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MCP Server for CST Studio Suite

A Model Context Protocol (MCP) server providing AI-driven access to CST Studio Suite for antenna design, RF/microwave simulation, and PCB layout.

Features

• 173 tools across 20 categories: geometry, materials, ports, boundaries, mesh, solvers, simulation, results, parameters, antenna templates, arrays, matching networks, diagnostics, optimization, PCB, and more
• Dual-mode operation: Connected mode (direct CST execution on Windows) and Offline mode (VBA script generation on any OS)
• 13 parametric antenna templates: Patch, dipole, monopole, horn, Yagi, helix, Vivaldi, slot, IFA, PIFA, spiral, bowtie: with automatic dimension calculations from target frequency
• PCB/SI tools: Stackup creation, trace routing with impedance calculation, via modeling, ground planes
• Material database: 30+ metals, dielectrics, and RF substrates with accurate electromagnetic properties
• Denylist-validated VBA: Generated and user-supplied VBA is checked against a regex denylist of dangerous patterns
• CST VBA reference: Built-in help system for CST VBA objects and methods

Installation

git clone https://github.com/RFingAdam/mcp-cst-studio.git
cd mcp-cst-studio
pip install -e ".[dev]"

Configuration

Claude Code (.mcp.json)

{
  "mcpServers": {
    "cst-studio": {
      "command": "mcp-cst-studio",
      "env": {
        "CST_PATH": "C:\\Program Files\\CST Studio Suite 2026",
        "CST_WORK_DIR": "C:\\cst_projects"
      }
    }
  }
}

Environment Variables

| Variable | Description | Default | |----------|-------------|---------| | CST_PATH | CST installation directory | Auto-detected on Windows | | CST_WORK_DIR | Project working directory | ~/cst_projects | | CST_VERSION | CST version year | 2026 |

Usage

Offline Mode (Any OS)

Works without CST installed. Tools generate VBA scripts that can be executed in CST Studio Suite.

"Design a 2.4 GHz rectangular patch antenna on FR-4 substrate"
→ Returns calculated dimensions + complete VBA script for CST

Connected Mode (Windows with CST)

When the CST Python library is available, tools execute directly:

"Create the antenna, run the time-domain simulation, and show me the S-parameters"
→ Builds geometry, configures solver, runs simulation, extracts results

Tool Categories

| Category | Tools | Description | |----------|-------|-------------| | Project | 8 | Create, open, save, close, export projects | | Geometry | 13 | Brick, cylinder, sphere, cone, torus, extrude, loft, wire, polygon | | Boolean | 4 | Add, subtract, intersect, insert operations | | Transforms | 4 | Translate, rotate, mirror, scale | | Materials | 15 | Create, load, assign materials; built-in material database; lossy metals; anisotropic | | Ports | 8 | Waveguide, discrete, lumped, plane wave, Floquet ports | | Boundaries | 6 | Boundary conditions, background, symmetry, frequency range | | Mesh | 8 | Mesh type, density, refinement, adaptive meshing, hex/tet controls | | Solvers | 8 | Time domain, frequency domain, eigenmode, integral equation, asymptotic | | Simulation | 6 | Run, status, pause, resume, stop simulations | | Results | 24 | S-parameters, far-field cuts, near-field, impedance, VSWR, gain, efficiency, Smith chart, numeric curves | | Import/Export | 5 | CAD import/export, Touchstone, far-field export | | Parameters | 11 | Parametric design, sweeps, expressions, dependencies | | Antenna Templates | 13 | Parametric antenna designs with RF calculations | | Arrays | 8 | Linear / planar / circular array synthesis, element factors, beamforming | | Matching | 8 | L / Pi / T networks, Smith-chart matching, stub matching | | PCB | 12 | Stackup, traces, vias, ground planes, Gerber import, differential pairs | | Diagnostics | 5 | Connection status, model integrity, mesh quality, solver convergence | | Optimization | 4 | Goal checks, impedance guidance, Nelder-Mead refine, one-step tune | | VBA | 3 | Raw VBA execution, help reference, object listing |

Antenna Templates

Each template calculates dimensions from target frequency and generates a complete, simulatable CST model:

| Template | Type | Typical Gain | Bandwidth | |----------|------|-------------|-----------| | Patch | Planar | 5-8 dBi | 1-5% | | Dipole | Wire | 2.15 dBi | 10-20% | | Monopole | Wire | 2-5 dBi | 10-20% | | Horn | Aperture | 10-25 dBi | 50%+ | | Yagi | Array | 7-15 dBi | 3-5% | | Helix | Wire | 8-15 dBi | 50%+ | | Vivaldi | Planar | 5-12 dBi | 100%+ | | IFA/PIFA | Planar | 1-3 dBi | 5-10% |

Connected Mode Setup (Windows)

To use with a live CST Studio installation:

Prerequisites

• Windows 10/11 with CST Studio Suite 2024+ installed
• CST's Python libraries linked into the interpreter that launches the MCP server
• Python 3.12, matching the interpreter CST ships (see Help if a version allows another 3.x)

The Windows library folder is AMD64\python_cst_libraries under the CST install (C:\Program Files\CST Studio Suite 20XX\AMD64\python_cst_libraries). LinuxAMD64 is the Linux layout and will not import on Windows.

Setting PYTHONPATH alone is not the supported link. CST Help → Automation and Scripting → Python gives a one-time command that registers that folder with your interpreter. Run it once, then confirm:

python -c "import cst.interface, cst.results; print('CST available')"

Setup

# 1. Clone and install
git clone https://github.com/RFingAdam/mcp-cst-studio.git
cd mcp-cst-studio
pip install -e .

# 2. Set environment (or let auto-detect find CST)
set CST_PATH=C:\Program Files\CST Studio Suite 2026
set CST_WORK_DIR=C:\cst_projects

# 3. Add CST Python libs to PYTHONPATH
set PYTHONPATH=%CST_PATH%\AMD64\python_cst_libraries;%PYTHONPATH%

# 4. Verify
python -c "import cst.interface; print('CST available')"
mcp-cst-studio  # starts stdio server

Claude Code / Claude Desktop

Add to your .mcp.json or Claude Desktop config:

{
  "mcpServers": {
    "cst-studio": {
      "command": "mcp-cst-studio",
      "env": {
        "CST_PATH": "C:\\Program Files\\CST Studio Suite 2026",
        "CST_WORK_DIR": "C:\\cst_projects",
        "PYTHONPATH": "C:\\Program Files\\CST Studio Suite 2026\\AMD64\\python_cst_libraries"
      }
    }
  }
}

Validation Checklist

Once connected, verify with these prompts:

1. Connection: "What is the CST connection status?": should show connected mode
2. Geometry: "Create a brick from (0,0,0) to (10,10,5) in component1": should appear in CST
3. Antenna: "Design a 2.4 GHz patch antenna on FR-4": should build full model
4. Simulation: "Run a time-domain simulation": should start solver
5. Results: "Show me the S-parameters": should extract S11 data

Security model / limitations

VBA validation is a denylist, not a sandbox. validate_vba_input() rejects known-dangerous patterns (for example Shell, CreateObject, CallByName, file I/O, and Declare statements), including line-continued (_) forms. It does not constrain VBA to an allowlist of CST statement shapes, so unknown or obfuscated calls may still pass.

Run CST Studio Suite with least privilege. Treat generated or user-supplied VBA as untrusted, and do not run the MCP server or CST under an account that can reach secrets or systems you would not want a script to touch.

Development

pip install -e ".[dev]"
pytest tests/ -v          # 215 tests, all offline
ruff check src/ tests/    # linting
mypy src/mcp_cst_studio/  # type checking

License

AGPL-3.0-or-later. Relicensed from Apache-2.0 in v0.2.0 to align with the eng-mcp-suite toolkit-wide AGPL move. CST Studio Suite itself (Dassault Systèmes) is a separate commercial product invoked at runtime; this wrapper does not bundle or redistribute it.