System Informer MCP

Give your AI agent the full power of System Informer (Process Hacker) on Windows.

A lightweight, native Model Context Protocol server — written in C, ~350 KB, zero runtime dependencies — that lets an LLM inspect and control Windows the same way a human does through the System Informer GUI: processes, threads, memory, handles, services, network, drivers, windows and more.

⬇ Download the prebuilt si-mcp.exe (v1.0.0, x64) — no compiler needed

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TL;DR — Ask your AI: "What's using port 3000?", "Why is my CPU at 100%?", "Which process is locking this DLL?", "Is this .exe validly signed?", "Start Notepad, then suspend it." — and it just does it, through 54 well-documented native tools.

Why this exists

Modern System Informer builds have no headless / command-line mode — the switches only configure the GUI. So instead of scraping a GUI (fragile and lossy), this server does exactly what System Informer itself does: it compiles against System Informer's own phnt NT-API headers and calls the same native Windows APIs (NtQuerySystemInformation, NtQueryInformationProcess/Thread, the Service Control Manager, IP Helper, WinVerifyTrust, ...). Results come back as structured JSON instead of GUI tables.

That is the tightest practical coupling to how System Informer actually works — and it means your AI never has to guess.

Highlights

• 54 tools covering every System Informer data view and action.
• Native & tiny. Pure C, a single ~350 KB si-mcp.exe, no Python/Node runtime, no DLLs to ship.
• The AI never guesses. A rich instructions block at startup, a fully documented JSON Schema for every argument (types, enums, defaults), and ready-made workflow prompts.
• Safe by default. Every destructive/irreversible action is guarded behind an explicit confirm: true; killing a critical process needs a second gate. Every handler runs under a structured-exception guard so a fault returns an error instead of crashing the server.
• Honest about privileges. server_status tells you exactly what you can and cannot see given your elevation.

See it in action

// Ask: "What is listening on port 3000?"
→ port_owner { "port": 3000 }
← { "port": 3000, "matches": 1,
    "owners": [ { "protocol": "TCP", "local": "0.0.0.0:3000",
                  "state": "LISTEN", "pid": 18240,
                  "processImage": "C:\\Program Files\\nodejs\\node.exe" } ] }

// Ask: "Start Notepad, then suspend it."
→ launch_process   { "command_line": "notepad.exe" }        → { "pid": 51432 }
→ suspend_process  { "pid": 51432, "confirm": true }        → { "status": "ok" }

How it works

flowchart LR
    A[AI Agent<br/>Claude / Cursor / ...] -- MCP over stdio --> B[si-mcp.exe<br/>~350 KB, C]
    B -- phnt NT-API headers --> C[Native Windows APIs<br/>Nt* / SCM / IP Helper / WinTrust]
    C --> D[Live System<br/>processes · threads · memory<br/>handles · services · network]
    B -. hand-off .-> E[System Informer GUI<br/>live graphs · PE Viewer]

Loading

Quick start

1. Get the binary

Option A — download (recommended). Grab si-mcp-v1.0.0-windows-x64.exe from the latest release and put it anywhere. It is a single ~340 KB file with no dependencies. SHA256SUMS.txt is provided for verification.

Option B — build from source. Requires Visual Studio 2022 (or the free Build Tools) with the Desktop development with C++ workload and a Windows 10/11 SDK. Nothing else — no CMake, no package manager.

git clone https://github.com/Xiaobocai08/system-informer-mcp.git
cd system-informer-mcp
build.bat
:: -> build\si-mcp.exe

The phnt headers are vendored in third_party/phnt, so the repo builds on its own.

2. Register with your MCP client

Claude Code

claude mcp add system-informer -- "C:\path\to\system-informer-mcp\build\si-mcp.exe"

Cursor / Claude Desktop / any stdio MCP client (config JSON)

{
  "mcpServers": {
    "system-informer": {
      "command": "C:\\path\\to\\system-informer-mcp\\build\\si-mcp.exe"
    }
  }
}

Run your client as Administrator for full coverage. Call server_status any time to see what you have.

3. Ask your AI

"Show me the top 5 processes by memory, then tell me if the biggest one is signed."

All 54 tools

Group	Tools
System	server_status · system_overview · system_cpu_usage · system_memory · system_uptime
Processes	list_processes · process_tree · process_details · process_token
Process control	launch_process · launch_process_elevated · terminate_process · terminate_process_tree · suspend_process · resume_process · set_process_priority · set_process_affinity · empty_working_set · set_process_critical · create_process_dump
Threads	process_threads · thread_details · suspend_thread · resume_thread · terminate_thread · set_thread_priority · set_thread_affinity
Memory	process_memory_regions · process_memory_summary · read_process_memory · write_process_memory · protect_process_memory · search_process_memory · process_memory_strings
Handles	list_handles · handle_type_summary · find_handles_by_name · close_handle
Services	list_services · service_details · control_service · set_service_start_type · create_service · delete_service
Network	network_connections · port_owner
Modules / Drivers	process_modules · list_drivers
Windows	list_windows · window_action
Files	file_details · verify_file_signature
GUI hand-off	launch_systeminformer_gui · launch_peview

Call tools/list for the full schema of each, and prompts/list for guided workflows: diagnose high CPU, triage a suspicious process, what-locks-this-file, what-owns-this-port, inspect a process.

Privileges

Windows — not this server — decides what is visible. Run elevated for full coverage:

Running as	Coverage
Standard user	Your own processes in full; others limited; kernel addresses hidden
Administrator	Nearly everything: all processes, service control, kernel addresses
Admin + KSystemInformer driver	Protected processes (PPL, antimalware) too

Safety model

Mutating or irreversible tools refuse to run without "confirm": true — terminate_*, suspend/resume, priority/affinity, empty_working_set, set_process_critical, write_process_memory, protect_process_memory, close_handle, all service mutations, and window_action. Terminating a Windows-critical process can bugcheck the machine, so that path has an extra allow_critical gate.

How it compares

	system-informer-mcp	Typical "system info" MCPs
Language / size	Native C, ~350 KB exe	Python/Node + runtime
Depth	Processes, threads, memory r/w, handles, tokens, services, network, drivers, windows, signatures	Usually read-only process/CPU/mem stats
Control actions	Terminate, suspend, priority, affinity, dumps, service & handle control	Rarely
Guidance to the LLM	Rich instructions + per-arg JSON Schema + prompts	Minimal
Safety	confirm guard + SEH isolation	Varies

Project layout

build.bat                 MSVC build script (no external build system)
src/
  main.c                  stdio JSON-RPC loop + MCP dispatch
  mcp.c / mcp.h           tool registry, argument & result helpers
  prompts.c               startup instructions + workflow prompts
  ntutil.c / ntutil.h     NT/Win32 helpers (phnt): UTF-8, SIDs, errors
  procsnap.c / procsnap.h shared process-snapshot helpers
  tools_*.c               one file per tool group
third_party/
  cJSON/                  vendored JSON library (MIT)
  phnt/                   vendored System Informer NT-API headers (MIT)
test/                     Python MCP client + end-to-end tests

Testing

python test\mcp_client.py            :: initialize + list every tool
python test\test_all.py              :: exercise all 54 tools end-to-end
python test\roundtrip.py             :: launch -> inspect -> control -> dump -> terminate

test_all.py launches a throwaway Notepad, drives all 54 tools against it and the live system, checks the confirm guards, and reports coverage. Latest run: 56/56 checks passed, 54/54 tools covered on Windows 11 (build 26200).

FAQ

Is this malware? No. It is an open-source, auditable MCP server. It exposes exactly what the System Informer GUI already exposes to any administrator, over a local stdio channel to your own AI client. Every dangerous action is gated behind confirm: true.

Does it need System Informer installed? No — every inspection/control tool works standalone. Only the two GUI hand-off tools (launch_systeminformer_gui, launch_peview) need the app; set SYSTEMINFORMER_PATH if it is installed in a non-default location.

macOS / Linux? No. This is deeply Windows-specific by design (NT native APIs).

Acknowledgements

• System Informer by Winsider Seminars & Solutions, Inc. — the phnt headers and the tool this project mirrors.
• cJSON by Dave Gamble.
• Model Context Protocol by Anthropic.

Star history

License

MIT. Builds against System Informer's phnt headers (MIT) and vendors cJSON (MIT).

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