diff --git a/install.bat b/install.bat
index 0fe6f0c..298a940 100644
--- a/install.bat
+++ b/install.bat
@@ -46,17 +46,23 @@ echo.
 echo codeagent-wrapper installed successfully at:
 echo   %DEST%
 
-rem Automatically ensure %USERPROFILE%\bin is in the USER (HKCU) PATH
+rem Ensure %USERPROFILE%\bin is in PATH without duplicating entries
 rem 1) Read current user PATH from registry (REG_SZ or REG_EXPAND_SZ)
 set "USER_PATH_RAW="
-set "USER_PATH_TYPE="
 for /f "tokens=1,2,*" %%A in ('reg query "HKCU\Environment" /v Path 2^>nul ^| findstr /I /R "^ *Path  *REG_"') do (
-    set "USER_PATH_TYPE=%%B"
     set "USER_PATH_RAW=%%C"
 )
 rem Trim leading spaces from USER_PATH_RAW
 for /f "tokens=* delims= " %%D in ("!USER_PATH_RAW!") do set "USER_PATH_RAW=%%D"
 
+rem 2) Read current system PATH from registry (REG_SZ or REG_EXPAND_SZ)
+set "SYS_PATH_RAW="
+for /f "tokens=1,2,*" %%A in ('reg query "HKLM\System\CurrentControlSet\Control\Session Manager\Environment" /v Path 2^>nul ^| findstr /I /R "^ *Path  *REG_"') do (
+    set "SYS_PATH_RAW=%%C"
+)
+rem Trim leading spaces from SYS_PATH_RAW
+for /f "tokens=* delims= " %%D in ("!SYS_PATH_RAW!") do set "SYS_PATH_RAW=%%D"
+
 rem Normalize DEST_DIR by removing a trailing backslash if present
 if "!DEST_DIR:~-1!"=="\" set "DEST_DIR=!DEST_DIR:~0,-1!"
 
@@ -67,42 +73,63 @@ set "SEARCH_EXP2=;!DEST_DIR!\;"
 set "SEARCH_LIT=;!PCT!USERPROFILE!PCT!\bin;"
 set "SEARCH_LIT2=;!PCT!USERPROFILE!PCT!\bin\;"
 
-rem Prepare user PATH variants for containment tests
-set "CHECK_RAW=;!USER_PATH_RAW!;"
-set "USER_PATH_EXP=!USER_PATH_RAW!"
-if defined USER_PATH_EXP call set "USER_PATH_EXP=%%USER_PATH_EXP%%"
-set "CHECK_EXP=;!USER_PATH_EXP!;"
+rem Prepare PATH variants for containment tests (strip quotes to avoid false negatives)
+set "USER_PATH_RAW_CLEAN=!USER_PATH_RAW:"=!"
+set "SYS_PATH_RAW_CLEAN=!SYS_PATH_RAW:"=!"
 
-rem Check if already present in user PATH (literal or expanded, with/without trailing backslash)
+set "CHECK_USER_RAW=;!USER_PATH_RAW_CLEAN!;"
+set "USER_PATH_EXP=!USER_PATH_RAW_CLEAN!"
+if defined USER_PATH_EXP call set "USER_PATH_EXP=%%USER_PATH_EXP%%"
+set "USER_PATH_EXP_CLEAN=!USER_PATH_EXP:"=!"
+set "CHECK_USER_EXP=;!USER_PATH_EXP_CLEAN!;"
+
+set "CHECK_SYS_RAW=;!SYS_PATH_RAW_CLEAN!;"
+set "SYS_PATH_EXP=!SYS_PATH_RAW_CLEAN!"
+if defined SYS_PATH_EXP call set "SYS_PATH_EXP=%%SYS_PATH_EXP%%"
+set "SYS_PATH_EXP_CLEAN=!SYS_PATH_EXP:"=!"
+set "CHECK_SYS_EXP=;!SYS_PATH_EXP_CLEAN!;"
+
+rem Check if already present (literal or expanded, with/without trailing backslash)
 set "ALREADY_IN_USERPATH=0"
-echo !CHECK_RAW! | findstr /I /C:"!SEARCH_LIT!" /C:"!SEARCH_LIT2!" >nul && set "ALREADY_IN_USERPATH=1"
+echo(!CHECK_USER_RAW! | findstr /I /C:"!SEARCH_LIT!" /C:"!SEARCH_LIT2!" >nul && set "ALREADY_IN_USERPATH=1"
 if "!ALREADY_IN_USERPATH!"=="0" (
-    echo !CHECK_EXP! | findstr /I /C:"!SEARCH_EXP!" /C:"!SEARCH_EXP2!" >nul && set "ALREADY_IN_USERPATH=1"
+    echo(!CHECK_USER_EXP! | findstr /I /C:"!SEARCH_EXP!" /C:"!SEARCH_EXP2!" >nul && set "ALREADY_IN_USERPATH=1"
+)
+
+set "ALREADY_IN_SYSPATH=0"
+echo(!CHECK_SYS_RAW! | findstr /I /C:"!SEARCH_LIT!" /C:"!SEARCH_LIT2!" >nul && set "ALREADY_IN_SYSPATH=1"
+if "!ALREADY_IN_SYSPATH!"=="0" (
+    echo(!CHECK_SYS_EXP! | findstr /I /C:"!SEARCH_EXP!" /C:"!SEARCH_EXP2!" >nul && set "ALREADY_IN_SYSPATH=1"
 )
 
 if "!ALREADY_IN_USERPATH!"=="1" (
     echo User PATH already includes %%USERPROFILE%%\bin.
 ) else (
-    rem Not present: append to user PATH using setx without duplicating system PATH
-    if defined USER_PATH_RAW (
-        set "USER_PATH_NEW=!USER_PATH_RAW!"
-        if not "!USER_PATH_NEW:~-1!"==";" set "USER_PATH_NEW=!USER_PATH_NEW!;"
-        set "USER_PATH_NEW=!USER_PATH_NEW!!PCT!USERPROFILE!PCT!\bin"
+    if "!ALREADY_IN_SYSPATH!"=="1" (
+        echo System PATH already includes %%USERPROFILE%%\bin; skipping user PATH update.
     ) else (
-        set "USER_PATH_NEW=!PCT!USERPROFILE!PCT!\bin"
-    )
-    rem Persist update to HKCU\Environment\Path (user scope)
-    setx PATH "!USER_PATH_NEW!" >nul
-    if errorlevel 1 (
-        echo WARNING: Failed to append %%USERPROFILE%%\bin to your user PATH.
-    ) else (
-        echo Added %%USERPROFILE%%\bin to your user PATH.
+        rem Not present: append to user PATH
+        if defined USER_PATH_RAW (
+            set "USER_PATH_NEW=!USER_PATH_RAW!"
+            if not "!USER_PATH_NEW:~-1!"==";" set "USER_PATH_NEW=!USER_PATH_NEW!;"
+            set "USER_PATH_NEW=!USER_PATH_NEW!!PCT!USERPROFILE!PCT!\bin"
+        ) else (
+            set "USER_PATH_NEW=!PCT!USERPROFILE!PCT!\bin"
+        )
+        rem Persist update to HKCU\Environment\Path (user scope)
+        setx Path "!USER_PATH_NEW!" >nul
+        if errorlevel 1 (
+            echo WARNING: Failed to append %%USERPROFILE%%\bin to your user PATH.
+        ) else (
+            echo Added %%USERPROFILE%%\bin to your user PATH.
+        )
     )
 )
 
-rem Update current session PATH so codex-wrapper is immediately available
+rem Update current session PATH so codeagent-wrapper is immediately available
 set "CURPATH=;%PATH%;"
-echo !CURPATH! | findstr /I /C:"!SEARCH_EXP!" /C:"!SEARCH_EXP2!" /C:"!SEARCH_LIT!" /C:"!SEARCH_LIT2!" >nul
+set "CURPATH_CLEAN=!CURPATH:"=!"
+echo(!CURPATH_CLEAN! | findstr /I /C:"!SEARCH_EXP!" /C:"!SEARCH_EXP2!" /C:"!SEARCH_LIT!" /C:"!SEARCH_LIT2!" >nul
 if errorlevel 1 set "PATH=!DEST_DIR!;!PATH!"
 
 goto :cleanup
diff --git a/install.sh b/install.sh
index 0e426a4..d9e2eec 100644
--- a/install.sh
+++ b/install.sh
@@ -48,11 +48,28 @@ else
     exit 1
 fi
 
-if [[ ":$PATH:" != *":${BIN_DIR}:"* ]]; then
+# Auto-add to shell config files with idempotency
+if [[ ":${PATH}:" != *":${BIN_DIR}:"* ]]; then
     echo ""
     echo "WARNING: ${BIN_DIR} is not in your PATH"
-    echo "Add this line to your ~/.bashrc or ~/.zshrc (then restart your shell):"
-    echo ""
-    echo "    export PATH=\"${BIN_DIR}:\$PATH\""
+
+    # Detect shell config file
+    if [ -n "$ZSH_VERSION" ]; then
+        RC_FILE="$HOME/.zshrc"
+    else
+        RC_FILE="$HOME/.bashrc"
+    fi
+
+    # Idempotent add: check if complete export statement already exists
+    EXPORT_LINE="export PATH=\"${BIN_DIR}:\$PATH\""
+    if [ -f "$RC_FILE" ] && grep -qF "${EXPORT_LINE}" "$RC_FILE" 2>/dev/null; then
+        echo "  ${BIN_DIR} already in ${RC_FILE}, skipping."
+    else
+        echo "  Adding to ${RC_FILE}..."
+        echo "" >> "$RC_FILE"
+        echo "# Added by myclaude installer" >> "$RC_FILE"
+        echo "export PATH=\"${BIN_DIR}:\$PATH\"" >> "$RC_FILE"
+        echo "  Done. Run 'source ${RC_FILE}' or restart shell."
+    fi
     echo ""
 fi