diff --git a/plugin/skills/agentmemory-config/REFERENCE.md b/plugin/skills/agentmemory-config/REFERENCE.md
index ed128793d..d152a7c62 100644
--- a/plugin/skills/agentmemory-config/REFERENCE.md
+++ b/plugin/skills/agentmemory-config/REFERENCE.md
@@ -3,10 +3,11 @@
 Generated by scanning `src/` for `AGENTMEMORY_*` usage. Do not edit the block below by hand; run `npm run skills:gen` after adding or removing a variable. Internal markers ending in two underscores are excluded.
 
 <!-- AUTOGEN:env START - generated by scripts/skills/generate.ts, do not edit by hand -->
-Configuration is read from the environment and from `~/.agentmemory/.env` (no `export` prefix). 42 recognized variables:
+Configuration is read from the environment and from `~/.agentmemory/.env` (no `export` prefix). 43 recognized variables:
 
 - `AGENTMEMORY_AGENT_SCOPE`
 - `AGENTMEMORY_ALLOW_AGENT_SDK`
+- `AGENTMEMORY_AUDIT_INDEX_PERSIST`
 - `AGENTMEMORY_AUTO_COMPRESS`
 - `AGENTMEMORY_COMMIT_SHA`
 - `AGENTMEMORY_CONSOLIDATION_COOLDOWN_MS`
diff --git a/src/state/index-persistence.ts b/src/state/index-persistence.ts
index 6df0e2fda..19b05cb59 100644
--- a/src/state/index-persistence.ts
+++ b/src/state/index-persistence.ts
@@ -17,6 +17,20 @@ const VECTOR_SHARD_SCOPE_PREFIX = `${KV.bm25Index}:vectors:`;
 const INDEX_SHARD_KEY = "data";
 const DEFAULT_INDEX_SHARD_CHARS = 2_000_000;
 
+// mem:audit exists to record structural deletions of user data — that is
+// the policy stated at the top of src/functions/audit.ts. Index shard
+// writes and manifest publishes remove no user rows, so they fall outside
+// it, yet a single save() emits three of them: on a real store they
+// reached 59876 of 84028 entries (71%), which is what makes the audit log
+// slow to query and bloats startup. Off by default; set
+// AGENTMEMORY_AUDIT_INDEX_PERSIST=1 when debugging index persistence.
+function auditIndexPersistEnabled(): boolean {
+  const raw = process.env.AGENTMEMORY_AUDIT_INDEX_PERSIST;
+  if (!raw) return false;
+  const normalized = raw.trim().toLowerCase();
+  return normalized === "1" || normalized === "true";
+}
+
 type IndexShardManifest = {
   v: 1;
   generation?: string;
@@ -271,6 +285,7 @@ export class IndexPersistence {
     targetIds: string[],
     details: Record<string, unknown>,
   ): Promise<void> {
+    if (!auditIndexPersistEnabled()) return;
     await safeAudit(
       this.kv,
       "index_persist",
diff --git a/test/index-persistence.test.ts b/test/index-persistence.test.ts
index 929791657..ba47c3ef7 100644
--- a/test/index-persistence.test.ts
+++ b/test/index-persistence.test.ts
@@ -791,3 +791,94 @@ describe("IndexPersistence", () => {
     await expect(persistence.load()).resolves.toBeDefined();
   });
 });
+
+describe("index_persist audit gating", () => {
+  let kv: ReturnType<typeof mockKV>;
+  let previousFlag: string | undefined;
+
+  beforeEach(() => {
+    // AGENTMEMORY_* variables are documented as living in
+    // ~/.agentmemory/.env, so a developer running the suite on a
+    // configured machine can inherit this one. Clear it going in and put
+    // whatever was there back on the way out.
+    previousFlag = process.env.AGENTMEMORY_AUDIT_INDEX_PERSIST;
+    delete process.env.AGENTMEMORY_AUDIT_INDEX_PERSIST;
+    vi.useFakeTimers();
+    kv = mockKV();
+  });
+
+  afterEach(() => {
+    vi.useRealTimers();
+    if (previousFlag === undefined) {
+      delete process.env.AGENTMEMORY_AUDIT_INDEX_PERSIST;
+    } else {
+      process.env.AGENTMEMORY_AUDIT_INDEX_PERSIST = previousFlag;
+    }
+  });
+
+  async function indexPersistEntries(): Promise<Array<{ operation: string }>> {
+    const entries = await kv.list<{ operation: string }>("mem:audit");
+    return entries.filter((entry) => entry.operation === "index_persist");
+  }
+
+  it("writes no index_persist audit entries by default", async () => {
+    const persistence = new IndexPersistence(
+      kv as never,
+      makeBm25("obs_1", "auth handler"),
+      null,
+    );
+
+    await persistence.save();
+
+    expect(await indexPersistEntries()).toEqual([]);
+  });
+
+  it.each(["1", " 1 ", "true", "TRUE", "  true  "])(
+    "writes index_persist audit entries when set to %j",
+    async (value) => {
+      process.env.AGENTMEMORY_AUDIT_INDEX_PERSIST = value;
+      const persistence = new IndexPersistence(
+        kv as never,
+        makeBm25("obs_1", "auth handler"),
+        null,
+      );
+
+      await persistence.save();
+
+      expect((await indexPersistEntries()).length).toBeGreaterThan(0);
+    },
+  );
+
+  // Anything that is not an affirmative stays off. "0" and "false" are the
+  // ones an operator is likely to reach for to disable it, and they must
+  // not read as "present, therefore enabled".
+  it.each(["0", "false", "yes", "", " "])(
+    "keeps auditing off when set to %j",
+    async (value) => {
+      process.env.AGENTMEMORY_AUDIT_INDEX_PERSIST = value;
+      const persistence = new IndexPersistence(
+        kv as never,
+        makeBm25("obs_1", "auth handler"),
+        null,
+      );
+
+      await persistence.save();
+
+      expect(await indexPersistEntries()).toEqual([]);
+    },
+  );
+
+  it("still persists the index when auditing is off", async () => {
+    const persistence = new IndexPersistence(
+      kv as never,
+      makeBm25("obs_1", "auth handler"),
+      null,
+    );
+
+    await persistence.save();
+
+    const loaded = await persistence.load();
+    expect(loaded.bm25).not.toBeNull();
+    expect(loaded.bm25!.size).toBe(1);
+  });
+});