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。

Stable 1.0 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, Markdown, standalone bilingual HTML/PDF, and reproducibility-manifest export.
• High-level run_circuit_experiment workflow.
• Durable submit_circuit_experiment queue with progress, cancellation, total/heartbeat timeouts, and isolated-worker recovery.
• Versioned ExperimentSpec verification with persisted PASS/FAIL/unverified evidence and theory-versus-simulation error.
• Parameter, tolerance, temperature, and seeded Monte Carlo sweeps with a 100-run hard limit and durable-worker support.
• MCP 2026-07-28 discovery plus automatic compatibility with legacy clients.
• Sixteen experiment artifact Resources, two sweep Resources, one job-status Resource, and five bilingual workflow Prompts.
• Validated structured output for the complete experiment workflow.

Completed experiments return an opaque experiment_id and resource URIs such as:

multisim://experiments/{experiment_id}/manifest
multisim://experiments/{experiment_id}/report
multisim://experiments/{experiment_id}/schematic
multisim://experiments/{experiment_id}/data
multisim://experiments/{experiment_id}/plot
multisim://experiments/{experiment_id}/verification
multisim://experiments/{experiment_id}/formal-html-zh
multisim://experiments/{experiment_id}/formal-html-en
multisim://experiments/{experiment_id}/formal-pdf-zh
multisim://experiments/{experiment_id}/formal-pdf-en
multisim://experiments/{experiment_id}/reproducibility-manifest
multisim://sweeps/{sweep_id}/summary
multisim://sweeps/{sweep_id}/data

Completed durable jobs restore their handles after restarting the server. For other historical output directories, call register_experiment_artifacts to restore a process-local handle. Resource reads are limited to the fixed artifact set and default to 16 MiB per file; set MULTISIM_MCP_RESOURCE_MAX_BYTES to a positive integer to change that limit.

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.
• Portable @KIND adapters synthesize transformer, potentiometer, relay, crystal, power semiconductor, D/T flip-flop, four-bit counter/register, and one-bit ADC/DAC models from ordinary primitives. See docs/COMPONENT_ADAPTERS.md.
• 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.

The Windows dependency set deliberately uses cryptography>=48.0.1,<49. 48.0.1 is the newest release line currently providing an official win32 wheel; newer releases would otherwise make 32-bit installation attempt an unsupported local Rust build. This boundary should be reviewed whenever a new win32 wheel becomes available.

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
C:\path\to\python32\python.exe .\tools\bootstrap_local_component_pack.py `
  --output C:\MultisimMcp\component-pack
$env:MULTISIM_MCP_TEMPLATE_DIR = 'C:\MultisimMcp\component-pack'

The generator connects to licensed Multisim and creates a temporary blank circuit so the project shell matches the installed file-format version. Save open work first. Version 1.0 writes a schema-2 local manifest; doctor rejects schema-1 packs generated by alpha releases and asks the user to rebuild them.

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
}

For normal agent use, submit the same arguments with submit_circuit_experiment. It returns immediately:

{
  "success": true,
  "job_id": "job-...",
  "state": "queued",
  "status_uri": "multisim://jobs/job-...",
  "output_dir": "C:\\experiments\\divider"
}

Poll get_experiment_job or the status Resource, and call cancel_experiment_job when needed. A failed, cancelled, or timed-out record can be resubmitted without copying its persisted source through retry_experiment_job. States are queued, running, cancelling, succeeded, failed, cancelled, or timed_out. A successful record contains the same structured result as run_circuit_experiment. list_experiment_jobs omits large results and supports state filtering.

The synchronous run_circuit_experiment compatibility tool 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.
6. Export Chinese/English HTML/PDF reports and manifest.json atomically.

Job records are stored as atomic JSON under %LOCALAPPDATA%\multisim-mcp\jobs by default. Set MULTISIM_MCP_JOB_DIR to select another private local state directory. Records contain the source netlist and settings required for restart recovery, so protect and back up that directory according to the sensitivity of your circuit. job_timeout limits the whole workflow; heartbeat_timeout detects a hung Multisim/codec worker. Output publication is guarded by a cross-process sibling lock and remains transactional. A queue-wide lease keeps execution serialized even if multiple MCP frontend processes use the same job state directory.

Design verification and sweeps

Use run_verified_circuit_experiment with an ExperimentSpec containing explicit measurement signals, criteria, tolerances, and optional theoretical values. Supported metrics include scalar statistics, gain, cutoff frequency, bandwidth, rise time, overshoot, ripple, and power. Each requirement is reported as pass, fail, or unverified; unavailable evidence is never guessed.

Use plan_experiment_sweep before execution to preview every rendered run. run_experiment_sweep executes synchronously, while submit_experiment_sweep uses the durable job worker. Modes are parameter, tolerance, temperature, and monte_carlo; Monte Carlo runs use an explicit integer seed. Sweep values are finite numbers substituted into declared {{NAME}} placeholders, and every rendered netlist passes the same safety validator as a normal experiment.

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.

Completed experiment data can also be read through read_virtual_multimeter, analyze_bode_response, and analyze_logic_signals. These tools return structured measurements and edge events; the Bode adapter explicitly leaves phase unavailable when the raw file contains no phase column.

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.
• Sweep expansion is capped at 100 runs and only finite numeric substitutions are accepted.
• Asynchronous job specifications are persisted locally for recovery; their state directory must not be shared with untrusted users.
• 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.