diff --git a/NEXT_STEPS.md b/NEXT_STEPS.md
index 4913f2d..c92f3ee 100644
--- a/NEXT_STEPS.md
+++ b/NEXT_STEPS.md
@@ -30,6 +30,7 @@ Estado al cierre:
   - `arts/conn/connection.ts` delega apertura/cierre logico e `isConnected` en `connection-lifecycle.ts`.
   - `arts/conn/connection.ts` delega la programacion de reconnect y exhaustion en `connection-reconnect-runtime.ts`.
   - `libs/perm/evaluator.ts` delega helpers puros de resultado, dependencias y comparacion en `evaluator-helpers.ts`.
+  - `arts/http/engine-http.ts` delega la validacion preflight de `bodySchema` en `request-validation.ts`.
   - `arts/conn/connection.ts` delega decode/routing de frames entrantes en `connection-message-router.ts`.
   - `arts/conn/connection.ts` delega el intento open/auth/flush/join en `connection-connect.ts`.
   - `arts/conn/connection.ts` delega current transport, attach/detach y close en `connection-transport-runtime.ts`.
diff --git a/src/arts/http/engine-http.ts b/src/arts/http/engine-http.ts
index e37885d..bb99f58 100644
--- a/src/arts/http/engine-http.ts
+++ b/src/arts/http/engine-http.ts
@@ -13,7 +13,6 @@ import {
 	HTTP_RESULT_KIND_NETWORK,
 	HTTP_RESULT_KIND_VALIDATION,
 	httpStatusErrorMessage,
-	requestBodyValidationErrorMessage,
 	HTTP_DIAGNOSTIC_EVENTS
 } from './consts.ts';
 import { emitHttpDiagnostic } from './diagnostics.ts';
@@ -24,7 +23,6 @@ import {
 	resolveHttpCallRetry,
 	type ResolvedHttpDefaults
 } from './engine-options.ts';
-import { HttpBodyValidationError } from './errors.ts';
 import {
 	runAfterResponse,
 	runBeforeError,
@@ -32,7 +30,8 @@ import {
 	runBeforeRetry
 } from './hooks.ts';
 import { computeRetryDelay, delayWithSignal, shouldRetryRequest } from './retry.ts';
-import { buildHttpFailure, buildOkOrValidation, runStandardValidate } from './results.ts';
+import { buildHttpFailure, buildOkOrValidation } from './results.ts';
+import { validateHttpRequestBody } from './request-validation.ts';
 import { appendSearch, normalizeSearch, resolveUrl } from './search.ts';
 import {
 	attemptTimeoutSignal,
@@ -115,25 +114,7 @@ async function execute<S extends StandardSchemaV1 | undefined>(
 			? (init as HttpBodyRequestInit<S, StandardSchemaV1 | undefined>).bodySchema
 			: undefined;
 
-	if (bodyInput !== undefined && bodySchema !== undefined) {
-		const validated = await runStandardValidate(bodySchema, bodyInput);
-		if (validated.issues !== undefined) {
-			const error = new HttpBodyValidationError(
-				requestBodyValidationErrorMessage(method, url),
-				validated.issues
-			);
-			// Programmer error: log it before throwing so the failure is visible
-			// in the logger pipeline even when the caller's catch swallows the
-			// throw.
-			emitHttpDiagnostic(diagnostics, HTTP_DIAGNOSTIC_EVENTS.BODY_SCHEMA_REJECTED, {
-				method,
-				url,
-				issueCount: validated.issues.length,
-				error
-			});
-			throw error;
-		}
-	}
+	await validateHttpRequestBody({ diagnostics, method, url, body: bodyInput, schema: bodySchema });
 
 	// URL resolution + search params.
 	const fullUrl = appendSearch(resolveUrl(url, defaults.baseUrl), normalizeSearch(init?.search));
diff --git a/src/arts/http/request-validation.ts b/src/arts/http/request-validation.ts
new file mode 100644
index 0000000..c4bdec0
--- /dev/null
+++ b/src/arts/http/request-validation.ts
@@ -0,0 +1,40 @@
+import type { StandardSchemaV1 } from '$libs/standard-schema';
+import {
+	HTTP_DIAGNOSTIC_EVENTS,
+	requestBodyValidationErrorMessage
+} from './consts.ts';
+import { emitHttpDiagnostic, type HttpDiagnostics } from './diagnostics.ts';
+import { HttpBodyValidationError } from './errors.ts';
+import { runStandardValidate } from './results.ts';
+import type { HttpMethod } from './types.ts';
+
+interface ValidateHttpRequestBodyInput {
+	readonly diagnostics: HttpDiagnostics;
+	readonly method: HttpMethod;
+	readonly url: string;
+	readonly body: unknown;
+	readonly schema: StandardSchemaV1 | undefined;
+}
+
+export async function validateHttpRequestBody(
+	input: ValidateHttpRequestBodyInput
+): Promise<void> {
+	if (input.body === undefined || input.schema === undefined) return;
+
+	const validated = await runStandardValidate(input.schema, input.body);
+	if (validated.issues === undefined) return;
+
+	const error = new HttpBodyValidationError(
+		requestBodyValidationErrorMessage(input.method, input.url),
+		validated.issues
+	);
+	// Programmer error: log it before throwing so the failure is visible in
+	// the logger pipeline even when the caller's catch swallows the throw.
+	emitHttpDiagnostic(input.diagnostics, HTTP_DIAGNOSTIC_EVENTS.BODY_SCHEMA_REJECTED, {
+		method: input.method,
+		url: input.url,
+		issueCount: validated.issues.length,
+		error
+	});
+	throw error;
+}