diff --git a/launcher/commands/playback-command.test.ts b/launcher/commands/playback-command.test.ts
index f85f5cae..c6102186 100644
--- a/launcher/commands/playback-command.test.ts
+++ b/launcher/commands/playback-command.test.ts
@@ -1,6 +1,9 @@
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import { EventEmitter } from 'node:events';
+import fs from 'node:fs';
+import os from 'node:os';
+import path from 'node:path';
 import type { LauncherCommandContext } from './context.js';
 import { runPlaybackCommandWithDeps } from './playback-command.js';
 import { state } from '../mpv.js';
@@ -271,6 +274,68 @@ test('plugin auto-start playback attaches a warm background app through the laun
   );
 });
 
+test('plugin auto-start attach mode reuses launcher-resolved config dir for app control', async () => {
+  const context = createContext();
+  const originalXdgConfigHome = process.env.XDG_CONFIG_HOME;
+  const xdgConfigHome = fs.mkdtempSync(path.join(os.tmpdir(), 'subminer-test-xdg-'));
+  const expectedConfigDir = path.join(xdgConfigHome, 'SubMiner');
+  fs.mkdirSync(expectedConfigDir, { recursive: true });
+  fs.writeFileSync(path.join(expectedConfigDir, 'config.jsonc'), '{}');
+  context.args = {
+    ...context.args,
+    target: '/tmp/movie.mkv',
+    targetKind: 'file',
+    useTexthooker: true,
+  };
+  context.pluginRuntimeConfig = {
+    socketPath: '/tmp/subminer.sock',
+    binaryPath: '',
+    backend: 'auto',
+    autoStart: true,
+    autoStartVisibleOverlay: true,
+    autoStartPauseUntilReady: true,
+    texthookerEnabled: true,
+    aniskipEnabled: true,
+    aniskipButtonKey: 'TAB',
+  };
+  let availabilityConfigDir: string | undefined;
+  let overlayConfigDir: string | undefined;
+
+  try {
+    process.env.XDG_CONFIG_HOME = xdgConfigHome;
+
+    await runPlaybackCommandWithDeps(context, {
+      ensurePlaybackSetupReady: async () => {},
+      chooseTarget: async () => ({ target: context.args.target, kind: 'file' }),
+      checkDependencies: () => {},
+      registerCleanup: () => {},
+      startMpv: async () => {},
+      waitForUnixSocketReady: async () => true,
+      startOverlay: async (_appPath, _args, _socketPath, _extraAppArgs = [], configDir) => {
+        overlayConfigDir = configDir;
+      },
+      launchAppCommandDetached: () => {},
+      log: () => {},
+      cleanupPlaybackSession: async () => {},
+      getMpvProc: () => null,
+      isAppControlServerAvailable: async (_logLevel, configDir) => {
+        availabilityConfigDir = configDir;
+        return true;
+      },
+    });
+
+    assert.equal(availabilityConfigDir, expectedConfigDir);
+    assert.equal(overlayConfigDir, expectedConfigDir);
+  } finally {
+    if (originalXdgConfigHome === undefined) {
+      delete process.env.XDG_CONFIG_HOME;
+    } else {
+      process.env.XDG_CONFIG_HOME = originalXdgConfigHome;
+    }
+    fs.rmSync(xdgConfigHome, { recursive: true, force: true });
+  }
+});
+
 test('plugin auto-start attach mode omits texthooker flag when CLI texthooker is disabled', async () => {
   const context = createContext();
   context.args = {
diff --git a/launcher/commands/playback-command.ts b/launcher/commands/playback-command.ts
index 5aeb62f0..db216989 100644
--- a/launcher/commands/playback-command.ts
+++ b/launcher/commands/playback-command.ts
@@ -30,6 +30,13 @@ import { hasLauncherExternalYomitanProfileConfig } from '../config.js';
 const SETUP_WAIT_TIMEOUT_MS = 10 * 60 * 1000;
 const SETUP_POLL_INTERVAL_MS = 500;
 
+function getLauncherConfigDir(): string {
+  return getDefaultConfigDir({
+    xdgConfigHome: process.env.XDG_CONFIG_HOME,
+    homeDir: os.homedir(),
+  });
+}
+
 function checkDependencies(args: Args): void {
   const missing: string[] = [];
 
@@ -100,10 +107,7 @@ async function ensurePlaybackSetupReady(context: LauncherCommandContext): Promis
   const { args, appPath } = context;
   if (!appPath) return;
 
-  const configDir = getDefaultConfigDir({
-    xdgConfigHome: process.env.XDG_CONFIG_HOME,
-    homeDir: os.homedir(),
-  });
+  const configDir = getLauncherConfigDir();
   const statePath = getSetupStatePath(configDir);
   const ready = await ensureLauncherSetupReady({
     readSetupState: () => readSetupState(statePath),
@@ -166,7 +170,7 @@ type PlaybackCommandDeps = {
   waitForUnixSocketReady: typeof waitForUnixSocketReady;
   startOverlay: typeof startOverlay;
   launchAppCommandDetached: typeof launchAppCommandDetached;
-  isAppControlServerAvailable?: (logLevel: Args['logLevel']) => Promise<boolean>;
+  isAppControlServerAvailable?: (logLevel: Args['logLevel'], configDir: string) => Promise<boolean>;
   log: typeof log;
   cleanupPlaybackSession: typeof cleanupPlaybackSession;
   getMpvProc: () => typeof state.mpvProc;
@@ -211,6 +215,7 @@ export async function runPlaybackCommandWithDeps(
   const isYoutubeUrl = selectedTarget.kind === 'url' && isYoutubeTarget(selectedTarget.target);
   const isAppOwnedYoutubeFlow = isYoutubeUrl;
   const youtubeMode = args.youtubeMode ?? 'download';
+  const configDir = getLauncherConfigDir();
 
   if (isYoutubeUrl) {
     deps.log('info', args.logLevel, 'YouTube subtitle flow: app-owned picker after mpv bootstrap');
@@ -222,7 +227,7 @@ export async function runPlaybackCommandWithDeps(
     !args.startOverlay &&
     !args.autoStartOverlay &&
     !isAppOwnedYoutubeFlow &&
-    ((await deps.isAppControlServerAvailable?.(args.logLevel)) ?? false);
+    ((await deps.isAppControlServerAvailable?.(args.logLevel, configDir)) ?? false);
   const effectivePluginRuntimeConfig = shouldLauncherAttachRunningApp
     ? { ...pluginRuntimeConfig, autoStart: false }
     : pluginRuntimeConfig;
@@ -287,7 +292,7 @@ export async function runPlaybackCommandWithDeps(
               : []),
           ]
         : [];
-    await deps.startOverlay(appPath, args, mpvSocketPath, extraAppArgs);
+    await deps.startOverlay(appPath, args, mpvSocketPath, extraAppArgs, configDir);
   } else if (pluginAutoStartEnabled) {
     if (ready) {
       deps.log('info', args.logLevel, 'MPV IPC socket ready, relying on mpv plugin auto-start');
diff --git a/launcher/config/args-normalizer.ts b/launcher/config/args-normalizer.ts
index e828cba7..e7f87b26 100644
--- a/launcher/config/args-normalizer.ts
+++ b/launcher/config/args-normalizer.ts
@@ -313,7 +313,10 @@ export function applyInvocationsToArgs(parsed: Args, invocations: CliInvocations
     const action = (invocations.configInvocation.action || '').toLowerCase();
     if (action === 'path') parsed.configPath = true;
     else if (action === 'show') parsed.configShow = true;
-    else fail(`Unknown config action: ${invocations.configInvocation.action || '(none)'}. Expected path or show.`);
+    else
+      fail(
+        `Unknown config action: ${invocations.configInvocation.action || '(none)'}. Expected path or show.`,
+      );
   }
 
   if (invocations.settingsInvocation) {
diff --git a/launcher/mpv.test.ts b/launcher/mpv.test.ts
index 86d8920c..18ca0ecc 100644
--- a/launcher/mpv.test.ts
+++ b/launcher/mpv.test.ts
@@ -6,6 +6,7 @@ import os from 'node:os';
 import net from 'node:net';
 import { EventEmitter } from 'node:events';
 import type { Args } from './types';
+import { getAppControlSocketPath } from '../src/shared/app-control';
 import {
   buildConfiguredMpvDefaultArgs,
   buildMpvBackendArgs,
@@ -826,6 +827,87 @@ test('startOverlay attaches through the running app control socket without spawn
   }
 });
 
+test('startOverlay uses caller config dir for app control socket discovery', async () => {
+  if (process.platform === 'win32') return;
+
+  const { dir, socketPath } = createTempSocketPath();
+  const configDir = path.join(dir, 'launcher-config');
+  const controlSocketPath = getAppControlSocketPath({ configDir, platform: 'linux' });
+  const appPath = path.join(dir, 'fake-subminer.sh');
+  const appInvocationsPath = path.join(dir, 'app-invocations.log');
+  const receivedControlArgv: string[][] = [];
+  const originalControlSocket = process.env.SUBMINER_APP_CONTROL_SOCKET;
+
+  fs.writeFileSync(
+    appPath,
+    [
+      '#!/bin/sh',
+      `printf '%s\\n' "$@" >> ${JSON.stringify(appInvocationsPath)}`,
+      'if [ "$1" = "--app-ping" ]; then exit 0; fi',
+      'exit 0',
+      '',
+    ].join('\n'),
+  );
+  fs.chmodSync(appPath, 0o755);
+
+  const mpvServer = net.createServer((socket) => socket.end());
+  const controlServer = net.createServer((socket) => {
+    let buffer = '';
+    socket.on('data', (chunk) => {
+      buffer += chunk.toString('utf8');
+      const newlineIndex = buffer.indexOf('\n');
+      if (newlineIndex < 0) return;
+      const payload = JSON.parse(buffer.slice(0, newlineIndex)) as { argv?: unknown };
+      if (Array.isArray(payload.argv)) {
+        receivedControlArgv.push(
+          payload.argv.filter((value): value is string => typeof value === 'string'),
+        );
+      }
+      socket.end(JSON.stringify({ ok: true }) + '\n');
+    });
+  });
+
+  try {
+    delete process.env.SUBMINER_APP_CONTROL_SOCKET;
+    await new Promise<void>((resolve, reject) => {
+      mpvServer.once('error', reject);
+      mpvServer.listen(socketPath, resolve);
+    });
+    await new Promise<void>((resolve, reject) => {
+      controlServer.once('error', reject);
+      controlServer.listen(controlSocketPath, resolve);
+    });
+
+    await startOverlay(appPath, makeArgs(), socketPath, [], configDir);
+
+    const invocationText = fs.existsSync(appInvocationsPath)
+      ? fs.readFileSync(appInvocationsPath, 'utf8')
+      : '';
+    assert.equal(invocationText, '');
+    assert.equal(receivedControlArgv.length, 1);
+    assert.deepEqual(receivedControlArgv[0]?.slice(0, 6), [
+      '--start',
+      '--managed-playback',
+      '--backend',
+      'x11',
+      '--socket',
+      socketPath,
+    ]);
+  } finally {
+    if (originalControlSocket === undefined) {
+      delete process.env.SUBMINER_APP_CONTROL_SOCKET;
+    } else {
+      process.env.SUBMINER_APP_CONTROL_SOCKET = originalControlSocket;
+    }
+    await new Promise<void>((resolve) => mpvServer.close(() => resolve()));
+    await new Promise<void>((resolve) => controlServer.close(() => resolve()));
+    state.overlayProc = null;
+    state.overlayManagedByLauncher = false;
+    state.appPath = '';
+    fs.rmSync(dir, { recursive: true, force: true });
+  }
+});
+
 test('startOverlay falls back to legacy app startup when control command fails', async () => {
   if (process.platform === 'win32') return;
 
diff --git a/launcher/mpv.ts b/launcher/mpv.ts
index a3a584eb..643b9019 100644
--- a/launcher/mpv.ts
+++ b/launcher/mpv.ts
@@ -1006,6 +1006,7 @@ export async function startOverlay(
   args: Args,
   socketPath: string,
   extraAppArgs: string[] = [],
+  configDir: string = getLauncherConfigDir(),
 ): Promise<void> {
   const backend = detectBackend(args.backend);
   log('info', args.logLevel, `Starting SubMiner overlay (backend: ${backend})...`);
@@ -1024,7 +1025,7 @@ export async function startOverlay(
   if (args.useTexthooker) overlayArgs.push('--texthooker');
 
   const controlResult = await sendAppControlCommand(overlayArgs, {
-    configDir: getLauncherConfigDir(),
+    configDir,
   });
   if (controlResult.ok) {
     log('debug', args.logLevel, 'Attached to running SubMiner app via control socket');
@@ -1107,9 +1108,12 @@ function getLauncherConfigDir(): string {
   });
 }
 
-export async function isRunningAppControlServerAvailable(logLevel: LogLevel): Promise<boolean> {
+export async function isRunningAppControlServerAvailable(
+  logLevel: LogLevel,
+  configDir: string = getLauncherConfigDir(),
+): Promise<boolean> {
   const available = await checkAppControlServerAvailable({
-    configDir: getLauncherConfigDir(),
+    configDir,
   });
   if (available) {
     log('debug', logLevel, 'Running SubMiner app control socket detected');
diff --git a/src/core/services/mpv.test.ts b/src/core/services/mpv.test.ts
index 1ca76ffd..184193b1 100644
--- a/src/core/services/mpv.test.ts
+++ b/src/core/services/mpv.test.ts
@@ -171,7 +171,11 @@ test('MpvIpcClient connect logs connect-request at debug level', () => {
 test('MpvIpcClient reconnect clears stale connected state and starts a fresh transport connect', () => {
   const client = new MpvIpcClient('/tmp/mpv.sock', makeDeps());
   const calls: string[] = [];
+  const connectionChanges: boolean[] = [];
   const resolved: unknown[] = [];
+  client.on('connection-change', ({ connected }) => {
+    connectionChanges.push(connected);
+  });
   (client as any).connected = true;
   (client as any).connecting = false;
   (client as any).socket = {};
@@ -191,6 +195,7 @@ test('MpvIpcClient reconnect clears stale connected state and starts a fresh tra
   assert.equal(client.connected, false);
   assert.equal((client as any).connecting, true);
   assert.equal((client as any).socket, null);
+  assert.deepEqual(connectionChanges, [false]);
   assert.deepEqual(resolved, [{ request_id: 10, error: 'disconnected' }]);
 });
 
diff --git a/src/core/services/mpv.ts b/src/core/services/mpv.ts
index 46f81475..bbabf357 100644
--- a/src/core/services/mpv.ts
+++ b/src/core/services/mpv.ts
@@ -277,11 +277,15 @@ export class MpvIpcClient implements MpvClient {
 
   reconnect(): void {
     logger.debug('MPV IPC reconnect requested.');
+    const wasConnected = this.connected;
     this.transport.shutdown();
     this.connected = false;
     this.connecting = false;
     this.socket = null;
     this.playbackPaused = null;
+    if (wasConnected) {
+      this.emit('connection-change', { connected: false });
+    }
     this.failPendingRequests();
     this.connect();
   }
diff --git a/src/main/runtime/app-control-server.test.ts b/src/main/runtime/app-control-server.test.ts
index cbe0581f..ac371294 100644
--- a/src/main/runtime/app-control-server.test.ts
+++ b/src/main/runtime/app-control-server.test.ts
@@ -1,5 +1,7 @@
 import assert from 'node:assert/strict';
+import { EventEmitter } from 'node:events';
 import fs from 'node:fs';
+import net from 'node:net';
 import os from 'node:os';
 import path from 'node:path';
 import test from 'node:test';
@@ -13,9 +15,7 @@ async function waitForSocketPath(socketPath: string): Promise<void> {
     if (fs.existsSync(socketPath)) return;
     await new Promise<void>((resolve) => setTimeout(resolve, 10));
   }
-  throw new Error(
-    `Timed out waiting for control socket ${socketPath} after ${timeoutMs}ms`,
-  );
+  throw new Error(`Timed out waiting for control socket ${socketPath} after ${timeoutMs}ms`);
 }
 
 test('app control server dispatches argv requests and replies ok', async () => {
@@ -62,9 +62,12 @@ test('app control server rejects requests larger than 64KB by UTF-8 byte length'
 
   try {
     await waitForSocketPath(socketPath);
-    const result = await sendAppControlCommand(Array.from({ length: 4 }, () => 'あ'.repeat(6000)), {
-      socketPath,
-    });
+    const result = await sendAppControlCommand(
+      Array.from({ length: 4 }, () => 'あ'.repeat(6000)),
+      {
+        socketPath,
+      },
+    );
 
     assert.deepEqual(result, { ok: false, error: 'App control request too large' });
     assert.deepEqual(received, []);
@@ -73,3 +76,56 @@ test('app control server rejects requests larger than 64KB by UTF-8 byte length'
     fs.rmSync(dir, { recursive: true, force: true });
   }
 });
+
+test('app control server logs and closes errored client sockets', () => {
+  const originalCreateServer = net.createServer;
+  let socketHandler: ((socket: net.Socket) => void) | null = null;
+  const fakeServer = new EventEmitter() as net.Server;
+  fakeServer.listen = (() => fakeServer) as net.Server['listen'];
+  fakeServer.close = ((callback?: (err?: Error) => void) => {
+    callback?.();
+    return fakeServer;
+  }) as net.Server['close'];
+  const received: string[][] = [];
+  const warnings: Array<{ message: string; error?: unknown }> = [];
+
+  try {
+    net.createServer = ((handler?: (socket: net.Socket) => void) => {
+      socketHandler = handler ?? null;
+      return fakeServer;
+    }) as typeof net.createServer;
+
+    const server = startAppControlServer({
+      socketPath: '\\\\.\\pipe\\subminer-test-control',
+      platform: 'win32',
+      handleArgv: (argv) => {
+        received.push(argv);
+      },
+      logWarn: (message, error) => {
+        warnings.push({ message, error });
+      },
+    });
+
+    const error = new Error('client reset');
+    let destroyed = false;
+    const socket = new EventEmitter() as net.Socket;
+    socket.destroy = (() => {
+      destroyed = true;
+      return socket;
+    }) as net.Socket['destroy'];
+
+    const handler = socketHandler as ((socket: net.Socket) => void) | null;
+    assert.ok(handler);
+    handler(socket);
+    socket.emit('error', error);
+    socket.emit('data', Buffer.from('{"argv":["--start"]}\n'));
+
+    assert.equal(destroyed, true);
+    assert.deepEqual(received, []);
+    assert.deepEqual(warnings, [{ message: 'App control client socket error.', error }]);
+
+    server.close();
+  } finally {
+    net.createServer = originalCreateServer;
+  }
+});
diff --git a/src/main/runtime/app-control-server.ts b/src/main/runtime/app-control-server.ts
index 5b11a7b3..a15e1496 100644
--- a/src/main/runtime/app-control-server.ts
+++ b/src/main/runtime/app-control-server.ts
@@ -47,6 +47,13 @@ export function startAppControlServer(options: AppControlServerOptions): AppCont
     let byteCount = 0;
     let handled = false;
 
+    socket.on('error', (error) => {
+      if (handled) return;
+      handled = true;
+      options.logWarn?.('App control client socket error.', error);
+      socket.destroy();
+    });
+
     socket.on('data', (chunk) => {
       if (handled) return;
       byteCount += chunk.length;