             options, controller.hass, notes=notes)
@@ -190,6 +210,9 @@ def build_app(controller, selfcfg=None) -> web.Application:
                    "notes": [n._asdict() for n in notes]}
         if unread:
             payload["device_note"] = DEVICE_NOTE % ", ".join(sorted(set(unread)))
+        if model is not None:
+            payload["messages"] = uipage.anchors(problems, notes, model,
+                                                 _keys_of(options))
         return web.json_response(payload)
 
     def _keys_of(options):
@@ -202,7 +225,27 @@ def build_app(controller, selfcfg=None) -> web.Application:
 
     async def config_save(request):
         """Validate, compare-and-swap, write. Or refuse and write NOTHING."""
-        body, options = await _proposed(request)
+        # The page model carries no stored values of the keys it shows, so the
+        # blob is settled against what is stored: an unchanged value is written
+        # exactly as stored (uipage.to_options).
+        try:
+            posted = await request.json()
+        except ValueError:
+            raise web.HTTPBadRequest(text="expected JSON")
+        stored_now = None
+        if isinstance(posted, dict) and isinstance(posted.get("model"), dict):
+            try:
+                stored_now = (await selfcfg.info()).get("options") or {}
+            except selfconfig.SupervisorUnavailable as err:
+                _LOG.error("saving options failed: %s", err)
+                return web.json_response({"error": str(err)}, status=502)
+        try:
+            body, options, model = await _proposed(request, stored_now)
+        except DeriveError as err:
+            return web.json_response(
+                {"kind": "invalid", "problems": [], "by_key": {},
+                 "unanchored": [], "messages": [uipage.derive_message(err)]},
+                status=422)
         expect = str(body.get("fingerprint") or "")
         try:
             result = await selfconfig.save(selfcfg, options, expect,
@@ -212,6 +255,9 @@ def build_app(controller, selfcfg=None) -> web.Application:
                 stored = refused.stored or {}
                 return web.json_response(
                     {"kind": "stale", "changed": refused.changed,
+                     "changed_fields": (uipage.fields_of(refused.changed,
+                                                         model)
+                                        if model is not None else []),
                      "stored": stored,
                      # The page needs the CURRENT token to be able to save
                      # again after the operator has read the difference. That
@@ -221,9 +267,12 @@ def build_app(controller, selfcfg=None) -> web.Application:
                     status=409)
             by_key, unanchored = problems_by_field(refused.problems,
                                                    _keys_of(options))
-            return web.json_response(
-                {"kind": "invalid", "problems": refused.problems,
-                 "by_key": by_key, "unanchored": unanchored}, status=422)
+            payload = {"kind": "invalid", "problems": refused.problems,
+                       "by_key": by_key, "unanchored": unanchored}
+            if model is not None:
+                payload["messages"] = uipage.anchors(refused.problems, [],
+                                                     model, _keys_of(options))
+            return web.json_response(payload, status=422)
         except selfconfig.SupervisorUnavailable as err:
             _LOG.error("saving options failed: %s", err)
             return web.json_response({"error": str(err)}, status=502)
diff --git a/goodwe_controller/test_haentities.py b/goodwe_controller/test_haentities.py
index 30ffb81..6db27e8 100644
--- a/goodwe_controller/test_haentities.py
+++ b/goodwe_controller/test_haentities.py
@@ -10,6 +10,7 @@ Mutating a module this file grades? Read MUTATION.md first (purge __pycache__).
 
 import asyncio
 import json
+import logging
 import sys
 import time
 
@@ -96,9 +97,29 @@ for name, handler in (("502 while HA restarts", bad_gateway),
                       ("a body that is not JSON", garbage),
                       ("JSON that is not a list", not_a_list)):
     check(f"{name} -> None", asyncio.run(read_with(handler)) is None)
+class _Lines(logging.Handler):
+    def __init__(self):
+        super().__init__()
+        self.lines = []
+
+    def emit(self, record):
+        if record.levelno >= logging.WARNING:
+            self.lines.append(record.getMessage())
+
+
+_lines = _Lines()
+logging.getLogger().addHandler(_lines)
 check("an answer slower than the timeout -> None, at the timeout",
       asyncio.run(read_with(slow, timeout_s=0.3)) is None
       and read_with.took < 1.0)
+# UX-13 P1 test finding (c): a timeout's own text is empty, which left
+# "Reading the entity list failed: " with no reason.
+check("...and its WARNING line gives the reason, not an empty one "
+      f"({_lines.lines})", any(
+          x == "Reading the entity list failed: no answer within 0.3 seconds."
+          for x in _lines.lines)
+      and not any(x.rstrip().endswith("failed:") for x in _lines.lines))
+logging.getLogger().removeHandler(_lines)
 check("no server at all -> None", asyncio.run(closed_port()) is None)
 check("the timeout for the list is the same 10 s as every other read",
       "STATES_TIMEOUT_S = 10 " in open(H.__file__, encoding="utf-8").read())
diff --git a/goodwe_controller/test_home.py b/goodwe_controller/test_home.py
index 40e21c2..1adf98f 100644
--- a/goodwe_controller/test_home.py
+++ b/goodwe_controller/test_home.py
@@ -321,11 +321,11 @@ check("the price bars are today's 24 hours, from the real series, with the "
       and s_arb["plan"]["prices"][19]["kind"] == "dear"
       and s_arb["plan"]["prices"][0]["kind"] == "mid"
       and s_arb["plan"]["prices"][13]["label"] == "13:00")
-check("the price line names the price now, today's cheapest and dearest, and "
+check("the price line names the price now, today's lowest and highest, and "
       "that tomorrow's prices are in",
       s_arb["plan"]["price_line"] == ("Price now €0.16 per kWh, all in. "
-                                      "Today: cheapest €0.14 at 13:00, "
-                                      "dearest €0.36 at 19:00.")
+                                      "Today: lowest €0.14 at 13:00, "
+                                      "highest €0.36 at 19:00.")
       and s_arb["plan"]["tomorrow_line"] == "Tomorrow's prices are in.")
 
 c_late = make(ARB)
@@ -454,6 +454,59 @@ check("...and every red, amber and settling row reaches Needs attention with "
       + [r["text"] for r in s_al["checks"] if not r["ok"] and r["warn"]]
       + [r["text"] for r in s_al["checks"] if r["ok"] and r["warn"]])
 
+# UX-13 P1 test finding (a): the page said "Held at 0 W" about 15 s before
+# the inverter's power request reached 0 W. Until the last accepted request
+# is 0 W it says "Going to 0 W".
+c_al.inverters[0].last_write = 20.0
+s_go = homeview.build(c_al, level="bad", checks=s_al["checks"], now=NOW)
+c_al.inverters[0].last_write = 0.0
+s_at = homeview.build(c_al, level="bad", checks=s_al["checks"], now=NOW)
+check("an alarm while the last power request is still 20 W says 'Going to "
+      "0 W', and 'Held at 0 W' once 0 W was accepted",
+      s_go["plan"]["verdict"] == "Going to 0 W"
+      and s_go["batteries"][0]["now"] == "Going to 0 W until the alarm clears."
+      and s_go["plan"]["head"].startswith("Every inverter goes to 0 W")
+      and s_at["plan"]["verdict"] == "Held at 0 W"
+      and s_at["batteries"][0]["now"] == "Held at 0 W until the alarm clears.")
+c_sp = make(TWO, auto=False)
+c_sp.inverters[1].last_write = -1500.0
+s_sp = status(c_sp)
+check("...and a stop does the same, per battery",
+      [b["now"] for b in s_sp["batteries"]]
+      == ["Held at 0 W while control is stopped.",
+          "Going to 0 W while control is stopped."])
+
+# Finding (b): a quarter-hourly feed. The block's price and the price line
+# name the same 15-minute point, and nothing says "the list".
+_q = []
+for _k, _p in enumerate(MOCK):
+    for _m in range(4):
+        _q.append(PricePoint(DAY0 + timedelta(hours=_k, minutes=15 * _m),
+                             round(_p + (0.0 if _m != 3 else -0.01), 4), False))
+_q += [PricePoint(p.start + timedelta(days=1), p.eur_per_kwh, False)
+       for p in list(_q)]
+c_q = make(ARB)
+c_q.tariff_plan = TariffPlan(PriceRead.series(tuple(_q), PriceProduct.DAY_AHEAD,
+                                              "generic_dayahead", NOW), None,
+                             "provider")
+c_q.tariff_at = NOW
+c_q.peak_guard = quiet_guard()
+s_q = status(c_q)
+_grid = [r for r in s_q["plan"]["runs"] if r["kind"] == "grid"]
+_lo = min(_q[:96], key=lambda p: p.eur_per_kwh)
+check("quarter-hour prices: the charge block, its price and the price line's "
+      "lowest are the same 15-minute period",
+      _grid and _grid[0]["from"] == homeview.hhmm(_lo.start)
+      and _grid[0]["why"] == f"Lowest published price, €{_lo.eur_per_kwh:.2f} "
+                             "per kWh."
+      and f"Today: lowest €{_lo.eur_per_kwh:.2f} at "
+          f"{homeview.hhmm(_lo.start)}," in s_q["plan"]["price_line"]
+      and "the list" not in json.dumps(s_q["plan"]))
+check("...and the hour bar says it is an hour average",
+      s_q["plan"]["prices"][13]["points"] == 4
+      and '"plan.average_tip"' in io.open(os.path.join(
+          HERE, "app", "static", "app.js"), encoding="utf-8").read())
+
 # --------------------------------------------------------------------------- #
 print("\n4. a fault in the Home view never costs the page its rows")
 # --------------------------------------------------------------------------- #
diff --git a/goodwe_controller/test_messages.py b/goodwe_controller/test_messages.py
index 33d3e72..f75653d 100644
--- a/goodwe_controller/test_messages.py
+++ b/goodwe_controller/test_messages.py
@@ -883,6 +883,8 @@ DATA = {
     "hass.py:msg", "hass.py:*args", "hass.py:entity_id", "hass.py:err",
     "hass.py:obj", "hass.py:raw", "hass.py:domain", "hass.py:service",
     "hass.py:resp.status", "hass.py:said", "hass.py:entity", "hass.py:what",
+    # UX-13 P2: the entity list's wait, and an error's text or else its name
+    "hass.py:STATES_TIMEOUT_S", "hass.py:str(err) or type(err).__name__",
     # main.py
     "main.py:'cancelled' if task.cancelled() else repr(exc) if exc else 'returned'",
     "main.py:EXIT_CONTROL_DIED", "main.py:first.name", "main.py:OPTIONS_PATH",
diff --git a/goodwe_controller/test_settings.py b/goodwe_controller/test_settings.py
new file mode 100644
index 0000000..c312adf
--- /dev/null
+++ b/goodwe_controller/test_settings.py
@@ -0,0 +1,437 @@
+"""UX-13 P2: the Installer settings view.  `python3 test_settings.py`
+
+The view is drawn from app/uilayout.py through app/uipage.py and saves the
+page model through app/uimodel.py and the shipped validator. Part 1 checks
+that every group and every mapped field reaches the page with its words,
+range and choices. Part 2 checks the page script names no option key. Parts
+3-5 drive the real routes over HTTP against a fake Supervisor: the save round
+trip, where a refusal lands, and a stale save. Part 6 holds the view's words
+to STYLE. The headless-browser click-through is in the PR, not in CI (the CI
+image has no browser).
+Mutating a module this file grades? Read MUTATION.md first (purge __pycache__).
+"""
+
+import asyncio
+import copy
+import glob
+import io
+import json
+import logging
+import os
+import re
+import sys
+
+HERE = os.path.dirname(os.path.abspath(__file__))
+sys.path.insert(0, os.path.join(HERE, "tools"))
+logging.disable(logging.WARNING)            # the validator's own log lines
+
+from aiohttp import ClientSession, web as aioweb                # noqa: E402
+
+import translations_lint as TL                                  # noqa: E402
+import ux13_demo as D                                           # noqa: E402
+from app import selfconfig, uilayout as L, uimodel as U, uipage, web  # noqa: E402
+from app.validate import validate_startup_config                # noqa: E402
+
+fails = []
+
+
+def check(name, cond):
+    print(f"  {'ok  ' if cond else 'FAIL'} {name}")
+    if not cond:
+        fails.append(name)
+
+
+SCHEMA = D.schema_ui(D.CONFIG)
+TRANSLATIONS = {"en": TL.parse_translation_file(
+    os.path.join(HERE, "translations", "en.yaml"))}
+DEFAULTS = D.defaults(D.CONFIG)
+SITE = dict(DEFAULTS, setpoint_entity="number.goodwe_setpoint",
+            soc_entity="sensor.soc", batt_entity="sensor.batt")
+TWO = dict(SITE, setpoint_entity="", inverters=[
+    {"name": "inverter-a", "setpoint_entity": "number.a", "max_w": 2500,
+     "bms_soc_floor": 10},
+    {"name": "inverter-b", "setpoint_entity": "number.b", "max_w": 2500,
+     "bms_soc_floor": 10}])
+UI_TEXT = uipage.ui_text()
+W = UI_TEXT["settings"]
+
+
+def browser(value):
+    """What JSON.parse then JSON.stringify does to a value: 3.0 becomes 3."""
+    if isinstance(value, float) and value.is_integer():
+        return int(value)
+    if isinstance(value, list):
+        return [browser(v) for v in value]
+    if isinstance(value, dict):
+        return {k: browser(v) for k, v in value.items()}
+    return value
+
+
+# --------------------------------------------------------------------------- #
+print("1. every group and every mapped field reaches the page")
+# --------------------------------------------------------------------------- #
+LAYOUT = uipage.layout(SCHEMA, TRANSLATIONS)
+_flat = []
+for _g in LAYOUT["groups"]:
+    for _p in _g["parts"]:
+        for _f in _p["fields"]:
+            _flat.append((_g["id"], _f))
+            _flat += [(_g["id"], _s) for _s in _f.get("fields", [])]
+_keys = [f["key"] for _g, f in _flat]
+check("the six groups, in the design's order",
+      [g["id"] for g in LAYOUT["groups"]]
+      == ["meter", "inverters", "tariff", "safety", "maintenance", "tuning"]
+      and [g["name"] for g in LAYOUT["groups"]]
+      == ["Meter", "Inverters and batteries", "Tariff and prices",
+          "Safety limits", "Maintenance", "Control tuning"])
+check(f"every field of the table is on the page once ({len(_keys)} fields)",
+      sorted(_keys) == sorted(f.key for _g, _p, f in L.fields())
+      and len(_keys) == len(set(_keys)))
+_counts = {g["id"]: sum(1 for gid, _f in _flat if gid == g["id"])
+           for g in LAYOUT["groups"]}
+print(f"    fields per group: {_counts}")
+check("every field has a label, and every option field's label is its "
+      "translation without the group prefix",
+      all(f["label"] and " · " not in f["label"] for _g, f in _flat)
+      and next(f for _g, f in _flat if f["key"] == "meter_source")["label"]
+      == "Where the meter reading comes from")
+_ranged = [(f["key"], f.get("min"), f.get("max")) for _g, f in _flat
+           if f["control"] in (L.SLIDER, L.LOCKED)]
+check(f"every slider and locked value has its range from the schema "
+      f"({len(_ranged)})", all(lo is not None and hi is not None
+                               for _k, lo, hi in _ranged)
+      and ("peak_cap_w", 500.0, 15000.0) in _ranged)
+check("the peak limit is a kW slider over a value stored in W",
+      next(f for _g, f in _flat if f["key"] == "peak_cap_w")["scale"] == 1000)
+_choice = [f for _g, f in _flat
+           if f["control"] in (L.SEGMENTED, L.SELECT, L.CHOICE)]
+check("every choice control has choices with words",
+      all(f["choices"] and all(c[1] for c in f["choices"]) for f in _choice))
+_ms = next(f for _g, f in _flat if f["key"] == "meter_source")
+check("the meter source is radio cards with a line of help on each",
+      _ms["control"] == L.CHOICE and set(_ms["hints"]) == {c[0] for c in
+                                                            _ms["choices"]})
+_reg = next(f for _g, f in _flat if f["key"] == "ui.region")
+check("the region shows its preset year beside the choice (P0 review)",
+      ["flanders", "Flanders, Fluvius Antwerpen, 2026 figures", False]
+      in _reg["choices"] and _reg["presets"]["flanders"]["year"] == 2026)
+check("...and says plainly that Wallonia and Brussels have no preset yet "
+      "(TARIFF-22)", _reg["later"] == [["wallonia", "Wallonia, no preset yet"],
+                                      ["brussels", "Brussels, no preset yet"]]
+      and "Wallonia or Brussels" in _reg["help"])
+_locked = sorted(f["key"] for _g, f in _flat if f["control"] == L.LOCKED)
+check(f"measured and derived values are locked behind 'Change' "
+      f"({len(_locked)}): every control tuning value, every safety stop and "
+      "the peak reserve",
+      {f.key for p in L.GROUPS[-1].parts for f in p.fields} <= set(_locked)
+      and "sign_disagree_w" in _locked and "peak_soc_floor" in _locked
+      and LAYOUT["groups"][-1]["support_only"])
+check("each group says when its settings apply",
+      all(g["applies"] == [UI_TEXT["applies"]["restart"]["name"]]
+          for g in LAYOUT["groups"]))
+_inv = next(f for _g, f in _flat if f["key"] == "inverters")
+check("the inverter cards carry their count, and adding one makes a list",
+      _inv["count"] == U.COUNT and _inv["grow"] == U.GROWN
+      and [s["key"] for s in _inv["fields"]]
+      == [f.key for f in L.ROSTER_FIELDS])
+check("a page-only field names the option keys it writes, for the grey key "
+      "line", _reg["writes"] == ["price_taxes_profile"]
+      and next(f for _g, f in _flat if f["key"] == "ui.solar")["writes"]
+      == ["pv_entities", "pv_entity", "pv_invert_entities"])
+check("without a Supervisor schema the page still draws, with no ranges",
+      len(uipage.layout([], {})["groups"]) == 6)
+
+# --------------------------------------------------------------------------- #
+print("\n2. the page script names no option key")
+# --------------------------------------------------------------------------- #
+JS = io.open(os.path.join(HERE, "app", "static", "settings.js"),
+             encoding="utf-8").read()
+ORDER, _nested = TL.config_surface(D.CONFIG)
+_leak = sorted(k for k in ORDER if re.search(
+    r"[^A-Za-z0-9_]" + re.escape(k) + r"[^A-Za-z0-9_]", JS))
+check(f"settings.js names no option key ({_leak})", not _leak)
+check("data is set as text, never as HTML",
+      "innerHTML" not in JS and "insertAdjacentHTML" not in JS)
+_fetch = sorted(set(re.findall(r'fetch\("([^"?]+)', JS)))
+check(f"every request is relative, to the add-on's own routes ({_fetch})",
+      _fetch == ["config/model", "config/restart", "config/save",
+                 "config/validate", "ha/entities"])
+
+
+def _resolve(path, node=W):
+    for k in path.split("."):
+        if not isinstance(node, dict) or k not in node:
+            return None
+        node = node[k]
+    return node
+
+
+_used = {re.sub(r"\.(replace|join|length)$", "", k) for k in
+         re.findall(r'\bW\.([a-z_]+(?:\.[a-z_]+)*)', JS)}
+_used |= set(re.findall(r'data-s(?:-ph|-label)?="([\w.]+)"', io.open(
+    os.path.join(HERE, "app", "static", "index.html"), encoding="utf-8").read()))
+_miss = sorted(k for k in _used if _resolve(k) is None)
+check(f"every word the view asks for is in app/ui_text ({len(_used)} keys, "
+      f"missing: {_miss})", len(_used) > 25 and not _miss)
+check("search matches a field's label, its key and its help",
+      "(f.label + \" \" + keys + \" \" + f.key + \" \" + (f.help || \"\"))"
+      in JS)
+check("a locked value shows no input until 'Change' is pressed",
+      re.search(r"function locked\(.*?\n  }\n", JS, re.S)
+      and "UNLOCKED.has(id)) { open(); return box; }" in JS)
+check("nothing is saved while the add-on's own checks refuse the model",
+      "if (MSG.some((m) => m.tier === \"bad\")) { toast(" in JS)
+check("the old settings page stays reachable (until P5)",
+      'href="config" id="set-classic"' in web.page())
+
+
+# --------------------------------------------------------------------------- #
+# The real routes, over HTTP, against a fake Supervisor
+# --------------------------------------------------------------------------- #
+class Supervisor:
+    def __init__(self, options):
+        self.options = copy.deepcopy(options)
+        self.writes = []
+
+    async def info(self):
+        return {"options": copy.deepcopy(self.options), "schema": SCHEMA,
+                "translations": TRANSLATIONS}
+
+    async def write_options(self, options):
+        self.writes.append(copy.deepcopy(options))
+        self.options = copy.deepcopy(options)
+
+    async def restart(self, confirm):
+        raise AssertionError("no restart here")
+
+
+class Hass:
+    session = None
+    token = ""
+
+    async def limits(self, _e):
+        return (-5000.0, 5000.0, 1.0)
+
+    async def states(self):
+        return []
+
+
+class Controller:
+    def __init__(self, opts):
+        self.o, self.hass, self.inverters = dict(opts), Hass(), []
+
+    def log_event(self, text, hint=None):
+        pass
+
+    def status_payload(self):
+        return {"banner": "", "level": "ok", "rows": [], "checks": []}
+
+    async def handle_action(self, what):
+        raise AssertionError(f"the settings view reached {what!r}")
+
+
+async def session(stored, steps):
+    """Run `steps(s, root)` against the app over a fake Supervisor."""
+    sup = Supervisor(stored)
+    runner = aioweb.AppRunner(web.build_app(Controller(stored), sup))
+    await runner.setup()
+    site = aioweb.TCPSite(runner, "127.0.0.1", 0)
+    await site.start()
+    root = f"http://127.0.0.1:{site._server.sockets[0].getsockname()[1]}/"
+    try:
+        async with ClientSession() as s:
+            out = await steps(s, root, sup)
+    finally:
+        await runner.cleanup()
+    return out, sup
+
+
+async def _get(s, url):
+    async with s.get(url) as r:
+        return await r.json()
+
+
+async def _post(s, url, body):
+    async with s.post(url, json=body) as r:
+        return r.status, await r.json()
+
+
+# --------------------------------------------------------------------------- #
+print("\n3. the save round trip")
+# --------------------------------------------------------------------------- #
+check("the fixture site starts (so a refusal below is the edit's)",
+      not validate_startup_config(TWO) and not validate_startup_config(SITE))
+
+
+async def _round(s, root, sup):
+    out = {}
+    m = await _get(s, root + "config/model?lang=en")
+    out["model"] = m
+    model = browser(m["ui"])
+    out["same"] = await _post(s, root + "config/save",
+                              {"model": model, "fingerprint": m["fingerprint"]})
+    out["after_same"] = copy.deepcopy(sup.options)
+    m = await _get(s, root + "config/model?lang=en")
+    model = browser(m["ui"])
+    model["peak_cap_w"] = 4200
+    model["inverters"][1]["max_w"] = 2200
+    out["edit"] = await _post(s, root + "config/save",
+                              {"model": model, "fingerprint": m["fingerprint"]})
+    return out
+
+
+_stored = dict(TWO, gain=0.5, target_grid_w=-10.0, peak_cap_w=3500)
+_r, _sup = asyncio.run(session(_stored, _round))
+check("config/model carries the layout and the page model",
+      _r["model"]["layout"] == json.loads(json.dumps(uipage.layout(
+          SCHEMA, TRANSLATIONS))) and _r["model"]["ui"]["inverter_count"] == 2)
+check("a save that changed nothing writes an identical blob: same values, "
+      "types and key order, although the browser turned -10.0 into -10",
+      _r["same"][0] == 200 and json.dumps(_r["after_same"])
+      == json.dumps(_stored) and isinstance(_r["after_same"]["target_grid_w"],
+                                            float))
+_written = _sup.writes[-1]
+print(f"    the edit: {_r['edit']}, changed "
+      f"{sorted(k for k in _stored if _written[k] != _stored[k])}")
+check("an edit writes exactly the fields edited, the peak limit in W",
+      _r["edit"][0] == 200
+      and sorted(k for k in _stored if _written[k] != _stored[k])
+      == ["inverters", "peak_cap_w"] and _written["peak_cap_w"] == 4200
+      and _written["inverters"][1]["max_w"] == 2200
+      and _written["inverters"][0] == _stored["inverters"][0])
+_blobs = [("config.yaml", DEFAULTS), ("site", SITE), ("two", TWO)] + [
+    (os.path.basename(f), json.load(open(f))) for f in sorted(glob.glob(
+        os.path.join(HERE, "scenarios", "ux13", "test23", "*.json")))]
+_bad = [n for n, o in _blobs if json.dumps(uipage.to_options(browser(
+    json.loads(json.dumps(U.options_to_ui(o)))), o)) != json.dumps(o)]
+check(f"every known blob comes back byte for byte through the browser "
+      f"({len(_blobs)} blobs, not: {_bad})", not _bad and len(_blobs) >= 8)
+_grown = U.options_to_ui(SITE)
+_grown["inverters"].append(dict(_grown["inverters"][0], name="b",
+                                setpoint_entity="number.b"))
+_grown["inverters"][0]["name"] = "a"
+_grown.update(U.GROWN)
+_g = U.ui_to_options(_grown)
+check("'Add an inverter' on a flat site writes a list and clears the flat "
+      "power request entity, which the validator refuses beside a list",
+      [e["name"] for e in _g["inverters"]] == ["a", "b"]
+      and _g["setpoint_entity"] == "" and not validate_startup_config(_g))
+
+# --------------------------------------------------------------------------- #
+print("\n4. a refusal lands beside the field it is about")
+# --------------------------------------------------------------------------- #
+
+
+async def _refuse(s, root, sup):
+    out = {}
+    m = await _get(s, root + "config/model?lang=en")
+    base = m["ui"]
+
+    async def validate(**edits):
+        model = copy.deepcopy(base)
+        for k, v in edits.items():
+            if k == "card":
+                model["inverters"][v[0]][v[1]] = v[2]
+            else:
+                model[k.replace("__", ".")] = v
+        return (await _post(s, root + "config/validate", {"model": model}))[1]
+
+    out["card"] = await validate(card=(1, "setpoint_entity", ""))
+    out["same"] = await validate(card=(1, "setpoint_entity", "number.a"))
+    out["floor"] = await validate(peak_soc_floor=5)
+    out["derive"] = await validate(ui__contract="dynamic", price_provider="")
+    model = copy.deepcopy(base)
+    model["inverters"][1]["setpoint_entity"] = ""
+    out["save"] = await _post(s, root + "config/save",
+                              {"model": model, "fingerprint": m["fingerprint"]})
+    return out
+
+
+_r, _sup = asyncio.run(session(TWO, _refuse))
+
+
+def _at(payload, tier="bad"):
+    return {(m["field"], m["card"]) for m in payload["messages"]
+            if m["tier"] == tier}
+
+
+print(f"    blank power request entity on card 2: {_r['card']['messages']}")
+check("a blank power request entity on the second card is refused beside "
+      "that card's field, and not beside the list as well",
+      ("inverters.setpoint_entity", 1) in _at(_r["card"])
+      and ("inverters", None) not in _at(_r["card"]))
+print(f"    two cards on one entity: {_r['same']['messages']}")
+check("two cards on one entity are refused beside that field on both cards",
+      {("inverters.setpoint_entity", 0), ("inverters.setpoint_entity", 1)}
+      == _at(_r["same"]))
+check("a peak reserve under the cut-out level lands on the peak reserve and "
+      "on each card's cut-out level",
+      {("peak_soc_floor", None), ("inverters.bms_soc_floor", 0),
+       ("inverters.bms_soc_floor", 1)} <= _at(_r["floor"]))
+check("a model no blob can say is refused beside its field, in plain words",
+      _r["derive"]["messages"] == [{
+          "field": "price_provider", "card": None, "tier": "bad",
+          "text": W["derive"]["no_source"]["description"]}])
+check("a refused save answers 422 with the same placement and writes nothing",
+      _r["save"][0] == 422 and ("inverters.setpoint_entity", 1)
+      in _at(_r["save"][1]) and _sup.writes == [])
+_fixed = U.options_to_ui(dict(TWO, static_profile="not json"))
+check("a sentence about a key the page derives goes to the field that writes "
+      "it, or to the visible choice that sets it",
+      uipage.targets("static_profile", "", _fixed) == [("ui.contract", None)]
+      and uipage.targets("max_w", "", U.options_to_ui(SITE))
+      == [("inverters.max_w", 0)]
+      and uipage.targets("pv_entity", "", _fixed) == [("ui.solar", None)])
+check("a sentence naming no setting on the page is kept, with no field",
+      uipage.anchors(["Something odd."], [], _fixed, ["gain"])
+      == [{"field": None, "card": None, "tier": "bad",
+           "text": "Something odd."}])
+
+# --------------------------------------------------------------------------- #
+print("\n5. a stale save names the fields that changed elsewhere")
+# --------------------------------------------------------------------------- #
+
+
+async def _stale(s, root, sup):
+    m = await _get(s, root + "config/model?lang=en")
+    sup.options["peak_cap_w"] = 5000          # the Configuration tab saves
+    model = copy.deepcopy(m["ui"])
+    model["gain"] = 0.4
+    return await _post(s, root + "config/save",
+                       {"model": model, "fingerprint": m["fingerprint"]})
+
+
+_r, _sup = asyncio.run(session(TWO, _stale))
+check("409 with the page fields to look at, and nothing written",
+      _r[0] == 409 and _r[1]["kind"] == "stale"
+      and "peak_cap_w" in _r[1]["changed_fields"] and _sup.writes == []
+      and _r[1]["fingerprint"] == selfconfig.fingerprint(_sup.options))
+
+# --------------------------------------------------------------------------- #
+print("\n6. the view's words keep to STYLE")
+# --------------------------------------------------------------------------- #
+
+
+def _texts(node, path=""):
+    for k, v in node.items():
+        if isinstance(v, dict):
+            yield from _texts(v, f"{path}{k}.")
+        elif isinstance(v, str):
+            yield f"{path}{k}", v
+
+
+_long = [(p, t) for p, t in _texts(W)
+         if len(t.split()) > (25 if p.endswith("description") else 6)
+         or (p.endswith("description") and len(re.findall(r"[.!?](?:\s|$)", t)) > 1)
+         or ";" in t]
+check(f"every settings string is one sentence of at most 25 words, or a "
+      f"name of at most 6 ({_long})", not _long)
+_labels = [c[1] for _g, f in _flat for c in f.get("choices", [])]
+check("every choice, including the region with its year, is at most 6 words",
+      all(len(x.split()) <= 6 for x in _labels))
+
+print()
+if fails:
+    print(f"{len(fails)} FAILED")
+    sys.exit(1)
+print("all passed")
diff --git a/goodwe_controller/test_uilayout.py b/goodwe_controller/test_uilayout.py
index 5d04ec5..70c4bdb 100644
--- a/goodwe_controller/test_uilayout.py
+++ b/goodwe_controller/test_uilayout.py
@@ -82,8 +82,9 @@ check("every control, entity kind and show operator is a known one",
       all(f.control in L.CONTROLS and (not f.kind or f.kind in L.ENTITY_KINDS)
           and all(op in L.SHOW_OPS for _n, op, _v in f.show)
           for _g, _p2, f in ROWS))
-_names = set(ORDER) | set(KEYS) | {"inverter_count"}
-check("every show condition reads an option, a page field or inverter_count",
+_names = set(ORDER) | set(KEYS) | {uimodel.COUNT} | set(uimodel.GROWN)
+check("every show condition reads an option, a page field, or the inverter "
+      "count or shape",
       all(n in _names for _g, _p2, f in ROWS for n, _o, _v in f.show))
 check("every entity control has a kind, and no other control has one",
       all((f.control in (L.ENTITY, L.ENTITY_LIST, L.SOLAR_LIST)) == bool(f.kind)
@@ -189,11 +190,13 @@ _owned = set(L.DERIVED) | {"inverters", "price_provider",
 _extra = sorted({k for k in _KEY.findall(_src) if k in ORDER} - _owned)
 check(f"uimodel.py names only the keys its derivations write (others: "
       f"{_extra})", not _extra)
-_leak = sorted({f"{name}:{k}" for name in ("haentities.py", "web.py")
+_leak = sorted({f"{name}:{k}" for name in ("haentities.py", "web.py",
+                                          "uipage.py")
                 for k in _KEY.findall(io.open(os.path.join(HERE, "app", name),
                                               encoding="utf-8").read())
                 if k in ORDER})
-check(f"haentities.py and web.py name no option key ({_leak})", not _leak)
+check(f"haentities.py, web.py and uipage.py name no option key ({_leak})",
+      not _leak)
 
 print()
 if fails:
diff --git a/goodwe_controller/tools/ux13_demo.py b/goodwe_controller/tools/ux13_demo.py
index 5b9067b..028f4c3 100644
--- a/goodwe_controller/tools/ux13_demo.py
+++ b/goodwe_controller/tools/ux13_demo.py
@@ -1,19 +1,29 @@
-"""UX-13 P1: serve the real page and routes over a fixture controller, for a
-headless browser check.  `python3 tools/ux13_demo.py STATE PORT`
+"""UX-13: serve the real page and routes over a fixture controller, for a
+headless browser check.  `python3 tools/ux13_demo.py STATE PORT [HOST]`
 
 STATE is running, shadow or alarm. The controller is the shipped `Controller`
 with its readings set by hand (two batteries, solar, today's prices in the
 mockup's shape, trading on). Nothing here talks to Home Assistant or to an
 inverter: `/action` changes only this fixture. Used for the P1 render check
 (no JS errors, tooltips, phone width, dark mode) described in the PR.
+
+P2: the fixture Supervisor serves config.yaml's defaults with this site's
+options, a schema read off config.yaml the way the Supervisor renders it
+(`schema_ui()`) and translations/en.yaml, and keeps what the settings view
+saves in memory, so the Installer view can be clicked through end to end.
 """
 
 import asyncio
+import io
+import json
 import os
+import re
 import sys
 from datetime import datetime, timedelta, timezone
 
-sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+HERE = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+sys.path.insert(0, HERE)
+sys.path.insert(0, os.path.join(HERE, "tools"))
 
 from aiohttp import web as aioweb                                # noqa: E402
 
@@ -22,6 +32,7 @@ from app.main import Controller                                  # noqa: E402
 from app.peakguard import PeakDecision                           # noqa: E402
 from app.price import PricePoint, PriceProduct, PriceRead        # noqa: E402
 from app.static_tariff import TariffPlan                         # noqa: E402
+import translations_lint as TL                                   # noqa: E402
 
 PRICES = [.24, .22, .21, .20, .21, .22, .24, .27, .26, .22, .18, .16, .15,
           .14, .16, .19, .23, .28, .33, .36, .34, .29, .26, .24]
@@ -73,12 +84,119 @@ class Hass:
         return True
 
     async def states(self):
-        return []
+        return STATES
+
+
+def _state(eid, name, state, unit=None, cls=None):
+    return {"entity_id": eid, "state": state,
+            "attributes": {"friendly_name": name, "unit_of_measurement": unit,
+                           "device_class": cls}}
+
+
+STATES = [
+    _state("sensor.grid", "Grid power", "-10", "W", "power"),
+    _state("sensor.grid_kw", "Grid power in kW", "-0.01", "kW", "power"),
+    _state("sensor.pv", "Solar power", "3900", "W", "power"),
+    _state("sensor.soc_a", "Battery A level", "62", "%", "battery"),
+    _state("sensor.soc_b", "Battery B level", "35", "%", "battery"),
+    _state("sensor.batt_a", "Battery A power", "-2500", "W", "power"),
+    _state("sensor.batt_b", "Battery B power", "-300", "W", "power"),
+    _state("number.a", "Battery A power request", "0", "W"),
+    _state("number.b", "Battery B power request", "0", "W"),
+    _state("sensor.peak_forecast", "Quarter-hour peak forecast", "1240", "W",
+           "power"),
+]
+
+
+# --- config.yaml as the Supervisor renders it (App.schema_ui) --------------- #
+def _node(name, spec):
+    spec = spec.strip()
+    optional = spec.endswith("?")
+    spec = spec.rstrip("?")
+    out = {"name": name, "required": not optional, "optional": optional}
+    m = re.match(r"(int|float)\(([^,]*),([^)]*)\)$", spec)
+    if m:
+        out.update(type="integer" if m.group(1) == "int" else "float",
+                   lengthMin=float(m.group(2)), lengthMax=float(m.group(3)))
+    elif spec.startswith("list("):
+        out.update(type="select", options=spec[5:-1].split("|"))
+    elif spec in ("bool",):
+        out["type"] = "boolean"
+    elif spec in ("int", "float"):
+        out["type"] = "integer" if spec == "int" else "float"
+    else:
+        out["type"] = "string"
+    return out
+
+
+def schema_ui(text):
+    """config.yaml's `schema:` block in the Supervisor's schema_ui shape: the
+    fixture for tests and this demo, which cannot run the Supervisor."""
+    block = text[text.index("\nschema:"):].splitlines()[1:]
+    out, i = [], 0
+    while i < len(block):
+        line = block[i]
+        m = re.match(r"^  ([a-z_0-9]+):\s*(\S.*?)?\s*$", line)
+        i += 1
+        if not m:
+            continue
+        name, spec = m.group(1), m.group(2)
+        if spec:
+            out.append(_node(name, spec))
+            continue
+        items = []
+        while i < len(block) and (block[i].startswith("    ") or not block[i].strip()):
+            if block[i].strip() and not block[i].strip().startswith("#"):
+                items.append(block[i].strip())
+            i += 1
+        if items and items[0].startswith("- ") and ":" in items[0]:
+            fields = [items[0][2:]] + items[1:]
+            out.append({"name": name, "type": "schema", "optional": True,
+                        "multiple": True,
+                        "schema": [_node(*f.split(":", 1)) for f in fields]})
+        else:
+            node = _node(name, items[0][2:] if items else "str")
+            node.update(multiple=True, required=False, optional=True)
+            out.append(node)
+    return out
+
+
+def defaults(text):
+    """config.yaml's `options:` block (as test_uimodel.py reads it)."""
+    block = text[text.index("\noptions:"):text.index("\nschema:")]
+    out = {}
+    for key, raw in re.findall(r"^  ([a-z_0-9]+):(.*)$", block, re.M):
+        raw = raw.split(" #")[0].strip()
+        try:
+            out[key] = json.loads(raw)
+        except ValueError:
+            out[key] = raw
+    return out
+
+
+CONFIG = io.open(os.path.join(HERE, "config.yaml"), encoding="utf-8").read()
 
 
 class Supervisor:
+    """The stored options, kept in memory: a save here writes nothing else."""
+
+    def __init__(self, options):
+        self.options = options
+        self.writes = 0
+
     async def info(self):
-        return {"options": {}, "schema": [], "translations": {}}
+        return {"options": json.loads(json.dumps(self.options)),
+                "schema": schema_ui(CONFIG),
+                "translations": {"en": TL.parse_translation_file(
+                    os.path.join(HERE, "translations", "en.yaml"))}}
+
+    async def write_options(self, options):
+        self.options = json.loads(json.dumps(options))
+        self.writes += 1
+        print(f"options saved ({self.writes})", flush=True)
+
+    async def restart(self, confirm):
+        print(f"restart asked ({confirm!r})", flush=True)
 
 
 OPTS = {"meter_entity": "sensor.grid", "meter_source": "off",
@@ -119,13 +237,21 @@ def controller(state):
     return c
 
 
-async def main(state, port):
-    runner = aioweb.AppRunner(web.build_app(controller(state), Supervisor()))
+async def main(state, port, host="127.0.0.1"):
+    c = controller(state)
+    stored = dict(defaults(CONFIG), **OPTS)
+    stored.update(setpoint_entity="", meter_source="ha_signed",
+                  p1_net_entity="sensor.grid", price_provider="generic_dayahead",
+                  peak_forecast_entity="sensor.peak_forecast",
+                  shadow_mode=c.o.get("shadow_mode", "off"),
+                  inverters=[dict(i, bms_soc_floor=10)
+                             for i in OPTS["inverters"]])
+    runner = aioweb.AppRunner(web.build_app(c, Supervisor(stored)))
     await runner.setup()
-    await aioweb.TCPSite(runner, "127.0.0.1", port).start()
+    await aioweb.TCPSite(runner, host, port).start()
     print(f"serving {state} on http://127.0.0.1:{port}/", flush=True)
     await asyncio.Event().wait()
 
 
 if __name__ == "__main__":
-    asyncio.run(main(sys.argv[1], int(sys.argv[2])))
+    asyncio.run(main(sys.argv[1], int(sys.argv[2]), *sys.argv[3:4]))