fix: resolve PowerShell as default shell on Windows when CLAUDE_CODE_USE_POWERSHELL_TOOL=true

.env.example

@@ -306,6 +306,12 @@ ANTHROPIC_API_KEY=sk-ant-your-key-here
 # Disable "Co-authored-by" line in git commits made by OpenClaude
 # OPENCLAUDE_DISABLE_CO_AUTHORED_BY=1
 
+# Enable PowerShell tool on Windows as the default shell for ! commands and bash-mode.
+# Without this, OpenClaude uses bash (Git Bash / WSL / MSYS2) on Windows.
+# Set to 1/true to activate; set to 0/false to explicitly disable.
+# Only takes effect on Windows; ignored on macOS and Linux.
+# OPENCLAUDE_USE_POWERSHELL_TOOL=1
+
 # Disable strict tool schema normalization for non-Gemini providers
 # Useful when MCP tools with complex optional params (e.g. list[dict])
 # trigger "Extra required key ... supplied" errors from OpenAI-compatible endpoints

src/services/tips/tipRegistry.ts

@@ -238,11 +238,11 @@ const externalTips: Tip[] = [
   {
     id: 'powershell-tool-env',
     content: async () =>
-      'Set CLAUDE_CODE_USE_POWERSHELL_TOOL=1 to enable the PowerShell tool (preview)',
+      'Set OPENCLAUDE_USE_POWERSHELL_TOOL=1 to enable the PowerShell tool (preview)',
     cooldownSessions: 10,
     isRelevant: async () =>
       getPlatform() === 'windows' &&
-      process.env.CLAUDE_CODE_USE_POWERSHELL_TOOL === undefined,
+      process.env.OPENCLAUDE_USE_POWERSHELL_TOOL === undefined,
   },
   {
     id: 'status-line',

src/utils/shell/resolveDefaultShell.ts

@@ -1,14 +1,22 @@
+import { isEnvTruthy } from '../envUtils.js'
+import { getPlatform } from '../platform.js'
 import { getInitialSettings } from '../settings/settings.js'
 
 /**
  * Resolve the default shell for input-box `!` commands.
  *
  * Resolution order (docs/design/ps-shell-selection.md §4.2):
- *   settings.defaultShell → 'bash'
+ *   settings.defaultShell -> (Windows + OPENCLAUDE_USE_POWERSHELL_TOOL) -> 'bash'
  *
- * Platform default is 'bash' everywhere — we do NOT auto-flip Windows to
- * PowerShell (would break existing Windows users with bash hooks).
+ * Platform default is 'bash' on all platforms, unless the user has explicitly
+ * opted into PowerShell via OPENCLAUDE_USE_POWERSHELL_TOOL=true on Windows.
+ * This restores the upstream behavior where setting the env var also makes
+ * PowerShell the default for ! commands without requiring a separate
+ * settings.defaultShell change.
  */
 export function resolveDefaultShell(): 'bash' | 'powershell' {
-  return getInitialSettings().defaultShell ?? 'bash'
+  return getInitialSettings().defaultShell ??
+    (getPlatform() === 'windows' && isEnvTruthy(process.env.OPENCLAUDE_USE_POWERSHELL_TOOL)
+      ? 'powershell'
+      : 'bash')
 }

src/utils/shell/shellToolUtils.ts

@@ -17,6 +17,6 @@ export const SHELL_TOOL_NAMES: string[] = [BASH_TOOL_NAME, POWERSHELL_TOOL_NAME]
 export function isPowerShellToolEnabled(): boolean {
   if (getPlatform() !== 'windows') return false
   return process.env.USER_TYPE === 'ant'
-    ? !isEnvDefinedFalsy(process.env.CLAUDE_CODE_USE_POWERSHELL_TOOL)
-    : isEnvTruthy(process.env.CLAUDE_CODE_USE_POWERSHELL_TOOL)
+    ? !isEnvDefinedFalsy(process.env.OPENCLAUDE_USE_POWERSHELL_TOOL)
+    : isEnvTruthy(process.env.OPENCLAUDE_USE_POWERSHELL_TOOL)
 }