diff --git a/continue.md b/continue.md
index 731e89fa9..02c453b6d 100644
--- a/continue.md
+++ b/continue.md
@@ -18,9 +18,16 @@ Actualizacion Eidos ecosystem 2026-05-16:
 - Guardia anadida: el contrato CSS de Eidos debe estar alineado con los
   renderers generados; cada token `static` debe aparecer en `renderStaticCss()`
   y cada token `theme` en `renderThemeCss('base-light')`.
+- Overrides runtime reforzados: `ActiveEidos` valida y clona `cssVariables`
+  iniciales aunque `applyDom:false`, y `setCssVariables(...)` es
+  transaccional. Un mapa invalido no reemplaza el bloque de variables vigente.
+- Validacion de config reforzada: documentos persistidos con `options`
+  malformadas fallan como `EidosConfigValidationError` con issues de contrato,
+  no como `TypeError` de runtime.
 - Validado:
-  - `npx vitest run src/uix/eidos/active-eidos-config.test.ts` -> 26 tests OK.
-  - `npx vitest run src/uix/eidos` -> 7 archivos, 65 tests OK.
+  - `npx vitest run src/uix/eidos/active-eidos-config.test.ts` -> 27 tests OK.
+  - `npx vitest run src/uix/eidos/active-eidos.test.ts` -> 19 tests OK.
+  - `npx vitest run src/uix/eidos` -> 7 archivos, 67 tests OK.
   - `npm run check` -> 0 errores, 0 warnings.
 
 Actualizacion permutation runner 2026-05-16:
diff --git a/src/uix/eidos/README.md b/src/uix/eidos/README.md
index dc21f931d..91b1931b9 100644
--- a/src/uix/eidos/README.md
+++ b/src/uix/eidos/README.md
@@ -437,7 +437,9 @@ activeEidos.setCssVariables({
 `ActiveEidos` lo escribe en `${styleId}-variables` como un `<style>`
 gestionado. Por defecto valida los nombres contra `getCssContract()`; si una
 app necesita variables locales fuera del contrato puede usar
-`{ strict: false }`.
+`{ strict: false }`. La actualizacion es transaccional: primero renderiza y
+valida el siguiente bloque, y solo reemplaza el estado runtime si el mapa es
+usable. Un token desconocido no deja el style block anterior a medias.
 
 No crear `ActiveEidos` desactiva la capa visual runtime de Eidos. Los
 componentes Soma siguen funcionando headless porque el comportamiento pertenece
diff --git a/src/uix/eidos/active-eidos-config.test.ts b/src/uix/eidos/active-eidos-config.test.ts
index eba54c7bf..3c2df0349 100644
--- a/src/uix/eidos/active-eidos-config.test.ts
+++ b/src/uix/eidos/active-eidos-config.test.ts
@@ -316,6 +316,28 @@ describe('ActiveEidos config', () => {
 		)
 	})
 
+	it('reports malformed persisted config options as validation issues', () => {
+		const malformed = {
+			kind: EIDOS_CONFIG_DOCUMENT_KIND,
+			version: EIDOS_CONFIG_DOCUMENT_VERSION,
+			options: {}
+		}
+
+		try {
+			createEidosFromDocument(malformed)
+			throw new Error('expected malformed config to fail')
+		} catch (error) {
+			expect(error).toBeInstanceOf(EidosConfigValidationError)
+			expect((error as EidosConfigValidationError).issues.map((issue) => issue.path)).toEqual(
+				expect.arrayContaining(['primitives', 'semantics.color.roles'])
+			)
+		}
+
+		expect(() => parseEidosConfigFromJson(JSON.stringify(malformed))).toThrow(
+			EidosConfigValidationError
+		)
+	})
+
 	it('ships typography families separately from typography styles', () => {
 		const typography = createThemeBaseEidos().snapshot().primitives.typography!
 
diff --git a/src/uix/eidos/active-eidos.svelte.ts b/src/uix/eidos/active-eidos.svelte.ts
index d909892ae..ad16ad651 100644
--- a/src/uix/eidos/active-eidos.svelte.ts
+++ b/src/uix/eidos/active-eidos.svelte.ts
@@ -165,7 +165,7 @@ export class ActiveEidos {
 		this.#themeSource = options.themeSource ?? 'auto';
 		this.#themeResolver = options.themeResolver ?? defaultActiveEidosThemeResolver;
 		this.#applyDom = options.applyDom !== false;
-		this.#cssVariables = options.cssVariables;
+		this.#cssVariables = options.cssVariables ? { ...options.cssVariables } : undefined;
 		this.#cssVariablesOptions = {
 			selector: options.cssVariablesSelector,
 			strict: options.cssVariablesStrict
@@ -175,6 +175,8 @@ export class ActiveEidos {
 			throw new ActiveEidosConfigError('dom service is required when applyDom is enabled');
 		}
 
+		if (this.#cssVariables) this.renderCssVariables(this.#cssVariables, this.#cssVariablesOptions);
+
 		if (this.#applyDom) {
 			this.apply();
 			this.#unsubscribe = this.#preferences.onPreferenceChange(() => this.apply());
@@ -340,11 +342,14 @@ export class ActiveEidos {
 		variables: EidosCssVariableMap,
 		renderOptions: ActiveEidosCssVariablesOptions = {}
 	): void {
-		this.#cssVariables = { ...variables };
-		this.#cssVariablesOptions = {
+		const nextVariables = { ...variables };
+		const nextOptions = {
 			...this.#cssVariablesOptions,
 			...renderOptions
 		};
+		this.renderCssVariables(nextVariables, nextOptions);
+		this.#cssVariables = nextVariables;
+		this.#cssVariablesOptions = nextOptions;
 		this.apply();
 	}
 
diff --git a/src/uix/eidos/active-eidos.test.ts b/src/uix/eidos/active-eidos.test.ts
index fdfe96289..a6fa7dd69 100644
--- a/src/uix/eidos/active-eidos.test.ts
+++ b/src/uix/eidos/active-eidos.test.ts
@@ -10,6 +10,7 @@ import {
 	createActiveEidos,
 	type ActiveEidosPreferenceSource
 } from './active-eidos.svelte';
+import { EidosCssVariableError } from './errors';
 
 function preferencesHarness(
 	initial: {
@@ -227,6 +228,14 @@ describe('ActiveEidos', () => {
 			'--size-md-control-height: 42px;'
 		);
 
+		const previousVariablesCss = document.getElementById('uix-eidos-variables')?.textContent;
+		expect(() => eidos.setCssVariables({ '--unknown-token': '1px' })).toThrow(
+			EidosCssVariableError
+		);
+		expect(document.getElementById('uix-eidos-variables')?.textContent).toBe(
+			previousVariablesCss
+		);
+
 		eidos.clearCssVariables();
 
 		expect(document.getElementById('uix-eidos-variables')).toBeNull();
@@ -262,6 +271,20 @@ describe('ActiveEidos', () => {
 		eidos.dispose();
 	});
 
+	it('validates initial runtime CSS variables even without DOM application', () => {
+		const { preferences } = preferencesHarness();
+
+		expect(() =>
+			createActiveEidos({
+				preferences,
+				applyDom: false,
+				cssVariables: {
+					'--unknown-token': '1px'
+				}
+			})
+		).toThrow(EidosCssVariableError);
+	});
+
 	it('requires an injected DOM service when applyDom is enabled', () => {
 		const { preferences } = preferencesHarness();
 
diff --git a/src/uix/eidos/lib/config.ts b/src/uix/eidos/lib/config.ts
index e566ce65d..8e7286d45 100644
--- a/src/uix/eidos/lib/config.ts
+++ b/src/uix/eidos/lib/config.ts
@@ -81,6 +81,13 @@ export function serializeEidosConfig(options: EidosConfig): string {
 export function validateEidosConfig(options: EidosConfig): EidosValidationReport {
 	const issues: EidosValidationIssue[] = []
 
+	if (!validateEidosConfigShape(options, issues)) {
+		return {
+			ok: false,
+			issues
+		}
+	}
+
 	validateColorScales(options, issues)
 	validateColorRoles(options, issues)
 	validateTypography(options, issues)
@@ -117,6 +124,61 @@ export function assertValidEidosConfig(options: EidosConfig): void {
 	throw new EidosConfigValidationError(report.issues)
 }
 
+function validateEidosConfigShape(
+	options: EidosConfig,
+	issues: EidosValidationIssue[]
+): options is EidosConfig {
+	const input = options as unknown
+
+	if (!isPlainRecord(input)) {
+		issues.push({
+			path: '',
+			message: 'Eidos config must be a plain object'
+		})
+		return false
+	}
+
+	let ok = true
+
+	if (!isPlainRecord(input.primitives)) {
+		issues.push({
+			path: 'primitives',
+			message: 'Eidos config must define a primitives object'
+		})
+		ok = false
+	}
+
+	const semantics = input.semantics
+	const color = isPlainRecord(semantics) ? semantics.color : undefined
+	const roles = isPlainRecord(color) ? color.roles : undefined
+
+	if (!isPlainRecord(roles)) {
+		issues.push({
+			path: 'semantics.color.roles',
+			message: 'Eidos config must define semantic color roles'
+		})
+		ok = false
+	}
+
+	if (input.themes !== undefined && !isPlainRecord(input.themes)) {
+		issues.push({
+			path: 'themes',
+			message: 'Eidos config themes must be a plain object'
+		})
+		ok = false
+	}
+
+	if (input.recipes !== undefined && !isPlainRecord(input.recipes)) {
+		issues.push({
+			path: 'recipes',
+			message: 'Eidos config recipes must be a plain object'
+		})
+		ok = false
+	}
+
+	return ok
+}
+
 export function listEidosColorScales(options: EidosConfig): readonly string[] {
 	return Object.keys(options.primitives.color?.scales ?? {})
 }