klayout-draw-mcp¶

An MCP server for drawing GDS layouts with KLayout — generate, edit and view chip layouts straight 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 when you want to view or hand-edit a result.

"Draw a CIS 4T APS pixel at 1 µm pitch, tile it 2×2, then save to out.gds and open it."

The assistant calls new_layout → drawing tools / run_script → save_gds(open_after=True). See the Examples for layouts produced exactly this way.

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 on two layers
`add_wire(layer, points, width)`	Manhattan wire (auto-inserts 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, …)

Install¶

pip install klayout-draw-mcp

The KLayout application is only required for open_layout / open_editor.

Register with Claude Code¶

claude mcp add klayout -s user -- python -m klayout_draw_mcp.server

When running from a checkout, point at the project's interpreter instead, e.g. <repo>/.venv/Scripts/python.exe on Windows or <repo>/.venv/bin/python on macOS/Linux.

For uvx, Claude Desktop, verification and troubleshooting, see the full Installation & Setup guide.

How it works¶

There are two complementary ways to produce geometry:

High-level drawing tools (new_layout, add_box, add_polygon, …) build a layout step by step. All coordinates are in micrometers.
run_script executes arbitrary Python with klayout.db available, for anything the high-level tools do not cover — cell hierarchy, array instances, boolean ops, DRC. See the run_script cookbook for copy-paste recipes.

Beyond drawing from scratch, you can load an existing layout with load_gds and keep editing it, inspect any file or the session with inspect_gds, and run simple DRC with drc_check — spacing, width, forbidden overlap, separation and enclosure rules, each violation reported with a location:

[
  {"type": "spacing", "layer": 3, "datatype": 0, "min": 0.15},
  {"type": "width",   "layer": 6, "datatype": 0, "min": 0.08},
  {"type": "overlap", "layer": 3, "layer2": 6}
]

Warning

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