UIPI (User Interface Privilege Isolation) Detection

File: internal/actions/uipi.go (110 lines)

Windows UIPI blocks low-integrity (non-admin) processes from sending input (SendInput) to elevated (admin) windows. The MCP server detects this mismatch and returns a clear error so the user knows to relaunch as admin.

Detection Functions

isForegroundElevated() → (bool, error)

1. GetForegroundWindow → hwnd
2. GetWindowThreadProcessId → pid
3. OpenProcess(PROCESS_QUERY_LIMITED_INFORMATION) → hProcess
   • If ERROR_ACCESS_DENIED → process is elevated (admin processes deny PROCESS_QUERY_LIMITED_INFORMATION to non-elevated callers)
4. OpenProcessToken(hProcess, TOKEN_QUERY) → hToken
5. GetTokenInformation(hToken, TokenElevation=20) → TOKEN_ELEVATION struct
6. Returns elevated != 0

isProcessElevated(pid uint32) → (bool, error)

Same logic as above but for an arbitrary PID.

isSelfElevated() → (bool, error)

Calls isProcessElevated(GetCurrentProcessId()).

warnElevated() → error

Three-tier check:

1. Target check — is foreground window elevated? If not → return nil
2. Self check — is the MCP server itself elevated? If yes → UIPI allows same-integrity input → return nil
3. Mismatch — foreground is elevated, server is not → return descriptive error with remediation

Error Message

foreground window is elevated (admin). Input from non-elevated MCP server
is blocked by Windows UIPI. Run mcp-server.exe as Administrator or target
a non-elevated window

C DLL Calls (advapi32.dll)

Proc	Signature
OpenProcessToken	OpenProcessToken(hProcess uintptr, DesiredAccess uint32, TokenHandle *uintptr) bool
GetTokenInformation	GetTokenInformation(TokenHandle uintptr, TokenInformationClass uint32, TokenInformation *uint32, TokenInformationLength uint32, ReturnLength *uint32) bool

Also calls via user32.dll: GetForegroundWindow, GetWindowThreadProcessId.
Also calls via kernel32.dll: OpenProcess, CloseHandle.

Call Sites

Caller File	Function	Trigger
chained.go:72	chainStep	Before each chain step
chained.go:185	chainStep	Before chain step (alt path)
keyboard.go:203	keyDown (type/send)	Before key down
keyboard.go:222	keyUp	Before key up
keyboard.go:241	keyPress	Before key press
keyboard.go:297	typeString	Before typing text

Cross-Reference

• docs/reference/windows-dll-ref.md — advapi32.dll and user32.dll proc listings
• docs/reference/codebase-map.md — tool→handler→action→file mapping