nx-ai-bridge

Let any AI tool drive Siemens NX (UG) modelling. 中文说明

⚠️ ALPHA - not yet verified on a real NX installation

The bridge (MCP server, CLI, mock) is tested on Windows, macOS and Linux. The part that runs inside NX was written without access to NX and has only been compiled and exercised against a stand-in for the NX Open API. Expect some tools to fail on real NX until the first self-check reports have been worked through. See Verification status.

Tell your AI assistant:

Install the plugin https://github.com/qiuyekai/nx-ai-bridge and draw an L-bracket with two holes in NX.

The assistant reads AGENTS.md, installs the bridge, asks you to start one journal inside NX, and then models directly in your NX window while you watch.

AI tool ──MCP (stdio)──▶ bridge (Python) ──127.0.0.1──▶ receiver journal inside NX ──▶ NX Open API
   └────── or CLI ───────┘

• Any AI tool: an MCP server for Claude Code / Claude Desktop / Cursor / Codex / Gemini CLI / VS Code, and an identical command line interface for tools that can only run commands.

• No installation inside NX: the receiver is a journal (Alt+F8). No NX Open author licence, no compiled DLL, no administrator rights. Windows-side setup is a folder copy.

• The AI can see and verify: every modelling step returns the body's volume and bounding box; screenshot returns a picture of the NX window.

• Errors the AI can act on: structured JSON with NX's original error text; failed steps are rolled back.

• Escape hatch: run_journal executes NX Open code written by the AI; nx_api_lookup lets it explore the API of the running NX version without documentation.

Related MCP server: CadKitty

Supported versions

Quick start (Windows with NX)

git clone https://github.com/qiuyekai/nx-ai-bridge.git
cd nx-ai-bridge
powershell -ExecutionPolicy Bypass -File install.ps1

install.ps1 needs no administrator rights. It locates NX, copies the receiver to %USERPROFILE%\.nx-ai-bridge\nx_receiver, prepares Python and prints the configuration for your AI tool. No Python on the machine? install.ps1 -InstallUv puts uv into your user profile.

Then the one manual step, inside NX:

1. Start NX and open or create a part.

2. Press Alt+F8 (menu Tools > Journal > Play...).

3. Select %USERPROFILE%\.nx-ai-bridge\nx_receiver\NxAiBridgeReceiver.cs and click Run.

4. A small "NX AI Bridge" window appears. Leave it open - closing it stops the receiver.

Configure your AI tool

install.ps1 prints the exact command for your machine. The generic form, using uv straight from GitHub:

claude mcp add nx -- uvx --from git+https://github.com/qiuyekai/nx-ai-bridge nx-ai-bridge serve

.cursor/mcp.json, claude_desktop_config.json, ~/.gemini/settings.json:

{
  "mcpServers": {
    "nx": {
      "command": "uvx",
      "args": ["--from", "git+https://github.com/qiuyekai/nx-ai-bridge", "nx-ai-bridge", "serve"]
    }
  }
}

[mcp_servers.nx]
command = "uvx"
args = ["--from", "git+https://github.com/qiuyekai/nx-ai-bridge", "nx-ai-bridge", "serve"]

{
  "servers": {
    "nx": { "type": "stdio", "command": "uvx", "args": ["--from", "git+https://github.com/qiuyekai/nx-ai-bridge", "nx-ai-bridge", "serve"] }
  }
}

nx-ai-bridge tools
nx-ai-bridge call nx_status
nx-ai-bridge call create_block length=100 width=50 height=20
nx-ai-bridge call create_hole '{"position": [50, 25, 20], "diameter": 10, "through": true}'

Every call prints a JSON envelope and exits with code 1 on failure.

A PyPI release (pip install nx-ai-bridge / uvx nx-ai-bridge) will follow once the receiver has been verified on real NX.

Try it without NX

Works on any OS; the mock receiver fakes NX with simple geometry:

git clone https://github.com/qiuyekai/nx-ai-bridge.git && cd nx-ai-bridge
NX_AI_BRIDGE_TRANSPORT=mock uv run nx-ai-bridge demo --part /tmp/bracket.prt

Tools

All lengths are millimetres, all angles degrees. nx-ai-bridge tools <name> shows the parameters of a tool.

Every tool answers with

{"ok": true, "result": {"feature": "BLOCK(1)", "body": "B1", "volume": 32000, "bbox": [0, 0, 0, 80, 40, 10]}}

or, on failure, with NX's own error message so the AI can correct itself:

{"ok": false, "error": {"code": "NX_ERROR", "message": "Tool body completely outside target body.",
                        "nx_error": {"type": "NXOpen.NXException", "error_code": 670030, "message": "..."}}}

Two modes

Two transports exist for live mode and are chosen automatically: a TCP socket on 127.0.0.1 and, as a fallback, polling a request folder (%USERPROFILE%\.nx-ai-bridge\ipc). Details: docs/protocol.md.

Self-check

Because the NX side was written blind, the project ships a self-check that replaces days of manual testing with two clicks. If you have NX, running it is the most valuable contribution you can make:

powershell -ExecutionPolicy Bypass -File selfcheck.ps1

Then play %USERPROFILE%\.nx-ai-bridge\nx_receiver\NxAiBridgeSelfCheck.cs in NX (Alt+F8) and answer one question. You get a single file, nx-ai-bridge-selfcheck-<time>.json (a copy lands on your Desktop). Please attach it to a GitHub issue. It contains: NX version and install path, whether run_journal.exe works under your licence, which transport works, whether NX stays responsive while the receiver runs, the result of every tool with the original NX error, analytic volume checks of a reference bracket, and a listing of NX Open member names (no geometry or personal files of yours; the report does include your Windows user name inside file paths).

Verification status

Findings from real machines are collected in docs/nx10-notes.md.

Security and limitations

• run_journal executes arbitrary code inside NX with your user's privileges - that is its purpose. Only connect AI tools you trust, and review what they are about to run when working on valuable data. To disable it, delete %USERPROFILE%\.nx-ai-bridge\nx_receiver\handlers\run_journal.cs.

• The receiver listens on 127.0.0.1 only and never opens a port to the network. There is no authentication: any program running under your Windows account can send it requests while the receiver window is open.

• The receiver compiles its own source files (C#) at start-up with the compiler that is part of Windows and caches the result under %USERPROFILE%\.nx-ai-bridge\cache - the same mechanism NX uses to play journals. Anyone who can write to that folder can change what runs inside NX.

• One request at a time; long NX operations block the queue.

• AI-driven modelling makes mistakes. Work on copies, save often, and check results before relying on them.

Not affiliated with Siemens

This is an independent open-source project. It is not a Siemens product and is not endorsed by Siemens. "NX" and "Unigraphics" are trademarks of Siemens Industry Software Inc. You need your own valid NX licence; the project contains no Siemens files (no DLLs, no documentation). It works through NX's own journal mechanism and the NX Open API of your installation; whether and how you may automate NX is governed by your NX licence terms.

Repository layout

AGENTS.md            instructions for AI agents (install, use, troubleshoot)
install.ps1          Windows setup, no admin rights
selfcheck.ps1        self-check part 1 (outside NX)
nx_receiver/         runs inside NX
  NxAiBridgeReceiver.cs    the journal you play (a small loader)
  NxAiBridgeSelfCheck.cs   the self-check journal
  kernel/                  JSON, transports, run-time compiler, dispatcher, control window (no NX Open calls)
  nxlib/                   shared NX Open helpers
  handlers/                one small C# file per tool group, compiled individually, hot-reloaded
  vb/                      VB.NET versions of the two journals (fallback)
src/nx_ai_bridge/    MCP server, CLI, transports, mock receiver
tests/               tests incl. a stand-in for NX Open used by CI
docs/                protocol, design notes, NX 10 findings

Design rationale: docs/design.md.

Development

uv venv && uv pip install -e ".[dev]"
uv run pytest                      # no NX needed
python scripts/sync_loaders.py     # after editing the loader journals

License

MIT