diff --git a/src/services/memory/index.js b/src/services/memory/index.js
index 494dc1d..dc86c12 100644
--- a/src/services/memory/index.js
+++ b/src/services/memory/index.js
@@ -330,8 +330,9 @@ export async function unpinMemory(id, options = {}) {
  * @param {string} id
  * @param {string} mergedInto
  */
-export async function markMemoryMerged(id, mergedInto) {
-  const merged = await memoryRepository.markMerged(id, mergedInto);
+export async function markMemoryMerged(id, mergedInto, options = {}) {
+  const repository = options.repository ?? memoryRepository;
+  const merged = await repository.markMerged(id, mergedInto);
   cache.clear();
   return merged;
 }
diff --git a/test/memory-admin.test.mjs b/test/memory-admin.test.mjs
index 7f43e0e..d27942c 100644
--- a/test/memory-admin.test.mjs
+++ b/test/memory-admin.test.mjs
@@ -6,6 +6,7 @@ import {
   ingestEvents,
   inspectMemory,
   listMemories,
+  markMemoryMerged,
   memoryStats,
   pinMemory,
   runPruneCycle,
@@ -133,3 +134,43 @@ test('runPruneCycle respects prune feature-flag modes', async () => {
   assert.equal(offResult.mode, 'off');
   assert.equal(offResult.pruned.length, 0);
 });
+
+test('markMemoryMerged delegates to repository and clears cache', async () => {
+  let callCount = 0;
+  const repository = {
+    async markMerged(id, mergedInto) {
+      callCount++;
+      return id === 'exists';
+    }
+  };
+
+  const result1 = await markMemoryMerged('exists', 'target', { repository });
+  assert.equal(result1, true);
+  assert.equal(callCount, 1);
+
+  const result2 = await markMemoryMerged('missing', 'target', { repository });
+  assert.equal(result2, false);
+  assert.equal(callCount, 2);
+
+  // Verify cache clearing
+  const telemetry = [];
+  const emitTelemetry = (event, payload) => telemetry.push({ event, payload });
+
+  // 1. Populate cache
+  await getRelevantMemories({ agent_id: 'cache-test', emitTelemetry });
+  const hit1 = telemetry.findLast(t => t.event === 'memory:retrieved');
+  assert.equal(hit1.payload.cache_hit, false);
+
+  // 2. Hit cache
+  await getRelevantMemories({ agent_id: 'cache-test', emitTelemetry });
+  const hit2 = telemetry.findLast(t => t.event === 'memory:retrieved');
+  assert.equal(hit2.payload.cache_hit, true);
+
+  // 3. Clear cache via side-effect
+  await markMemoryMerged('exists', 'target', { repository });
+
+  // 4. Miss cache
+  await getRelevantMemories({ agent_id: 'cache-test', emitTelemetry });
+  const hit3 = telemetry.findLast(t => t.event === 'memory:retrieved');
+  assert.equal(hit3.payload.cache_hit, false);
+});