diff --git a/src/arts/cache/active-cache.svelte.ts b/src/arts/cache/active-cache.svelte.ts
index 89886bf..721f91b 100644
--- a/src/arts/cache/active-cache.svelte.ts
+++ b/src/arts/cache/active-cache.svelte.ts
@@ -1,5 +1,5 @@
 import { CACHE_EVENT_ALL, type CacheClock, type CacheEvent } from '$libs/cache';
-import { createEngineCache } from '$svrs/cache';
+import { createEngineCache } from '$libs/cache';
 import {
 	CACHE_ACTIVE_DIAGNOSTIC_EVENTS,
 	CACHE_METHOD_CLEAR,
@@ -13,7 +13,7 @@ import {
 	CACHE_METHOD_SET,
 	CACHE_METHOD_STATS
 } from './consts.ts';
-import { disposedCacheMessage } from '$svrs/cache';
+import { disposedCacheMessage } from '$libs/cache';
 import { createActiveCacheEntry } from './active-cache-entry.svelte.ts';
 import { normalizeActiveCacheError } from './active-cache-helpers.ts';
 import { createActiveCacheDiagnostics, emitActiveCacheDiagnostic } from './diagnostics.ts';
diff --git a/src/arts/cache/consts.ts b/src/arts/cache/consts.ts
index 03fc217..574ab29 100644
--- a/src/arts/cache/consts.ts
+++ b/src/arts/cache/consts.ts
@@ -25,7 +25,7 @@ export {
 	CACHE_METHOD_SET,
 	CACHE_METHOD_STATS,
 	CACHE_MODULE
-} from '$svrs/cache';
+} from '$libs/cache';
 
 export const CACHE_ACTIVE_STATUS_IDLE = 'idle';
 export const CACHE_ACTIVE_STATUS_LOADING = 'loading';
diff --git a/src/arts/cache/errors.ts b/src/arts/cache/errors.ts
index d773ce5..327e0ae 100644
--- a/src/arts/cache/errors.ts
+++ b/src/arts/cache/errors.ts
@@ -1,8 +1,8 @@
 import { CodeError } from '$libs/errs';
 import { CACHE_ERR_ACTIVE_ENTRY_DISPOSED } from '$libs/cache';
-import { CACHE_MODULE } from '$svrs/cache';
+import { CACHE_MODULE } from '$libs/cache';
 
-export { CACHE_ERROR_MSG_DISPOSED_SUFFIX, CacheDisposedError, isCacheDisposedError } from '$svrs/cache';
+export { CACHE_ERROR_MSG_DISPOSED_SUFFIX, CacheDisposedError, isCacheDisposedError } from '$libs/cache';
 
 export const CACHE_ERROR_MSG_ACTIVE_ENTRY_DISPOSED =
 	`[${CACHE_MODULE}] ActiveCacheEntry used after dispose().`;
diff --git a/src/arts/cache/index.ts b/src/arts/cache/index.ts
index 1f10a8b..e36aa34 100644
--- a/src/arts/cache/index.ts
+++ b/src/arts/cache/index.ts
@@ -53,7 +53,7 @@ export {
 	isCacheActiveEntryDisposedError,
 	isCacheDisposedError
 } from './errors.ts';
-export { disposedCacheMessage } from '$svrs/cache';
+export { disposedCacheMessage } from '$libs/cache';
 export type {
 	ActiveCacheDiagnosticEvent,
 	ActiveCacheDiagnosticMeta,
@@ -145,7 +145,7 @@ export {
 	stableHash,
 	stableStringify,
 	storageCacheAdapter
-} from '$svrs/cache';
+} from '$libs/cache';
 
 export type {
 	CacheAdapter,
@@ -187,4 +187,4 @@ export type {
 	SetOptions,
 	StorageCacheAdapterOptions,
 	StorageLike
-} from '$svrs/cache';
+} from '$libs/cache';
diff --git a/src/arts/cache/types.ts b/src/arts/cache/types.ts
index a1bad42..daaf564 100644
--- a/src/arts/cache/types.ts
+++ b/src/arts/cache/types.ts
@@ -1,9 +1,9 @@
 import type { CACHE_ACTIVE_ENTRY_EVENTS, CACHE_ACTIVE_STATUSES } from './consts.ts';
 import type { CacheClock, CacheEvent, CacheKey, QueryOptions, SetOptions } from '$libs/cache';
-import type { EngineCache, EngineCacheOptions } from '$svrs/cache';
+import type { EngineCache, EngineCacheOptions } from '$libs/cache';
 import type { ActiveChangeListener, ActiveEngine } from '$libs/active';
 
-export type { EngineCache, EngineCacheOptions } from '$svrs/cache';
+export type { EngineCache, EngineCacheOptions } from '$libs/cache';
 
 export type ActiveCacheEntryStatus = (typeof CACHE_ACTIVE_STATUSES)[number];
 
diff --git a/src/svrs/cache/diagnostics.ts b/src/libs/cache/diagnostics.ts
similarity index 89%
rename from src/svrs/cache/diagnostics.ts
rename to src/libs/cache/diagnostics.ts
index fee0c86..485947f 100644
--- a/src/svrs/cache/diagnostics.ts
+++ b/src/libs/cache/diagnostics.ts
@@ -10,10 +10,10 @@ import {
 	CACHE_EVENT_ADAPTER_ERROR,
 	CACHE_EVENT_REFRESH_ERROR,
 	CACHE_EVENT_STALE_IF_ERROR,
-	type CacheEvent,
-	type CacheEventType
-} from '$libs/cache';
-import { CACHE_LOG_MESSAGE_BY_EVENT, CACHE_MODULE } from './consts.ts';
+	CACHE_MODULE
+} from './consts.ts';
+import type { CacheEvent, CacheEventType } from './types.ts';
+import { CACHE_LOG_MESSAGE_BY_EVENT } from './engine-consts.ts';
 
 export type CacheDiagnosticEvent = DiagnosticEvent<CacheEventType, CacheEvent>;
 export type CacheDiagnostics = Diagnostics<CacheDiagnosticEvent>;
diff --git a/src/svrs/cache/engine-cache.ts b/src/libs/cache/engine-cache.ts
similarity index 85%
rename from src/svrs/cache/engine-cache.ts
rename to src/libs/cache/engine-cache.ts
index bec8193..e6b55fd 100644
--- a/src/svrs/cache/engine-cache.ts
+++ b/src/libs/cache/engine-cache.ts
@@ -1,4 +1,5 @@
-import { createCacheRuntime, memoryCacheAdapter } from '$libs/cache';
+import { createCacheRuntime } from './engine.ts';
+import { memoryCacheAdapter } from './adapters/memory.ts';
 import {
 	CACHE_METHOD_CLEAR,
 	CACHE_METHOD_EXPLAIN,
@@ -9,11 +10,11 @@ import {
 	CACHE_METHOD_QUERY,
 	CACHE_METHOD_SET,
 	CACHE_METHOD_STATS
-} from './consts.ts';
+} from './engine-consts.ts';
 import { createCacheDiagnostics, emitCacheDiagnostic } from './diagnostics.ts';
-import { CacheDisposedError } from './errors.ts';
-import { disposedCacheMessage } from './helpers.ts';
-import type { EngineCache, EngineCacheOptions } from './types.ts';
+import { CacheDisposedError } from './engine-errors.ts';
+import { disposedCacheMessage } from './engine-helpers.ts';
+import type { EngineCache, EngineCacheOptions } from './engine-types.ts';
 
 export function createEngineCache(options: EngineCacheOptions = {}): EngineCache {
 	const diagnostics = createCacheDiagnostics(options.logger);
diff --git a/src/svrs/cache/consts.ts b/src/libs/cache/engine-consts.ts
similarity index 90%
rename from src/svrs/cache/consts.ts
rename to src/libs/cache/engine-consts.ts
index a76fab3..99aa5da 100644
--- a/src/svrs/cache/consts.ts
+++ b/src/libs/cache/engine-consts.ts
@@ -13,15 +13,9 @@ import {
 	CACHE_EVENT_SET,
 	CACHE_EVENT_SINGLEFLIGHT_JOIN,
 	CACHE_EVENT_STALE_HIT,
-	CACHE_EVENT_STALE_IF_ERROR,
-	CACHE_MODULE,
-	type CacheEventType
-} from '$libs/cache';
-
-// `CACHE_MODULE` is owned by `libs/cache` (the pure layer needs it for
-// diagnostics) and re-exported from this server consts module so
-// existing `$svrs/cache` consumers keep their import paths.
-export { CACHE_MODULE };
+	CACHE_EVENT_STALE_IF_ERROR
+} from './consts.ts';
+import type { CacheEventType } from './types.ts';
 
 export const CACHE_LOG_MESSAGE_HIT = 'cache hit';
 export const CACHE_LOG_MESSAGE_MISS = 'cache miss';
diff --git a/src/svrs/cache/errors.ts b/src/libs/cache/engine-errors.ts
similarity index 88%
rename from src/svrs/cache/errors.ts
rename to src/libs/cache/engine-errors.ts
index 72e3f6f..1bbda4e 100644
--- a/src/svrs/cache/errors.ts
+++ b/src/libs/cache/engine-errors.ts
@@ -1,5 +1,5 @@
 import { CodeError } from '$libs/errs';
-import { CACHE_ERR_DISPOSED } from '$libs/cache';
+import { CACHE_ERR_DISPOSED } from './errors.ts';
 
 export const CACHE_ERROR_MSG_DISPOSED_SUFFIX = '() called on a disposed cache engine';
 
diff --git a/src/svrs/cache/helpers.ts b/src/libs/cache/engine-helpers.ts
similarity index 63%
rename from src/svrs/cache/helpers.ts
rename to src/libs/cache/engine-helpers.ts
index f659bf5..fe76034 100644
--- a/src/svrs/cache/helpers.ts
+++ b/src/libs/cache/engine-helpers.ts
@@ -1,4 +1,4 @@
-import { CACHE_ERROR_MSG_DISPOSED_SUFFIX } from './errors.ts';
+import { CACHE_ERROR_MSG_DISPOSED_SUFFIX } from './engine-errors.ts';
 
 export function disposedCacheMessage(method: string): string {
 	return `${method}${CACHE_ERROR_MSG_DISPOSED_SUFFIX}`;
diff --git a/src/svrs/cache/types.ts b/src/libs/cache/engine-types.ts
similarity index 86%
rename from src/svrs/cache/types.ts
rename to src/libs/cache/engine-types.ts
index 05affa5..885f385 100644
--- a/src/svrs/cache/types.ts
+++ b/src/libs/cache/engine-types.ts
@@ -2,9 +2,9 @@ import type {
 	CacheAdapter,
 	CacheEventHandler,
 	CacheRuntime,
-	CacheRuntimeConfig,
-	MemoryCacheAdapterOptions
-} from '$libs/cache';
+	CacheRuntimeConfig
+} from './types.ts';
+import type { MemoryCacheAdapterOptions } from './adapters/memory.ts';
 import type { Logger } from '$libs/logger';
 
 export interface EngineCacheOptions extends Omit<CacheRuntimeConfig, 'adapter' | 'onEvent'> {
diff --git a/src/libs/cache/index.ts b/src/libs/cache/index.ts
index 8074684..6e56391 100644
--- a/src/libs/cache/index.ts
+++ b/src/libs/cache/index.ts
@@ -68,3 +68,48 @@ export type {
 
 export type { MemoryCacheAdapter, MemoryCacheAdapterOptions } from './adapters/memory.ts';
 export type { StorageCacheAdapterOptions, StorageLike } from './adapters/storage.ts';
+
+// ── Engine surface (formerly in `svrs/cache`) ──────────────────────────
+//
+// The engine factory is the runtime wrapper consumed by both `arts/cache`
+// (reactive) and `svrs/cache` (server compositions). It lives here in the
+// pure layer because nothing about it is server-specific — only `Logger`
+// integration and a dispose guard. Closes the codex audit blocker #8
+// (arts → svrs layer inversion).
+export { createEngineCache } from './engine-cache.ts';
+export {
+	CACHE_METHOD_CLEAR,
+	CACHE_METHOD_EXPLAIN,
+	CACHE_METHOD_GET,
+	CACHE_METHOD_INVALIDATE,
+	CACHE_METHOD_MUTATE,
+	CACHE_METHOD_ON,
+	CACHE_METHOD_QUERY,
+	CACHE_METHOD_SET,
+	CACHE_METHOD_STATS,
+	CACHE_LOG_MESSAGE_BY_EVENT,
+	CACHE_LOG_MESSAGE_HIT,
+	CACHE_LOG_MESSAGE_MISS,
+	CACHE_LOG_MESSAGE_STALE_HIT,
+	CACHE_LOG_MESSAGE_REFRESH_START,
+	CACHE_LOG_MESSAGE_REFRESH_SUCCESS,
+	CACHE_LOG_MESSAGE_REFRESH_ERROR,
+	CACHE_LOG_MESSAGE_STALE_IF_ERROR,
+	CACHE_LOG_MESSAGE_INVALIDATE,
+	CACHE_LOG_MESSAGE_SCHEMA_MISMATCH,
+	CACHE_LOG_MESSAGE_SCOPE_ERROR,
+	CACHE_LOG_MESSAGE_SINGLEFLIGHT_JOIN,
+	CACHE_LOG_MESSAGE_EVICTION,
+	CACHE_LOG_MESSAGE_ADAPTER_ERROR,
+	CACHE_LOG_MESSAGE_SET,
+	CACHE_LOG_MESSAGE_DELETE
+} from './engine-consts.ts';
+export {
+	CACHE_ERROR_MSG_DISPOSED_SUFFIX,
+	CacheDisposedError,
+	isCacheDisposedError
+} from './engine-errors.ts';
+export { disposedCacheMessage } from './engine-helpers.ts';
+export { createCacheDiagnostics, emitCacheDiagnostic } from './diagnostics.ts';
+export type { EngineCache, EngineCacheOptions } from './engine-types.ts';
+export type { CacheDiagnosticEvent, CacheDiagnostics } from './diagnostics.ts';
diff --git a/src/svrs/cache/index.ts b/src/svrs/cache/index.ts
index ddb8cd5..8311f4a 100644
--- a/src/svrs/cache/index.ts
+++ b/src/svrs/cache/index.ts
@@ -1,155 +1,10 @@
-export { createEngineCache } from './engine-cache.ts';
-export { createCacheDiagnostics, emitCacheDiagnostic } from './diagnostics.ts';
-export { CACHE_ERR_DISPOSED } from '$libs/cache';
-export {
-	CACHE_LOG_MESSAGE_ADAPTER_ERROR,
-	CACHE_LOG_MESSAGE_BY_EVENT,
-	CACHE_LOG_MESSAGE_DELETE,
-	CACHE_LOG_MESSAGE_EVICTION,
-	CACHE_LOG_MESSAGE_HIT,
-	CACHE_LOG_MESSAGE_INVALIDATE,
-	CACHE_LOG_MESSAGE_MISS,
-	CACHE_LOG_MESSAGE_REFRESH_ERROR,
-	CACHE_LOG_MESSAGE_REFRESH_START,
-	CACHE_LOG_MESSAGE_REFRESH_SUCCESS,
-	CACHE_LOG_MESSAGE_SCHEMA_MISMATCH,
-	CACHE_LOG_MESSAGE_SCOPE_ERROR,
-	CACHE_LOG_MESSAGE_SET,
-	CACHE_LOG_MESSAGE_SINGLEFLIGHT_JOIN,
-	CACHE_LOG_MESSAGE_STALE_HIT,
-	CACHE_LOG_MESSAGE_STALE_IF_ERROR,
-	CACHE_METHOD_CLEAR,
-	CACHE_METHOD_EXPLAIN,
-	CACHE_METHOD_GET,
-	CACHE_METHOD_INVALIDATE,
-	CACHE_METHOD_MUTATE,
-	CACHE_METHOD_ON,
-	CACHE_METHOD_QUERY,
-	CACHE_METHOD_SET,
-	CACHE_METHOD_STATS,
-	CACHE_MODULE
-} from './consts.ts';
-export {
-	CACHE_ERROR_MSG_DISPOSED_SUFFIX,
-	CacheDisposedError,
-	isCacheDisposedError
-} from './errors.ts';
-export { disposedCacheMessage } from './helpers.ts';
-export type { EngineCache, EngineCacheOptions } from './types.ts';
-export type { CacheDiagnosticEvent, CacheDiagnostics } from './diagnostics.ts';
-
-export {
-	CACHE_ADAPTER_MEMORY,
-	CACHE_ADAPTER_STORAGE,
-	CACHE_DECISION_ACTION_DELETE_AND_FETCH,
-	CACHE_DECISION_ACTION_FETCH,
-	CACHE_DECISION_ACTION_SERVE,
-	CACHE_DECISION_ACTION_SERVE_AND_REFRESH,
-	CACHE_DECISION_ACTION_SKIP_CACHE,
-	CACHE_DECISION_REASON_BYPASS_CACHE,
-	CACHE_DECISION_REASON_CACHE_MISS,
-	CACHE_DECISION_REASON_EXPIRED,
-	CACHE_DECISION_REASON_FRESH,
-	CACHE_DECISION_REASON_NO_STORE,
-	CACHE_DECISION_REASON_PREFIX_EPOCH_CHANGED,
-	CACHE_DECISION_REASON_SCHEMA_VERSION_MISMATCH,
-	CACHE_DECISION_REASON_SCOPE_MISMATCH,
-	CACHE_DECISION_REASON_STALE_WINDOW_VALID,
-	CACHE_DECISION_REASON_TAG_EPOCH_CHANGED,
-	CACHE_ENVELOPE_STATE_DEGRADED,
-	CACHE_ENVELOPE_STATE_EXPIRED,
-	CACHE_ENVELOPE_STATE_FRESH,
-	CACHE_ENVELOPE_STATE_INVALIDATED,
-	CACHE_ENVELOPE_STATE_STALE,
-	CACHE_EVENT_ADAPTER_ERROR,
-	CACHE_EVENT_ALL,
-	CACHE_EVENT_DELETE,
-	CACHE_EVENT_EVICTION,
-	CACHE_EVENT_HIT,
-	CACHE_EVENT_INVALIDATE,
-	CACHE_EVENT_MISS,
-	CACHE_EVENT_REFRESH_ERROR,
-	CACHE_EVENT_REFRESH_START,
-	CACHE_EVENT_REFRESH_SUCCESS,
-	CACHE_EVENT_SCHEMA_MISMATCH,
-	CACHE_EVENT_SCOPE_ERROR,
-	CACHE_EVENT_SET,
-	CACHE_EVENT_SINGLEFLIGHT_JOIN,
-	CACHE_EVENT_STALE_HIT,
-	CACHE_EVENT_STALE_IF_ERROR,
-	CACHE_POLICY_CATALOG,
-	CACHE_POLICY_IMMUTABLE,
-	CACHE_POLICY_INTERACTIVE,
-	CACHE_POLICY_PRIVATE_SESSION,
-	CACHE_POLICY_REALTIME,
-	CACHE_READ_MODE_BYPASS_CACHE,
-	CACHE_READ_MODE_CACHE_FIRST,
-	CACHE_READ_MODE_MUST_REVALIDATE,
-	CACHE_READ_MODE_NO_STORE,
-	CACHE_READ_MODE_STALE_WHILE_REVALIDATE,
-	CACHE_SCOPE_ACTOR,
-	CACHE_SCOPE_CUSTOM,
-	CACHE_SCOPE_PERMISSION,
-	CACHE_SCOPE_PUBLIC,
-	CACHE_SCOPE_TENANT,
-	CacheKeyError,
-	CachePolicyError,
-	CacheScopeError,
-	createMapStorage,
-	defaultCachePolicies,
-	durationToMs,
-	isCacheKeyError,
-	isCachePolicyError,
-	isCacheScopeError,
-	memoryCacheAdapter,
-	normalizeKey,
-	normalizeKeyPrefixes,
-	normalizeTag,
-	normalizeTags,
-	resolveScope,
-	stableHash,
-	stableStringify,
-	storageCacheAdapter
-} from '$libs/cache';
-
-export type {
-	CacheAdapter,
-	CacheAdapterSetOptions,
-	CacheClock,
-	CacheDecision,
-	CacheDecisionAction,
-	CacheDecisionReason,
-	CacheEnvelope,
-	CacheEnvelopeState,
-	CacheEvent,
-	CacheEventHandler,
-	CacheEventSelector,
-	CacheEventType,
-	CacheExplain,
-	CacheKey,
-	CachePolicy,
-	CacheReadMode,
-	CacheRuntime,
-	CacheRuntimeConfig,
-	CacheScopeInput,
-	CacheScopeMode,
-	CacheStats,
-	CacheTagLike,
-	CacheTagObject,
-	CustomCacheScope,
-	ExplainOptions,
-	GetOptions,
-	InvalidateOptions,
-	MemoryCacheAdapter,
-	MemoryCacheAdapterOptions,
-	MemoryCacheEvictReason,
-	MutateOptions,
-	QueryOptions,
-	ResolvedCachePolicy,
-	ResolvedCacheScope,
-	ResolvedScopeValues,
-	ScopeResolver,
-	SetOptions,
-	StorageCacheAdapterOptions,
-	StorageLike
-} from '$libs/cache';
+/**
+ * Server-side surface for `cache`. After the codex audit blocker #8 fix,
+ * the engine factory + diagnostics + types live in `$libs/cache` (the
+ * pure layer) so `arts/cache` can consume them without inverting layers.
+ *
+ * This module re-exports the same names from `$libs/cache` so historical
+ * `import { ... } from '$svrs/cache'` callers keep working — production
+ * compositions, READMEs, docs and ecosystem tests all flow through here.
+ */
+export * from '$libs/cache';
diff --git a/src/web/routes/test/aapp/+page.svelte b/src/web/routes/test/aapp/+page.svelte
index 4ae7ea4..8c69eb4 100644
--- a/src/web/routes/test/aapp/+page.svelte
+++ b/src/web/routes/test/aapp/+page.svelte
@@ -1,7 +1,15 @@
 <script lang="ts">
 	import { onDestroy } from 'svelte';
 	import { createActiveApp } from '$active-app';
-	import { cookieAdapter, localAdapter } from '$storage';
+	import {
+		defineActiveCache,
+		defineActiveFormat,
+		defineActiveFrontend,
+		defineActiveLang,
+		defineActiveStorage,
+		defineEngineSium
+	} from '$active-app/services';
+	import { localAdapter } from '$storage';
 	import type { SupportedLocale } from '$lang';
 	import { siumLangs, type Issue } from '$sium';
 	import { LogLevel, type LogEntry, type Transport } from '$logger';
@@ -25,39 +33,36 @@
 	let appRoot = $state<HTMLElement | null>(null);
 
 	const App = createActiveApp({
-		lang: { schema: langSchema, defaultLocale: 'es', fallbackChain: ['en'] },
 		logger: {
 			level: LogLevel.TRACE,
 			globalContext: { surface: '/test/aapp' },
 			transports: [captureTransport]
 		},
-		storage: { adapter: localAdapter, namespace: 'test-aapp' },
-		cache: {
-			defaultMemoryAdapter: { suppressProductionWarning: true }
-		},
-		frontend: {
-			theme: 'base',
-			mode: 'auto',
-			density: 'normal',
-			target: () => appRoot,
-			persist: {
-				// Theme via cookie (server-readable for SSR demos), the rest in
-				// localStorage with the App's namespace.
-				overrides: {
-					theme: {
-						adapter: cookieAdapter({ path: '/', sameSite: 'lax', maxAge: 31_536_000 }),
-						namespace: false,
-						raw: true
-					}
-				}
-			}
+		services: {
+			lang: defineActiveLang({
+				schema: langSchema,
+				defaultLocale: 'es',
+				fallbackChain: ['en']
+			}),
+			storage: defineActiveStorage({ adapter: localAdapter, namespace: 'test-aapp' }),
+			format: defineActiveFormat(),
+			cache: defineActiveCache({
+				defaultMemoryAdapter: { suppressProductionWarning: true }
+			}),
+			frontend: defineActiveFrontend({
+				theme: 'base',
+				mode: 'auto',
+				density: 'comfortable',
+				target: () => appRoot
+			}),
+			sium: defineEngineSium()
 		}
 	});
 
-	// Sium is page-scoped — `App.createSiumEngine()` wires App.lang +
-	// App.Logger so issues translate live and validation diagnostics flow
-	// through the same bus.
-	const sium = App.createSiumEngine();
+	// Sium is now an App service — `App.sium` is the validation engine,
+	// wired to App.lang for i18n issue messages and to App.Logger for
+	// diagnostics through the same bus.
+	const sium = App.sium;
 
 	onDestroy(() => App.dispose());
 
@@ -76,7 +81,7 @@
 	];
 
 	function setLocale(locale: SupportedLocale): void {
-		App.setLocale(locale);
+		App.lang.setLocale(locale);
 		App.Logger.info('locale', `Locale switched to ${locale}`, {
 			context: { locale }
 		});
@@ -121,7 +126,7 @@
 		loginIssues.map((entry) => ({
 			path: entry.path.length === 0 ? '<root>' : entry.path.join('.'),
 			code: entry.code,
-			message: sium.resolveIssue(entry, App.getLocale())
+			message: sium.resolveIssue(entry, App.lang.getLocale())
 		}))
 	);
 
@@ -199,7 +204,7 @@
 	<section class="locale" dir="ltr">
 		<h2>1. Locale (single source of truth)</h2>
 		<p class="hint">
-			<code>App.setLocale(...)</code> propagates to <strong>Lang</strong>,
+			<code>App.lang.setLocale(...)</code> propagates to <strong>Lang</strong>,
 			<strong>Format</strong> and <strong>Frontend</strong> through a shared
 			<code>LocaleSource</code>. BCP 47 resolution runs per record on every
 			<code>Lang.t()</code> call.
@@ -208,7 +213,7 @@
 			{#each LOCALES as { code, label, flag } (code)}
 				<button
 					type="button"
-					class:active={App.getLocale() === code}
+					class:active={App.lang.getLocale() === code}
 					onclick={() => setLocale(code)}
 				>
 					<span aria-hidden="true">{flag}</span>
@@ -218,7 +223,7 @@
 			{/each}
 		</div>
 		<p class="active-line">
-			<strong>Active:</strong> <code>{App.getLocale()}</code>
+			<strong>Active:</strong> <code>{App.lang.getLocale()}</code>
 		</p>
 	</section>
 
diff --git a/src/web/routes/test/aapp/+page.ts b/src/web/routes/test/aapp/+page.ts
deleted file mode 100644
index d11d80a..0000000
--- a/src/web/routes/test/aapp/+page.ts
+++ /dev/null
@@ -1,8 +0,0 @@
-/**
- * Skip static prerender for the legacy aapp demo. The page still
- * relies on pre-service-schema App methods that the current runtime
- * no longer exposes; until it is migrated to
- * `createActiveApp({ services })`, render it on-demand only so the
- * static gate stays green and the page remains reachable in dev.
- */
-export const prerender = false;
diff --git a/src/web/routes/test/cach/+page.svelte b/src/web/routes/test/cach/+page.svelte
index db17e04..b980ee6 100644
--- a/src/web/routes/test/cach/+page.svelte
+++ b/src/web/routes/test/cach/+page.svelte
@@ -1,5 +1,6 @@
 <script lang="ts">
 	import { createActiveApp } from '$active-app';
+	import { defineActiveCache } from '$active-app/services';
 	import {
 		CACHE_EVENT_ALL,
 		CACHE_POLICY_INTERACTIVE,
@@ -54,32 +55,34 @@
 	let logSeq = 0;
 
 	const App = createActiveApp({
-		cache: {
-			defaultMemoryAdapter: { suppressProductionWarning: true },
-			scopeResolver: (): ResolvedScopeValues => ({
-				tenantId,
-				actorId,
-				permissionHash,
-				locale
-			}),
-			policies: {
-				[CACHE_POLICY_INTERACTIVE]: {
-					freshFor: 2_000,
-					staleFor: 30_000,
-					staleIfErrorFor: 60_000,
-					gcAfter: 120_000,
-					mode: CACHE_READ_MODE_STALE_WHILE_REVALIDATE,
-					persist: true
-				},
-				[CACHE_POLICY_PRIVATE_SESSION]: {
-					freshFor: 1_000,
-					staleFor: 3_000,
-					staleIfErrorFor: 0,
-					gcAfter: 15_000,
-					mode: CACHE_READ_MODE_STALE_WHILE_REVALIDATE,
-					persist: false
+		services: {
+			cache: defineActiveCache({
+				defaultMemoryAdapter: { suppressProductionWarning: true },
+				scopeResolver: (): ResolvedScopeValues => ({
+					tenantId,
+					actorId,
+					permissionHash,
+					locale
+				}),
+				policies: {
+					[CACHE_POLICY_INTERACTIVE]: {
+						freshFor: 2_000,
+						staleFor: 30_000,
+						staleIfErrorFor: 60_000,
+						gcAfter: 120_000,
+						mode: CACHE_READ_MODE_STALE_WHILE_REVALIDATE,
+						persist: true
+					},
+					[CACHE_POLICY_PRIVATE_SESSION]: {
+						freshFor: 1_000,
+						staleFor: 3_000,
+						staleIfErrorFor: 0,
+						gcAfter: 15_000,
+						mode: CACHE_READ_MODE_STALE_WHILE_REVALIDATE,
+						persist: false
+					}
 				}
-			}
+			})
 		}
 	});
 
diff --git a/src/web/routes/test/cach/+page.ts b/src/web/routes/test/cach/+page.ts
deleted file mode 100644
index cd89b14..0000000
--- a/src/web/routes/test/cach/+page.ts
+++ /dev/null
@@ -1,2 +0,0 @@
-/** Skip static prerender — uses pre-service-schema App API. See /test/aapp. */
-export const prerender = false;
diff --git a/src/web/routes/test/conn/+page.svelte b/src/web/routes/test/conn/+page.svelte
index e395c72..40a0bbc 100644
--- a/src/web/routes/test/conn/+page.svelte
+++ b/src/web/routes/test/conn/+page.svelte
@@ -2,6 +2,11 @@
 	import { onDestroy } from 'svelte';
 	import { resolve } from '$app/paths';
 	import { createActiveApp } from '$active-app';
+	import {
+		defineActiveCache,
+		defineActiveConnections,
+		defineActiveSession
+	} from '$active-app/services';
 	import { LogLevel } from '$logger';
 	import {
 		CONNECTION_BUFFER_POLICY_BUFFER,
@@ -88,24 +93,44 @@
 		at: string;
 	};
 
+	// Declared up here so the session factory's `onRefresh` closure can
+	// capture them. They are mutated by UI actions later in the file.
+	let refreshMode: 'success' | 'expired' = 'success';
+	let tokenSerial = 1;
+
 	const App = createActiveApp({
 		logger: { level: LogLevel.NONE, transports: [] },
-		cache: {
-			defaultMemoryAdapter: { suppressProductionWarning: true }
-		},
-		connections: {
-			defaults: {
-				heartbeat: false,
-				buffer: {
-					policy: CONNECTION_BUFFER_POLICY_BUFFER,
-					maxMessages: 12
-				},
-				reconnect: {
-					minDelayMs: 650,
-					maxDelayMs: 650,
-					jitterMs: 0
+		services: {
+			cache: defineActiveCache({
+				defaultMemoryAdapter: { suppressProductionWarning: true }
+			}),
+			session: defineActiveSession<ChatUser, ChatCredential>({
+				schemas: {},
+				onRefresh: async (current) => {
+					if (refreshMode === 'expired') return null;
+					tokenSerial += 1;
+					return {
+						...current,
+						credential: { token: `chat-token-${tokenSerial}` },
+						issuedAt: Date.now(),
+						expiresAt: Date.now() + 120_000
+					};
 				}
-			}
+			}),
+			connections: defineActiveConnections({
+				defaults: {
+					heartbeat: false,
+					buffer: {
+						policy: CONNECTION_BUFFER_POLICY_BUFFER,
+						maxMessages: 12
+					},
+					reconnect: {
+						minDelayMs: 650,
+						maxDelayMs: 650,
+						jitterMs: 0
+					}
+				}
+			})
 		}
 	});
 
@@ -114,8 +139,6 @@
 	let draft = $state('Hola, esto va por WebSocket real');
 	let pendingQuestion = $state(false);
 	let serverTyping = $state(false);
-	let refreshMode: 'success' | 'expired' = 'success';
-	let tokenSerial = 1;
 	let messages = $state<ChatMessage[]>([]);
 	let states = $state<ConnectionStateChange[]>([]);
 	let frames = $state<FrameLog[]>([]);
@@ -166,21 +189,9 @@
 		}
 	};
 
-	const Sess = App.createActiveSession<ChatUser, ChatCredential>({
-		schemas: {},
-		onRefresh: async (current) => {
-			if (refreshMode === 'expired') return null;
-			tokenSerial += 1;
-			return {
-				...current,
-				credential: { token: `chat-token-${tokenSerial}` },
-				issuedAt: Date.now(),
-				expiresAt: Date.now() + 120_000
-			};
-		}
-	});
+	const Sess = App.session;
 
-	const Connections = App.createActiveConnections<AppConnections>();
+	const Connections = App.connections;
 	const Chat = Connections.createConnection(CONNECTION_NAME, {
 		transport: () =>
 			createWebSocketTransport({
diff --git a/src/web/routes/test/conn/+page.ts b/src/web/routes/test/conn/+page.ts
deleted file mode 100644
index cd89b14..0000000
--- a/src/web/routes/test/conn/+page.ts
+++ /dev/null
@@ -1,2 +0,0 @@
-/** Skip static prerender — uses pre-service-schema App API. See /test/aapp. */
-export const prerender = false;
diff --git a/src/web/routes/test/ecosystem/+page.svelte b/src/web/routes/test/ecosystem/+page.svelte
index 8108620..2b18d13 100644
--- a/src/web/routes/test/ecosystem/+page.svelte
+++ b/src/web/routes/test/ecosystem/+page.svelte
@@ -2,6 +2,18 @@
 	import { onDestroy, untrack } from 'svelte';
 	import { resolve } from '$app/paths';
 	import { createActiveApp } from '$active-app';
+	import {
+		defineActiveAuth,
+		defineActiveCache,
+		defineActiveConnections,
+		defineActiveFrontend,
+		defineActiveLang,
+		defineActivePerm,
+		defineActiveSession,
+		defineActiveStorage,
+		defineEngineHttp,
+		defineEngineSium
+	} from '$active-app/services';
 	import {
 		CACHE_EVENT_ALL,
 		CACHE_POLICY_INTERACTIVE,
@@ -347,60 +359,80 @@
 		return jsonResponse({ error: 'not-found', path }, 404);
 	}) as typeof fetch;
 
+	// `currentLocale` mirrors `App.lang.getLocale()` so the cache scope
+	// resolver can read it without referencing the App handle (which
+	// doesn't exist yet at the moment the resolver is captured).
+	let currentLocale: SupportedLocale = DEFAULT_ECOSYSTEM_LOCALE;
+
 	const App = createActiveApp({
-		lang: {
-			schema: translations,
-			defaultLocale: DEFAULT_ECOSYSTEM_LOCALE,
-			fallbackChain: ['en-US']
-		},
 		logger: {
 			level: LogLevel.TRACE,
 			globalContext: { surface: DEMO_PATH },
 			transports: [captureTransport]
 		},
-		storage: {
-			adapter: createMemoryAdapter(),
-			namespace: 'test-ecosystem'
-		},
-		frontend: {
-			target: () => appRoot,
-			theme: 'base',
-			mode: 'auto',
-			density: 'comfortable'
-		},
-		http: {
-			fetch: demoFetch,
-			timeout: 0,
-			retry: { limit: 0 }
-		},
-		cache: {
-			defaultMemoryAdapter: { suppressProductionWarning: true },
-			scopeResolver: (): ResolvedScopeValues => ({
-				tenantId: data.sessionSeed.tenantId,
-				actorId: data.sessionSeed.actorId,
-				permissionHash: `${actorRole}:${mfaEnabled ? AUTH_AAL.MULTI_FACTOR : AUTH_AAL.SINGLE_FACTOR}`,
-				locale: App.getLocale()
+		services: {
+			lang: defineActiveLang({
+				schema: translations,
+				defaultLocale: DEFAULT_ECOSYSTEM_LOCALE,
+				fallbackChain: ['en-US']
 			}),
-			policies: {
-				[CACHE_POLICY_INTERACTIVE]: {
-					freshFor: 1_500,
-					staleFor: 20_000,
-					staleIfErrorFor: 60_000,
-					gcAfter: 90_000,
-					mode: CACHE_READ_MODE_STALE_WHILE_REVALIDATE,
-					persist: true
+			storage: defineActiveStorage({
+				adapter: createMemoryAdapter(),
+				namespace: 'test-ecosystem'
+			}),
+			frontend: defineActiveFrontend({
+				target: () => appRoot,
+				theme: 'base',
+				mode: 'auto',
+				density: 'comfortable'
+			}),
+			http: defineEngineHttp({
+				fetch: demoFetch,
+				timeout: 0,
+				retry: { limit: 0 }
+			}),
+			cache: defineActiveCache({
+				defaultMemoryAdapter: { suppressProductionWarning: true },
+				scopeResolver: (): ResolvedScopeValues => ({
+					tenantId: data.sessionSeed.tenantId,
+					actorId: data.sessionSeed.actorId,
+					permissionHash: `${actorRole}:${mfaEnabled ? AUTH_AAL.MULTI_FACTOR : AUTH_AAL.SINGLE_FACTOR}`,
+					locale: currentLocale
+				}),
+				policies: {
+					[CACHE_POLICY_INTERACTIVE]: {
+						freshFor: 1_500,
+						staleFor: 20_000,
+						staleIfErrorFor: 60_000,
+						gcAfter: 90_000,
+						mode: CACHE_READ_MODE_STALE_WHILE_REVALIDATE,
+						persist: true
+					}
 				}
-			}
-		},
-		connections: {
-			defaults: {
-				heartbeat: false,
-				reconnect: false
-			}
+			}),
+			connections: defineActiveConnections({
+				defaults: {
+					heartbeat: false,
+					reconnect: false
+				}
+			}),
+			sium: defineEngineSium(),
+			auth: defineActiveAuth({ initial: initialData.authCurrent }),
+			session: defineActiveSession<DemoUser, undefined, DemoSessionData>({
+				storage: {
+					adapter: createMemoryAdapter(),
+					key: SESSION_STORAGE_KEY
+				}
+			}),
+			perm: defineActivePerm({
+				endpoint: PERM_ENDPOINT,
+				cacheTtlMs: 8_000,
+				scopeKey: () => `${data.sessionSeed.actorId}:${actorRole}:${mfaEnabled}`
+			})
 		}
 	});
 
-	const Sium = App.createSiumEngine();
+	const Sium = App.sium;
 	const projectDraftSchema = Sium.object({
 		title: Sium.pipe(Sium.string(), Sium.min(4), Sium.meta({ label: 'Title' })),
 		budget: Sium.pipe(Sium.number(), Sium.min(1000), Sium.meta({ label: 'Budget' }))
@@ -422,13 +454,8 @@
 		{ mergeDefaults: true }
 	);
 
-	const Auth = App.createActiveAuth({ initial: initialData.authCurrent });
-	const Sess = App.createActiveSession<DemoUser, undefined, DemoSessionData>({
-		storage: {
-			adapter: createMemoryAdapter(),
-			key: SESSION_STORAGE_KEY
-		}
-	});
+	const Auth = App.auth;
+	const Sess = App.session;
 	Sess.adoptServer({
 		user: {
 			id: initialData.sessionSeed.actorId,
@@ -444,13 +471,7 @@
 		expiresAt: initialData.sessionSeed.expiresAt
 	});
 
-	const Perms = setPermsContext(
-		App.createActivePerms({
-			endpoint: PERM_ENDPOINT,
-			cacheTtlMs: 8_000,
-			scopeKey: () => `${data.sessionSeed.actorId}:${actorRole}:${mfaEnabled}`
-		})
-	);
+	const Perms = setPermsContext(App.perm);
 
 	const transport = createMockTransport();
 	const loggingSerializer: ConnectionSerializer<ConnectionFrame> = {
@@ -501,7 +522,7 @@
 			key: `${issue.path.join('.')}:${issue.code}`,
 			path: issue.path.length === 0 ? '<root>' : issue.path.join('.'),
 			code: issue.code,
-			message: Sium.resolveIssue(issue, App.getLocale())
+			message: Sium.resolveIssue(issue, App.lang.getLocale())
 		}))
 	);
 
@@ -509,7 +530,7 @@
 		void App.lang.getLocale();
 		void App.frontend.getTheme();
 		return {
-			locale: App.getLocale(),
+			locale: App.lang.getLocale(),
 			dir: App.frontend.getDir(),
 			theme: App.frontend.getTheme(),
 			mode: App.frontend.getMode(),
@@ -552,7 +573,8 @@
 
 	function setLocale(locale: SupportedLocale): void {
 		selectedLocale = locale;
-		App.setLocale(locale);
+		currentLocale = locale;
+		App.lang.setLocale(locale);
 		pushEvent('lang', `locale -> ${locale}`);
 	}
 
diff --git a/src/web/routes/test/http/+page.svelte b/src/web/routes/test/http/+page.svelte
index d780b9e..c4e4222 100644
--- a/src/web/routes/test/http/+page.svelte
+++ b/src/web/routes/test/http/+page.svelte
@@ -369,7 +369,7 @@
 				<aside class="resolved">
 					<h3>Resolved issue messages</h3>
 					<p class="hint">
-						<code>App.createSiumEngine().resolveIssues(r.issues)</code> — the
+						<code>App.sium.resolveIssues(r.issues)</code> — the
 						raw <code>#?sium.errors.type|...</code> refs above become readable
 						text via Sium's lang resolver (here lang-less, so the
 						<code>|fallback</code> text is interpolated with each issue's
diff --git a/src/web/routes/test/http/+page.ts b/src/web/routes/test/http/+page.ts
deleted file mode 100644
index adcb8bd..0000000
--- a/src/web/routes/test/http/+page.ts
+++ /dev/null
@@ -1,6 +0,0 @@
-/**
- * Skip static prerender for the legacy http demo. The page still
- * relies on pre-service-schema App methods that the current runtime
- * no longer exposes; render it on-demand only.
- */
-export const prerender = false;
diff --git a/src/web/routes/test/perm/+page.svelte b/src/web/routes/test/perm/+page.svelte
index a1a8255..375e00f 100644
--- a/src/web/routes/test/perm/+page.svelte
+++ b/src/web/routes/test/perm/+page.svelte
@@ -2,6 +2,11 @@
 	import { onDestroy, untrack } from 'svelte';
 	import { resolve } from '$app/paths';
 	import { createActiveApp } from '$active-app';
+	import {
+		defineActiveCache,
+		defineActivePerm,
+		defineEngineHttp
+	} from '$active-app/services';
 	import { LogLevel } from '$logger';
 	import Can from '$perm/Can.svelte';
 	import {
@@ -267,21 +272,23 @@
 
 	const App = createActiveApp({
 		logger: { level: LogLevel.NONE, transports: [] },
-		http: {
-			fetch: permFetch,
-			timeout: 0,
-			retry: { limit: 0 }
-		},
-		cache: {
-			defaultMemoryAdapter: { suppressProductionWarning: true }
-		},
-		permissions: {
-			endpoint: PERM_ENDPOINT,
-			cacheTtlMs: 10_000
+		services: {
+			http: defineEngineHttp({
+				fetch: permFetch,
+				timeout: 0,
+				retry: { limit: 0 }
+			}),
+			cache: defineActiveCache({
+				defaultMemoryAdapter: { suppressProductionWarning: true }
+			}),
+			perm: defineActivePerm({
+				endpoint: PERM_ENDPOINT,
+				cacheTtlMs: 10_000
+			})
 		}
 	});
 
-	const Perms = setPermsContext(App.createActivePerms());
+	const Perms = setPermsContext(App.perm);
 
 	function effectClass(decision: PermDecision | null | undefined): string {
 		if (!decision) return 'none';
diff --git a/src/web/routes/test/perm/+page.ts b/src/web/routes/test/perm/+page.ts
deleted file mode 100644
index cd89b14..0000000
--- a/src/web/routes/test/perm/+page.ts
+++ /dev/null
@@ -1,2 +0,0 @@
-/** Skip static prerender — uses pre-service-schema App API. See /test/aapp. */
-export const prerender = false;
diff --git a/tsconfig.json b/tsconfig.json
index 1e17ffe..9df3e9f 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -25,12 +25,7 @@
 		// `+page.ts`; excluding them here keeps `npm run check` green until they
 		// are migrated. The codex follow-up (audit-2 §3) tracks the migration.
 		"./src/web/routes/demo/**",
-		"./src/web/routes/test/aapp/**",
-		"./src/web/routes/test/cach/**",
-		"./src/web/routes/test/conn/**",
 		"./src/web/routes/test/ecosystem/**",
-		"./src/web/routes/test/http/**",
-		"./src/web/routes/test/perm/**",
 		"./src/web/routes/test/auth/**/*",
 		"./src/web/routes/test/auth/+page.server.ts",
 		"./src/web/routes/active/_data/artifact-docs.ts",