diff --git a/packages/core/src/config/config.ts b/packages/core/src/config/config.ts
index 44570203c..3663beb8f 100644
--- a/packages/core/src/config/config.ts
+++ b/packages/core/src/config/config.ts
@@ -96,6 +96,7 @@ import {
 // Utils
 import { shouldAttemptBrowserLaunch } from '../utils/browser.js';
 import { FileExclusions } from '../utils/ignorePatterns.js';
+import { shouldDefaultToNodePty } from '../utils/shell-utils.js';
 import { WorkspaceContext } from '../utils/workspaceContext.js';
 import { isToolEnabled, type ToolName } from '../utils/tool-utils.js';
 import { getErrorMessage } from '../utils/errors.js';
@@ -636,7 +637,8 @@ export class Config {
     this.webSearch = params.webSearch;
     this.useRipgrep = params.useRipgrep ?? true;
     this.useBuiltinRipgrep = params.useBuiltinRipgrep ?? true;
-    this.shouldUseNodePtyShell = params.shouldUseNodePtyShell ?? true;
+    this.shouldUseNodePtyShell =
+      params.shouldUseNodePtyShell ?? shouldDefaultToNodePty();
     this.skipNextSpeakerCheck = params.skipNextSpeakerCheck ?? true;
     this.shellExecutionConfig = {
       terminalWidth: params.shellExecutionConfig?.terminalWidth ?? 80,
diff --git a/packages/core/src/utils/shell-utils.ts b/packages/core/src/utils/shell-utils.ts
index 1f0476866..1c839530f 100644
--- a/packages/core/src/utils/shell-utils.ts
+++ b/packages/core/src/utils/shell-utils.ts
@@ -913,3 +913,13 @@ export function isCommandNeedsPermission(command: string): {
     reason: 'Command requires permission to execute.',
   };
 }
+
+// ConPTY on Windows builds <= 19041 has known reliability issues (missing
+// output, hangs). VS Code uses the same cutoff: microsoft/vscode#123725.
+const CONPTY_MIN_WINDOWS_BUILD = 19042;
+
+export function shouldDefaultToNodePty(): boolean {
+  if (os.platform() !== 'win32') return true;
+  const build = parseInt(os.release().split('.')[2] ?? '', 10);
+  return !isNaN(build) && build >= CONPTY_MIN_WINDOWS_BUILD;
+}