diff --git a/packages/core/src/services/shellExecutionService.test.ts b/packages/core/src/services/shellExecutionService.test.ts
index f1aa08f41f2..993c46cb319 100644
--- a/packages/core/src/services/shellExecutionService.test.ts
+++ b/packages/core/src/services/shellExecutionService.test.ts
@@ -2192,4 +2192,131 @@ describe('ShellExecutionService environment variables', () => {
 
     vi.unstubAllEnvs();
   });
+
+  it('should inject Full Access (YOLO) env vars on top of the !isInteractive block', async () => {
+    // Real production flow: shell.ts forces shouldUseNodePty=false when
+    // approvalMode === YOLO, so execute() runs the child_process path with
+    // isInteractive=false. Both env blocks compose: `!isInteractive`
+    // contributes GIT_TERMINAL_PROMPT / GH_PROMPT_DISABLED / GCM_INTERACTIVE
+    // (and GIT_CONFIG_* shaping); the YOLO block contributes the
+    // package-manager / installer vars on top.
+    vi.resetModules();
+    vi.stubEnv('CI', undefined);
+    vi.stubEnv('npm_config_yes', undefined);
+    vi.stubEnv('DEBIAN_FRONTEND', undefined);
+    vi.stubEnv('GIT_CONFIG_COUNT', undefined);
+
+    const { ShellExecutionService } = await import(
+      './shellExecutionService.js'
+    );
+    const { ApprovalMode } = await import('../policy/types.js');
+
+    mockGetPty.mockResolvedValue(null); // child_process fallback
+    await ShellExecutionService.execute(
+      'test-cp-yolo-env',
+      '/',
+      vi.fn(),
+      new AbortController().signal,
+      false, // YOLO real flow: PTY skipped → isInteractive=false
+      { ...shellExecutionConfig, approvalMode: ApprovalMode.YOLO },
+    );
+
+    expect(mockCpSpawn).toHaveBeenCalled();
+    const cpEnv = mockCpSpawn.mock.calls[0][2].env;
+    // From the YOLO block (this PR):
+    expect(cpEnv).toHaveProperty('CI', '1');
+    expect(cpEnv).toHaveProperty('npm_config_yes', 'true');
+    expect(cpEnv).toHaveProperty('npm_config_fund', 'false');
+    expect(cpEnv).toHaveProperty('npm_config_audit', 'false');
+    expect(cpEnv).toHaveProperty('YARN_ENABLE_INTERACTIVE', 'false');
+    expect(cpEnv).toHaveProperty('DEBIAN_FRONTEND', 'noninteractive');
+    expect(cpEnv).toHaveProperty('NEEDRESTART_MODE', 'a');
+    expect(cpEnv).toHaveProperty('PIP_DISABLE_PIP_VERSION_CHECK', '1');
+    // From the pre-existing !isInteractive block — included here so a
+    // regression that decouples the two blocks gets caught:
+    expect(cpEnv).toHaveProperty('GIT_TERMINAL_PROMPT', '0');
+    expect(cpEnv).toHaveProperty('GH_PROMPT_DISABLED', '1');
+    expect(cpEnv).toHaveProperty('GCM_INTERACTIVE', 'never');
+
+    mockChildProcess.emit('exit', 0, null);
+    mockChildProcess.emit('close', 0, null);
+    await new Promise(process.nextTick);
+    vi.unstubAllEnvs();
+  });
+
+  it('should NOT inject Full Access env vars when approvalMode is DEFAULT', async () => {
+    vi.resetModules();
+    vi.stubEnv('CI', undefined);
+    vi.stubEnv('npm_config_yes', undefined);
+    vi.stubEnv('DEBIAN_FRONTEND', undefined);
+
+    const { ShellExecutionService } = await import(
+      './shellExecutionService.js'
+    );
+    const { ApprovalMode } = await import('../policy/types.js');
+
+    mockGetPty.mockResolvedValue(null);
+    await ShellExecutionService.execute(
+      'test-cp-default-env',
+      '/',
+      vi.fn(),
+      new AbortController().signal,
+      true, // interactive
+      { ...shellExecutionConfig, approvalMode: ApprovalMode.DEFAULT },
+    );
+
+    expect(mockCpSpawn).toHaveBeenCalled();
+    const cpEnv = mockCpSpawn.mock.calls[0][2].env;
+    expect(cpEnv).not.toHaveProperty('CI');
+    expect(cpEnv).not.toHaveProperty('npm_config_yes');
+    expect(cpEnv).not.toHaveProperty('DEBIAN_FRONTEND');
+    expect(cpEnv).not.toHaveProperty('NEEDRESTART_MODE');
+
+    mockChildProcess.emit('exit', 0, null);
+    mockChildProcess.emit('close', 0, null);
+    await new Promise(process.nextTick);
+    vi.unstubAllEnvs();
+  });
+
+  it('should preserve pre-existing user env values in Full Access mode (?? coalesce)', async () => {
+    vi.resetModules();
+    vi.stubEnv('CI', '0');
+    vi.stubEnv('DEBIAN_FRONTEND', 'dialog');
+
+    const { ShellExecutionService } = await import(
+      './shellExecutionService.js'
+    );
+    const { ApprovalMode } = await import('../policy/types.js');
+
+    mockGetPty.mockResolvedValue(null);
+    await ShellExecutionService.execute(
+      'test-cp-yolo-preserve',
+      '/',
+      vi.fn(),
+      new AbortController().signal,
+      true,
+      {
+        ...shellExecutionConfig,
+        approvalMode: ApprovalMode.YOLO,
+        sanitizationConfig: {
+          ...shellExecutionConfig.sanitizationConfig,
+          allowedEnvironmentVariables: ['CI', 'DEBIAN_FRONTEND'],
+        },
+      },
+    );
+
+    expect(mockCpSpawn).toHaveBeenCalled();
+    const cpEnv = mockCpSpawn.mock.calls[0][2].env;
+    // User-set values take precedence over the YOLO defaults
+    expect(cpEnv).toHaveProperty('CI', '0');
+    expect(cpEnv).toHaveProperty('DEBIAN_FRONTEND', 'dialog');
+    // The non-conflicting Full Access defaults still get injected
+    expect(cpEnv).toHaveProperty('npm_config_yes', 'true');
+    expect(cpEnv).toHaveProperty('NEEDRESTART_MODE', 'a');
+
+    mockChildProcess.emit('exit', 0, null);
+    mockChildProcess.emit('close', 0, null);
+    await new Promise(process.nextTick);
+    vi.unstubAllEnvs();
+  });
 });
diff --git a/packages/core/src/services/shellExecutionService.ts b/packages/core/src/services/shellExecutionService.ts
index 5817ffd3381..58973a07125 100644
--- a/packages/core/src/services/shellExecutionService.ts
+++ b/packages/core/src/services/shellExecutionService.ts
@@ -37,6 +37,7 @@ import {
   type SandboxPermissions,
 } from './sandboxManager.js';
 import type { SandboxConfig } from '../config/config.js';
+import { ApprovalMode } from '../policy/types.js';
 import { killProcessGroup } from '../utils/process-utils.js';
 import {
   ExecutionLifecycleService,
@@ -105,6 +106,10 @@ export interface ShellExecutionConfig {
   backgroundCompletionBehavior?: 'inject' | 'notify' | 'silent';
   originalCommand?: string;
   sessionId?: string;
+  // When set to YOLO, prepareExecution injects non-interactive env vars
+  // (CI=1, npm_config_yes=true, DEBIAN_FRONTEND=noninteractive, etc.) so
+  // package managers and installers auto-confirm instead of hanging on stdin.
+  approvalMode?: ApprovalMode;
 }
 
 /**
@@ -481,6 +486,36 @@ export class ShellExecutionService {
       });
     }
 
+    // Full Access mode opts the user into "auto-everything". Make common
+    // installers / package managers run non-interactively so they don't hang
+    // on prompts like `npx`'s "Ok to proceed? [y]" or `apt`'s "Do you want
+    // to continue?". Pre-existing user values pass through (?? coalesce).
+    //
+    // GIT_TERMINAL_PROMPT, GH_PROMPT_DISABLED, GCM_INTERACTIVE are NOT set
+    // here: the `!isInteractive` block above already does (in YOLO we force
+    // shouldUseNodePty=false in shell.ts → isInteractive=false → that block
+    // runs and overwrites them unconditionally). Listing them here would be
+    // redundant and the `??` would be misleading — user values for those
+    // three are not preserved by either path.
+    //
+    // Codex CLI does the always-on equivalent at exec (codex-rs
+    // `UNIFIED_EXEC_ENV`); Claude Code propagates these vars from the user's
+    // env. We gate on YOLO because outside Full Access the user has not
+    // opted in to skipping prompts.
+    if (shellExecutionConfig.approvalMode === ApprovalMode.YOLO) {
+      Object.assign(baseEnv, {
+        CI: baseEnv['CI'] ?? '1',
+        npm_config_yes: baseEnv['npm_config_yes'] ?? 'true',
+        npm_config_fund: baseEnv['npm_config_fund'] ?? 'false',
+        npm_config_audit: baseEnv['npm_config_audit'] ?? 'false',
+        YARN_ENABLE_INTERACTIVE: baseEnv['YARN_ENABLE_INTERACTIVE'] ?? 'false',
+        DEBIAN_FRONTEND: baseEnv['DEBIAN_FRONTEND'] ?? 'noninteractive',
+        NEEDRESTART_MODE: baseEnv['NEEDRESTART_MODE'] ?? 'a',
+        PIP_DISABLE_PIP_VERSION_CHECK:
+          baseEnv['PIP_DISABLE_PIP_VERSION_CHECK'] ?? '1',
+      });
+    }
+
     // 3. Prepare Sandboxed Command
     const sandboxedCommand = await sandboxManager.prepareCommand({
       command: resolvedExecutable,
diff --git a/packages/core/src/tools/shell.test.ts b/packages/core/src/tools/shell.test.ts
index e1dd6bdf84c..479eb46c551 100644
--- a/packages/core/src/tools/shell.test.ts
+++ b/packages/core/src/tools/shell.test.ts
@@ -52,6 +52,7 @@ import {
 } from './shell.js';
 import { debugLogger } from '../index.js';
 import { type Config } from '../config/config.js';
+import { ApprovalMode } from '../policy/types.js';
 import { NoopSandboxManager } from '../services/sandboxManager.js';
 import {
   type ShellExecutionResult,
@@ -898,6 +899,58 @@ EOF`;
         await promise;
       });
     });
+
+    describe('PTY routing vs Full Access (YOLO)', () => {
+      it('should enable PTY when interactive shell is on and approvalMode is not YOLO', async () => {
+        vi.mocked(mockConfig.getEnableInteractiveShell).mockReturnValue(true);
+        vi.mocked(mockConfig.getApprovalMode).mockReturnValue(
+          ApprovalMode.DEFAULT,
+        );
+
+        const invocation = shellTool.build({ command: 'echo hi' });
+        const promise = invocation.execute({ abortSignal: mockAbortSignal });
+        resolveShellExecution();
+        await promise;
+
+        const call = mockShellExecutionService.mock.calls.at(-1);
+        // 5th positional arg (index 4) is shouldUseNodePty.
+        expect(call?.[4]).toBe(true);
+      });
+
+      it('should skip PTY in Full Access (YOLO) so sudo cannot prompt for a password', async () => {
+        // PTY would give sudo a real TTY and let it hang forever waiting for
+        // a password. The child_process fallback uses stdio:['ignore', ...]
+        // so sudo fails fast with "a password is required" (matches Codex's
+        // Stdio::null() in codex-rs/utils/pty/src/pipe.rs:144).
+        vi.mocked(mockConfig.getEnableInteractiveShell).mockReturnValue(true);
+        vi.mocked(mockConfig.getApprovalMode).mockReturnValue(
+          ApprovalMode.YOLO,
+        );
+
+        const invocation = shellTool.build({ command: 'sudo apt update' });
+        const promise = invocation.execute({ abortSignal: mockAbortSignal });
+        resolveShellExecution();
+        await promise;
+
+        const call = mockShellExecutionService.mock.calls.at(-1);
+        expect(call?.[4]).toBe(false);
+      });
+
+      it('should still skip PTY when interactive shell is disabled, regardless of approvalMode', async () => {
+        vi.mocked(mockConfig.getEnableInteractiveShell).mockReturnValue(false);
+        vi.mocked(mockConfig.getApprovalMode).mockReturnValue(
+          ApprovalMode.DEFAULT,
+        );
+
+        const invocation = shellTool.build({ command: 'echo hi' });
+        const promise = invocation.execute({ abortSignal: mockAbortSignal });
+        resolveShellExecution();
+        await promise;
+
+        const call = mockShellExecutionService.mock.calls.at(-1);
+        expect(call?.[4]).toBe(false);
+      });
+    });
   });
 
   describe('shouldConfirmExecute', () => {
diff --git a/packages/core/src/tools/shell.ts b/packages/core/src/tools/shell.ts
index 13965d94f6e..f6b2cc18ced 100644
--- a/packages/core/src/tools/shell.ts
+++ b/packages/core/src/tools/shell.ts
@@ -651,11 +651,18 @@ export class ShellToolInvocation extends BaseToolInvocation<
             }
           },
           combinedController.signal,
-          this.context.config.getEnableInteractiveShell(),
+          // In Full Access (YOLO) skip the PTY: a real TTY lets `sudo` and
+          // similar prompt for a password indefinitely. The child_process
+          // fallback uses stdio:['ignore', ...] so sudo fails fast with
+          // "a password is required" (matches Codex's Stdio::null() in
+          // codex-rs/utils/pty/src/pipe.rs:144).
+          this.context.config.getEnableInteractiveShell() &&
+            this.context.config.getApprovalMode() !== ApprovalMode.YOLO,
           {
             ...shellExecutionConfig,
             sessionId: this.context.config?.getSessionId?.() ?? 'default',
             pager: 'cat',
+            approvalMode: this.context.config.getApprovalMode(),
             sanitizationConfig:
               shellExecutionConfig?.sanitizationConfig ??
               this.context.config.sanitizationConfig,