diff --git a/README.md b/README.md
index 424972be..84732dff 100644
--- a/README.md
+++ b/README.md
@@ -206,7 +206,9 @@ The installer auto-creates config and profile templates during installation:
 **macOS / Linux**: `~/.ccs/config.json`
 **Windows**: `%USERPROFILE%\.ccs\config.json`
 
-If you need to customize:
+### macOS / Linux Configuration
+
+Uses settings file paths:
 
 ```json
 {
@@ -218,33 +220,43 @@ If you need to customize:
 }
 ```
 
-**Note**: Config uses Unix-style paths (`~/`) for cross-platform compatibility. Windows version automatically converts paths.
-
 Each profile points to a Claude settings JSON file. Create settings files per [Claude CLI docs](https://docs.claude.com/en/docs/claude-code/installation).
 
-### GLM Profile Configuration
+### Windows Configuration
 
-The installer automatically configures GLM profiles with enhanced environment variables:
+**Important**: Windows Claude CLI uses **environment variables** instead of settings files.
+
+Config format:
 
 ```json
 {
-  "env": {
-    "ANTHROPIC_BASE_URL": "https://api.z.ai/api/anthropic",
-    "ANTHROPIC_AUTH_TOKEN": "YOUR_GLM_API_KEY_HERE",
-    "ANTHROPIC_MODEL": "glm-4.6",
-    "ANTHROPIC_DEFAULT_OPUS_MODEL": "glm-4.6",
-    "ANTHROPIC_DEFAULT_SONNET_MODEL": "glm-4.6",
-    "ANTHROPIC_DEFAULT_HAIKU_MODEL": "glm-4.6"
+  "profiles": {
+    "glm": {
+      "ANTHROPIC_BASE_URL": "https://api.z.ai/api/anthropic",
+      "ANTHROPIC_AUTH_TOKEN": "your_glm_api_key",
+      "ANTHROPIC_MODEL": "glm-4.6",
+      "ANTHROPIC_DEFAULT_OPUS_MODEL": "glm-4.6",
+      "ANTHROPIC_DEFAULT_SONNET_MODEL": "glm-4.6",
+      "ANTHROPIC_DEFAULT_HAIKU_MODEL": "glm-4.6"
+    },
+    "son": {},
+    "default": {}
   }
 }
 ```
 
-**Environment Variables**:
-- `ANTHROPIC_DEFAULT_OPUS_MODEL`: Default model for Opus-class requests
-- `ANTHROPIC_DEFAULT_SONNET_MODEL`: Default model for Sonnet-class requests
-- `ANTHROPIC_DEFAULT_HAIKU_MODEL`: Default model for Haiku-class requests
+**Profile types**:
+- **With env vars** (GLM): Sets environment variables for API providers
+- **Empty object** `{}` (Claude): Uses Claude subscription (no API key needed)
+- **Empty object** `{}` (default): Uses current environment variables
 
-These variables ensure GLM is used as the default provider when switching profiles.
+**Environment Variables**:
+- `ANTHROPIC_BASE_URL`: API endpoint URL
+- `ANTHROPIC_AUTH_TOKEN`: Your API key
+- `ANTHROPIC_MODEL`: Default model
+- `ANTHROPIC_DEFAULT_OPUS_MODEL`: Model for Opus-class requests
+- `ANTHROPIC_DEFAULT_SONNET_MODEL`: Model for Sonnet-class requests
+- `ANTHROPIC_DEFAULT_HAIKU_MODEL`: Model for Haiku-class requests
 
 ## Usage
 
diff --git a/ccs.ps1 b/ccs.ps1
index 246ea2bf..fc3657f7 100644
--- a/ccs.ps1
+++ b/ccs.ps1
@@ -1,5 +1,5 @@
 # CCS - Claude Code Switch (Windows PowerShell)
-# Cross-platform Claude CLI profile switcher
+# Cross-platform Claude CLI profile switcher using environment variables
 # https://github.com/kaitranntt/ccs
 
 param(
@@ -50,10 +50,10 @@ if (-not $Config.profiles) {
     exit 1
 }
 
-# Get settings path for profile
-$SettingsPath = $Config.profiles.$Profile
+# Get profile config
+$ProfileConfig = $Config.profiles.$Profile
 
-if (-not $SettingsPath) {
+if (-not $ProfileConfig) {
     Write-Host "Error: Profile '$Profile' not found in $ConfigFile" -ForegroundColor Red
     Write-Host ""
     Write-Host "Available profiles:"
@@ -63,31 +63,64 @@ if (-not $SettingsPath) {
     exit 1
 }
 
-# Path expansion and normalization
-# 1. Handle Unix-style tilde expansion (~/path -> %USERPROFILE%\path)
-if ($SettingsPath -match '^~[/\\]') {
-    $SettingsPath = $SettingsPath -replace '^~', $env:USERPROFILE
-}
+# Profile config can be either a string (settings file path) or object (env vars)
+# For backward compatibility with Unix, support both formats
 
-# 2. Expand Windows environment variables (%USERPROFILE%, etc.)
-$SettingsPath = [System.Environment]::ExpandEnvironmentVariables($SettingsPath)
-
-# 3. Convert forward slashes to backslashes (Unix path compatibility)
-$SettingsPath = $SettingsPath -replace '/', '\'
-
-# Validate settings file exists
-if (-not (Test-Path $SettingsPath)) {
-    Write-Host "Error: Settings file not found: $SettingsPath" -ForegroundColor Red
+if ($ProfileConfig -is [string]) {
+    # Legacy format: path to settings file (for cross-platform configs)
+    # This won't work on Windows Claude CLI, show helpful error
+    Write-Host "Error: Windows Claude CLI doesn't support settings files." -ForegroundColor Red
     Write-Host ""
-    Write-Host "Create the settings file or update the path in $ConfigFile"
+    Write-Host "Windows uses environment variables instead."
+    Write-Host "Update your profile in $ConfigFile to use this format:"
+    Write-Host ""
+    Write-Host '  "' + $Profile + '": {'
+    Write-Host '    "ANTHROPIC_AUTH_TOKEN": "your_api_key",'
+    Write-Host '    "ANTHROPIC_BASE_URL": "https://api.z.ai/api/anthropic",'
+    Write-Host '    "ANTHROPIC_MODEL": "glm-4.6"'
+    Write-Host '  }'
+    Write-Host ""
+    Write-Host "Or leave empty {} for Claude subscription (no API key needed)."
     exit 1
 }
 
-# Execute claude with settings
-# Pass arguments directly to Claude CLI with proper splatting
-if ($RemainingArgs) {
-    & claude --settings $SettingsPath @RemainingArgs
-} else {
-    & claude --settings $SettingsPath
+# Apply environment variables from profile
+# Save original values to restore after command execution
+$OriginalEnvVars = @{}
+
+if ($ProfileConfig.PSObject.Properties.Count -gt 0) {
+    foreach ($Property in $ProfileConfig.PSObject.Properties) {
+        $VarName = $Property.Name
+        $VarValue = $Property.Value
+
+        # Save original value
+        $OriginalEnvVars[$VarName] = [System.Environment]::GetEnvironmentVariable($VarName, 'Process')
+
+        # Set new value for this process
+        [System.Environment]::SetEnvironmentVariable($VarName, $VarValue, 'Process')
+    }
 }
-exit $LASTEXITCODE
+
+# Execute claude with environment variables set
+try {
+    if ($RemainingArgs) {
+        & claude @RemainingArgs
+    } else {
+        & claude
+    }
+    $ExitCode = $LASTEXITCODE
+} finally {
+    # Restore original environment variables
+    foreach ($VarName in $OriginalEnvVars.Keys) {
+        $OriginalValue = $OriginalEnvVars[$VarName]
+        if ($null -eq $OriginalValue) {
+            # Variable didn't exist before, remove it
+            [System.Environment]::SetEnvironmentVariable($VarName, $null, 'Process')
+        } else {
+            # Restore original value
+            [System.Environment]::SetEnvironmentVariable($VarName, $OriginalValue, 'Process')
+        }
+    }
+}
+
+exit $ExitCode
diff --git a/install.ps1 b/install.ps1
index a4b9f45f..93e7d130 100644
--- a/install.ps1
+++ b/install.ps1
@@ -186,8 +186,6 @@ Write-Host ""
 # Profile Setup
 
 $CurrentProvider = Detect-CurrentProvider
-$GlmSettings = "$CcsDir\glm.settings.json"
-$SonnetSettings = "$CcsDir\sonnet.settings.json"
 
 $ProviderLabel = switch ($CurrentProvider) {
     "glm" { " (detected: GLM)" }
@@ -200,30 +198,33 @@ Write-Host "┌─ Configuring Profiles$ProviderLabel"
 
 $NeedsGlmKey = $false
 
-if (-not (Test-Path $GlmSettings)) {
-    New-GlmProfile -Provider $CurrentProvider | Out-Null
-    Write-Host "|  [OK] GLM profile -> $env:USERPROFILE\.ccs\glm.settings.json"
-    if ($CurrentProvider -ne "glm") { $NeedsGlmKey = $true }
-}
-
-if (-not (Test-Path $SonnetSettings)) {
-    New-SonnetProfile -Provider $CurrentProvider | Out-Null
-    Write-Host "|  [OK] Sonnet profile -> $env:USERPROFILE\.ccs\sonnet.settings.json"
-}
-
-# Create ccs config (using Unix-style paths for cross-platform compatibility)
+# Create ccs config (Windows uses environment variables, not settings files)
 $ConfigFile = "$CcsDir\config.json"
 if (-not (Test-Path $ConfigFile)) {
+    # Detect if user has GLM API key set in environment
+    $HasGlmKey = $env:ANTHROPIC_AUTH_TOKEN -and $env:ANTHROPIC_BASE_URL -match "z\.ai"
+
     $ConfigContent = @{
         profiles = @{
-            glm = "~/.ccs/glm.settings.json"
-            son = "~/.ccs/sonnet.settings.json"
-            default = "~/.claude/settings.json"
+            glm = @{
+                ANTHROPIC_BASE_URL = "https://api.z.ai/api/anthropic"
+                ANTHROPIC_AUTH_TOKEN = if ($HasGlmKey) { $env:ANTHROPIC_AUTH_TOKEN } else { "YOUR_GLM_API_KEY_HERE" }
+                ANTHROPIC_MODEL = $GlmModel
+                ANTHROPIC_DEFAULT_OPUS_MODEL = $GlmModel
+                ANTHROPIC_DEFAULT_SONNET_MODEL = $GlmModel
+                ANTHROPIC_DEFAULT_HAIKU_MODEL = $GlmModel
+            }
+            son = @{}  # Empty = use Claude subscription (no env vars needed)
+            default = @{}  # Empty = use current environment settings
         }
     }
 
     $ConfigContent | ConvertTo-Json -Depth 10 | Set-Content $ConfigFile
     Write-Host "|  [OK] Config -> $env:USERPROFILE\.ccs\config.json"
+
+    if (-not $HasGlmKey) {
+        $NeedsGlmKey = $true
+    }
 }
 
 Write-Host "└─"
@@ -253,8 +254,8 @@ if ($UserPath -notlike "*$CcsDir*") {
 if ($NeedsGlmKey) {
     Write-Host "[!]  ACTION REQUIRED"
     Write-Host ""
-    Write-Host "   Edit $env:USERPROFILE\.ccs\glm.settings.json and add your GLM API key"
-    Write-Host "   Replace: YOUR_GLM_API_KEY_HERE"
+    Write-Host "   Edit $env:USERPROFILE\.ccs\config.json and add your GLM API key"
+    Write-Host "   Replace YOUR_GLM_API_KEY_HERE in the 'glm' profile with your actual API key"
     Write-Host ""
 }