Cst Studio

Python-first MCP server for CST Studio Suite · version 1.1.0

Drive CST from an AI assistant: open projects, build geometry, set materials and ports, run solvers, read S-parameters and farfield metrics, and generate design reports — through structured MCP tools on your Windows machine.

Package	cst-studio-mcp · entry point cst-studio-mcp
Tools	180+ (workflows, geometry, antennas, solvers, results, PCB, …)
Python	3.10+ (3.12 recommended)
OS	Windows 10/11 + licensed CST Studio Suite
Docs	Interactive EN/TR browser: docs/index.html

Project presentation: presentation/index.html, a self-contained Turkish architecture and validation overview. See the reliability review for historical checks. Current evidence and limits are in the 2026 API review.

Start with the agent installation and acceptance guide. Official Python results were verified against all 4 × 4,001 complex samples in a completed CST 2026 project; an isolated modeler fixture also passed. The full tool catalog is not a blanket certification of advanced CST features.

Agent (Cursor / Claude / …)
        │  MCP stdio
        ▼
   cst-studio-mcp server
        │
        ├─ Python API   connect · project · solve · results (cst.interface / cst.results)
        └─ History VBA  geometry · materials · ports · monitors (model3d.add_to_history)
                │
                ▼
        CST Studio Suite (local install + license)

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Table of contents

1. What you get
2. Requirements
3. Installation
4. Environment variables
5. MCP client setup
6. Verify the install
7. Quick start (agents)
8. Farfield & results notes
9. Architecture
10. Documentation site
11. Development & tests
12. Troubleshooting
13. License
14. Full tool catalog

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What you get

• Full tool surface — project control, geometry, booleans, transforms, materials, ports, boundaries, mesh, solvers, simulation control, results, import/export, parameters, optimization helpers, antenna templates, arrays, PCB/SI, matching networks, VBA escape hatch.
• Workflow helpers — one-shot patch antenna, solve + S11, design report, structure views, farfield discovery/metrics.
• Portable paths — auto-detects CST on any drive letter; prefers AMD64\python_cst_libraries (CST 2024–2026). No hard-coded E:\ in library code.
• Bilingual docs — English / Türkçe tool browser with light/dark theme.
• Offline fallback — if CST is unreachable, many tools still return VBA for manual paste.

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Requirements

Component	Notes
Windows	10 or 11 (64-bit)
CST Studio Suite	Core paths tested on 2026; its Python result reader supports saved 2025/2026 files. Other versions need local acceptance
CST license	Valid license for the solver you use
Python	3.10 – 3.13 (3.12 works well with CST’s bundled cp312 libs)
Disk	CST install + project work directory (simulations can be large)

CST Python libraries ship with the product, typically:

<CST_ROOT>\AMD64\python_cst_libraries

Examples:

• C:\Program Files\CST Studio Suite 2026\AMD64\python_cst_libraries
• E:\CST Studio Suite 2026\AMD64\python_cst_libraries

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Installation

1. Clone the repository

git clone https://github.com/ismailakdag/cst-studio-mcp.git
cd cst-studio-mcp

2. Create a virtual environment and install (recommended)

In PowerShell, from the repo root (the folder that contains pyproject.toml):

python -m venv .venv
.\.venv\Scripts\Activate.ps1
pip install -U pip
pip install -e ".[dev]"

This installs:

• Runtime dependencies: mcp>=1.29,<3, anyio>=4.5, and jsonschema>=4.20
• Console script: cst-studio-mcp (also at .\.venv\Scripts\cst-studio-mcp.exe)
• Dev extras: pytest, pytest-asyncio, ruff

Tip: open docs/index.html — the Setup section has Copy buttons for every PowerShell block, and a form that fills CST_PATH / PYTHONPATH / MCP JSON from the path you type.

3. Point Python / MCP at your CST install

You must tell the process where CST lives. Typical roots:

• C:\Program Files\CST Studio Suite 2026
• E:\CST Studio Suite 2026

Not the AMD64 folder itself — one level above. PYTHONPATH then points at:

%CST_PATH%\AMD64\python_cst_libraries

Session-only (current PowerShell window)

Replace the path with yours, then paste:

$env:CST_PATH = "C:\Program Files\CST Studio Suite 2026"
$env:PYTHONPATH = "$env:CST_PATH\AMD64\python_cst_libraries"
$env:CST_WORK_DIR = "C:\cst_projects"
$env:CST_VERSION = "2026"
New-Item -ItemType Directory -Force -Path $env:CST_WORK_DIR | Out-Null

Permanent (optional, Windows user env)

[Environment]::SetEnvironmentVariable("CST_PATH", "C:\Program Files\CST Studio Suite 2026", "User")
[Environment]::SetEnvironmentVariable("PYTHONPATH", "C:\Program Files\CST Studio Suite 2026\AMD64\python_cst_libraries", "User")
[Environment]::SetEnvironmentVariable("CST_WORK_DIR", "C:\cst_projects", "User")

For Cursor / Claude / other MCP clients, prefer putting the same keys in the server env block (next section) — that is what the AI process actually sees.

---

Environment variables

Nothing in the library hard-codes a drive letter. Discovery order:

1. If CST_PATH is set → use it
2. Else scan all drive letters for CST Studio Suite {CST_VERSION}
3. Resolve AMD64\python_cst_libraries (fallback LinuxAMD64\... on dual layouts)

Variable	Required	Meaning	Example
CST_PATH	Recommended	CST install root	C:\Program Files\CST Studio Suite 2026
PYTHONPATH	Strongly recommended	Official CST Python package path	…\AMD64\python_cst_libraries
CST_WORK_DIR	Optional	Projects, exports, reports	%USERPROFILE%\cst_projects
CST_VERSION	Optional	Year for auto-detect (default 2026)	2026
CST_QUIET	Legacy	Accepted for compatibility; connecting no longer changes the user's CST UI mode	1
CST_CONNECT_MODE	Optional	Startup behavior: auto, manual, or disabled (default manual)	manual
CST_LOG_LEVEL	Optional	Logging level	INFO
CST_TOOLSETS	Optional	Comma-separated tool categories to expose (default: all). Alias core = connection + official + project + workflows + simulation + results. Connection tools are always exposed. Use it to reduce the number of tool schemas sent to the model	core,geometry
CST_ALLOW_RAW_VBA	Optional	Default off. Set to 1 to let cst_execute_vba (raw VBA) run in connected mode. The VBA denylist is best-effort and not a sandbox: enabling this effectively grants the connected MCP client arbitrary code execution on this machine. Enable it only for fully trusted clients	1

auto attaches to a running Design Environment or starts one when the MCP process starts. Use disabled for catalog inspection, client setup checks, and offline VBA generation: it does not import the CST Python package or connect to CST. manual skips the startup connection while leaving CST available to the explicit cst_connect tool and connection workflows. It is the default, so adding an MCP server never implicitly launches CST. cst_disconnect detaches the MCP session; it does not close the application or its projects.

Template file: .mcp.example.json
Local machine paths: .mcp.json (edit paths only; keep out of shared commits if needed).

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MCP client setup

Claude Desktop / Cursor JSON config

{
  "mcpServers": {
    "cst-studio": {
      "command": "cst-studio-mcp",
      "args": [],
      "env": {
        "CST_PATH": "C:\\Program Files\\CST Studio Suite 2026",
        "CST_WORK_DIR": "C:\\cst_projects",
        "CST_VERSION": "2026",
        "CST_CONNECT_MODE": "manual",
        "PYTHONPATH": "C:\\Program Files\\CST Studio Suite 2026\\AMD64\\python_cst_libraries",
        "CST_LOG_LEVEL": "INFO"
      }
    }
  }
}

If cst-studio-mcp is not on PATH (for example a venv), use the full executable:

"command": "C:\\path\\to\\cst-studio-mcp\\.venv\\Scripts\\cst-studio-mcp.exe"

Or:

"command": "python",
"args": ["-m", "cst_mcp.server"]

(with PYTHONPATH including CST libs).

Codex

Add the server to your Codex config.toml. Literal single-quoted TOML strings keep Windows backslashes intact; replace the example paths with your local installation paths.

[mcp_servers.cst-studio]
command = 'C:\path\to\cst-studio-mcp\.venv\Scripts\cst-studio-mcp.exe'
args = []

[mcp_servers.cst-studio.env]
CST_PATH = 'C:\Program Files\CST Studio Suite 2026'
CST_WORK_DIR = 'C:\cst_projects'
CST_VERSION = '2026'
CST_CONNECT_MODE = 'manual'
PYTHONPATH = 'C:\Program Files\CST Studio Suite 2026\AMD64\python_cst_libraries'

Reload the MCP configuration, confirm the cst-studio tools are available, and call cst_connect only when you are ready to attach to CST. See the official Codex MCP documentation for current configuration locations and controls.

Cursor

1. Open Cursor Settings → MCP (or project MCP JSON / root .mcp.json, depending on Cursor version).
2. Add the cst-studio server block with your CST_PATH and PYTHONPATH.
3. Restart MCP / reload the window.
4. Confirm the full tool list (180+) under server cst-studio (fewer if CST_TOOLSETS is set).

After code changes, restart the MCP server process so Python reloads the package.

Claude Desktop

Edit the Claude Desktop config JSON (Windows typically under %APPDATA%\Claude\) and add the same mcpServers.cst-studio block. Fully quit and restart Claude Desktop.

Claude Code / CLI

Register the server in one line (user scope; use --scope project to write a shared .mcp.json instead):

claude mcp add cst-studio --scope user -e CST_PATH="C:\Program Files\CST Studio Suite 2026" -e PYTHONPATH="C:\Program Files\CST Studio Suite 2026\AMD64\python_cst_libraries" -e CST_WORK_DIR="C:\cst_projects" -e CST_CONNECT_MODE=manual '--' "C:\path\to\cst-studio-mcp\.venv\Scripts\cst-studio-mcp.exe"

Everything after -- is the server command. In PowerShell keep the quotes around '--': if claude resolves to the npm .ps1 shim, PowerShell otherwise strips a bare --. Check it with claude mcp list (or /mcp inside a session). Alternatively, add the same command + env to your MCP config JSON. Restart the session after edits.

Other MCP hosts

Any client that supports MCP stdio servers can use cst-studio-mcp with the same environment variables.

The process uses newline-delimited JSON-RPC on stdout. Logs and diagnostics are written to stderr, so clients must keep stdout reserved for MCP messages. For a first client-side check, set CST_CONNECT_MODE to disabled, restart the MCP process, and verify that initialize, tools/list, and cst_connection_status succeed. Change it to auto only when the client configuration points to the intended CST installation.

MCP clients use two common configuration envelopes. Clients such as Claude Desktop and Cursor use the mcpServers object shown above. Clients whose schema uses a servers object generally need the same process definition in this shape:

{
  "servers": {
    "cst-studio": {
      "type": "stdio",
      "command": "C:\\path\\to\\.venv\\Scripts\\cst-studio-mcp.exe",
      "args": [],
      "env": {
        "CST_PATH": "C:\\Program Files\\CST Studio Suite 2026",
        "CST_WORK_DIR": "C:\\cst_projects",
        "CST_CONNECT_MODE": "manual"
      }
    }
  }
}

Use the field names required by the client, but keep command, args, and env unchanged. Prefer the absolute console-script path on Windows; it avoids differences in each client's PATH.

Tools carry MCP annotations (readOnlyHint / destructiveHint), so clients that honor them can auto-approve read-only tools and still prompt for mutating ones. Some result tools also declare an outputSchema and return structuredContent alongside the text result.

---

Verify the install

# 1) Package entry point exists
Get-Command cst-studio-mcp

# 2) CST Python libs importable
python -c "import cst.interface; print('CST interface OK')"

# 3) Config auto-detect
python -c "from cst_mcp.config import CSTConfig; c=CSTConfig.from_env(); print(c.cst_path); print(c.python_lib_path); print('available', c.cst_available)"

# 4) Offline unit tests (no live solve required)
python -m pytest tests/ -q
# If global pytest plugins break collection, disable autoload but load pytest-asyncio explicitly:
#   $env:PYTEST_DISABLE_PLUGIN_AUTOLOAD = "1"; python -m pytest tests/ -q -p asyncio

From an MCP client, call:

1. cst_connect — explicitly attach to CST when ready (or opt into CST_CONNECT_MODE=auto); then cst_connection_status reports the session. With disabled, the server remains offline.
2. Prefer workflows for smoke tests (see below)

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Quick start (agents)

Recommended order for a first successful run:

Step	Tool	Purpose
1	cst_connection_status	Confirm connected mode
2	cst_workflow_patch_antenna	Parametric microstrip patch (substrate, ground, feed, WG port, farfield monitor)
3	cst_workflow_simulate_and_report or cst_run_simulation	Solve
4	cst_get_s_parameters / cst_get_farfield_metrics	S11 + antenna metrics
5	cst_workflow_design_report	Package: params, S-params, farfield, views

Long solves: for anything that takes longer than about a minute, start it with cst_run_simulation_async, then call cst_wait_for_simulation repeatedly until it reports completion. Each wait call returns within about max_wait_s + 2 s (default max_wait_s 45), which keeps individual calls under typical client tool-call timeouts. A wait that sees the solver idle before the async start was observed keeps polling (status starting) instead of reporting a premature finished. All CST calls run on one dedicated worker thread, so a long blocking cst_run_simulation queues other CST tools but no longer freezes the MCP server.

Other useful entry points:

• cst_antenna_patch — template builder (similar geometry stack)
• cst_design_patch_only — offline dimension calculator (no CST)
• cst_export_structure_views — multi-view structure images
• cst_discover_farfield_monitors — find farfield results on disk

Publication figures (install the extra: pip install -e ".[figures]", i.e. numpy + matplotlib):

• cst_plot_1d_results — IEEE-style S11 / S-parameters / VSWR / Smith / impedance / phase / efficiency figures read directly from a saved .cst (no GUI), with resonance and −10 dB band annotation, run comparison and measured-CSV overlay. Returns no_results with next steps when the project has not been solved.
• cst_plot_farfield — polar E/H cuts, rectangular cuts, θ–φ or u–v heatmaps and 3D patterns, with max gain, HPBW, F/B, SLL and XPD. Works offline from a CST farfield ASCII export or exports it itself when connected; no_results distinguishes a missing monitor from an unsolved one.
• cst_technical_drawing — dimensioned orthographic drawing (top/front/side/iso) of the model with title block and parameter table, as PDF/SVG/PNG. Exports each solid as STL (in mm) without touching model history, or renders offline from an existing STL folder.

Parametric tip: dimensions should live in the CST Parameter List and geometry history should use expressions (for example patch_L/2). Then parameter change → delete results → rebuild → solve updates the model without rewriting history by hand.

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Farfield & results notes

These details matter for reliable automation on CST 2026:

Topic	Guidance
Monitor VBA	Official Monitor API: .Frequency, FieldType "Farfield", frequency domain. Prefer EnableNearfieldCalculation "True".
Tree path	After TD solve: Farfields\farfield (f=2.4) [1] (port excitation suffix [1]).
Metrics API	Prefer FarfieldPlot.Plot then GetMax / GetRadiationEfficiency. Do not rely on ASCIIExportSummary (often fails with export/HEX mesh errors and Message spam).
MCP tool	cst_get_farfield_metrics — 1D Results (S11, efficiencies) + GetMax when the tree item is available.
1D Results	cst.results.ProjectFile is reliable for S-parameters and efficiencies when the .cst path is known.

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Architecture

src/cst_mcp/
  server.py          MCP entry (stdio)
  config.py          Multi-drive CST discovery
  session.py         Design Environment / project / solve / export / farfield metrics
  cst_client.py      Public client façade used by tools
  tools/             One module per category (workflows, geometry, …)
  execution/         VBA helpers, port VBA, farfield, results_api, CSV readers
  domain/            Pure design math (e.g. patch sizing)
  data/              Material / template JSON

Layer	Role
MCP tools	Schemas + handlers; agent-facing
CSTClient / Session	Connection lifecycle, history VBA, Python solver/results
execution/	Portable VBA snippets (ports, farfield metrics dump)
CST product	Mesh, TD/FD solvers, result tree

Reference / upstream history (not required at runtime): _reference/.
Official VBA object dump for alignment: vba_cst/.

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Documentation site

Path	Content
docs/index.html	Interactive EN/TR tool browser, light/dark, search, copy full tool text, install guide
docs/TOOLS.md	Markdown catalog
docs/tools.json	Machine-readable schemas
docs/VBA_ALIGNMENT.md	VBA fixes vs CST Online Help dump
docs/README.md	How to open/rebuild docs

# Open UI
start docs\index.html

# Or local server
python -m http.server 8080 --directory docs

# Rebuild HTML + JSON + Markdown + README catalog from live tools
python scripts/build_docs.py

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Development & tests

pip install -e ".[dev]"
$env:PYTEST_DISABLE_PLUGIN_AUTOLOAD = "1"   # optional: avoid broken global pytest plugins
python -m pytest tests/ -v -p asyncio       # -p asyncio is required when autoload is disabled
python scripts/build_docs.py
ruff check src tests

Optional live CST scripts under scripts/ (require license). Prefer unit tests for offline checks.

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Troubleshooting

Symptom	What to try
import cst / cst.interface fails	Set PYTHONPATH to …\AMD64\python_cst_libraries (not only install root).
MCP shows few tools / old behavior	Restart the MCP server process after pip install -e . or code edits.
mode=offline	Set CST_PATH + PYTHONPATH. Confirm license. Start Design Environment once.
Port “floating” in air	Free port plane with PortOnBound False flush to feed edge (workflow port helper).
Farfield Message spam / “No HEX mesh”	Avoid ASCIIExportSummary spam. Use cst_get_farfield_metrics. Create monitor before solve.
SelectTreeItem fails for farfield	Full path Farfields\farfield (f=<freq>) [1].
Parameter List empty / rebuild no shape change	History must use parameter expressions, not only bare numbers.
Dialogs block automation	CST_QUIET=1; diagnostics / dismiss-dialog tools.
results_exist error, or CST frozen on "Results May Get Incompatible With Model"	Editing the model of a solved project makes CST open that modal dialog inside the automation call, where it cannot be answered. Model-editing tools now refuse with results_exist instead; export what you need, call cst_delete_results, then retry. If an older build already froze CST, it must be force-quit.
pytest plugin import errors	PYTEST_DISABLE_PLUGIN_AUTOLOAD=1 plus -p asyncio (e.g. python -m pytest tests/ -q -p asyncio); without -p asyncio the async tests fail.

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License

MIT

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Full tool catalog (192 tools)

Interactive bilingual docs: open docs/index.html (EN/TR toggle, search, full-width cards). Rebuild: python scripts/build_docs.py.

VBA for geometry/ports/transforms is cross-checked against the CST help dump in vba_cst/.

Official API and saved results (4)

Read local CST Python/VBA help and complex saved results without opening CST.

Tool	What it does
cst_search_help	Full-text search of the installed official CST Python/VBA help (offline; does not start CST). Every query word must appear in the topic's…
cst_read_help	Read a paginated official local CST help topic returned by cst_search_help. No GUI or solver.
cst_list_saved_results	List exact result tree paths and run IDs from a saved, unpacked, completed .cst file using cst.results. No connection or CST GUI is requi…
cst_read_saved_result	Read a complete complex 1D curve by exact tree path and run_id from a completed saved .cst, without opening CST. Raw real/imag are preser…

Explicit connection (2)

Attach to CST explicitly; disconnect without closing user projects.

Tool	What it does
cst_connect	Explicitly attach to a CST Design Environment (DE). Disabled mode never connects. mode='any' (default) uses connect_to_any_or_new(): it a…
cst_disconnect	Detach this MCP session without closing CST, projects, or a running solver.

Workflows (start here) (8)

One-shot helpers for common tasks. New users should start here.

Tool	What it does
cst_workflow_patch_antenna	END-TO-END / Uçtan uca: size a rectangular microstrip patch, build substrate/ground/patch/feed, frequency, open BCs, waveguide port, farf…
cst_workflow_run_and_s11	Run solver and return structured S11/Sij with metrics (min dB, bandwidth). BLOCKING: waits for the whole solve (up to timeout_s) inside o…
cst_design_patch_only	Calculate microstrip patch dimensions only (offline, no CST). Sadece boyut hesabı — CST gerekmez.
cst_export_structure_views	Export structure screenshots (perspective/xy/xz/yz) via Plot.ExportImage. Yapı görünüm görsellerini dışa aktarır. Connected mode required.
cst_workflow_design_report	ONE-SHOT design package after modeling/simulation: project status, parameters/dimensions, S-parameters (+metrics), best-effort farfield e…
cst_workflow_simulate_and_report	Run the solver, then immediately build a design report (S-params + views + optional farfield). BLOCKING: waits for the whole solve (up to…
cst_discover_farfield_monitors	Discover farfield monitors from the project Result folder and tree-path heuristics. Uzak alan monitörlerini disk + path sezgisiyle listeler.
cst_get_farfield_metrics	Read antenna metrics after a solve: S11 + radiation/total efficiency from 1D Results, plus max realized gain via official FarfieldPlot.Ge…

Project & connection (8)

Create, open, save projects and check CST connection.

Tool	What it does
cst_create_project	Create a new CST Studio Suite project file. In connected mode the project is created directly; in offline mode a VBA script is returned f…
cst_open_project	Open an existing CST Studio Suite project. In connected mode the project is opened in the running instance; in offline mode a reference i…
cst_save_project	Save the currently open CST project. Optionally provide a new path to 'Save As'.
cst_close_project	Close the currently open CST project and release its resources.
cst_project_info	Get information about the currently open CST project, including connection mode, project path, and status.
cst_project_tree	List items in the CST project navigation tree. Optionally specify a subtree path such as 'Components', 'Materials', 'Ports', 'Monitors', …
cst_export_project	Export the current CST project or its geometry to another format such as STL, STEP, IGES, SAT, OBJ, or NASTRAN.
cst_connection_status	Get the current CST Studio connection status, including mode (connected/offline), CST availability, version, and work directory.

Geometry (13)

3D shapes: bricks, cylinders, spheres, extrusions, wires…

Tool	What it does
cst_create_brick	Create a rectangular brick (box) in CST Studio.
cst_create_cylinder	Create a cylinder in CST Studio. Use inner_radius=0 for a solid cylinder.
cst_create_cone	Create a cone or truncated cone in CST Studio.
cst_create_sphere	Create a sphere in CST Studio.
cst_create_torus	Create a torus in CST Studio.
cst_create_extrude	Extrude a 2D polygon profile into a 3D solid in CST Studio (Extrude object, Mode 'pointlist'). The profile lies in the plane normal to 'a…
cst_create_loft	Create a lofted solid between two or more 2D profiles in CST Studio.
cst_create_wire	Create a bondwire / wire between two points in CST Studio.
cst_create_polygon3d	Create a 3D polygon curve in CST Studio.
cst_create_analytical_curve	Create a parametric analytical curve in CST Studio using expressions of parameter t.
cst_create_face_from_curves	Create a planar face from one or more closed curves in CST Studio.
cst_create_ecylinder	Create an elliptical cylinder in CST Studio.
cst_create_polygon_extrude	Create a polygon and extrude it along an axis in CST Studio. Convenience tool combining polygon profile creation (Polygon3D curve) and ex…

Boolean operations (4)

Combine solids: add, subtract, intersect, insert.

Tool	What it does
cst_boolean_add	Unite/add two solids together. The result replaces solid1 with the combined volume of both shapes.
cst_boolean_subtract	Subtract solid2 from solid1. The overlapping volume of solid2 is removed from solid1. Solid2 is deleted.
cst_boolean_intersect	Intersect two solids. Only the overlapping volume is kept, replacing solid1. Solid2 is deleted.
cst_boolean_insert	Insert solid2 into solid1. Solid2 is embedded within solid1, maintaining both material regions at the overlap.

Transforms (4)

Move, rotate, mirror, and scale solids.

Tool	What it does
cst_transform_translate	Translate (move) a solid by a displacement vector (dx, dy, dz). Optionally create a translated copy.
cst_transform_rotate	Rotate a solid by a given angle around an axis (x, y, or z). An optional center point can be specified.
cst_transform_mirror	Mirror a solid across a plane (xy, xz, or yz). An optional center point can be specified.
cst_transform_scale	Scale a solid by independent factors along each axis. An optional center point can be specified.

Materials (15)

Metals, dielectrics, and advanced material models.

Tool	What it does
cst_create_material	Create a new material with electromagnetic properties in CST Studio. Specify relative permittivity (epsilon), relative permeability (mu),…
cst_create_lossy_metal	Create a lossy metal material in CST Studio. Lossy metals model finite conductivity skin-effect losses, essential for accurate loss calcu…
cst_create_anisotropic_material	Create an anisotropic material with per-axis permittivity, permeability, and loss tangent values. Used for crystals, metamaterials, and c…
cst_load_material	Load a material from the CST material library by its library name. The material is added to the project under the given name.
cst_list_materials	List available materials from the bundled material database. Optionally filter by category: 'metals', 'dielectrics', or 'substrates'. Ret…
cst_assign_material	Assign a material to an existing solid in CST Studio. The solid is specified as 'Component:SolidName'.
cst_get_material_info	Get electromagnetic properties of a material from the bundled database. Returns epsilon_r, mu_r, conductivity, loss tangent, and usage no…
cst_delete_material	Delete a material from the current CST project.
cst_create_debye_material	Create a frequency-dependent dielectric material using the Debye relaxation model. Models polar dielectrics where permittivity decreases …
cst_create_lorentz_material	Create a Lorentz oscillator dispersive material. Models resonant dielectric behaviour near absorption bands: eps(w) = eps_inf + delta_eps…
cst_create_drude_material	Create a Drude metal model material for plasmonic and metamaterial simulations. Models free-electron metals: eps(w) = 1 - wp^2 / (w^2 + j…
cst_create_ferrite_material	Create a ferrite material with gyrotropic permeability tensor (Polder model). Essential for circulators, isolators, and phase shifters. T…
cst_create_temperature_dependent_material	Create a material with temperature-dependent electromagnetic properties. Specify base properties and temperature coefficients for thermal…
cst_create_cole_cole_material	Create a Cole-Cole dispersive material. Generalisation of the Debye model with a distribution parameter alpha (0-1) that broadens the rel…
cst_list_ferrite_materials	List available ferrite materials from the bundled database. Returns name, permittivity, saturation magnetisation, linewidth, loss tangent…

Ports & excitations (8)

Waveguide, discrete, plane wave, Floquet…

Tool	What it does
cst_add_waveguide_port	Add a waveguide port for S-parameter excitation. Defines a port face on the boundary of the simulation domain for guided-wave excitation.…
cst_add_discrete_port	Add a discrete (lumped) port between two points. Used for circuit-level excitation with a defined impedance.
cst_add_lumped_element	Add a lumped R, L, C, or RLC element between two points. Value is in ohms for R, henries for L, farads for C.
cst_add_plane_wave	Add a plane wave excitation source. Defines an incident plane wave with given direction and polarization for scattering / RCS analysis.
cst_add_floquet_port	Add a Floquet port for periodic structures such as frequency selective surfaces, metamaterials, and phased arrays.
cst_list_ports	List all ports defined in the current CST project. Returns VBA to query port information, or a description in offline mode.
cst_delete_port	Delete a port by its port number.
cst_add_multipin_port	Add a waveguide port with multiple mode monitoring for higher-order mode analysis. Used for multimode waveguides, mode converters, and st…

Boundaries & setup (6)

Open/electric walls, background, symmetry, frequency range.

Tool	What it does
cst_set_boundary	Set boundary conditions for the simulation domain. Each face of the bounding box can be assigned an independent boundary type (open, elec…
cst_set_background	Set the background material properties of the simulation domain. The background fills all space not occupied by defined solids.
cst_set_symmetry	Set symmetry planes to reduce computation time. Each axis can be assigned electric or magnetic symmetry, or none. Requires the model geom…
cst_set_frequency_range	Set the simulation frequency range in GHz. This determines the bandwidth over which the solver computes results.
cst_set_periodic_boundary	Configure periodic boundary conditions with optional phase shift for unit cell simulation. Sets X and Y boundaries to periodic and config…
cst_set_floquet_port_advanced	Configure advanced Floquet port settings for periodic structures. Controls the number of Floquet modes and scan angle for phased array el…

Mesh (8)

Mesh type, density, refinement, adaptive meshing.

Tool	What it does
cst_set_mesh_type	Set the mesh type for the simulation. Hexahedral is used for time-domain, Tetrahedral for frequency-domain, Surface for integral-equation…
cst_set_mesh_density	Set global mesh density parameters controlling automatic mesh generation. Higher cells_per_wavelength gives finer mesh and better accurac…
cst_add_mesh_refinement	Add local mesh refinement to a specific solid. This creates finer mesh around critical geometry features like feed points, gaps, or thin …
cst_set_adaptive_mesh	Configure adaptive mesh refinement. When enabled, the solver runs multiple passes, refining the mesh in regions of high field gradient un…
cst_get_mesh_info	Get current mesh statistics and settings. In connected mode this queries the live mesh data; in offline mode it returns the VBA to retrie…
cst_get_mesh_quality	Extract mesh quality metrics including total cells, aspect ratios, and cells per wavelength. In connected mode this queries actual mesh s…
cst_set_pml_properties	Configure PML (Perfectly Matched Layer) absorbing boundary properties. Controls the number of absorbing layers and the target reflection …
cst_add_fixpoint_mesh	Add a fixed mesh point at specific coordinates for precise field sampling. Ensures the mesh contains a node exactly at the specified loca…

Solvers (8)

Time domain, frequency domain, eigenmode, IE…

Tool	What it does
cst_configure_time_domain_solver	Configure the time domain (transient) solver. This is CST's flagship solver for broadband simulations — it excites the structure with a p…
cst_configure_frequency_domain_solver	Configure the frequency domain solver. Best for narrowband problems, resonant structures, and when field distributions at specific freque…
cst_configure_eigenmode_solver	Configure the eigenmode solver. Computes resonant frequencies and field distributions of cavity structures. Used for filter design, reson…
cst_configure_integral_equation_solver	Configure the integral equation (IE) solver. Best for electrically large, open-boundary problems like antenna placement on vehicles, RCS …
cst_get_solver_info	Get current solver configuration and status. In connected mode this queries the active solver settings; in offline mode it describes expe…
cst_configure_eigenmode_advanced	Advanced eigenmode solver configuration for higher-order modes. Use this for waveguide mode analysis, cavity resonator design, and filter…
cst_configure_ie_solver_advanced	Advanced Integral Equation solver configuration for electrically large structures. Provides control over preconditioner, MLFMM accelerati…
cst_configure_multilayer_solver	Configure the solver for planar multilayer structures. Optimised for antenna-on-PCB, frequency selective surfaces (FSS), and radome analy…

Simulation control (7)

Run, pause, resume, stop simulations.

Tool	What it does
cst_run_simulation	Start a CST simulation with the current solver settings and block until it completes (up to timeout_s). The server stays responsive, but …
cst_run_simulation_async	Start a CST simulation asynchronously (non-blocking). The simulation launches and control returns immediately. Then call cst_wait_for_sim…
cst_get_simulation_status	Read whether a CST simulation is running and return any solver-run metadata exposed by the CST Python API. This does not show a dialog or…
cst_wait_for_simulation	Wait a bounded time for the running CST solve to finish, polling only the read-only 'is solver running' flag about every 2 s. Returns sta…
cst_pause_simulation	Pause a currently running CST simulation. The simulation can be resumed later with cst_resume_simulation.
cst_resume_simulation	Resume a previously paused CST simulation. Use after cst_pause_simulation to continue from where it stopped.
cst_stop_simulation	Stop and abort a running CST simulation. Unlike pause, a stopped simulation cannot be resumed — it must be restarted from the beginning.

Results (22)

S-parameters, far-field, VSWR, gain, Smith, bandwidth…

Tool	What it does
cst_get_s_parameters	Extract S-parameter results from a completed CST simulation. Returns S-parameter data (magnitude, phase, real/imaginary) for the specifie…
cst_get_farfield	Get far-field radiation pattern results from a completed CST simulation at a specific frequency. Returns gain, directivity, radiation eff…
cst_add_field_monitor	Add a field monitor at a specific frequency to the CST project. Field monitors must be defined before running a simulation to capture fie…
cst_get_impedance	Get input impedance (Z-parameters) for a port from a completed CST simulation. Returns real and imaginary impedance vs frequency. Useful …
cst_get_vswr	Get Voltage Standing Wave Ratio (VSWR) for a port from a completed CST simulation. VSWR indicates impedance matching quality: 1.0 is perf…
cst_get_gain	Get antenna gain at a specific frequency from a completed CST simulation. Returns peak gain in dBi and the direction (theta, phi) of maxi…
cst_get_efficiency	Get antenna radiation efficiency from a completed CST simulation at a specific frequency. Returns total efficiency (including mismatch), …
cst_list_results	List all available results in the CST result tree. Optionally specify a subtree path to narrow the listing. Useful for discovering what s…
cst_export_result	Export a simulation result to a file (CSV, Touchstone, or text). Specify the result tree path and desired output format. Useful for post-…
cst_get_result_summary	Get a summary of all key simulation results from a completed CST simulation. Returns an overview of S-parameters, gain, efficiency, and i…
cst_get_s_parameter_phase	Extract S-parameter phase response from a completed CST simulation. Returns the phase of the specified S-parameter vs frequency. Optional…
cst_get_group_delay	Compute group delay from S-parameter phase for a port pair. Group delay is defined as tau = -d(phase)/d(2pif) and represents the signal…
cst_get_pattern_cut	Extract an E-plane, H-plane, or custom radiation pattern cut from a completed CST simulation at a specific frequency. Returns gain vs ang…
cst_get_cross_polarization	Extract cross-polarization level and cross-polarization discrimination (XPD) from a completed CST simulation. Supports Ludwig-3, Ludwig-2…
cst_get_axial_ratio	Extract axial ratio for circularly polarized antennas from a completed CST simulation. Axial ratio (AR) indicates the quality of circular…
cst_get_surface_current	Extract surface current density distribution from a completed CST simulation at a specific frequency. Useful for understanding current fl…
cst_get_efficiency_breakdown	Get a detailed efficiency breakdown with loss budget from a completed CST simulation. Returns radiation efficiency, total efficiency, and…
cst_get_time_domain_signal	Extract time-domain port signal waveforms from a completed CST time-domain simulation. Returns incident, reflected, or transmitted signal…
cst_get_smith_chart_data	Extract Smith chart formatted impedance data from a completed CST simulation. Computes normalized impedance from S11 reflection coefficie…
cst_get_bandwidth	Calculate impedance bandwidth from S-parameter results. Finds the frequency range where S11 (or VSWR) meets the specified threshold. Retu…
cst_get_radiation_pattern_3d	Export full 3D radiation pattern data from a completed CST simulation at a specific frequency. Returns gain values over the full sphere i…
cst_get_current_distribution	Extract volume current distribution from a completed CST simulation at a specific frequency. Complements surface current extraction by pr…

Import / export (5)

CAD and Touchstone import/export, far-field export.

Tool	What it does
cst_import_cad	Import a CAD file into CST Studio. Supports STEP (.stp/.step), IGES (.igs/.iges), STL (.stl), SAT/ACIS (.sat), DXF (.dxf), and OBJ (.obj)…
cst_export_cad	Export the current CST model (or a specific component) to a CAD format. Supports STL, SAT/ACIS, STEP, IGES, OBJ, and NASTRAN.
cst_import_touchstone	Import a Touchstone S-parameter file (.s1p, .s2p, .snp) into CST Studio for use as a reference or circuit element.
cst_export_touchstone	Export S-parameter simulation results to a Touchstone file. Requires a completed simulation with S-parameter data.
cst_export_farfield	Export far-field radiation pattern data to a file. Requires a completed simulation with far-field monitor results.

Parameters & optimizers (11)

Design parameters, sweeps, optimizers, sensitivity, yield.

Tool	What it does
cst_set_parameter	Set or create a design parameter in CST Studio. Parameters can hold numeric values or string expressions referencing other parameters. Th…
cst_get_parameter	Get the current value of a design parameter. Returns both the stored expression and the evaluated numeric value.
cst_list_parameters	List all design parameters in the current CST project with their names, expressions, and evaluated numeric values.
cst_delete_parameter	Delete a design parameter from the CST project. The parameter must not be referenced by other parameters or geometry. Uses the parameter …
cst_parameter_sweep	Configure a CST parameter sweep (ParameterSweep object; not a model-history step) that solves once per sample of the parameter. By defaul…
cst_optimizer	Configure the native CST optimizer (Optimizer object; not a model-history step). Define a goal (minimize, maximize, or target a value for…
cst_multi_objective_optimizer	Set up a multi-objective optimization with weighted goals and optional constraints. Uses a weighted sum of goals with an evaluation cap; …
cst_sensitivity_analysis	Set up a one-at-a-time sensitivity analysis to rank parameters by their impact on a result. Varies each parameter individually while keep…
cst_yield_analysis	Set up a Monte Carlo yield analysis to estimate manufacturing yield. Randomly varies parameters according to their tolerances and evaluat…
cst_constrained_optimizer	Single-objective optimization with explicit inequality constraints. Example: minimize S11 subject to gain > 8 dBi and bandwidth > 100 MHz…
cst_parameter_interpolation	Read-only: linearly interpolate a saved 1D result between the two parameter sweep runs that bracket target_value (runs come from a finish…

Antenna evaluation (3)

Goal-driven evaluation and refinement helpers.

Tool	What it does
cst_evaluate_antenna	Evaluate current antenna simulation results against performance goals. Exports S-parameter data and checks VSWR (or return loss) against …
cst_analyze_impedance	Analyze antenna impedance match quality across frequency bands using S-parameter data. Exports S11 from a completed simulation, computes …
cst_refine_antenna	Run an automated Nelder-Mead optimization loop to tune CST design parameters toward VSWR goals across specified frequency bands. Each ite…

Diagnostics (7)

Logs, delete results, auto-dismiss blocking CST dialogs.

Tool	What it does
cst_delete_results	Delete simulation results from the current CST project. This prevents the 'Results May Get Incompatible With Model' dialog that blocks au…
cst_read_project_log	Read solver log files and project status information from the current CST project. Returns solver running state and the contents of the m…
cst_dismiss_dialogs	Find and dismiss any visible CST dialog windows (error popups, 'Results Incompatible' dialogs, solver warnings). Returns the title and te…
cst_start_dialog_watcher	Start a background thread that automatically detects and dismisses CST dialog windows as they appear. Essential for long-running operatio…
cst_stop_dialog_watcher	Stop the background dialog watcher and return its log of all dialogs that were auto-dismissed. Use after completing an operation that req…
cst_check_power_balance	Read-only power-balance diagnostic. From 1D Results\Power\Excitation [n]\ (Power Stimulated/Accepted/Radiated, Loss in Dielectrics/Metals…
cst_check_model_setup	Read-only sanity check of a described setup (nothing is sent to CST). Warns when a waveguide port sits on an 'open' (no added space) boun…

Antenna templates (13)

Parametric antennas: patch, dipole, horn, Yagi, helix…

Tool	What it does
cst_antenna_patch	Create a rectangular microstrip patch antenna with calculated dimensions for a target frequency. Supports inset, microstrip, and probe fe…
cst_antenna_dipole	Create a half-wave dipole antenna at a target frequency. Generates two wire arms with a discrete port at the feed gap.
cst_antenna_monopole	Create a quarter-wave monopole antenna over a ground plane. Generates a vertical wire element, ground plane, and feed port.
cst_antenna_horn	Create a pyramidal horn antenna for a target frequency and gain. Generates the waveguide section, flared horn, and waveguide port.
cst_antenna_yagi	Create a Yagi-Uda antenna with a reflector, driven element, and configurable number of directors. Generates wire elements and a discrete …
cst_antenna_helix	Create an axial-mode helical antenna for circular polarization. Generates helix coil, ground plane, and feed.
cst_antenna_vivaldi	Create a Vivaldi (tapered slot) antenna on a dielectric substrate. Generates substrate, exponential taper metallisation, and feed.
cst_antenna_slot	Create a slot antenna in a ground plane. Generates the ground plane with a resonant slot and microstrip feed.
cst_antenna_ifa	Create an Inverted-F antenna (IFA) suitable for mobile devices. Generates ground plane, radiating arm, shorting pin, and feed.
cst_antenna_pifa	Create a Planar Inverted-F Antenna (PIFA) for compact wireless devices. Generates ground plane, top patch, shorting wall, and feed.
cst_antenna_spiral	Create a wideband Archimedean spiral antenna. Generates two spiral arms with a discrete port feed at the center.
cst_antenna_bowtie	Create a planar bowtie antenna. Generates two triangular arms with a discrete port at the feed gap.
cst_list_antenna_templates	List all available parametric antenna templates with descriptions and typical use cases. No arguments required.

Antenna arrays (8)

Linear/planar/circular arrays, beam steering, taper.

Tool	What it does
cst_array_linear	Create a linear antenna array by replicating an element along a chosen axis. Uses Transform.Translate to produce copies named Element_1 t…
cst_array_planar	Create a 2D planar antenna array with rectangular or triangular lattice. Replicates an element in X and Y using Transform.Translate.
cst_array_circular	Create a circular antenna array by placing elements at equal angular intervals around a circle of given radius.
cst_array_compute_factor	Compute the array factor analytically for a linear or planar array. Returns AF(theta) in dB, half-power beamwidth, first null beamwidth, …
cst_array_beam_steering	Calculate progressive phase weights to steer the main beam to a specified angle. Returns phase weights and VBA to set port phases in CST.
cst_array_taper_design	Design amplitude taper weights for sidelobe control. Supports uniform, cosine, Hamming, Hanning, Blackman, Taylor, and Chebyshev window f…
cst_array_grating_lobe_analysis	Analyse whether grating lobes exist for a given element spacing and maximum scan angle. Returns safe spacing and grating lobe angles.
cst_array_mutual_coupling	Set up a multi-port S-parameter simulation in CST for mutual coupling extraction between array elements.

PCB / SI (13)

Stackups, traces, vias, ground planes, Gerber import.

Tool	What it does
cst_pcb_create_stackup	Create a PCB layer stackup in CST Studio. Generates brick geometry for each layer (signal, ground, power, dielectric) positioned vertical…
cst_pcb_create_trace	Create a PCB trace (microstrip, stripline, coplanar waveguide, or grounded CPW) in CST Studio. Optionally calculates trace width from a t…
cst_pcb_create_via	Create a PCB via (through, blind, or buried) in CST Studio. Generates the cylindrical via barrel with specified drill and pad dimensions.…
cst_pcb_create_ground_plane	Create a ground or power plane with optional cutouts (split planes, isolation slots) in CST Studio. Generates a solid copper brick and su…
cst_pcb_import_gerber	Import a Gerber/ODB++/DXF file for PCB analysis in CST Studio. Generates VBA for the CST Gerber import wizard. In offline mode, explains …
cst_pcb_list_stackup_templates	List predefined PCB stackup templates with complete layer definitions. Includes standard 2/4/6-layer FR-4 and RF-grade Rogers stackups. U…
cst_pcb_differential_pair	Create a differential pair of PCB traces in CST Studio. Generates two parallel bricks separated by a gap and calculates the differential …
cst_pcb_via_model	Create a detailed PCB via model in CST Studio with parasitic inductance and capacitance estimates. Uses the Goldfarb model for via induct…
cst_pcb_via_fence	Create a row (or multiple rows) of vias along a path for isolation or Substrate Integrated Waveguide (SIW) construction. Generates an arr…
cst_pcb_cpw_transition	Create a coplanar waveguide (CPW) to microstrip transition in CST Studio. Generates a tapered geometry that linearly tapers the center co…
cst_pcb_calculate_coupling	Calculate electromagnetic coupling between parallel PCB traces. Computes even/odd mode impedances, coupling coefficient, and near-end/far…
cst_pcb_siw_waveguide	Create a Substrate Integrated Waveguide (SIW) in CST Studio. Generates top and bottom copper planes with two rows of via fences forming t…
cst_add_sma_edge_connector	Add a parametric edge-launch SMA connector at a board edge: PEC body (default 9.5 x 9.5 x 6 mm) standing off the edge by 'gap', PTFE coax…

Matching networks (8)

L / Pi / T networks, stubs, quarter-wave, Smith transforms.

Tool	What it does
cst_matching_l_network	Design an L-section impedance matching network. Computes inductor and capacitor values for matching a source impedance to a load impedanc…
cst_matching_pi_network	Design a Pi-section impedance matching network (C-L-C or L-C-L). Uses two back-to-back L-sections via a virtual resistance for controllab…
cst_matching_t_network	Design a T-section impedance matching network (L-C-L). Dual of Pi-network, uses two back-to-back L-sections. Pure Python computation.
cst_matching_stub	Design a single-stub impedance matching network. Computes the stub length and distance from the load using Smith chart transmission-line …
cst_matching_quarter_wave	Design a quarter-wave transformer matching network. Supports single and multi-section designs with maximally flat (binomial) or Chebyshev…
cst_matching_create_lumped	Generate CST VBA code to create a lumped-element matching network. Each component (inductor, capacitor, resistor) is placed as a CST Lump…
cst_impedance_smith_transform	Apply a reactive element transformation to an impedance on the Smith chart. Supports series L/C, shunt L/C, and transmission line operati…
cst_matching_microstrip_impedance	Calculate microstrip transmission line characteristic impedance from physical dimensions using the Hammerstad-Jensen model with optional …

Publication figures (1)

IEEE-style 1D result and farfield figures from saved projects (PDF/SVG/PNG).

Tool	What it does
cst_plot_1d_results	Publication-quality (IEEE column, serif, PDF/SVG/PNG) figures of 1D results read offline from a saved .cst via cst.results (no GUI, no so…

Farfield figures (2)

Polar cuts, heatmaps and 3D patterns with gain/HPBW/F-B metrics.

Tool	What it does
cst_plot_farfield	Publication-quality farfield figures (IEEE sizes, serif, grayscale-safe): polar dB cuts (E/H-plane, co/cross-pol when Ludwig-3/spherical …
cst_plot_surface_current	Top-view surface-current |J| map(s) in dB with matplotlib (shared scale across panels optional, maximum marked) plus metrics (max A/m a…

Technical drawings (1)

Dimensioned orthographic views of the model with title block and parameter table.

Tool	What it does
cst_technical_drawing	Render an academic, dimensioned orthographic technical drawing (third-angle top/front/side views, optional isometric) of the CST model. C…

VBA escape hatch (3)

Raw VBA execution and built-in VBA object reference.

Tool	What it does
cst_execute_vba	Execute raw VBA code in CST Studio Suite (history VBA). DISABLED BY DEFAULT in connected mode: it only runs when the server process has t…
cst_vba_help	Get VBA reference documentation for a CST Studio object. Returns the object description and a list of its common methods and properties.
cst_list_vba_objects	List available CST Studio VBA objects, optionally filtered by category. Returns object names with brief descriptions.