diff --git a/NEXT_STEPS.md b/NEXT_STEPS.md
index de6f76b..b77bfd0 100644
--- a/NEXT_STEPS.md
+++ b/NEXT_STEPS.md
@@ -25,6 +25,7 @@ Estado al cierre:
   - `arts/conn/connection.ts` delega current transport, attach/detach y close en `connection-transport-runtime.ts`.
   - `arts/timr/engine-timers.ts` delega fan-out de listeners y diagnostico de listeners en `timer-events.ts`.
   - `arts/timr/engine-timers.ts` delega la construccion de entradas internas en `timer-entry.ts`.
+  - `arts/timr/engine-timers.ts` delega cancelacion y seleccion por scope en `timer-cancel.ts`.
 - Integracion total ampliada: `Auth.signOut()` valida anonimizacion, invalidacion de `Permissions` y evento `Cache.invalidate`.
 - Tanda focalizada verde: `npx vitest run src/arts/conn src/libs/cach src/arts/cach src/svrs/cach src/arts/auth src/svrs/auth src/libs/auth src/arts/aapp/test/ecosystem.integration.test.ts` -> 19 archivos, 82 tests.
 - `/test/ecosystem` revisado en navegador: carga sin errores de consola, `ar` cambia a `rtl`, Formats se actualiza por locale, Perm cambia con rol `viewer`, Cach re-scopea por locale y Conn loopback publica/recibe.
diff --git a/src/arts/timr/engine-timers.ts b/src/arts/timr/engine-timers.ts
index 696fd23..5fae6fa 100644
--- a/src/arts/timr/engine-timers.ts
+++ b/src/arts/timr/engine-timers.ts
@@ -30,7 +30,6 @@ import {
 	ENGINE_METHOD_SCHEDULE,
 	ENGINE_METHOD_SCHEDULE_AT,
 	TIMER_DIAGNOSTIC_EVENTS,
-	TIMER_EVENT_CANCELLED,
 	TIMER_EVENT_COMPLETED,
 	TIMER_EVENT_DISPOSED,
 	TIMER_EVENT_FAILED,
@@ -46,9 +45,9 @@ import {
 } from './consts.ts';
 import { createTimerDiagnostics, emitTimerDiagnostic } from './diagnostics.ts';
 import { TimrDuplicateKeyError } from './errors.ts';
+import { cancelTimerEntry, collectTimerKeysInScope } from './timer-cancel.ts';
 import {
 	createInternalTimerEntry,
-	isTimerKeyInScope,
 	timerEntrySnapshot,
 	type InternalTimerEntry
 } from './timer-entry.ts';
@@ -238,15 +237,7 @@ export function createEngineTimers(options: EngineTimersOptions = {}): EngineTim
 	// ── Cancellation ────────────────────────────────────────────────────────
 
 	function cancelEntry(entry: InternalTimerEntry): void {
-		entry.version += 1;
-		entry.status = TIMER_STATUS_CANCELLED;
-		if (entry.native !== null) {
-			clock.clearTimeout(entry.native);
-			entry.native = null;
-		}
-		entry.controller.abort();
-		entries.delete(entry.key);
-		emit({ type: TIMER_EVENT_CANCELLED, entry: timerEntrySnapshot(entry) });
+		cancelTimerEntry({ entry, entries, clock, emit });
 	}
 
 	// ── Public scheduling ───────────────────────────────────────────────────
@@ -369,11 +360,7 @@ export function createEngineTimers(options: EngineTimersOptions = {}): EngineTim
 		cancelAll(scope) {
 			ensureLive(ENGINE_METHOD_CANCEL_ALL);
 			let count = 0;
-			// Snapshot keys to avoid mutating during iteration.
-			const keys: string[] = [];
-			for (const k of entries.keys()) {
-				if (scope === undefined || isTimerKeyInScope(k, scope)) keys.push(k);
-			}
+			const keys = collectTimerKeysInScope(entries, scope);
 			for (const k of keys) {
 				const entry = entries.get(k);
 				if (entry === undefined) continue;
diff --git a/src/arts/timr/timer-cancel.ts b/src/arts/timr/timer-cancel.ts
new file mode 100644
index 0000000..a2dd423
--- /dev/null
+++ b/src/arts/timr/timer-cancel.ts
@@ -0,0 +1,38 @@
+import { TIMER_EVENT_CANCELLED, TIMER_STATUS_CANCELLED } from './consts.ts';
+import {
+	isTimerKeyInScope,
+	timerEntrySnapshot,
+	type InternalTimerEntry
+} from './timer-entry.ts';
+import type { TimerClock, TimerEvent } from './types.ts';
+
+export interface CancelTimerEntryInput {
+	readonly entry: InternalTimerEntry;
+	readonly entries: Map<string, InternalTimerEntry>;
+	readonly clock: TimerClock;
+	emit(event: TimerEvent): void;
+}
+
+export function cancelTimerEntry(input: CancelTimerEntryInput): void {
+	const { entry, entries, clock } = input;
+	entry.version += 1;
+	entry.status = TIMER_STATUS_CANCELLED;
+	if (entry.native !== null) {
+		clock.clearTimeout(entry.native);
+		entry.native = null;
+	}
+	entry.controller.abort();
+	entries.delete(entry.key);
+	input.emit({ type: TIMER_EVENT_CANCELLED, entry: timerEntrySnapshot(entry) });
+}
+
+export function collectTimerKeysInScope(
+	entries: Map<string, InternalTimerEntry>,
+	scope: string | undefined
+): string[] {
+	const keys: string[] = [];
+	for (const key of entries.keys()) {
+		if (scope === undefined || isTimerKeyInScope(key, scope)) keys.push(key);
+	}
+	return keys;
+}