Klayout Draw

An MCP server for drawing GDS layouts with KLayout — generate, edit, and view layouts from an AI assistant such as Claude Code or Claude Desktop.

Layout geometry is built in-process with the standalone klayout Python module (no GUI needed). The installed KLayout application is launched only for viewing or manual editing.

Tools

Tool	Purpose
new_layout(top_cell, dbu)	Start a new in-memory layout (coordinates in micrometers)
add_box(layer, x1, y1, x2, y2, datatype)	Add a rectangle
add_polygon(layer, points, datatype)	Add a polygon from [x, y] vertices
add_path(layer, points, width, datatype)	Add a path with width
add_label(layer, x, y, text, datatype)	Add a text label
create_cell(name) / use_cell(name)	Create/select the active drawing cell
place_cell(cell, x, y, orient, nx, ny, dx, dy)	Place an instance or array of a cell
add_via(x, y, bottom_layer, top_layer, cut_layer, …)	Via: cut array + enclosing metal
add_wire(layer, points, width)	Manhattan wire (auto L-corners)
layout_info()	Inspect current layout (layers, bbox, shape count)
load_gds(path, top_cell?)	Load an existing GDS/OASIS into the session for editing
inspect_gds(path?)	Per-layer shape count, area and bbox of a file or the session
drc_check(rules, path?)	Simple DRC: spacing / width / overlap / separation / enclosure
save_gds(path, open_after)	Write GDS/OASIS; optionally open in the editor
open_layout(file_path)	Open a file in KLayout (viewer)
open_editor(file_path?)	Open KLayout in editor mode, or a blank layout
run_script(code)	Run arbitrary Python with klayout.db (cell hierarchy, arrays, booleans, DRC, ...)

Requirements

• Python ≥ 3.10
• The klayout and mcp Python packages (installed via the steps below)
• The KLayout application — only needed for open_layout / open_editor

Install

uv sync

Register with Claude Code

claude mcp add klayout -s user -- "<repo>/.venv/Scripts/python.exe" -m klayout_draw_mcp.server

On macOS/Linux use .venv/bin/python.

Usage

"Draw a 5×5 µm box on layer 1 and a 2 µm-wide path, then save to out.gds and open it."

Claude calls new_layout → add_box / add_path → save_gds(open_after=True).

You can also open and check an existing layout:

"Load chip.gds, check that M1 spacing ≥ 0.15 µm and that OD never overlaps POLY, and report violations."

Claude calls load_gds → inspect_gds → drc_check([...]), then edits and save_gds. See Editing & DRC.

For anything beyond the basic shapes, run_script exposes the full klayout.db API.

Examples

Self-contained scripts in examples/. Each builds a layout with the standalone klayout.db module and writes a GDS:

uv run python examples/cis_aps_pixel.py out.gds

You can also paste the body of a script's build() function into the run_script tool. The scripts share one layer map (OD 3/0, POLY 6/0, NPLUS 4/0, METAL1 9/0, ...).

Example	What it draws
basic_shapes.py	The four primitives: box, path, polygon, label
nmos_transistor.py	A single NMOS (active, poly gate, n+, contacts, M1 S/G/D)
cmos_inverter.py	A CMOS inverter: PMOS over NMOS, shared gate, Vdd/Vss rails
cis_aps_pixel.py	A 1 µm 4T CMOS image-sensor pixel, tiled as a 2×2 array

Place & route skill

skills/klayout-pnr/ packages place-and-route recipes — row placement, power rails, and an obstacle-aware maze (Lee) router — plus a SKILL.md workflow guide for assistants. Copy it to your skills directory to have it auto-discovered:

cp -r skills/klayout-pnr ~/.claude/skills/

Documentation

Full docs (Getting Started walkthrough, examples, editing/DRC, place & route) are at https://geniuskey.github.io/klayout-draw-mcp/.

Note

run_script executes arbitrary Python locally, in-process. Only run scripts you trust.