Multisim MCP

Unofficial Windows MCP server for creating NI Multisim schematics, running experiments, exporting data, and generating reproducible reports.

非官方 Multisim 自动化 MCP：从受限 SPICE 网表生成可编辑电路图，调用本机 Multisim 执行实验，并导出 .ms14、原理图、raw、CSV、SVG 和 Markdown 报告。

Alpha software. This project is not affiliated with NI. Multisim must be installed and licensed locally. The current COM worker requires 32-bit Python.

Linux and Docker support MCP initialization, tool discovery, and runtime_status diagnostics only. They do not run Multisim. On an unsupported platform the server starts in introspection-only mode, while every COM-backed operation fails closed with a Windows compatibility message. The repository's minimal non-root Docker image exists for registry validation and contains no NI software, samples, licenses, or extracted templates.

Current capability

Stable and verified on Multisim 14.3:

• MCP stdio lifecycle and 32-bit runtime diagnostics.
• Open/save circuits and enumerate components, inputs, and outputs.
• DC operating point, AC sweep, single-frequency AC, and transient analysis.
• Input waveform injection and RLC value read/write.
• SPICE netlist execution with safe op, dc, ac, and tran commands.
• Netlist, BOM, schematic image, raw data, CSV, SVG, and Markdown export.
• High-level run_circuit_experiment workflow.

Experimental:

• Editable schematic generation supports R/L/C, scalar and waveform voltage/current sources, B/E/F/G/H controlled sources, T/O/U distributed lines, coupled inductors, modeled diodes, NPN/PNP BJT, NMOS/PMOS, JFET/MESFET, voltage switches, five-terminal op-amps, and generic two-to-sixteen-terminal X subcircuits. Extended families currently use verified carrier symbols pending dedicated artwork. Native NOT/AND/OR/NAND/NOR/XOR/XNOR and JK flip-flop symbols are available as a preview; their open/export and authoritative timing-data paths are verified. Native XSC oscilloscope and configurable XFG function-generator state are generated alongside authoritative CSV/SVG experiment data. Multisim's exported native netlist is checked after opening so silently omitted parts fail the run.
• Generated schematic probes are not enabled by default. Experiment data is obtained authoritatively from the same netlist through Multisim's engine.

Install

Requirements:

• Windows and a licensed Multisim 14+ installation.
• 32-bit Python 3.10+.
• Node.js 18+ only for .ms14 XML conversion.

Install the Python package once; the server launcher never installs packages or writes setup logs to MCP stdout:

cd mcp_server
.\setup.ps1 -Python C:\path\to\python32\python.exe
npm install --global electronics-workbench-decoder@0.2.0

The public wheel is intentionally code-only: it contains the provenance manifest but no XML extracted from NI samples. Before generating schematics, build a local component pack from your own licensed installation as described below and set MULTISIM_MCP_TEMPLATE_DIR. Other Automation API tools can still be installed without that pack.

Diagnose the installation before starting the server:

# Human-readable output (Chinese or English)
C:\path\to\python32\Scripts\multisim-mcp.exe doctor --lang zh
C:\path\to\python32\Scripts\multisim-mcp.exe doctor --lang en

# Explicitly start/connect to Multisim and verify licensing plus COM activation.
C:\path\to\python32\Scripts\multisim-mcp.exe doctor --connect

# Stable JSON for agents and CI. Add --strict to require the full workflow.
C:\path\to\python32\Scripts\multisim-mcp.exe --json doctor
C:\path\to\python32\Scripts\multisim-mcp.exe doctor --json --strict

doctor is side-effect free by default: it does not activate Multisim. It checks the Python version and architecture, pywin32, the 32-bit COM registration, the local template pack, and the pinned .ms14 codecs. A normal diagnostic run returns exit code zero even when setup is incomplete so an agent can parse all checks. --strict returns non-zero unless the complete workflow is ready. --connect is the explicit opt-in that may start Multisim; it restores a previously disconnected COM state after the probe and does not disturb an already connected instance.

Start the server. Calling multisim-mcp without a subcommand remains backward compatible; serve is the explicit equivalent:

.\run_server.ps1
C:\path\to\python32\Scripts\multisim-mcp.exe serve

Generate a client configuration fragment:

# Claude Desktop JSON
C:\path\to\python32\Scripts\multisim-mcp.exe config `
  --client claude-desktop `
  --python C:\path\to\python32\python.exe `
  --template-dir C:\MultisimMcp\component-pack `
  --work-dir C:\msre_exp

# Codex config.toml
C:\path\to\python32\Scripts\multisim-mcp.exe config `
  --client codex `
  --python C:\path\to\python32\python.exe `
  --template-dir C:\MultisimMcp\component-pack

# Unwrapped command/args/env JSON for another stdio client
C:\path\to\python32\Scripts\multisim-mcp.exe config --client generic

The generator previews content on stdout. --output <new-file> writes a fragment, refuses to overwrite by default, and accepts --force only when the caller explicitly wants replacement. It does not merge into a live client configuration.

Manual MCP client configuration:

{
  "mcpServers": {
    "multisim": {
      "command": "C:\\path\\to\\python32\\python.exe",
      "args": ["-m", "multisim_mcp.server"]
    }
  }
}

Call runtime_status first when diagnosing installation problems.

CLI JSON contract

multisim-mcp --json doctor emits one JSON object with schema_version, success, readiness booleans (including activation state), runtime facts, and a stable checks[] array. Each check has a stable id, status, and message; failed checks may include repair. Missing setup is reported as data rather than a JSON error.

multisim-mcp config ... --json emits a result envelope containing the client, server name, optional output path, and generated content. Invalid input or an overwrite refusal uses this error shape and exit code 2:

{
  "schema_version": 1,
  "command": "config",
  "success": false,
  "error": {"type": "ValueError", "message": "..."}
}

JSON stdout never contains progress text or credentials. Import-time COM cache diagnostics are redirected to stderr.

User-local component packs

To keep licensed/reverse-engineered component assets separate from the open engine, a contributor can derive a local pack from the NI samples installed on their own machine:

$env:PYTHONPATH = (Resolve-Path .\mcp_server).Path
.\tools\python32\python.exe .\tools\bootstrap_local_component_pack.py `
  --output C:\MultisimMcp\component-pack
$env:MULTISIM_MCP_TEMPLATE_DIR = 'C:\MultisimMcp\component-pack'

The configured pack is the public release's schematic-template source. A local development checkout may contain ignored fallback templates, but public wheels do not. The generated manifest records relative sample provenance. Local reverse-engineering authorization does not itself grant permission to publish the resulting XML files.

Recommended agent workflow

The high-level tool accepts a SPICE netlist and a safe experiment command:

{
  "netlist": "VIN vin 0 DC 10\nR1 vin vout 1k\nR2 vout 0 1k\n.end\n",
  "commands": "dc VIN 0 10 0.1",
  "output_dir": "C:\\experiments\\divider",
  "title": "Resistor divider",
  "overwrite": false
}

run_circuit_experiment will:

1. Validate the supported netlist and analysis command.
2. Generate and encode an editable circuit.ms14.
3. Open the design in Multisim and export schematic.png.
4. Run the requested analysis through Multisim's engine.
5. Export result.raw, data.csv, plot.svg, logs, and report.md.

Use create_schematic_from_netlist when only an editable schematic is needed, or run_spice_netlist for netlist-only simulation.

Virtual instruments use explicit pseudo-device records in the same netlist:

XFG1 out 0 inv FGEN WAVE=SINE FREQ=1k AMPLITUDE=2 OFFSET=0.5
XSC1 out inv 0 0 out 0 OSCILLOSCOPE

The XSC terminal order is A, B, C, D, EXT+, EXT-. XFG supports WAVE (SINE, SQUARE, or TRIANGLE), FREQ, AMPLITUDE, OFFSET, DUTY, and RISE.

Safety model

• Safe analysis commands are allowlisted: op, dc, ac, and tran.
• do_command_line is disabled by default. It requires the server-side MULTISIM_MCP_ENABLE_UNSAFE_COMMANDS=1 opt-in.
• Runtime npm downloads are disabled. On Windows the npx fallback remains disabled even when opted in because .cmd shims are not safe for caller-controlled paths. Install the pinned codec globally, or set MULTISIM_MCP_EWD and MULTISIM_MCP_EWE to its dist/ewd.js and dist/ewe.js entry points; the server invokes them through node.exe.
• Existing experiment artifacts are not overwritten unless overwrite=true.
• The server is intended for trusted local stdio clients, not public network exposure. See SECURITY.md in the repository root.

Test

COM-free tests:

$env:PYTHONPATH = (Resolve-Path .\mcp_server).Path
C:\path\to\python32\python.exe -m unittest discover -s mcp_server\tests -p 'test_*.py' -v

Real Multisim E2E:

$env:MULTISIM_MCP_E2E_SAMPLE='C:\path\to\fixture.ms14'
tools\python32\python.exe mcp_server\tests\e2e_mcp_test.py

The E2E test requires a local fixture with RLC components and at least one simulation output; proprietary NI sample designs are not distributed.

License

Project code is MIT licensed. NI Multisim, its formats, trademarks, and locally installed samples remain subject to their respective owners' terms.