diff --git a/changelog.d/fixes/9624-telemetry-cleanup-wiring.md b/changelog.d/fixes/9624-telemetry-cleanup-wiring.md
new file mode 100644
index 0000000000..01e389606e
--- /dev/null
+++ b/changelog.d/fixes/9624-telemetry-cleanup-wiring.md
@@ -0,0 +1 @@
+- fix(db): wire telemetry cleanup scheduler in Next.js startup path (#9624)
diff --git a/src/instrumentation-node.ts b/src/instrumentation-node.ts
index d0407e437a..7be56fb919 100755
--- a/src/instrumentation-node.ts
+++ b/src/instrumentation-node.ts
@@ -306,6 +306,7 @@ export async function registerNodejs(): Promise<void> {
     { applyRuntimeSettings },
     { startRuntimeConfigHotReload },
     { startSpendBatchWriter },
+    { startCleanupScheduler },
     { registerDefaultGuardrails },
     { ensurePersistentManagementPasswordHash },
     { skillExecutor },
@@ -320,6 +321,7 @@ export async function registerNodejs(): Promise<void> {
     import("@/lib/config/runtimeSettings"),
     import("@/lib/config/hotReload"),
     import("@/lib/spend/batchWriter"),
+    import("@/lib/db/cleanup"),
     import("@/lib/guardrails"),
     import("@/lib/auth/managementPassword"),
     import("@/lib/skills/executor"),
@@ -489,6 +491,17 @@ export async function registerNodejs(): Promise<void> {
     console.warn("[STARTUP] Could not initialize vacuum scheduler (non-fatal):", msg);
   }
 
+  // Retention cleanup scheduler (#4691/#6988, #9624): runs the general retention
+  // cleanup once after startup and then every 6 hours. Previously this was only
+  // wired into the unused src/server-init.ts, so telemetry tables grew unboundedly
+  // even with retention.autoCleanupEnabled=true. Idempotent (guarded internally).
+  try {
+    startCleanupScheduler();
+  } catch (err: unknown) {
+    const msg = err instanceof Error ? err.message : String(err);
+    console.warn("[STARTUP] Could not start cleanup scheduler (non-fatal):", msg);
+  }
+
   // Warm the model catalog's durable, apiKey-independent sub-caches at
   // startup — see warmModelCatalogCache() for why the top-level Response
   // cache alone doesn't deliver this. Fire-and-forget, non-fatal.
diff --git a/tests/unit/repro-9624.test.ts b/tests/unit/repro-9624.test.ts
new file mode 100644
index 0000000000..a73e83eddf
--- /dev/null
+++ b/tests/unit/repro-9624.test.ts
@@ -0,0 +1,52 @@
+import { describe, it } from "node:test";
+import { strict as assert } from "node:assert";
+import { readFileSync } from "node:fs";
+import { fileURLToPath } from "node:url";
+import { dirname, resolve } from "node:path";
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
+
+const INSTRUMENTATION_NODE_PATH = resolve(
+  __dirname,
+  "../../src/instrumentation-node.ts"
+);
+
+describe("repro-9624: startCleanupScheduler wired in Next.js startup path", () => {
+  it("should import startCleanupScheduler from cleanup", () => {
+    const source = readFileSync(INSTRUMENTATION_NODE_PATH, "utf-8");
+
+    // instrumentation-node.ts loads all startup modules via dynamic imports in a
+    // Promise.all destructure, e.g.:
+    //   const [{ startCleanupScheduler }, ...] = await Promise.all([
+    //     import("@/lib/db/cleanup"), ...
+    //   ]);
+    // So the binding and the module import appear separately in the file.
+    const cleanupModuleImported = /import\(\s*["']@\/lib\/db\/cleanup["']\s*\)/.test(
+      source
+    );
+    const schedulerBound = /\bstartCleanupScheduler\b/.test(source);
+
+    assert.ok(
+      cleanupModuleImported,
+      "@/lib/db/cleanup should be imported (dynamic import) in instrumentation-node.ts"
+    );
+    assert.ok(
+      schedulerBound,
+      "startCleanupScheduler should be bound in instrumentation-node.ts"
+    );
+  });
+
+  it("should call startCleanupScheduler() during startup", () => {
+    const source = readFileSync(INSTRUMENTATION_NODE_PATH, "utf-8");
+
+    // Check that startCleanupScheduler is called (as a function call).
+    // It can be called directly or as part of a conditional.
+    const hasCall = /\bstartCleanupScheduler\s*\(/.test(source);
+
+    assert.ok(
+      hasCall,
+      "startCleanupScheduler() should be called in instrumentation-node.ts"
+    );
+  });
+});
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