gitcad

Headless, git-native boundary-representation (B-rep) CAD — mechanical and electrical.

Models are stored as canonical text; geometry is a build artifact and is not committed. Entity and feature identity is derived from construction lineage rather than ordinal position, so references survive upstream edits. Each build produces a report, and designs diff, branch, review, and merge at each kind's natural grain. The primary interface is an MCP server; a browser viewer is optional.

Website: gitcad.xyz · Registry: gitcad-xyz/registry

Packages

• gitcad-core — canonical text, identity, the Part standard, report pipeline.

• gitcad-mech — document model, exact-arithmetic geometry kernel, sketches, drawings, importers.

• gitcad-ecad — schematic and ERC, board and DRC, connectivity, fabrication outputs.

• gitcad — metapackage installing the three above and the MCP server.

Related MCP server: openscad-mcp

A project is a repo

widget/
├── widget.gitcad        # top-level assembly (mechanical + electrical parts)
├── housing.part         # a mechanical part
├── housing.model        # its feature tree
├── mainboard.pcba       # an electrical assembly
├── mainboard.board      # the board
├── mainboard.sch        # the schematic
├── requirements.reqs    # executable requirements
└── release-*/           # built artifacts + fab-lot provenance

gitcad-init widget scaffolds a project with the merge driver and CI gates configured. Roles are detected by file content.

Console commands

Install

pip install gitcad            # core, mechanical, electrical, MCP server, native kernel

gitcad is an MCP server — there is no application to open. Wire it into an MCP client (either form):

claude mcp add gitcad -- gitcad-mcp

{ "mcpServers": { "gitcad": { "command": "gitcad-mcp" } } }

Once connected, the agent calls the get_started tool and opens the live browser viewer (viewer_open) as the project takes shape. Run gitcad (or python -m gitcad) any time to reprint this wiring and the viewer story.

• Windows per-user installs: console scripts land in %APPDATA%\Python\PythonXY\Scripts, which is typically not on PATH, so gitcad-mcp can be "not recognized" right after install. Use the PATH-proof spelling { "mcpServers": { "gitcad": { "command": "python", "args": ["-m", "gitcad.mcp"] } } } or add that Scripts directory to PATH.

• Introspection: gitcad is a namespace package shared by gitcad-core/-mech/-ecad. Without the metapackage installed, gitcad.__file__ is None — introspect with gitcad.__path__ or importlib.metadata, never os.path.dirname(gitcad.__file__). The metapackage provides gitcad.__version__.

The geometry kernel is forge (forgekernel), the project's own exact-arithmetic kernel and the only one (ADR-0020); its native build is installed by default on common platforms. Geometric and topological decisions use exact rational arithmetic or certified intervals, and an operation the kernel cannot do exactly refuses by name rather than approximating. The test suite also runs with no geometry kernel installed — a null backend covers identity, documents, netlists, checks, and merge; tests needing geometry are marked and skipped otherwise.

Capabilities

Mechanical — primitives and booleans, including booleans over freeform (lofted NURBS) solids whose volume is reported as a certified interval; fillet, chamfer, shell, plus taper and variable-radius fillets and composite boss blends; extrude, revolve, loft, sweep, mirror; direct editing (move/offset/delete face with exact heal, recorded as replayable intent); molding draft with face selection, exact rational tangents, and parting lines; sketch planes and sketch-on-face; an authoring-time constraint solver; holes with counterbore (countersink currently refuses, pending the cone-cut stage); patterns; sheet metal; weldments; stable entity identity; exact mass properties with provenance (exact, or certified ± e where the volume is a proven bracket); STEP/STL/DXF; STEP import that audits shell closure at the border — a file whose CLOSED_SHELL lies is refused with a gap report in millimetres, and the opt-in exact heal is recorded as intent; dimensioned drawings (third-angle and section views, GD&T, BOM and balloons); exploded views; mate checking and solving; exact interference with clash budgets; feature recognition from STEP.

Electrical — schematic capture with typed pins and sheet authoring; hierarchical sheets, buses, and multi-sheet systems; ERC, electrical envelopes, and power budgets; forward and back annotation; multi-layer boards with net classes, keepouts, courtyard DRC, copper zones, and silkscreen text; connectivity and guided routing; Gerber, Excellon, pick-and-place, IPC-D-356, and netlist export; board statistics and length checks; SPICE export and simulation-as-test.

Cross-domain — parts with typed interfaces, interface semantic versioning, and lockfiles; registry parts; electrical assemblies as parts (.pcba); enclosure fit checks; all-or-nothing release gates; fab-lot records.

Documentation

See docs/adr/ for design decisions and CLAUDE.md for the rules agents follow.

License

Apache-2.0.