diff --git a/docs/ARCHITECTURE.md b/docs/ARCHITECTURE.md
index 673cf6b8..699f874e 100644
--- a/docs/ARCHITECTURE.md
+++ b/docs/ARCHITECTURE.md
@@ -1499,3 +1499,27 @@ dialog).
   need their own rollback.
 - **Split invariant.** `splitRoomPath` guarantees a partition: the two parts'
   areas sum to the original (within epsilon) or the cut is rejected.
+
+## Schema as the source of truth (#33, 2026-08-30)
+
+The Voluptuous schema in `custom_components/houseplan/validation.py` is the
+single owner of the persisted config/layout shape. Three artefacts keep every
+other world honest against it:
+
+- `scripts/dump-config-schema.py` walks the schema into the deterministic
+  `scripts/config-schema-manifest.json` (265 leaf paths at introduction);
+  a pytest regenerates it and fails on any uncommitted drift.
+- `test/config-schema-parity.test.mjs` compares manifest enums with the
+  exported frontend const lists (`DISPLAY_MODES`, `TAP_ACTIONS`,
+  `SPACE_FILL_MODES`/`ROOM_FILL_MODES`, `OPENING_TYPES`,
+  `VACUUM_TRAIL_MODES`, `ZERO_WALL_STYLES`, `BG_MODES`). Every divergence
+  must be blessed in `scripts/schema-compat-allowlist.mjs` with a reason and
+  an owning issue — and an allow-list entry that stops matching a real
+  divergence fails the test too, so the list cannot rot.
+- `scripts/config-field-registry.mjs` stays the DECISION layer on top of the
+  manifest: only fields with a non-trivial fate live there, each resolving to
+  a manifest path or carrying an explicit `schema: 'allow-extra'` /
+  `'lovelace-card'` passport; implemented mechanisms cite their code point in
+  `enforcedBy`. The lifecycle fixtures in `test/fixtures/config-lifecycle/`
+  pin the load contract: oldest-supported and future-field configs pass the
+  schema losslessly.
diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index 7b8548de..f25e9f3d 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -2,6 +2,13 @@
 
 ## Unreleased
 
+- Old and future plan configs are now guarded by machinery instead of habit:
+  the backend schema is dumped into a committed manifest, frontend and
+  backend value lists are compared in CI with an explicit allow-list for the
+  few legitimate compatibility divergences, and lifecycle fixtures prove a
+  config from the oldest supported era — or one from the future — loads
+  without silent loss ([#33](https://github.com/Matysh/houseplan-card/issues/33)).
+
 - Clicking the already-selected binding in the marker dialog no longer silently
   resets the configured value source and badge to automatic — the reset now
   happens only on an actual change of binding
diff --git a/docs/CHANGELOG.ru.md b/docs/CHANGELOG.ru.md
index 851d270c..02d38e80 100755
--- a/docs/CHANGELOG.ru.md
+++ b/docs/CHANGELOG.ru.md
@@ -8,6 +8,13 @@
 
 ## Не выпущено
 
+- Старые и будущие конфигурации плана теперь защищены механикой, а не
+  привычкой: схема бэкенда выгружается в закоммиченный манифест, списки
+  значений фронта и бэкенда сверяются в CI с явным allow-list'ом немногих
+  легитимных компат-расхождений, а lifecycle-фикстуры доказывают, что конфиг
+  старейшей поддерживаемой эпохи — или из будущего — загружается без тихих
+  потерь ([#33](https://github.com/Matysh/houseplan-card/issues/33)).
+
 - Клик по уже выбранной привязке в диалоге маркера больше не сбрасывает молча
   настроенный источник значения и бейдж на «авто» — сброс происходит только
   при реальной смене привязки
diff --git a/scripts/config-audit.mjs b/scripts/config-audit.mjs
index 52c98667..25529747 100644
--- a/scripts/config-audit.mjs
+++ b/scripts/config-audit.mjs
@@ -77,6 +77,16 @@ if (isMain) {
         const parsed = JSON.parse(readFileSync(absolute, 'utf8'));
         return { file: absolute, findings: auditConfig(parsed) };
       });
+      // #33: exit-code contract — 0 = clean, 3 = migration available
+      // (any finding whose status names a pending mechanism), 2 = invalid
+      // input (unchanged). 3 is chosen to avoid colliding with 2.
+      const MIGRATION_STATUSES = new Set([
+        'migrate-on-write', 'migrate-on-settings-save', 'deprecated-read',
+        'drop-on-validation', 'decision-required',
+      ]);
+      const migrationFindings = reports.some((report) => report.findings
+        .some((finding) => MIGRATION_STATUSES.has(finding.status)));
+      if (migrationFindings) process.exitCode = 3;
       if (jsonOutput) {
         console.log(JSON.stringify(reports, null, 2));
       } else {
diff --git a/scripts/config-field-registry.mjs b/scripts/config-field-registry.mjs
index 447d1acd..5f38f7fb 100644
--- a/scripts/config-field-registry.mjs
+++ b/scripts/config-field-registry.mjs
@@ -9,6 +9,7 @@
 export const CONFIG_FIELD_REGISTRY = Object.freeze([
   {
     id: 'card.tap_action',
+    schema: 'lovelace-card', // #33: Lovelace card option — not in the backend manifest by design
     selector: { path: ['tap_action'] },
     storage: 'Lovelace card config',
     type: "'info' | 'more-info' | 'toggle'",
@@ -23,6 +24,8 @@ export const CONFIG_FIELD_REGISTRY = Object.freeze([
   },
   {
     id: 'settings.show_all',
+    schema: 'allow-extra', // #33: lives only through extra=ALLOW_EXTRA, absent from CONFIG_SCHEMA
+    enforcedBy: 'houseplan-card.ts materialisation: seeds hidden markers, then `delete st.show_all`',
     selector: { path: ['settings', 'show_all'] },
     storage: 'House Plan server config',
     type: 'boolean',
@@ -37,6 +40,7 @@ export const CONFIG_FIELD_REGISTRY = Object.freeze([
   },
   {
     id: 'settings.group_lights',
+    schema: 'allow-extra', // #33: lives only through extra=ALLOW_EXTRA, absent from CONFIG_SCHEMA
     selector: { path: ['settings', 'group_lights'] },
     storage: 'House Plan server config',
     type: 'boolean',
@@ -51,6 +55,7 @@ export const CONFIG_FIELD_REGISTRY = Object.freeze([
   },
   {
     id: 'settings.exclude_integrations',
+    schema: 'allow-extra', // #33: lives only through extra=ALLOW_EXTRA, absent from CONFIG_SCHEMA
     selector: { path: ['settings', 'exclude_integrations'] },
     storage: 'House Plan server config',
     type: 'string[]',
@@ -65,6 +70,7 @@ export const CONFIG_FIELD_REGISTRY = Object.freeze([
   },
   {
     id: 'settings.weather_entity',
+    enforcedBy: 'houseplan-editor-runtime.ts _saveSettingsDialog: `delete settings.weather_entity` on every save',
     selector: { path: ['settings', 'weather_entity'] },
     storage: 'House Plan server config',
     type: 'string | null',
@@ -79,6 +85,7 @@ export const CONFIG_FIELD_REGISTRY = Object.freeze([
   },
   {
     id: 'markers[].display=ripple',
+    enforcedBy: 'logic.ts normalizeDeviceDisplay (read) + editor-runtime _dropLegacySegments rewrites on every write',
     selector: { path: ['markers', '*', 'display'], equals: 'ripple' },
     storage: 'House Plan server config',
     type: "legacy enum value 'ripple'",
@@ -135,6 +142,7 @@ export const CONFIG_FIELD_REGISTRY = Object.freeze([
   },
   {
     id: 'spaces[].aspect',
+    enforcedBy: 'validation.py vol.Remove — the backend drops the field during validation',
     selector: { path: ['spaces', '*', 'aspect'] },
     storage: 'House Plan server config',
     type: 'number',
@@ -149,6 +157,7 @@ export const CONFIG_FIELD_REGISTRY = Object.freeze([
   },
   {
     id: 'spaces[].segments',
+    enforcedBy: 'validation.py vol.Remove — the backend drops the field during validation',
     selector: { path: ['spaces', '*', 'segments'] },
     storage: 'House Plan server config',
     type: 'unknown[]',
@@ -357,6 +366,48 @@ export const CONFIG_FIELD_REGISTRY = Object.freeze([
     migration: 'embed the reference into text on text edit or explicit plan optimization',
     compatibility: 'backend accepts bounded values while old labels remain supported',
   })),
+  {
+    id: 'settings.decor_default_style',
+    selector: { path: ['settings', 'decor_default_style'] },
+    storage: 'House Plan server config',
+    type: '{ color?, opacity?, width_cm?, fill?, fill_color?, fill_opacity? }',
+    default: 'unset (absence IS the factory default)',
+    level: 'global',
+    ui: 'Background editor main-toolbar picker',
+    runtime: 'seeds the editor default decor style once per page (#377)',
+    introduced: 'v1.69.0',
+    status: 'current',
+    migration: 'none — reset to default removes the key',
+    compatibility: 'optional; partial keys inherit the factory default per field',
+  },
+  {
+    id: "spaces[].decor[]<kind='furniture'>",
+    selector: { path: ['spaces', '*', 'decor', '*', 'kind'], equals: 'furniture' },
+    storage: 'House Plan server config',
+    type: "decor item variant: symbol + box (x, y, w, h, angle)",
+    default: 'n/a',
+    level: 'space',
+    ui: 'Background editor furniture tool (#159/#359)',
+    runtime: 'plan-art rendering, placement preview, stroke zoom (#361)',
+    introduced: 'v1.69.0',
+    status: 'current',
+    migration: 'none',
+    compatibility: 'unknown symbols render as generic box; assets ship with the bundle',
+  },
+  {
+    id: "spaces[].openings[].host=partition",
+    selector: { path: ['spaces', '*', 'openings', '*', 'host', 'kind'], equals: 'partition' },
+    storage: 'House Plan server config',
+    type: "{ kind: 'partition', id, t }",
+    default: 'n/a',
+    level: 'space',
+    ui: 'Plan editor: openings hosted on partitions (model v9, v1.68)',
+    runtime: 'opening geometry, junction limits, glow cuts',
+    introduced: 'v1.68.0',
+    status: 'current',
+    migration: 'v9 migration resolves opening-vs-zero-wall conflicts (#316)',
+    compatibility: 'v8 configs without partition hosts stay valid',
+  },
 ]);
 
 export const CONFIG_FIELD_STATUSES = Object.freeze([
diff --git a/scripts/config-schema-manifest.json b/scripts/config-schema-manifest.json
new file mode 100644
index 00000000..b49a8b15
--- /dev/null
+++ b/scripts/config-schema-manifest.json
@@ -0,0 +1,1371 @@
+{
+  "_comment": "#33: generated by scripts/dump-config-schema.py — do not edit by hand",
+  "fields": {
+    "config": {
+      "allowExtra": true
+    },
+    "config.markers": {
+      "default": {
+        "factory": "list"
+      },
+      "required": false
+    },
+    "config.markers[]": {
+      "allowExtra": true
+    },
+    "config.markers[].angle": {
+      "max": 360,
+      "min": -360,
+      "nullable": true,
+      "required": false,
+      "type": "float"
+    },
+    "config.markers[].area": {
+      "nullable": true,
+      "required": false,
+      "type": "str"
+    },
+    "config.markers[].binding": {
+      "maxLength": 500,
+      "minLength": 1,
+      "opaque": "Match('^(device:.+|entity:.+|virtual)$', msg=None)",
+      "required": true,
+      "type": "str"
+    },
+    "config.markers[].controls": {
+      "list": {
+        "maxLength": 500,
+        "type": "str"
+      },
+      "maxLength": 200,
+      "nullable": true,
+      "required": false
+    },
+    "config.markers[].description": {
+      "maxLength": 4000,
+      "nullable": true,
+      "required": false,
+      "type": "str"
+    },
+    "config.markers[].display": {
+      "required": false,
+      "variants": [
+        {
+          "const": "badge"
+        },
+        {
+          "const": "ripple"
+        },
+        {
+          "const": "icon_ripple"
+        },
+        {
+          "const": "value"
+        },
+        {
+          "const": "static_icon"
+        },
+        {
+          "type": "null"
+        }
+      ]
+    },
+    "config.markers[].glow_color": {
+      "nullable": true,
+      "required": false
+    },
+    "config.markers[].glow_color.bri": {
+      "max": 1.0,
+      "min": 0.01,
+      "nullable": true,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.markers[].glow_color.c": {
+      "opaque": "Match('\\\\A#[0-9a-fA-F]{6}\\\\Z', msg=None)",
+      "required": true
+    },
+    "config.markers[].glow_radius_cm": {
+      "max": 10000,
+      "min": 10,
+      "nullable": true,
+      "required": false,
+      "type": "float"
+    },
+    "config.markers[].hidden": {
+      "required": false,
+      "type": "bool"
+    },
+    "config.markers[].icon": {
+      "maxLength": 500,
+      "nullable": true,
+      "required": false,
+      "type": "str"
+    },
+    "config.markers[].id": {
+      "required": true,
+      "type": "str"
+    },
+    "config.markers[].is_light": {
+      "nullable": true,
+      "required": false,
+      "type": "bool"
+    },
+    "config.markers[].light_entity": {
+      "required": false,
+      "type": "object"
+    },
+    "config.markers[].link": {
+      "maxLength": 2000,
+      "nullable": true,
+      "required": false,
+      "type": "str"
+    },
+    "config.markers[].model": {
+      "maxLength": 500,
+      "nullable": true,
+      "required": false,
+      "type": "str"
+    },
+    "config.markers[].name": {
+      "maxLength": 500,
+      "nullable": true,
+      "required": false,
+      "type": "str"
+    },
+    "config.markers[].pdfs": {
+      "required": false
+    },
+    "config.markers[].pdfs[]": {
+      "allowExtra": true
+    },
+    "config.markers[].pdfs[].name": {
+      "maxLength": 500,
+      "required": true,
+      "type": "str"
+    },
+    "config.markers[].pdfs[].url": {
+      "maxLength": 2000,
+      "required": true,
+      "type": "str"
+    },
+    "config.markers[].removed": {
+      "required": false,
+      "type": "bool"
+    },
+    "config.markers[].ripple_color": {
+      "nullable": true,
+      "opaque": "Match('\\\\A#[0-9a-fA-F]{6}\\\\Z', msg=None)",
+      "required": false
+    },
+    "config.markers[].ripple_size": {
+      "max": 20,
+      "min": 1,
+      "nullable": true,
+      "required": false,
+      "type": "float"
+    },
+    "config.markers[].room_id": {
+      "nullable": true,
+      "required": false,
+      "type": "str"
+    },
+    "config.markers[].size": {
+      "max": 6,
+      "min": 0.2,
+      "nullable": true,
+      "required": false,
+      "type": "float"
+    },
+    "config.markers[].space": {
+      "nullable": true,
+      "required": false,
+      "type": "str"
+    },
+    "config.markers[].tap_action": {
+      "required": false,
+      "variants": [
+        {
+          "const": "info"
+        },
+        {
+          "const": "more-info"
+        },
+        {
+          "const": "toggle"
+        },
+        {
+          "const": "run"
+        },
+        {
+          "const": "none"
+        },
+        {
+          "const": "cover"
+        },
+        {
+          "type": "null"
+        }
+      ]
+    },
+    "config.markers[].tap_confirm": {
+      "nullable": true,
+      "required": false,
+      "type": "bool"
+    },
+    "config.markers[].tap_target": {
+      "maxLength": 500,
+      "nullable": true,
+      "opaque": "Match('^(automation|script|scene)\\\\.[A-Za-z0-9_]+$', msg=None)",
+      "required": false,
+      "type": "str"
+    },
+    "config.markers[].toggle_entity": {
+      "required": false,
+      "type": "object"
+    },
+    "config.markers[].use_climate_temp": {
+      "nullable": true,
+      "required": false,
+      "type": "bool"
+    },
+    "config.markers[].vacuum": {
+      "nullable": true,
+      "required": false
+    },
+    "config.markers[].vacuum.calibration": {
+      "required": false
+    },
+    "config.markers[].vacuum.calibration.*[]": {
+      "opaque": "<function _finite>"
+    },
+    "config.markers[].vacuum.live": {
+      "nullable": true,
+      "required": false,
+      "type": "bool"
+    },
+    "config.markers[].vacuum.room_highlight": {
+      "nullable": true,
+      "required": false,
+      "type": "bool"
+    },
+    "config.markers[].vacuum.segment_map": {
+      "required": false
+    },
+    "config.markers[].vacuum.segment_map.*": {
+      "type": "str"
+    },
+    "config.markers[].vacuum.source": {
+      "nullable": true,
+      "required": false,
+      "type": "str"
+    },
+    "config.markers[].vacuum.trail": {
+      "nullable": true,
+      "required": false,
+      "type": "bool"
+    },
+    "config.markers[].vacuum.trail_mode": {
+      "enum": [
+        "always",
+        "cleaning",
+        "never"
+      ],
+      "nullable": true,
+      "required": false
+    },
+    "config.markers[].value_badge": {
+      "allowExtra": true,
+      "nullable": true,
+      "required": false
+    },
+    "config.markers[].value_badge.enabled": {
+      "required": false,
+      "type": "object"
+    },
+    "config.markers[].value_badge.position": {
+      "required": false,
+      "type": "object"
+    },
+    "config.markers[].value_badge.source": {
+      "allowExtra": true,
+      "nullable": true,
+      "required": false
+    },
+    "config.markers[].value_source": {
+      "allowExtra": true,
+      "nullable": true,
+      "required": false
+    },
+    "config.model_version": {
+      "max": 1000000,
+      "min": 0,
+      "required": false,
+      "type": "int"
+    },
+    "config.settings": {
+      "allowExtra": true,
+      "default": {
+        "factory": "dict"
+      },
+      "required": false
+    },
+    "config.settings.bg_color": {
+      "opaque": "Match('\\\\A#[0-9a-fA-F]{6}\\\\Z', msg=None)",
+      "required": false
+    },
+    "config.settings.bg_mode": {
+      "enum": [
+        "daynight",
+        "static"
+      ],
+      "required": false
+    },
+    "config.settings.decor_default_style": {
+      "required": false
+    },
+    "config.settings.decor_default_style.color": {
+      "opaque": "Match('\\\\A#[0-9a-fA-F]{6}\\\\Z', msg=None)",
+      "required": false
+    },
+    "config.settings.decor_default_style.fill": {
+      "required": false,
+      "type": "bool"
+    },
+    "config.settings.decor_default_style.fill_color": {
+      "opaque": "Match('\\\\A#[0-9a-fA-F]{6}\\\\Z', msg=None)",
+      "required": false
+    },
+    "config.settings.decor_default_style.fill_opacity": {
+      "max": 1,
+      "min": 0,
+      "required": false,
+      "type": "float"
+    },
+    "config.settings.decor_default_style.opacity": {
+      "max": 1,
+      "min": 0,
+      "required": false,
+      "type": "float"
+    },
+    "config.settings.decor_default_style.width_cm": {
+      "max": 100,
+      "min": 0.1,
+      "required": false,
+      "type": "float"
+    },
+    "config.settings.fill_colors": {
+      "required": false
+    },
+    "config.settings.fill_colors.*.a": {
+      "max": 1,
+      "min": 0,
+      "required": true,
+      "type": "float"
+    },
+    "config.settings.fill_colors.*.c": {
+      "opaque": "Match('\\\\A#[0-9a-fA-F]{6}\\\\Z', msg=None)",
+      "required": true
+    },
+    "config.settings.glow_radius_cm": {
+      "max": 10000,
+      "min": 10,
+      "required": false,
+      "type": "float"
+    },
+    "config.settings.known_devices": {
+      "required": false
+    },
+    "config.settings.known_devices[]": {
+      "maxLength": 500,
+      "type": "str"
+    },
+    "config.settings.new_device_ids": {
+      "required": false
+    },
+    "config.settings.new_device_ids[]": {
+      "maxLength": 500,
+      "type": "str"
+    },
+    "config.settings.north_deg": {
+      "opaque": "<function _north_deg>",
+      "required": false
+    },
+    "config.settings.sun_rays": {
+      "required": false,
+      "type": "bool"
+    },
+    "config.settings.weather_entity": {
+      "maxLength": 500,
+      "nullable": true,
+      "required": false,
+      "type": "str"
+    },
+    "config.spaces": {
+      "required": true
+    },
+    "config.spaces[]": {
+      "allowExtra": true
+    },
+    "config.spaces[].aspect": {
+      "removed": true
+    },
+    "config.spaces[].cell_cm": {
+      "max": 1000.0,
+      "min": 0.1,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].decor": {
+      "required": false
+    },
+    "config.spaces[].decor[]<ellipse|rect>": {
+      "allowExtra": true
+    },
+    "config.spaces[].decor[]<ellipse|rect>.angle": {
+      "max": 360.0,
+      "min": -360.0,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].decor[]<ellipse|rect>.color": {
+      "opaque": "Match('\\\\A#[0-9a-fA-F]{6}\\\\Z', msg=None)",
+      "required": false
+    },
+    "config.spaces[].decor[]<ellipse|rect>.fill": {
+      "required": false,
+      "type": "bool"
+    },
+    "config.spaces[].decor[]<ellipse|rect>.fill_color": {
+      "opaque": "Match('\\\\A#[0-9a-fA-F]{6}\\\\Z', msg=None)",
+      "required": false
+    },
+    "config.spaces[].decor[]<ellipse|rect>.fill_opacity": {
+      "max": 1.0,
+      "min": 0.0,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].decor[]<ellipse|rect>.h": {
+      "max": 5000.0,
+      "min": 0.001,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].decor[]<ellipse|rect>.id": {
+      "required": true,
+      "type": "str"
+    },
+    "config.spaces[].decor[]<ellipse|rect>.kind": {
+      "enum": [
+        "ellipse",
+        "rect"
+      ],
+      "required": true
+    },
+    "config.spaces[].decor[]<ellipse|rect>.opacity": {
+      "max": 1.0,
+      "min": 0.0,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].decor[]<ellipse|rect>.w": {
+      "max": 5000.0,
+      "min": 0.001,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].decor[]<ellipse|rect>.width": {
+      "max": 30,
+      "min": 0.1,
+      "required": false,
+      "type": "float"
+    },
+    "config.spaces[].decor[]<ellipse|rect>.width_cm": {
+      "max": 100,
+      "min": 0.1,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].decor[]<ellipse|rect>.x": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].decor[]<ellipse|rect>.y": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].decor[]<furniture>": {
+      "allowExtra": true
+    },
+    "config.spaces[].decor[]<furniture>.angle": {
+      "max": 360.0,
+      "min": -360.0,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].decor[]<furniture>.color": {
+      "opaque": "Match('\\\\A#[0-9a-fA-F]{6}\\\\Z', msg=None)",
+      "required": false
+    },
+    "config.spaces[].decor[]<furniture>.flip_h": {
+      "required": false,
+      "type": "bool"
+    },
+    "config.spaces[].decor[]<furniture>.flip_v": {
+      "required": false,
+      "type": "bool"
+    },
+    "config.spaces[].decor[]<furniture>.h": {
+      "max": 5000.0,
+      "min": 1e-07,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].decor[]<furniture>.id": {
+      "required": true,
+      "type": "str"
+    },
+    "config.spaces[].decor[]<furniture>.kind": {
+      "const": "furniture",
+      "required": true
+    },
+    "config.spaces[].decor[]<furniture>.opacity": {
+      "max": 1.0,
+      "min": 0.0,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].decor[]<furniture>.symbol": {
+      "maxLength": 32,
+      "minLength": 1,
+      "opaque": "Match('^[a-z0-9_]+$', msg=None)",
+      "required": true,
+      "type": "str"
+    },
+    "config.spaces[].decor[]<furniture>.w": {
+      "max": 5000.0,
+      "min": 1e-07,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].decor[]<furniture>.width": {
+      "max": 30,
+      "min": 0.1,
+      "required": false,
+      "type": "float"
+    },
+    "config.spaces[].decor[]<furniture>.width_cm": {
+      "max": 100,
+      "min": 0.1,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].decor[]<furniture>.x": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].decor[]<furniture>.y": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].decor[]<line>": {
+      "allowExtra": true
+    },
+    "config.spaces[].decor[]<line>.color": {
+      "opaque": "Match('\\\\A#[0-9a-fA-F]{6}\\\\Z', msg=None)",
+      "required": false
+    },
+    "config.spaces[].decor[]<line>.id": {
+      "required": true,
+      "type": "str"
+    },
+    "config.spaces[].decor[]<line>.kind": {
+      "const": "line",
+      "required": true
+    },
+    "config.spaces[].decor[]<line>.line_style": {
+      "enum": [
+        "dashed",
+        "solid"
+      ],
+      "required": false
+    },
+    "config.spaces[].decor[]<line>.opacity": {
+      "max": 1.0,
+      "min": 0.0,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].decor[]<line>.width": {
+      "max": 30,
+      "min": 0.1,
+      "required": false,
+      "type": "float"
+    },
+    "config.spaces[].decor[]<line>.width_cm": {
+      "max": 100,
+      "min": 0.1,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].decor[]<line>.x1": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].decor[]<line>.x2": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].decor[]<line>.y1": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].decor[]<line>.y2": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].decor[]<text>": {
+      "allowExtra": true
+    },
+    "config.spaces[].decor[]<text>.angle": {
+      "max": 360.0,
+      "min": -360.0,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].decor[]<text>.attr": {
+      "maxLength": 64,
+      "nullable": true,
+      "required": false,
+      "type": "str"
+    },
+    "config.spaces[].decor[]<text>.color": {
+      "opaque": "Match('\\\\A#[0-9a-fA-F]{6}\\\\Z', msg=None)",
+      "required": false
+    },
+    "config.spaces[].decor[]<text>.entity": {
+      "maxLength": 255,
+      "minLength": 3,
+      "nullable": true,
+      "opaque": "Match('^[a-z0-9_]+\\\\.[a-z0-9_]+$', msg=None)",
+      "required": false,
+      "type": "str"
+    },
+    "config.spaces[].decor[]<text>.id": {
+      "required": true,
+      "type": "str"
+    },
+    "config.spaces[].decor[]<text>.kind": {
+      "const": "text",
+      "required": true
+    },
+    "config.spaces[].decor[]<text>.opacity": {
+      "max": 1.0,
+      "min": 0.0,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].decor[]<text>.scale": {
+      "max": 20.0,
+      "min": 0.15,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].decor[]<text>.size": {
+      "enum": [
+        "l",
+        "m",
+        "s"
+      ],
+      "required": false
+    },
+    "config.spaces[].decor[]<text>.size_cm": {
+      "max": 2000.0,
+      "min": 0.1,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].decor[]<text>.text": {
+      "maxLength": 200,
+      "minLength": 1,
+      "required": true,
+      "type": "str"
+    },
+    "config.spaces[].decor[]<text>.unit": {
+      "maxLength": 16,
+      "nullable": true,
+      "required": false,
+      "type": "str"
+    },
+    "config.spaces[].decor[]<text>.width": {
+      "max": 30,
+      "min": 0.1,
+      "required": false,
+      "type": "float"
+    },
+    "config.spaces[].decor[]<text>.width_cm": {
+      "max": 100,
+      "min": 0.1,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].decor[]<text>.x": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].decor[]<text>.y": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].id": {
+      "opaque": "Match('^[a-z0-9_-]{1,64}$', msg=None)",
+      "required": true,
+      "type": "str"
+    },
+    "config.spaces[].open_spans": {
+      "required": false
+    },
+    "config.spaces[].open_spans[]": {
+      "opaque": "<function _open_span>"
+    },
+    "config.spaces[].openings": {
+      "required": false
+    },
+    "config.spaces[].openings[]": {
+      "allowExtra": true
+    },
+    "config.spaces[].openings[].angle": {
+      "max": 360.0,
+      "min": -360.0,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].openings[].contact": {
+      "nullable": true,
+      "required": false,
+      "type": "str"
+    },
+    "config.spaces[].openings[].flip_h": {
+      "required": false,
+      "type": "bool"
+    },
+    "config.spaces[].openings[].flip_v": {
+      "required": false,
+      "type": "bool"
+    },
+    "config.spaces[].openings[].host": {
+      "required": false
+    },
+    "config.spaces[].openings[].host<partition>.id": {
+      "maxLength": 64,
+      "minLength": 1,
+      "required": true,
+      "type": "str"
+    },
+    "config.spaces[].openings[].host<partition>.kind": {
+      "const": "partition",
+      "required": true
+    },
+    "config.spaces[].openings[].host<partition>.t": {
+      "max": 1,
+      "min": 0,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].openings[].host<wall>.id": {
+      "maxLength": 64,
+      "minLength": 1,
+      "required": true,
+      "type": "str"
+    },
+    "config.spaces[].openings[].host<wall>.kind": {
+      "const": "wall",
+      "required": true
+    },
+    "config.spaces[].openings[].host<wall>.t": {
+      "max": 1,
+      "min": 0,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].openings[].id": {
+      "required": true,
+      "type": "str"
+    },
+    "config.spaces[].openings[].invert": {
+      "required": false,
+      "type": "bool"
+    },
+    "config.spaces[].openings[].length": {
+      "max": 5000.0,
+      "min": 0.001,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].openings[].lock": {
+      "nullable": true,
+      "required": false,
+      "type": "str"
+    },
+    "config.spaces[].openings[].type": {
+      "required": true,
+      "variants": [
+        {
+          "const": "door"
+        },
+        {
+          "const": "window"
+        },
+        {
+          "const": "gate"
+        },
+        {
+          "const": "passage"
+        }
+      ]
+    },
+    "config.spaces[].openings[].x": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].openings[].y": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].partitions": {
+      "required": false
+    },
+    "config.spaces[].partitions[]": {
+      "allowExtra": true
+    },
+    "config.spaces[].partitions[].a": {
+      "required": true
+    },
+    "config.spaces[].partitions[].a[]": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>"
+    },
+    "config.spaces[].partitions[].b": {
+      "required": true
+    },
+    "config.spaces[].partitions[].b[]": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>"
+    },
+    "config.spaces[].partitions[].cm": {
+      "max": 100,
+      "min": 0,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].partitions[].id": {
+      "maxLength": 64,
+      "minLength": 1,
+      "required": true,
+      "type": "str"
+    },
+    "config.spaces[].plan_angle": {
+      "max": 360.0,
+      "min": -360.0,
+      "nullable": true,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].plan_aspect": {
+      "max": 20,
+      "min": 0.05,
+      "nullable": true,
+      "required": false,
+      "type": "float"
+    },
+    "config.spaces[].plan_scale": {
+      "max": 100.0,
+      "min": 0.01,
+      "nullable": true,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].plan_scale_x": {
+      "max": 100.0,
+      "min": 0.01,
+      "nullable": true,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].plan_scale_y": {
+      "max": 100.0,
+      "min": 0.01,
+      "nullable": true,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].plan_url": {
+      "nullable": true,
+      "required": false,
+      "type": "str"
+    },
+    "config.spaces[].plan_x": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "nullable": true,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].plan_y": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "nullable": true,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].room_drafts": {
+      "required": false
+    },
+    "config.spaces[].room_drafts[]": {
+      "allowExtra": true
+    },
+    "config.spaces[].room_drafts[].id": {
+      "maxLength": 64,
+      "minLength": 1,
+      "required": true,
+      "type": "str"
+    },
+    "config.spaces[].room_drafts[].points": {
+      "required": true
+    },
+    "config.spaces[].room_drafts[].points[][]": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>"
+    },
+    "config.spaces[].room_drafts[].segments": {
+      "required": true
+    },
+    "config.spaces[].room_drafts[].segments[]": {
+      "allowExtra": true
+    },
+    "config.spaces[].room_drafts[].segments[].cm": {
+      "max": 100,
+      "min": 0,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].room_drafts[].segments[].id": {
+      "maxLength": 64,
+      "minLength": 1,
+      "required": false,
+      "type": "str"
+    },
+    "config.spaces[].rooms": {
+      "required": true
+    },
+    "config.spaces[].rooms[]": {
+      "allowExtra": true
+    },
+    "config.spaces[].rooms[].area": {
+      "maxLength": 500,
+      "nullable": true,
+      "required": false,
+      "type": "str"
+    },
+    "config.spaces[].rooms[].h": {
+      "max": 5000.0,
+      "min": 0.001,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].rooms[].id": {
+      "maxLength": 500,
+      "required": true,
+      "type": "str"
+    },
+    "config.spaces[].rooms[].name": {
+      "maxLength": 500,
+      "required": true,
+      "type": "str"
+    },
+    "config.spaces[].rooms[].open_to": {
+      "required": false
+    },
+    "config.spaces[].rooms[].open_to[]": {
+      "maxLength": 500,
+      "type": "str"
+    },
+    "config.spaces[].rooms[].poly": {
+      "required": false
+    },
+    "config.spaces[].rooms[].poly[][]": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>"
+    },
+    "config.spaces[].rooms[].settings": {
+      "allowExtra": true,
+      "nullable": true,
+      "required": false
+    },
+    "config.spaces[].rooms[].settings.custom_fill": {
+      "nullable": true,
+      "required": false
+    },
+    "config.spaces[].rooms[].settings.custom_fill.a": {
+      "max": 1.0,
+      "min": 0.0,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].rooms[].settings.custom_fill.c": {
+      "opaque": "Match('\\\\A#[0-9a-fA-F]{6}\\\\Z', msg=None)",
+      "required": true
+    },
+    "config.spaces[].rooms[].settings.fill_mode": {
+      "enum": [
+        "custom",
+        "glow",
+        "light",
+        "lqi",
+        "none",
+        "temp"
+      ],
+      "nullable": true,
+      "required": false
+    },
+    "config.spaces[].rooms[].settings.glow": {
+      "nullable": true,
+      "required": false,
+      "type": "bool"
+    },
+    "config.spaces[].rooms[].settings.hum_source": {
+      "nullable": true,
+      "required": false,
+      "type": "str"
+    },
+    "config.spaces[].rooms[].settings.label_scale": {
+      "max": 3,
+      "min": 0.5,
+      "nullable": true,
+      "required": false,
+      "type": "float"
+    },
+    "config.spaces[].rooms[].settings.name_scale": {
+      "max": 3,
+      "min": 0.5,
+      "nullable": true,
+      "required": false,
+      "type": "float"
+    },
+    "config.spaces[].rooms[].settings.temp_source": {
+      "nullable": true,
+      "required": false,
+      "type": "str"
+    },
+    "config.spaces[].rooms[].w": {
+      "max": 5000.0,
+      "min": 0.001,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].rooms[].wall_ids": {
+      "required": false
+    },
+    "config.spaces[].rooms[].wall_ids[]": {
+      "maxLength": 64,
+      "minLength": 1,
+      "type": "str"
+    },
+    "config.spaces[].rooms[].x": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].rooms[].y": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].segments": {
+      "removed": true
+    },
+    "config.spaces[].settings": {
+      "allowExtra": true,
+      "required": false
+    },
+    "config.spaces[].settings.bg_color": {
+      "opaque": "Match('\\\\A#[0-9a-fA-F]{6}\\\\Z', msg=None)",
+      "required": false
+    },
+    "config.spaces[].settings.bg_mode": {
+      "enum": [
+        "daynight",
+        "static"
+      ],
+      "nullable": true,
+      "required": false
+    },
+    "config.spaces[].settings.card_font_scale": {
+      "max": 3,
+      "min": 0.5,
+      "required": false,
+      "type": "float"
+    },
+    "config.spaces[].settings.custom_fill": {
+      "nullable": true,
+      "required": false
+    },
+    "config.spaces[].settings.custom_fill.a": {
+      "max": 1.0,
+      "min": 0.0,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].settings.custom_fill.c": {
+      "opaque": "Match('\\\\A#[0-9a-fA-F]{6}\\\\Z', msg=None)",
+      "required": true
+    },
+    "config.spaces[].settings.fill_mode": {
+      "enum": [
+        "custom",
+        "glow",
+        "light",
+        "lqi",
+        "none",
+        "temp"
+      ],
+      "required": false
+    },
+    "config.spaces[].settings.glow_enabled": {
+      "required": false,
+      "type": "bool"
+    },
+    "config.spaces[].settings.hide_decor": {
+      "required": false,
+      "type": "bool"
+    },
+    "config.spaces[].settings.hide_openings": {
+      "required": false,
+      "type": "bool"
+    },
+    "config.spaces[].settings.label_hum": {
+      "required": false,
+      "type": "bool"
+    },
+    "config.spaces[].settings.label_light": {
+      "required": false,
+      "type": "bool"
+    },
+    "config.spaces[].settings.label_lqi": {
+      "required": false,
+      "type": "bool"
+    },
+    "config.spaces[].settings.label_temp": {
+      "required": false,
+      "type": "bool"
+    },
+    "config.spaces[].settings.north_deg": {
+      "nullable": true,
+      "opaque": "<function _north_deg>",
+      "required": false
+    },
+    "config.spaces[].settings.room_color": {
+      "opaque": "Match('\\\\A#[0-9a-fA-F]{6}\\\\Z', msg=None)",
+      "required": false
+    },
+    "config.spaces[].settings.room_opacity": {
+      "max": 1,
+      "min": 0,
+      "required": false,
+      "type": "float"
+    },
+    "config.spaces[].settings.show_borders": {
+      "required": false,
+      "type": "bool"
+    },
+    "config.spaces[].settings.show_lqi": {
+      "required": false,
+      "type": "bool"
+    },
+    "config.spaces[].settings.show_names": {
+      "required": false,
+      "type": "bool"
+    },
+    "config.spaces[].settings.sun_rays": {
+      "nullable": true,
+      "required": false,
+      "type": "bool"
+    },
+    "config.spaces[].settings.temp_max": {
+      "required": false,
+      "type": "float"
+    },
+    "config.spaces[].settings.temp_min": {
+      "required": false,
+      "type": "float"
+    },
+    "config.spaces[].title": {
+      "required": true,
+      "type": "str"
+    },
+    "config.spaces[].view_box": {
+      "opaque": "<function _view_box>",
+      "required": true
+    },
+    "config.spaces[].wall_columns": {
+      "required": false
+    },
+    "config.spaces[].wall_columns[]": {
+      "allowExtra": true
+    },
+    "config.spaces[].wall_columns[].angle": {
+      "max": 90,
+      "min": 0,
+      "opaque": "<function _finite>",
+      "required": false
+    },
+    "config.spaces[].wall_columns[].center": {
+      "required": true
+    },
+    "config.spaces[].wall_columns[].center[]": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>"
+    },
+    "config.spaces[].wall_columns[].cm": {
+      "max": 150,
+      "min": 1,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].wall_columns[].id": {
+      "maxLength": 64,
+      "minLength": 1,
+      "required": true,
+      "type": "str"
+    },
+    "config.spaces[].wall_columns[].shape": {
+      "enum": [
+        "circle",
+        "square"
+      ],
+      "required": true
+    },
+    "config.spaces[].wall_segments": {
+      "required": false
+    },
+    "config.spaces[].wall_segments[]": {
+      "allowExtra": true
+    },
+    "config.spaces[].wall_segments[].a": {
+      "required": true
+    },
+    "config.spaces[].wall_segments[].a[]": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>"
+    },
+    "config.spaces[].wall_segments[].b": {
+      "required": true
+    },
+    "config.spaces[].wall_segments[].b[]": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>"
+    },
+    "config.spaces[].wall_segments[].cm": {
+      "max": 100,
+      "min": 0,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].wall_segments[].id": {
+      "maxLength": 64,
+      "minLength": 1,
+      "required": true,
+      "type": "str"
+    },
+    "config.spaces[].walls": {
+      "required": false
+    },
+    "config.spaces[].walls[]": {
+      "allowExtra": true
+    },
+    "config.spaces[].walls[].a": {
+      "required": false
+    },
+    "config.spaces[].walls[].a[]": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>"
+    },
+    "config.spaces[].walls[].b": {
+      "required": false
+    },
+    "config.spaces[].walls[].b[]": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>"
+    },
+    "config.spaces[].walls[].cm": {
+      "max": 100,
+      "min": 1,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "config.spaces[].walls[].key": {
+      "maxLength": 64,
+      "minLength": 1,
+      "required": true,
+      "type": "str"
+    },
+    "config.spaces[].zero_wall_style": {
+      "enum": [
+        "dashed",
+        "solid"
+      ],
+      "required": false
+    },
+    "layout.*": {
+      "allowExtra": true
+    },
+    "layout.*.x": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>",
+      "required": true
+    },
+    "layout.*.y": {
+      "max": 5000.0,
+      "min": -5000.0,
+      "opaque": "<function _finite>",
+      "required": true
+    }
+  }
+}
diff --git a/scripts/dump-config-schema.py b/scripts/dump-config-schema.py
new file mode 100644
index 00000000..f479d525
--- /dev/null
+++ b/scripts/dump-config-schema.py
@@ -0,0 +1,284 @@
+#!/usr/bin/env python3
+"""#33: dump the canonical persisted-config schema into a deterministic JSON.
+
+The Voluptuous schema in custom_components/houseplan/validation.py is the
+single owner of the persisted config/layout shape. This walker turns it into
+scripts/config-schema-manifest.json — the machine-readable manifest the
+frontend parity test and the field registry completeness test consume.
+
+Determinism contract: two runs on the same tree produce byte-identical
+output (sorted paths, sorted keys, stable value rendering). A validator this
+walker does not understand is written fail-closed as {"opaque": "<repr>"} —
+the manifest stays fresh and the parity test simply does not judge that node.
+
+The importer stubs the parent packages so custom_components/houseplan/
+__init__.py (which needs homeassistant) never executes; validation.py itself
+is dependency-free apart from voluptuous.
+"""
+from __future__ import annotations
+
+import importlib.util
+import json
+import re
+import sys
+import types
+from pathlib import Path
+
+REPO = Path(__file__).resolve().parent.parent
+OUT = REPO / "scripts" / "config-schema-manifest.json"
+
+
+def _safe_repr(value) -> str:
+    """repr() without memory addresses — the manifest must be deterministic."""
+    if callable(value) and hasattr(value, "__qualname__"):
+        return f"<function {value.__qualname__}>"
+    return re.sub(r" at 0x[0-9a-fA-F]+", "", repr(value))
+
+
+def _load_validation():
+    for name, path in (
+        ("custom_components", REPO / "custom_components"),
+        ("custom_components.houseplan", REPO / "custom_components" / "houseplan"),
+    ):
+        module = types.ModuleType(name)
+        module.__path__ = [str(path)]
+        sys.modules[name] = module
+
+    def load(name: str, file: Path):
+        spec = importlib.util.spec_from_file_location(name, file)
+        module = importlib.util.module_from_spec(spec)
+        sys.modules[name] = module
+        spec.loader.exec_module(module)
+        return module
+
+    load(
+        "custom_components.houseplan.coordinate_canonicalization",
+        REPO / "custom_components" / "houseplan" / "coordinate_canonicalization.py",
+    )
+    return load(
+        "custom_components.houseplan.validation",
+        REPO / "custom_components" / "houseplan" / "validation.py",
+    )
+
+
+def _render_default(value):
+    """Stable, JSON-safe rendering of a schema default."""
+    try:
+        if callable(value):
+            produced = value()
+            return {"factory": type(produced).__name__}
+        json.dumps(value)
+        return value
+    except (TypeError, ValueError):
+        return {"opaque": _safe_repr(value)}
+
+
+def build_manifest():
+    import voluptuous as vol
+
+    validation = _load_validation()
+
+    def describe(validator):  # noqa: C901 - a walker is naturally branchy
+        """Describe one value validator as a JSON-able dict."""
+        if isinstance(validator, vol.Schema):
+            return describe(validator.schema) | _extra_flag(validator)
+        if isinstance(validator, vol.All):
+            merged: dict = {}
+            for part in validator.validators:
+                for key, value in describe(part).items():
+                    if key in merged and merged[key] != value:
+                        merged.setdefault("conflicts", []).append({key: value})
+                    else:
+                        merged[key] = value
+            return merged or {"opaque": _safe_repr(validator)}
+        if isinstance(validator, vol.Any):
+            variants = [describe(part) for part in validator.validators]
+            if any(v == {"type": "null"} for v in variants):
+                rest = [v for v in variants if v != {"type": "null"}]
+                if len(rest) == 1:
+                    return rest[0] | {"nullable": True}
+            return {"variants": variants}
+        if isinstance(validator, vol.In):
+            return {"enum": sorted(validator.container, key=str)}
+        if isinstance(validator, vol.Range):
+            out = {}
+            if validator.min is not None:
+                out["min"] = validator.min
+            if validator.max is not None:
+                out["max"] = validator.max
+            return out
+        if isinstance(validator, vol.Length):
+            out = {}
+            if validator.min is not None:
+                out["minLength"] = validator.min
+            if validator.max is not None:
+                out["maxLength"] = validator.max
+            return out
+        if isinstance(validator, vol.Equal):
+            return {"const": validator.target}
+        if isinstance(validator, vol.Coerce):
+            return {"type": getattr(validator.type, "__name__", _safe_repr(validator.type))}
+        if validator is None or validator is type(None):
+            return {"type": "null"}
+        if validator is bool:
+            return {"type": "bool"}
+        if validator is int:
+            return {"type": "int"}
+        if validator is float:
+            return {"type": "float"}
+        if validator is str:
+            return {"type": "str"}
+        if validator is dict or validator is object:
+            return {"type": "object"}
+        if isinstance(validator, dict):
+            return {"object": True}
+        if isinstance(validator, (list, tuple)):
+            items = [describe(part) for part in validator]
+            return {"list": items[0] if len(items) == 1 else items}
+        if isinstance(validator, (str, int, float, bool)):
+            return {"const": validator}
+        if isinstance(validator, type):
+            return {"type": validator.__name__}
+        return {"opaque": _safe_repr(validator)}
+
+    def _extra_flag(schema):
+        if getattr(schema, "extra", None) == vol.ALLOW_EXTRA:
+            return {"allowExtra": True}
+        return {}
+
+    leaves: dict[str, dict] = {}
+
+    def _variant_tag(schema, index: int) -> str:
+        """Discriminator for an Any-of-dicts variant: kind const/enum, else index."""
+        inner = schema.schema if isinstance(schema, vol.Schema) else schema
+        if isinstance(inner, dict):
+            for key, value in inner.items():
+                name = key.schema if isinstance(key, (vol.Optional, vol.Required)) else key
+                if name == "kind":
+                    if isinstance(value, str):
+                        return value
+                    if isinstance(value, vol.In):
+                        return "|".join(sorted(value.container, key=str))
+                    if isinstance(value, vol.Equal):
+                        return str(value.target)
+        return f"var{index}"
+
+    def _is_struct(candidate) -> bool:
+        return isinstance(candidate, (vol.Schema, dict)) and isinstance(
+            candidate.schema if isinstance(candidate, vol.Schema) else candidate, dict)
+
+    def walk(node, path: str):
+        if isinstance(node, vol.Any):
+            non_null = [p for p in node.validators if p is not None and p is not type(None)]
+            nullable = len(non_null) != len(node.validators)
+            if non_null and all(_is_struct(p) for p in non_null):
+                if nullable:
+                    leaves.setdefault(path or "<root>", {})["nullable"] = True
+                if len(non_null) == 1:
+                    walk(non_null[0], path)
+                    return
+                for index, variant in enumerate(non_null):
+                    walk(variant, f"{path}<{_variant_tag(variant, index)}>")
+                return
+            leaves[path or "<root>"] = describe(node)
+            return
+        if isinstance(node, vol.Schema):
+            entry_extra = _extra_flag(node)
+            if entry_extra and path:
+                leaves.setdefault(path or "<root>", {}).update(entry_extra)
+            walk(node.schema, path)
+            return
+        if isinstance(node, vol.All):
+            # A dict wrapped in vol.All carries semantic validators after the
+            # structural schema; walk the structural part only.
+            structural = [p for p in node.validators
+                          if isinstance(p, (vol.Schema, dict, list, tuple))]
+            if structural:
+                for part in structural:
+                    walk(part, path)
+                return
+            leaves[path] = describe(node)
+            return
+        if isinstance(node, dict):
+            for key, value in node.items():
+                marker = key
+                info: dict = {}
+                if isinstance(key, vol.Remove):
+                    inner = key.schema
+                    name = inner if isinstance(inner, str) else _safe_repr(inner)
+                    leaves[f"{path}.{name}".lstrip(".")] = {"removed": True}
+                    continue
+                if isinstance(key, (vol.Optional, vol.Required)):
+                    info["required"] = isinstance(key, vol.Required)
+                    default = getattr(key, "default", vol.UNDEFINED)
+                    if default is not vol.UNDEFINED:
+                        info["default"] = _render_default(default)
+                    marker = key.schema
+                if isinstance(marker, str):
+                    child = f"{path}.{marker}".lstrip(".")
+                elif marker is str:
+                    child = f"{path}.*".lstrip(".")
+                else:
+                    child = f"{path}.<{getattr(marker, '__name__', _safe_repr(marker))}>".lstrip(".")
+                if isinstance(value, (vol.Schema, dict)):
+                    if info:
+                        leaves.setdefault(child, {}).update(info)
+                    walk(value, child)
+                elif isinstance(value, (list, tuple)) and len(value) == 1 \
+                        and isinstance(value[0], (vol.Schema, dict, vol.All)):
+                    if info:
+                        leaves.setdefault(f"{child}[]", {}).update(info)
+                    walk(value[0], f"{child}[]")
+                elif isinstance(value, vol.All) and any(
+                        isinstance(p, (vol.Schema, dict, list, tuple))
+                        for p in value.validators):
+                    if info:
+                        leaves.setdefault(child, {}).update(info)
+                    walk(value, child)
+                elif isinstance(value, vol.Any) and value.validators and all(
+                        _is_struct(p) or p is None or p is type(None)
+                        for p in value.validators) and any(
+                        _is_struct(p) for p in value.validators):
+                    if info:
+                        leaves.setdefault(child, {}).update(info)
+                    walk(value, child)
+                elif isinstance(value, (list, tuple)) and len(value) == 1 \
+                        and isinstance(value[0], vol.Any):
+                    if info:
+                        leaves.setdefault(f"{child}[]", {}).update(info)
+                    walk(value[0], f"{child}[]")
+                else:
+                    leaves[child] = info | describe(value)
+            return
+        if isinstance(node, (list, tuple)) and len(node) == 1:
+            walk(node[0], f"{path}[]")
+            return
+        leaves[path or "<root>"] = describe(node)
+
+    walk(validation.CONFIG_SCHEMA, "config")
+    walk(validation.LAYOUT_SCHEMA, "layout")
+
+    return {
+        "_comment": "#33: generated by scripts/dump-config-schema.py — do not edit by hand",
+        "fields": {path: dict(sorted(entry.items())) for path, entry in sorted(leaves.items())},
+    }
+
+
+def main() -> int:
+    manifest = build_manifest()
+    rendered = json.dumps(manifest, ensure_ascii=False, indent=2, sort_keys=True) + "\n"
+    if "--check" in sys.argv:
+        current = OUT.read_text(encoding="utf-8") if OUT.exists() else ""
+        if current != rendered:
+            sys.stderr.write(
+                "config-schema-manifest.json is stale: run python3 scripts/dump-config-schema.py\n")
+            return 1
+        print(f"manifest fresh: {len(manifest['fields'])} paths")
+        return 0
+    OUT.write_text(rendered, encoding="utf-8")
+    print(f"manifest written: {len(manifest['fields'])} paths")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
diff --git a/scripts/mutation-gate.mjs b/scripts/mutation-gate.mjs
index 143292dc..d80d14d0 100644
--- a/scripts/mutation-gate.mjs
+++ b/scripts/mutation-gate.mjs
@@ -735,6 +735,29 @@ const MUTANT_DEFINITIONS = [
       replace: "      this._persistDecorStyle();\n    }, 0);",
     }],
   },
+  {
+    id: 'schema-manifest-enum-drift',
+    guard: 'node --test test/config-schema-parity.test.mjs',
+    because: 'a backend enum value the frontend does not know (and the allow-list does not '
+      + 'bless) is exactly the schema drift #33 exists to catch — the manifest mutation '
+      + 'simulates the backend change without the frontend pair',
+    patches: [{
+      file: 'scripts/config-schema-manifest.json',
+      find: "    \"config.spaces[].settings.fill_mode\": {\n      \"enum\": [\n        \"custom\",",
+      replace: "    \"config.spaces[].settings.fill_mode\": {\n      \"enum\": [\n        \"phantom-33\",\n        \"custom\",",
+    }],
+  },
+  {
+    id: 'registry-selector-dead-decision',
+    guard: 'node --test test/config-schema-parity.test.mjs',
+    because: 'a registry decision whose selector no longer matches the schema is a dead '
+      + 'decision — the completeness test must refuse to let them accumulate (#33 AC4)',
+    patches: [{
+      file: 'scripts/config-field-registry.mjs',
+      find: "    selector: { path: ['spaces', '*', 'zero_wall_style'] },",
+      replace: "    selector: { path: ['spaces', '*', 'zero_wall_stylo'] },",
+    }],
+  },
   {
     id: 'same-binding-click-resets-source',
     guard: 'node demo/smoke_value_face_source.mjs',
diff --git a/scripts/schema-compat-allowlist.mjs b/scripts/schema-compat-allowlist.mjs
new file mode 100644
index 00000000..c4b66e05
--- /dev/null
+++ b/scripts/schema-compat-allowlist.mjs
@@ -0,0 +1,42 @@
+/**
+ * #33: the machine-readable list of LEGITIMISED enum divergences between the
+ * backend schema manifest (scripts/config-schema-manifest.json) and the
+ * frontend const declarations.
+ *
+ * The parity test fails on any divergence that is not listed here — and on
+ * any entry here that no longer corresponds to a real divergence, so the
+ * list cannot rot. Every entry names the owning side, the value, the reason
+ * and the issue that owns the decision.
+ */
+export const SCHEMA_COMPAT_ALLOWLIST = Object.freeze([
+  {
+    pair: 'space.fill_mode',
+    side: 'backend-only',
+    value: 'glow',
+    reason: 'legacy stored value from the pre-#20 glow era; the space editor '
+      + 'projects it and never writes it back',
+    issue: '#33',
+  },
+  {
+    pair: 'room.fill_mode',
+    side: 'backend-only',
+    value: 'glow',
+    reason: 'same read-compatibility as the space level',
+    issue: '#33',
+  },
+  {
+    pair: 'marker.display',
+    side: 'backend-only',
+    value: 'ripple',
+    reason: 'read-compatibility value; normalizeDeviceDisplay canonicalises '
+      + 'it to icon_ripple and the editor rewrites it on every write',
+    issue: '#33',
+  },
+  {
+    pair: 'marker.tap_action',
+    side: 'backend-only',
+    value: 'cover',
+    reason: 'read/backend compatibility token; the editor no longer offers it',
+    issue: '#33',
+  },
+]);
diff --git a/src/sun.ts b/src/sun.ts
index dedcba05..1c200a7b 100644
--- a/src/sun.ts
+++ b/src/sun.ts
@@ -670,7 +670,8 @@ export function northDegOf(settings: any, spaceSettings: any): number | null {
   return intDeg(settings?.north_deg);
 }
 
-export type BgMode = 'static' | 'daynight';
+export const BG_MODES = ['static', 'daynight'] as const; // #33 parity
+export type BgMode = (typeof BG_MODES)[number];
 
 /** Effective background mode; anything unknown falls back to 'static'. */
 export function bgModeOf(settings: any, spaceSettings: any): BgMode {
diff --git a/src/types.ts b/src/types.ts
index fd94e8a1..b486da50 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -51,7 +51,10 @@ export interface WallSegmentEntry {
   [key: string]: unknown;
 }
 
-export type ZeroWallStyle = 'dashed' | 'solid';
+// #33: exported list drives the schema parity test; the type derives from it
+// so the two can never diverge.
+export const ZERO_WALL_STYLES = ['dashed', 'solid'] as const;
+export type ZeroWallStyle = (typeof ZERO_WALL_STYLES)[number];
 
 /** Persisted open room contour. Coordinates are normalised in config and
  * render units in SpaceModel, exactly like rooms. */
@@ -110,6 +113,9 @@ export interface MarkerValueBadge {
 }
 
 /** Config marker: edits/augments an auto-discovered device OR describes a manual/virtual icon. */
+export const VACUUM_TRAIL_MODES = ['never', 'cleaning', 'always'] as const; // #33 parity
+export type VacuumTrailMode = (typeof VACUUM_TRAIL_MODES)[number];
+
 export interface Marker {
   id: string;
   binding: string; // 'device:<id>' | 'entity:<eid>' | 'virtual'
@@ -136,7 +142,7 @@ export interface Marker {
   vacuum?: {
     live?: boolean | null;
     trail?: boolean | null; // legacy bool; trail_mode wins
-    trail_mode?: 'never' | 'cleaning' | 'always' | null;
+    trail_mode?: VacuumTrailMode | null;
     room_highlight?: boolean | null;
     source?: string | null;
     calibration?: Record<string, number[]>;
@@ -207,9 +213,12 @@ export interface WallOpeningHost {
 
 export type OpeningHost = PartitionOpeningHost | WallOpeningHost;
 
+export const OPENING_TYPES = ['door', 'window', 'gate', 'passage'] as const; // #33 parity
+export type OpeningType = (typeof OPENING_TYPES)[number];
+
 export interface OpeningCfg {
   id: string;
-  type: 'door' | 'window' | 'gate' | 'passage';
+  type: OpeningType;
   x: number;       // center, normalized by plan width
   y: number;       // center, normalized by plan height
   angle: number;   // wall angle, degrees
diff --git a/test/config-audit.test.mjs b/test/config-audit.test.mjs
index bdef2cf6..ec2136e7 100644
--- a/test/config-audit.test.mjs
+++ b/test/config-audit.test.mjs
@@ -63,3 +63,25 @@ test('config audit reports malformed JSON without a raw stack trace', () => {
     rmSync(directory, { recursive: true, force: true });
   }
 });
+
+// #33 AC6: the CLI exit-code contract — 0 clean, 3 migration available,
+// 2 invalid input — proven on the lifecycle fixtures.
+test('#33 config audit exit codes distinguish clean, migration and invalid', () => {
+  const run = (file) => spawnSync(process.execPath, ['scripts/config-audit.mjs', file], {
+    cwd: resolve('.'), encoding: 'utf8',
+  });
+  const clean = run('test/fixtures/config-lifecycle/current.json');
+  assert.equal(clean.status, 0,
+    `the current fixture must be clean, got ${clean.status}: ${clean.stdout}`);
+  const legacy = run('test/fixtures/config-lifecycle/oldest-supported.json');
+  assert.equal(legacy.status, 3,
+    'show_all/weather_entity/ripple in the oldest fixture must report "migration available"');
+  const directory = mkdtempSync(resolve(tmpdir(), 'houseplan-audit-codes-'));
+  const broken = resolve(directory, 'broken.json');
+  try {
+    writeFileSync(broken, '{nope', 'utf8');
+    assert.equal(run(broken).status, 2, 'invalid input keeps the existing code 2');
+  } finally {
+    rmSync(directory, { recursive: true, force: true });
+  }
+});
diff --git a/test/config-schema-parity.test.mjs b/test/config-schema-parity.test.mjs
new file mode 100644
index 00000000..d0af7b41
--- /dev/null
+++ b/test/config-schema-parity.test.mjs
@@ -0,0 +1,99 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { readFileSync } from 'node:fs';
+import { SCHEMA_COMPAT_ALLOWLIST } from '../scripts/schema-compat-allowlist.mjs';
+import { CONFIG_FIELD_REGISTRY } from '../scripts/config-field-registry.mjs';
+import {
+  DISPLAY_MODES, TAP_ACTIONS, SPACE_FILL_MODES, ROOM_FILL_MODES,
+} from '../test-build/logic.js';
+import {
+  OPENING_TYPES, VACUUM_TRAIL_MODES, ZERO_WALL_STYLES,
+} from '../test-build/types.js';
+import { BG_MODES } from '../test-build/sun.js';
+
+const manifest = JSON.parse(readFileSync(
+  new URL('../scripts/config-schema-manifest.json', import.meta.url), 'utf8')).fields;
+
+/** Enum values of a manifest entry: `enum` list or const-variants (null skipped). */
+const backendValues = (path) => {
+  const entry = manifest[path];
+  assert.ok(entry, `manifest is missing ${path} — regenerate scripts/config-schema-manifest.json`);
+  if (entry.enum) return [...entry.enum];
+  if (entry.variants) {
+    return entry.variants
+      .filter((variant) => 'const' in variant)
+      .map((variant) => variant.const);
+  }
+  assert.fail(`${path} carries neither enum nor const variants`);
+  return [];
+};
+
+/** #33 AC2/AC3: every backend<->frontend enum pair, judged through the allow-list. */
+const PAIRS = [
+  { pair: 'space.fill_mode', path: 'config.spaces[].settings.fill_mode', front: SPACE_FILL_MODES },
+  { pair: 'room.fill_mode', path: 'config.spaces[].rooms[].settings.fill_mode', front: ROOM_FILL_MODES },
+  { pair: 'marker.display', path: 'config.markers[].display', front: DISPLAY_MODES },
+  { pair: 'marker.tap_action', path: 'config.markers[].tap_action', front: TAP_ACTIONS },
+  { pair: 'opening.type', path: 'config.spaces[].openings[].type', front: OPENING_TYPES },
+  { pair: 'vacuum.trail_mode', path: 'config.markers[].vacuum.trail_mode', front: VACUUM_TRAIL_MODES },
+  { pair: 'space.zero_wall_style', path: 'config.spaces[].zero_wall_style', front: ZERO_WALL_STYLES },
+  { pair: 'settings.bg_mode', path: 'config.settings.bg_mode', front: BG_MODES },
+];
+
+test('#33 AC2: backend and frontend enums agree, divergences only via the allow-list', () => {
+  const usedAllowEntries = new Set();
+  for (const { pair, path, front } of PAIRS) {
+    const backend = new Set(backendValues(path));
+    const frontend = new Set(front);
+    for (const value of backend) {
+      if (frontend.has(value)) continue;
+      const allowed = SCHEMA_COMPAT_ALLOWLIST.find((entry) =>
+        entry.pair === pair && entry.side === 'backend-only' && entry.value === value);
+      assert.ok(allowed,
+        `${pair}: backend knows '${value}' but the frontend list does not — `
+        + 'add the value or a schema-compat-allowlist entry with a reason');
+      usedAllowEntries.add(allowed);
+    }
+    for (const value of frontend) {
+      if (backend.has(value)) continue;
+      const allowed = SCHEMA_COMPAT_ALLOWLIST.find((entry) =>
+        entry.pair === pair && entry.side === 'frontend-only' && entry.value === value);
+      assert.ok(allowed,
+        `${pair}: frontend offers '${value}' but the backend schema rejects it — `
+        + 'a write would fail validation');
+      usedAllowEntries.add(allowed);
+    }
+  }
+  // AC3: the allow-list cannot rot — every entry must justify a REAL divergence.
+  for (const entry of SCHEMA_COMPAT_ALLOWLIST) {
+    assert.ok(usedAllowEntries.has(entry),
+      `allow-list entry ${entry.pair}/'${entry.value}' no longer matches a real `
+      + 'divergence — the sides converged, remove the entry');
+  }
+});
+
+/** #33 AC4: every registry decision must resolve against the schema reality. */
+test('#33 AC4: every registry entry resolves to a manifest path or an explicit passport', () => {
+  // Variant tags (<line>, <wall>...) are a manifest detail — registry
+  // selectors are variant-agnostic, so both sides compare untagged.
+  const untagged = new Set(Object.keys(manifest).map((key) => key.replace(/<[^>]+>/g, '')));
+  for (const entry of CONFIG_FIELD_REGISTRY) {
+    if (entry.schema === 'allow-extra' || entry.schema === 'lovelace-card') continue;
+    const path = 'config.' + entry.selector.path
+      .map((segment) => (segment === '*' ? '[]' : segment))
+      .join('.')
+      .replace(/\.\[\]/g, '[]');
+    assert.ok(untagged.has(path),
+      `registry entry '${entry.id}' points at '${path}' which is not in the schema `
+      + 'manifest — dead decisions must not accumulate (fix the selector, add a '
+      + "schema: 'allow-extra' passport, or drop the entry)");
+  }
+});
+
+/** #33 AC7: the manifest is a build/test artefact — the bundle must not grow. */
+test('#33 AC7: no production source imports the schema manifest', () => {
+  const source = readFileSync(new URL('../src/houseplan-card.ts', import.meta.url), 'utf8')
+    + readFileSync(new URL('../src/houseplan-editor-runtime.ts', import.meta.url), 'utf8');
+  assert.ok(!source.includes('config-schema-manifest'),
+    'the manifest is test infrastructure, not runtime data');
+});
diff --git a/test/fixtures/config-lifecycle/current.json b/test/fixtures/config-lifecycle/current.json
new file mode 100644
index 00000000..3e75b406
--- /dev/null
+++ b/test/fixtures/config-lifecycle/current.json
@@ -0,0 +1,188 @@
+{
+  "model_version": 9,
+  "spaces": [
+    {
+      "id": "ground",
+      "title": "Ground",
+      "view_box": [
+        0,
+        0,
+        1000,
+        750
+      ],
+      "rooms": [
+        {
+          "id": "hall",
+          "name": "Hall",
+          "poly": [
+            [
+              100,
+              100
+            ],
+            [
+              400,
+              100
+            ],
+            [
+              400,
+              400
+            ],
+            [
+              100,
+              400
+            ]
+          ],
+          "wall_ids": [
+            "w1",
+            "w2",
+            "w3",
+            "w4"
+          ]
+        }
+      ],
+      "wall_segments": [
+        {
+          "id": "w1",
+          "a": [
+            100,
+            100
+          ],
+          "b": [
+            400,
+            100
+          ],
+          "cm": 15
+        },
+        {
+          "id": "w2",
+          "a": [
+            400,
+            100
+          ],
+          "b": [
+            400,
+            400
+          ],
+          "cm": 15
+        },
+        {
+          "id": "w3",
+          "a": [
+            400,
+            400
+          ],
+          "b": [
+            100,
+            400
+          ],
+          "cm": 15
+        },
+        {
+          "id": "w4",
+          "a": [
+            100,
+            400
+          ],
+          "b": [
+            100,
+            100
+          ],
+          "cm": 15
+        }
+      ],
+      "walls": [
+        {
+          "key": "[100, 100]|[400, 100]",
+          "a": [
+            100,
+            100
+          ],
+          "b": [
+            400,
+            100
+          ],
+          "cm": 15
+        },
+        {
+          "key": "[400, 100]|[400, 400]",
+          "a": [
+            400,
+            100
+          ],
+          "b": [
+            400,
+            400
+          ],
+          "cm": 15
+        },
+        {
+          "key": "[400, 400]|[100, 400]",
+          "a": [
+            400,
+            400
+          ],
+          "b": [
+            100,
+            400
+          ],
+          "cm": 15
+        },
+        {
+          "key": "[100, 400]|[100, 100]",
+          "a": [
+            100,
+            400
+          ],
+          "b": [
+            100,
+            100
+          ],
+          "cm": 15
+        }
+      ],
+      "decor": [
+        {
+          "id": "d1",
+          "kind": "line",
+          "x1": 0.1,
+          "y1": 0.1,
+          "x2": 0.3,
+          "y2": 0.1,
+          "color": "#8b0000",
+          "width_cm": 5
+        },
+        {
+          "id": "d2",
+          "kind": "furniture",
+          "symbol": "sofa",
+          "x": 0.2,
+          "y": 0.2,
+          "w": 0.1,
+          "h": 0.05
+        }
+      ],
+      "settings": {
+        "bg_mode": "daynight",
+        "north_deg": 45
+      }
+    }
+  ],
+  "markers": [
+    {
+      "id": "sensor",
+      "binding": "entity:sensor.temp",
+      "space": "ground",
+      "display": "value",
+      "value_source": {
+        "kind": "entity_attr",
+        "attr": "temperature"
+      }
+    }
+  ],
+  "settings": {
+    "decor_default_style": {
+      "color": "#8b0000",
+      "width_cm": 5
+    }
+  }
+}
\ No newline at end of file
diff --git a/test/fixtures/config-lifecycle/future-fields.json b/test/fixtures/config-lifecycle/future-fields.json
new file mode 100644
index 00000000..9d95c92e
--- /dev/null
+++ b/test/fixtures/config-lifecycle/future-fields.json
@@ -0,0 +1,201 @@
+{
+  "model_version": 9,
+  "spaces": [
+    {
+      "id": "ground",
+      "title": "Ground",
+      "view_box": [
+        0,
+        0,
+        1000,
+        750
+      ],
+      "rooms": [
+        {
+          "id": "hall",
+          "name": "Hall",
+          "poly": [
+            [
+              100,
+              100
+            ],
+            [
+              400,
+              100
+            ],
+            [
+              400,
+              400
+            ],
+            [
+              100,
+              400
+            ]
+          ],
+          "wall_ids": [
+            "w1",
+            "w2",
+            "w3",
+            "w4"
+          ]
+        }
+      ],
+      "wall_segments": [
+        {
+          "id": "w1",
+          "a": [
+            100,
+            100
+          ],
+          "b": [
+            400,
+            100
+          ],
+          "cm": 15
+        },
+        {
+          "id": "w2",
+          "a": [
+            400,
+            100
+          ],
+          "b": [
+            400,
+            400
+          ],
+          "cm": 15
+        },
+        {
+          "id": "w3",
+          "a": [
+            400,
+            400
+          ],
+          "b": [
+            100,
+            400
+          ],
+          "cm": 15
+        },
+        {
+          "id": "w4",
+          "a": [
+            100,
+            400
+          ],
+          "b": [
+            100,
+            100
+          ],
+          "cm": 15
+        }
+      ],
+      "walls": [
+        {
+          "key": "[100, 100]|[400, 100]",
+          "a": [
+            100,
+            100
+          ],
+          "b": [
+            400,
+            100
+          ],
+          "cm": 15
+        },
+        {
+          "key": "[400, 100]|[400, 400]",
+          "a": [
+            400,
+            100
+          ],
+          "b": [
+            400,
+            400
+          ],
+          "cm": 15
+        },
+        {
+          "key": "[400, 400]|[100, 400]",
+          "a": [
+            400,
+            400
+          ],
+          "b": [
+            100,
+            400
+          ],
+          "cm": 15
+        },
+        {
+          "key": "[100, 400]|[100, 100]",
+          "a": [
+            100,
+            400
+          ],
+          "b": [
+            100,
+            100
+          ],
+          "cm": 15
+        }
+      ],
+      "decor": [
+        {
+          "id": "d1",
+          "kind": "line",
+          "x1": 0.1,
+          "y1": 0.1,
+          "x2": 0.3,
+          "y2": 0.1,
+          "color": "#8b0000",
+          "width_cm": 5
+        },
+        {
+          "id": "d2",
+          "kind": "furniture",
+          "symbol": "sofa",
+          "x": 0.2,
+          "y": 0.2,
+          "w": 0.1,
+          "h": 0.05
+        }
+      ],
+      "settings": {
+        "bg_mode": "daynight",
+        "north_deg": 45,
+        "future_display": true
+      },
+      "future_space_field": "kept"
+    }
+  ],
+  "markers": [
+    {
+      "id": "sensor",
+      "binding": "entity:sensor.temp",
+      "space": "ground",
+      "display": "value",
+      "value_source": {
+        "kind": "entity_attr",
+        "attr": "temperature"
+      },
+      "future_marker_field": {
+        "nested": "kept"
+      }
+    }
+  ],
+  "settings": {
+    "decor_default_style": {
+      "color": "#8b0000",
+      "width_cm": 5
+    },
+    "future_setting": [
+      1,
+      2,
+      3
+    ]
+  },
+  "future_root_field": {
+    "kept": true
+  }
+}
\ No newline at end of file
diff --git a/test/fixtures/config-lifecycle/oldest-supported.json b/test/fixtures/config-lifecycle/oldest-supported.json
new file mode 100644
index 00000000..b2a282d9
--- /dev/null
+++ b/test/fixtures/config-lifecycle/oldest-supported.json
@@ -0,0 +1,57 @@
+{
+  "spaces": [
+    {
+      "id": "ground",
+      "title": "Ground",
+      "view_box": [
+        0,
+        0,
+        1000,
+        750
+      ],
+      "rooms": [
+        {
+          "id": "hall",
+          "name": "Hall",
+          "poly": [
+            [
+              100,
+              100
+            ],
+            [
+              400,
+              100
+            ],
+            [
+              400,
+              400
+            ],
+            [
+              100,
+              400
+            ]
+          ]
+        }
+      ],
+      "aspect": 1.33,
+      "settings": {
+        "fill_mode": "glow"
+      }
+    }
+  ],
+  "markers": [
+    {
+      "id": "lamp",
+      "binding": "entity:light.hall",
+      "space": "ground",
+      "display": "ripple",
+      "tap_action": "cover",
+      "is_light": true
+    }
+  ],
+  "settings": {
+    "show_all": true,
+    "weather_entity": "weather.home",
+    "bg_mode": "static"
+  }
+}
\ No newline at end of file
diff --git a/tests_backend/test_config_schema_manifest.py b/tests_backend/test_config_schema_manifest.py
new file mode 100644
index 00000000..efc5797d
--- /dev/null
+++ b/tests_backend/test_config_schema_manifest.py
@@ -0,0 +1,82 @@
+"""#33: the committed schema manifest must stay fresh, and the lifecycle
+fixtures must pass the real schema losslessly.
+
+The dump script stubs the package parents itself, so this module runs both in
+the sandbox (no homeassistant) and in CI.
+"""
+from __future__ import annotations
+
+import copy
+import importlib.util
+import json
+import sys
+from pathlib import Path
+
+REPO = Path(__file__).resolve().parent.parent
+
+
+def _load_dump_module():
+    spec = importlib.util.spec_from_file_location(
+        "houseplan_dump_config_schema", REPO / "scripts" / "dump-config-schema.py")
+    module = importlib.util.module_from_spec(spec)
+    sys.modules["houseplan_dump_config_schema"] = module
+    spec.loader.exec_module(module)
+    return module
+
+
+def _validation():
+    _load_dump_module()  # its importer registers the stubbed packages
+    return sys.modules["custom_components.houseplan.validation"]
+
+
+def test_issue_33_manifest_is_fresh_and_deterministic():
+    dump = _load_dump_module()
+    first = dump.build_manifest()
+    second = dump.build_manifest()
+    assert first == second, "the walker must be deterministic"
+    rendered = json.dumps(first, ensure_ascii=False, indent=2, sort_keys=True) + "\n"
+    committed = (REPO / "scripts" / "config-schema-manifest.json").read_text(encoding="utf-8")
+    assert rendered == committed, (
+        "scripts/config-schema-manifest.json is stale — the schema changed; "
+        "run python3 scripts/dump-config-schema.py and commit the diff"
+    )
+    # AC1: the manifest is not a stub — it must cover the whole persisted shape.
+    assert len(first["fields"]) > 200
+
+
+def _collect_paths(node, prefix=""):
+    paths = set()
+    if isinstance(node, dict):
+        for key, value in node.items():
+            paths |= _collect_paths(value, f"{prefix}.{key}" if prefix else key)
+    elif isinstance(node, list):
+        for item in node:
+            paths |= _collect_paths(item, f"{prefix}[]")
+    else:
+        paths.add(prefix)
+    return paths
+
+
+def test_issue_33_lifecycle_fixtures_pass_the_schema_losslessly():
+    validation = _validation()
+    fixtures = REPO / "test" / "fixtures" / "config-lifecycle"
+    dropped_by_design = {"spaces[].aspect", "spaces[].segments"}  # vol.Remove
+    for name in ("oldest-supported", "current", "future-fields"):
+        raw = json.loads((fixtures / f"{name}.json").read_text(encoding="utf-8"))
+        validated = validation.CONFIG_SCHEMA(copy.deepcopy(raw))
+        before = _collect_paths(raw)
+        after = _collect_paths(validated)
+        lost = before - after - dropped_by_design
+        assert not lost, f"{name}: validation silently dropped {sorted(lost)}"
+
+
+def test_issue_33_future_fields_round_trip_exactly():
+    validation = _validation()
+    fixtures = REPO / "test" / "fixtures" / "config-lifecycle"
+    raw = json.loads((fixtures / "future-fields.json").read_text(encoding="utf-8"))
+    validated = validation.CONFIG_SCHEMA(copy.deepcopy(raw))
+    assert validated["future_root_field"] == {"kept": True}
+    assert validated["settings"]["future_setting"] == [1, 2, 3]
+    assert validated["spaces"][0]["future_space_field"] == "kept"
+    assert validated["spaces"][0]["settings"]["future_display"] is True
+    assert validated["markers"][0]["future_marker_field"] == {"nested": "kept"}