diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index dd36ad78..bd6fc894 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -19,6 +19,7 @@ import { BridgeManager } from './bridge/manager';
 import { createNotificationManager } from './notifications/manager';
 import { createStateWiring } from './webui/state-wiring';
 import { bindSystemFaceCatalog } from './sys-face-catalog';
+import { readAppVersion, startNativeStageSync, tempStagePath } from './native-stage-sync';
 
 const log = createLogger('App');
 
@@ -48,6 +49,11 @@ async function main() {
     perUinEnabled: runtimeConfig.logPerUin ?? DEFAULT_LOG_PER_UIN,
   });
   log.info('SnowLuma starting');
+  const stopNativeStageSync = startNativeStageSync({
+    version: readAppVersion(import.meta.url),
+    dataDir: 'data',
+    tempPath: tempStagePath(),
+  });
 
   // One-shot: lift a legacy per-UIN musicSignUrl into the global store before
   // any session (and thus any per-UIN config rewrite) can drop it.
@@ -133,6 +139,10 @@ async function main() {
       exitCode = 1;
       log.error('state wiring shutdown failed: %s', error instanceof Error ? (error.stack ?? error.message) : String(error));
     }
+    try { stopNativeStageSync.stop(); } catch (error) {
+      exitCode = 1;
+      log.error('stage sync shutdown failed: %s', error instanceof Error ? error.message : String(error));
+    }
     try { hookManager.dispose(); } catch (error) {
       exitCode = 1;
       log.error('hook shutdown failed: %s', error instanceof Error ? (error.stack ?? error.message) : String(error));
diff --git a/packages/core/src/native-stage-sync.ts b/packages/core/src/native-stage-sync.ts
new file mode 100644
index 00000000..3be9e76d
--- /dev/null
+++ b/packages/core/src/native-stage-sync.ts
@@ -0,0 +1,268 @@
+import { readFileSync, writeFileSync, mkdirSync, statSync, openSync, readSync, closeSync, fstatSync } from 'node:fs';
+import os from 'node:os';
+import path from 'node:path';
+import { createLogger, type Logger } from '@snowluma/common/logger';
+
+export const STAGE_FILE_NAME = 's7.log';
+export const MIRROR_LIMIT_BYTES = 1024 * 1024;
+
+const VERSION_HEADER = /^v\d+\.\d+\.\d+(?:[-+][0-9A-Za-z.-]+)?$/;
+
+export function isVersionHeader(line: string): boolean {
+  return VERSION_HEADER.test(line);
+}
+
+export function lineSeverity(line: string): 'info' | 'error' {
+  const parts = line.trim().split(/\s+/);
+  return parts.length >= 4 && parts[3] === '1' ? 'error' : 'info';
+}
+
+export function publicLine(version: string, raw: string): string {
+  return `${version} ${raw.trim()}`;
+}
+
+function byteSize(lines: readonly string[]): number {
+  if (lines.length === 0) return 0;
+  return Buffer.byteLength(`${lines.join('\n')}\n`, 'utf8');
+}
+
+export function trimMirror(text: string, limit = MIRROR_LIMIT_BYTES): string {
+  const lines = text.split('\n').filter((line) => line.length > 0);
+  const size = () => byteSize(lines);
+  while (lines.length > 0 && size() > limit) {
+    const body = lines.findIndex((line) => !isVersionHeader(line));
+    if (body >= 0) {
+      lines.splice(body, 1);
+      continue;
+    }
+    if (lines.length <= 1) break;
+    lines.shift();
+  }
+  if (lines.length === 0) return '';
+  return `${lines.join('\n')}\n`;
+}
+
+export function appendEvents(
+  mirror: string,
+  version: string,
+  events: readonly string[],
+  limit = MIRROR_LIMIT_BYTES,
+): string {
+  const fresh = events.map((line) => line.trim()).filter((line) => line.length > 0);
+  if (fresh.length === 0) return mirror;
+  const header = `v${version}`;
+  const lines = mirror.split('\n').filter((line) => line.length > 0);
+  let lastHeader = '';
+  for (const line of lines) {
+    if (isVersionHeader(line)) lastHeader = line;
+  }
+  const next = [...lines];
+  if (lastHeader !== header) next.push(header);
+  next.push(...fresh);
+  return trimMirror(`${next.join('\n')}\n`, limit);
+}
+
+export function tempStagePath(
+  platform = process.platform,
+  env: NodeJS.ProcessEnv = process.env,
+): string {
+  if (platform === 'win32') {
+    const base = env.TMP || env.TEMP || os.tmpdir();
+    return path.join(base, STAGE_FILE_NAME);
+  }
+  const uid = typeof process.getuid === 'function' ? process.getuid() : 0;
+  return `/tmp/sl-${uid}/${STAGE_FILE_NAME}`;
+}
+
+export function readAppVersion(moduleUrl: string | URL = import.meta.url): string {
+  if (typeof __APP_VERSION__ === 'string' && __APP_VERSION__) return __APP_VERSION__;
+  try {
+    const raw = readFileSync(new URL('../package.json', moduleUrl), 'utf8');
+    const version = JSON.parse(raw).version;
+    if (typeof version === 'string' && version.trim()) return version.trim();
+  } catch {
+    // Built layouts that do not sit next to a package manifest keep the fallback.
+  }
+  return '0.0.0';
+}
+
+export function errorCode(error: unknown): string {
+  if (error && typeof error === 'object' && 'code' in error) {
+    const code = (error as { code?: unknown }).code;
+    if (typeof code === 'string' && code) return code;
+  }
+  return 'ERR';
+}
+
+export interface StageSyncOptions {
+  version: string;
+  dataDir: string;
+  tempPath: string;
+  log?: Logger;
+  intervalMs?: number;
+}
+
+interface IngestResult {
+  mirror: string;
+  offset: number;
+  lines: string[];
+  missing: boolean;
+  errorCode?: string;
+}
+
+export function ingestTemp(args: {
+  tempText: string;
+  offset: number;
+  mirror: string;
+  version: string;
+  missing?: boolean;
+  errorCode?: string;
+}): IngestResult {
+  if (args.missing) {
+    return { mirror: args.mirror, offset: args.offset, lines: [], missing: true };
+  }
+  if (args.errorCode) {
+    return {
+      mirror: args.mirror,
+      offset: args.offset,
+      lines: [],
+      missing: false,
+      errorCode: args.errorCode,
+    };
+  }
+  const start = args.offset > args.tempText.length ? 0 : args.offset;
+  const chunk = args.tempText.slice(start);
+  const newline = chunk.lastIndexOf('\n');
+  if (newline < 0) {
+    return { mirror: args.mirror, offset: start, lines: [], missing: false };
+  }
+  const complete = chunk.slice(0, newline + 1);
+  const lines = complete.split('\n').map((line) => line.trim()).filter((line) => line.length > 0);
+  return {
+    mirror: appendEvents(args.mirror, args.version, lines),
+    offset: start + newline + 1,
+    lines,
+    missing: false,
+  };
+}
+
+function readOffset(file: string): number {
+  try {
+    const raw = readFileSync(file, 'utf8').trim();
+    const value = Number(raw);
+    return Number.isSafeInteger(value) && value >= 0 ? value : 0;
+  } catch {
+    return 0;
+  }
+}
+
+function readTemp(file: string): { text: string; missing: boolean; errorCode?: string } {
+  let fd: number | undefined;
+  try {
+    fd = openSync(file, 'r');
+    const info = fstatSync(fd);
+    const size = info.size;
+    if (size > 8 * 1024 * 1024) {
+      return { text: '', missing: false, errorCode: 'E2BIG' };
+    }
+    const buf = Buffer.alloc(size);
+    let got = 0;
+    while (got < size) {
+      const n = readSync(fd, buf, got, size - got, got);
+      if (n <= 0) break;
+      got += n;
+    }
+    return { text: buf.subarray(0, got).toString('utf8'), missing: false };
+  } catch (error) {
+    const code = errorCode(error);
+    if (code === 'ENOENT') return { text: '', missing: true };
+    return { text: '', missing: false, errorCode: code };
+  } finally {
+    if (fd !== undefined) closeSync(fd);
+  }
+}
+
+export function startNativeStageSync(options: StageSyncOptions): { stop: () => void } {
+  const log = options.log ?? createLogger('native');
+  const mirrorPath = path.join(options.dataDir, STAGE_FILE_NAME);
+  const offsetPath = path.join(options.dataDir, 's7.off');
+  let offset = readOffset(offsetPath);
+  let failed = false;
+  let stopped = false;
+
+  const tick = () => {
+    if (stopped) return;
+    let tempSize = 0;
+    try {
+      tempSize = statSync(options.tempPath).size;
+    } catch (error) {
+      const code = errorCode(error);
+      if (code === 'ENOENT') return;
+      if (!failed) {
+        failed = true;
+        log.error('sync failed %s', code);
+      }
+      return;
+    }
+    if (tempSize < offset) offset = 0;
+    const temp = readTemp(options.tempPath);
+    if (temp.missing) return;
+    if (temp.errorCode) {
+      if (!failed) {
+        failed = true;
+        log.error('sync failed %s', temp.errorCode);
+      }
+      return;
+    }
+    let mirror = '';
+    try {
+      mirror = readFileSync(mirrorPath, 'utf8');
+    } catch (error) {
+      if (errorCode(error) !== 'ENOENT') {
+        if (!failed) {
+          failed = true;
+          log.error('sync failed %s', errorCode(error));
+        }
+        return;
+      }
+    }
+    const ingested = ingestTemp({
+      tempText: temp.text,
+      offset,
+      mirror,
+      version: options.version,
+    });
+    if (ingested.lines.length === 0 && ingested.offset === offset) {
+      failed = false;
+      return;
+    }
+    try {
+      mkdirSync(options.dataDir, { recursive: true });
+      writeFileSync(mirrorPath, ingested.mirror);
+      writeFileSync(offsetPath, `${ingested.offset}\n`);
+      offset = ingested.offset;
+      failed = false;
+    } catch (error) {
+      if (!failed) {
+        failed = true;
+        log.error('sync failed %s', errorCode(error));
+      }
+      return;
+    }
+    for (const line of ingested.lines) {
+      const text = publicLine(options.version, line);
+      if (lineSeverity(line) === 'error') log.error('%s', text);
+      else log.info('%s', text);
+    }
+  };
+
+  tick();
+  const timer = setInterval(tick, options.intervalMs ?? 500);
+  timer.unref?.();
+  return {
+    stop() {
+      stopped = true;
+      clearInterval(timer);
+    },
+  };
+}
diff --git a/packages/core/tests/native-stage-sync.test.ts b/packages/core/tests/native-stage-sync.test.ts
new file mode 100644
index 00000000..796bdb6d
--- /dev/null
+++ b/packages/core/tests/native-stage-sync.test.ts
@@ -0,0 +1,65 @@
+import { describe, expect, it } from 'vitest';
+import {
+  appendEvents,
+  ingestTemp,
+  lineSeverity,
+  publicLine,
+  trimMirror,
+} from '../src/native-stage-sync';
+
+const VERSION = '1.14.22';
+const EVENT = 'a'.repeat(64);
+const infoLine = `2026-10-09T00:00:00Z 42 1 0 ${EVENT}`;
+const failLine = `2026-10-09T00:00:01Z 42 1 1 ${EVENT} ${'b'.repeat(16)}=7`;
+
+describe('native stage sync', () => {
+  it('keeps a version marker and copies the record without extra wording', () => {
+    const mirror = appendEvents('', VERSION, [infoLine, failLine]);
+    expect(mirror.startsWith(`v${VERSION}\n`)).toBe(true);
+    expect(mirror).toContain(infoLine);
+    expect(mirror).toContain(failLine);
+    const shown = [publicLine(VERSION, infoLine), publicLine(VERSION, failLine)].join('\n');
+    expect(shown).toBe(`${VERSION} ${infoLine}\n${VERSION} ${failLine}`);
+  });
+
+  it('opens a new version section without dropping the previous marker', () => {
+    const first = appendEvents('', '1.14.22', [infoLine]);
+    const second = appendEvents(first, '1.14.23', [failLine]);
+    expect(second).toContain('v1.14.22\n');
+    expect(second).toContain('v1.14.23\n');
+    expect(second.indexOf('v1.14.22')).toBeLessThan(second.indexOf(infoLine));
+    expect(second.indexOf('v1.14.23')).toBeLessThan(second.indexOf(failLine));
+  });
+
+  it('drops the oldest record first and keeps the version marker', () => {
+    const long = `2026-10-09T00:00:00Z 1 1 0 ${'c'.repeat(64)} ${'d'.repeat(40)}`;
+    let mirror = appendEvents('', VERSION, [long, long, long], 80);
+    mirror = trimMirror(mirror, 80);
+    expect(mirror).toContain(`v${VERSION}`);
+    expect(mirror.split('\n').filter((line) => line.startsWith('2026')).length).toBeLessThan(3);
+  });
+
+  it('treats severity 1 as a failure and ignores a missing file', () => {
+    expect(lineSeverity(failLine)).toBe('error');
+    expect(lineSeverity(infoLine)).toBe('info');
+    const ingested = ingestTemp({
+      tempText: `${infoLine}\n${failLine}\npartial`,
+      offset: 0,
+      mirror: '',
+      version: VERSION,
+    });
+    expect(ingested.lines).toEqual([infoLine, failLine]);
+    expect(ingested.mirror).toContain(`v${VERSION}\n`);
+    expect(ingested.offset).toBe(`${infoLine}\n${failLine}\n`.length);
+    const missing = ingestTemp({
+      tempText: '',
+      offset: 4,
+      mirror: 'keep',
+      version: VERSION,
+      missing: true,
+    });
+    expect(missing.mirror).toBe('keep');
+    expect(missing.lines).toEqual([]);
+    expect(missing.errorCode).toBeUndefined();
+  });
+});
diff --git a/packages/runtime/native/snowluma-linux-arm64.node b/packages/runtime/native/snowluma-linux-arm64.node
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diff --git a/packages/runtime/native/snowluma-linux-arm64.so b/packages/runtime/native/snowluma-linux-arm64.so
index c436bbff..8bb3e9b9 100644
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diff --git a/packages/runtime/native/snowluma-linux-x64.node b/packages/runtime/native/snowluma-linux-x64.node
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diff --git a/packages/runtime/native/snowluma-win32-x64.dll b/packages/runtime/native/snowluma-win32-x64.dll
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