diff --git a/src/ccs.ts b/src/ccs.ts
index 0d735973..09b94e34 100644
--- a/src/ccs.ts
+++ b/src/ccs.ts
@@ -44,7 +44,12 @@ import { handleShellCompletionCommand } from './commands/shell-completion-comman
 import { handleUpdateCommand } from './commands/update-command';
 
 // Import extracted utility functions
-import { execClaude, escapeShellArg, stripClaudeCodeEnv } from './utils/shell-executor';
+import {
+  execClaude,
+  escapeShellArg,
+  stripClaudeCodeEnv,
+  getClaudeLaunchEnvOverrides,
+} from './utils/shell-executor';
 import { wireChildProcessSignals } from './utils/signal-forwarder';
 
 // Import target adapter system
@@ -210,8 +215,10 @@ async function execClaudeWithProxy(
   const needsShell = isWindows && /\.(cmd|bat)$/i.test(claudeCli);
   const webSearchEnv = getWebSearchHookEnv();
   const imageAnalysisEnv = getImageAnalysisHookEnv(profileName);
+  const claudeLaunchEnv = getClaudeLaunchEnvOverrides();
   const env = stripClaudeCodeEnv({
     ...process.env,
+    ...claudeLaunchEnv,
     ...envVars,
     ...webSearchEnv,
     ...imageAnalysisEnv,
diff --git a/src/delegation/headless-executor.ts b/src/delegation/headless-executor.ts
index a4695560..85265534 100644
--- a/src/delegation/headless-executor.ts
+++ b/src/delegation/headless-executor.ts
@@ -17,7 +17,7 @@ import { StreamBuffer, formatToolVerbose } from './executor/stream-parser';
 import { buildExecutionResult } from './executor/result-aggregator';
 import { getCcsDir, getModelDisplayName } from '../utils/config-manager';
 import { getProfileLookupCandidates } from '../utils/profile-compat';
-import { stripClaudeCodeEnv } from '../utils/shell-executor';
+import { getClaudeLaunchEnvOverrides, stripClaudeCodeEnv } from '../utils/shell-executor';
 
 // Re-export types for consumers
 export type { ExecutionOptions, ExecutionResult, StreamMessage } from './executor/types';
@@ -210,7 +210,10 @@ export class HeadlessExecutor {
 
       // Strip Claude Code nested session guard env var to allow CCS delegation
       // (Claude Code v2.1.39+ sets CLAUDECODE to detect nested sessions)
-      const cleanEnv = stripClaudeCodeEnv(process.env);
+      const cleanEnv = stripClaudeCodeEnv({
+        ...process.env,
+        ...getClaudeLaunchEnvOverrides(),
+      });
 
       const proc = spawn(claudeCli, args, {
         cwd,
diff --git a/src/utils/shell-executor.ts b/src/utils/shell-executor.ts
index d8ea89d3..0d9cbd45 100644
--- a/src/utils/shell-executor.ts
+++ b/src/utils/shell-executor.ts
@@ -8,6 +8,7 @@ import { spawn, spawnSync, ChildProcess } from 'child_process';
 import { ErrorManager } from './error-manager';
 import { getWebSearchHookEnv } from './websearch-manager';
 import { wireChildProcessSignals } from './signal-forwarder';
+import { loadOrCreateUnifiedConfig } from '../config/unified-config-loader';
 
 /**
  * Strip ANTHROPIC_* env vars from an environment object.
@@ -40,6 +41,22 @@ export function stripClaudeCodeEnv(env: NodeJS.ProcessEnv): NodeJS.ProcessEnv {
   return result;
 }
 
+/**
+ * Resolve CCS-managed environment overrides for Claude launch.
+ * - preferences.auto_update: false -> DISABLE_AUTOUPDATER=1
+ */
+export function getClaudeLaunchEnvOverrides(): NodeJS.ProcessEnv {
+  try {
+    const config = loadOrCreateUnifiedConfig();
+    if (config.preferences?.auto_update === false) {
+      return { DISABLE_AUTOUPDATER: '1' };
+    }
+  } catch {
+    // Config read errors should never block Claude launch.
+  }
+  return {};
+}
+
 /**
  * Escape arguments for shell execution (cross-platform)
  *
@@ -84,6 +101,7 @@ export function execClaude(
 
   // Get WebSearch hook config env vars
   const webSearchEnv = getWebSearchHookEnv();
+  const claudeLaunchEnv = getClaudeLaunchEnvOverrides();
 
   // For account/default profiles, strip ANTHROPIC_* from parent env to prevent
   // stale proxy config (e.g., from prior CLIProxy sessions) from interfering
@@ -97,8 +115,8 @@ export function execClaude(
 
   // Prepare environment (merge with base env if envVars provided)
   const mergedEnv = envVars
-    ? { ...baseEnv, ...envVars, ...webSearchEnv }
-    : { ...baseEnv, ...webSearchEnv };
+    ? { ...baseEnv, ...claudeLaunchEnv, ...envVars, ...webSearchEnv }
+    : { ...baseEnv, ...claudeLaunchEnv, ...webSearchEnv };
 
   // Strip Claude Code nested session guard env var to allow CCS delegation
   // (Claude Code v2.1.39+ sets CLAUDECODE to detect nested sessions)
diff --git a/tests/unit/utils/claudecode-env-stripping.test.ts b/tests/unit/utils/claudecode-env-stripping.test.ts
index 3950ae52..64a2323a 100644
--- a/tests/unit/utils/claudecode-env-stripping.test.ts
+++ b/tests/unit/utils/claudecode-env-stripping.test.ts
@@ -1,6 +1,9 @@
 import { afterAll, afterEach, beforeAll, beforeEach, describe, expect, it, mock } from 'bun:test';
 import { EventEmitter } from 'events';
 import * as childProcess from 'child_process';
+import * as fs from 'fs';
+import * as os from 'os';
+import * as path from 'path';
 
 type SpawnCall = {
   command: string;
@@ -13,6 +16,8 @@ const originalPlatform = process.platform;
 let baselineSigintListeners: Array<(...args: unknown[]) => void> = [];
 let baselineSigtermListeners: Array<(...args: unknown[]) => void> = [];
 let baselineSighupListeners: Array<(...args: unknown[]) => void> = [];
+let originalCcsHome: string | undefined;
+let originalDisableAutoUpdater: string | undefined;
 const realSpawn = childProcess.spawn.bind(childProcess);
 const realSpawnSync = childProcess.spawnSync.bind(childProcess);
 const realExecSync = childProcess.execSync.bind(childProcess);
@@ -95,6 +100,18 @@ function registerChildProcessMock(): void {
   }));
 }
 
+function writeConfigWithAutoUpdatePreference(enabled: boolean): void {
+  const tempHome = fs.mkdtempSync(path.join(os.tmpdir(), 'ccs-auto-update-pref-'));
+  process.env.CCS_HOME = tempHome;
+  const ccsDir = path.join(tempHome, '.ccs');
+  fs.mkdirSync(ccsDir, { recursive: true });
+  const yaml = `version: 8
+preferences:
+  auto_update: ${enabled ? 'true' : 'false'}
+`;
+  fs.writeFileSync(path.join(ccsDir, 'config.yaml'), yaml, 'utf8');
+}
+
 let execClaude: typeof import('../../../src/utils/shell-executor').execClaude;
 let stripClaudeCodeEnv: typeof import('../../../src/utils/shell-executor').stripClaudeCodeEnv;
 let HeadlessExecutor: typeof import('../../../src/delegation/headless-executor').HeadlessExecutor;
@@ -118,6 +135,9 @@ describe('CLAUDECODE environment stripping', () => {
   beforeEach(() => {
     spawnCalls.length = 0;
     process.env.CCS_QUIET = '1';
+    originalCcsHome = process.env.CCS_HOME;
+    originalDisableAutoUpdater = process.env.DISABLE_AUTOUPDATER;
+    delete process.env.DISABLE_AUTOUPDATER;
     baselineSigintListeners = process.listeners('SIGINT');
     baselineSigtermListeners = process.listeners('SIGTERM');
     baselineSighupListeners = process.listeners('SIGHUP');
@@ -128,6 +148,13 @@ describe('CLAUDECODE environment stripping', () => {
     delete process.env.CLAUDECODE;
     delete process.env.claudecode;
     delete process.env.CCS_QUIET;
+    if (originalCcsHome !== undefined) process.env.CCS_HOME = originalCcsHome;
+    else delete process.env.CCS_HOME;
+    if (originalDisableAutoUpdater !== undefined) {
+      process.env.DISABLE_AUTOUPDATER = originalDisableAutoUpdater;
+    } else {
+      delete process.env.DISABLE_AUTOUPDATER;
+    }
 
     for (const listener of process.listeners('SIGINT')) {
       if (!baselineSigintListeners.includes(listener)) {
@@ -197,7 +224,26 @@ describe('CLAUDECODE environment stripping', () => {
     expect(Object.keys(env).map((k) => k.toUpperCase())).not.toContain('CLAUDECODE');
   });
 
+  it('execClaude sets DISABLE_AUTOUPDATER=1 when preferences.auto_update is false', () => {
+    writeConfigWithAutoUpdatePreference(false);
+    execClaude('claude', ['--version'], { CCS_PROFILE_TYPE: 'default' });
+
+    expect(spawnCalls.length).toBeGreaterThan(0);
+    const env = spawnCalls[0].options?.env as NodeJS.ProcessEnv;
+    expect(env.DISABLE_AUTOUPDATER).toBe('1');
+  });
+
+  it('execClaude does not force DISABLE_AUTOUPDATER when preferences.auto_update is true', () => {
+    writeConfigWithAutoUpdatePreference(true);
+    execClaude('claude', ['--version'], { CCS_PROFILE_TYPE: 'default' });
+
+    expect(spawnCalls.length).toBeGreaterThan(0);
+    const env = spawnCalls[0].options?.env as NodeJS.ProcessEnv;
+    expect(env.DISABLE_AUTOUPDATER).toBeUndefined();
+  });
+
   it('headless executor spawn path strips CLAUDECODE before spawn', async () => {
+    writeConfigWithAutoUpdatePreference(false);
     process.env.CLAUDECODE = 'nested';
     process.env.claudecode = 'nested-lower';
 
@@ -237,5 +283,6 @@ describe('CLAUDECODE environment stripping', () => {
     expect(spawnCalls.length).toBeGreaterThan(0);
     const env = spawnCalls[0].options?.env as NodeJS.ProcessEnv;
     expect(Object.keys(env).map((k) => k.toUpperCase())).not.toContain('CLAUDECODE');
+    expect(env.DISABLE_AUTOUPDATER).toBe('1');
   });
 });