diff --git a/sdk/typescript/src/scan-logs.ts b/sdk/typescript/src/scan-logs.ts
index 36ca1164..e65f24e4 100644
--- a/sdk/typescript/src/scan-logs.ts
+++ b/sdk/typescript/src/scan-logs.ts
@@ -75,6 +75,13 @@ export async function readScanLogs(options: ScanLogOptions) {
       }
     }
   }
+  const parsedCompletedAt =
+    options.completedAt === undefined || options.completedAt === null
+      ? Number.NaN
+      : Date.parse(options.completedAt);
+  const completedAt = Number.isFinite(parsedCompletedAt)
+    ? parsedCompletedAt
+    : null;
   const events: Record<string, unknown>[] = [];
   for (const session of sessions) {
     let replaying = false;
@@ -96,6 +103,10 @@ export async function readScanLogs(options: ScanLogOptions) {
         }
         replaying = false;
       }
+      if (completedAt !== null && typeof event["timestamp"] === "string") {
+        const timestamp = Date.parse(event["timestamp"]);
+        if (Number.isFinite(timestamp) && timestamp > completedAt) continue;
+      }
       events.push({ threadId: session.threadId, event });
     }
   }
diff --git a/sdk/typescript/tests-ts/scan-logs-completion.test.ts b/sdk/typescript/tests-ts/scan-logs-completion.test.ts
new file mode 100644
index 00000000..bc3b9037
--- /dev/null
+++ b/sdk/typescript/tests-ts/scan-logs-completion.test.ts
@@ -0,0 +1,61 @@
+import { mkdir, mkdtemp, rm, writeFile } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { expect, test } from "bun:test";
+import { readScanLogs } from "../src/scan-logs.js";
+
+test("excludes same-thread events emitted after saved scan completion", async () => {
+  const home = await mkdtemp(join(tmpdir(), "codex-security-scan-log-boundary-"));
+  const directory = join(home, "sessions", "2026", "08", "18");
+  const path = join(directory, "rollout-parent.jsonl");
+  await mkdir(directory, { recursive: true });
+
+  try {
+    await writeFile(
+      path,
+      [
+        {
+          type: "session_meta",
+          payload: {
+            id: "parent",
+            timestamp: "2026-08-18T08:00:00.000Z",
+          },
+        },
+        {
+          type: "response_item",
+          timestamp: "2026-08-18T08:01:00.000Z",
+          payload: { type: "message", role: "assistant", content: "SCAN EVENT" },
+        },
+        {
+          type: "response_item",
+          timestamp: "2026-08-18T08:03:00.000Z",
+          payload: {
+            type: "message",
+            role: "assistant",
+            content: "POST SCAN EVENT",
+          },
+        },
+        {
+          type: "response_item",
+          payload: { type: "message", role: "assistant", content: "LEGACY EVENT" },
+        },
+      ]
+        .map((event) => JSON.stringify(event))
+        .join("\n"),
+    );
+
+    const result = await readScanLogs({
+      scanId: "scan-1",
+      threadId: "parent",
+      codexHome: home,
+      completedAt: "2026-08-18T08:02:00.000Z",
+    });
+    const serialized = JSON.stringify(result);
+
+    expect(serialized).toContain("SCAN EVENT");
+    expect(serialized).toContain("LEGACY EVENT");
+    expect(serialized).not.toContain("POST SCAN EVENT");
+  } finally {
+    await rm(home, { recursive: true, force: true });
+  }
+});