solidworks-mcp
Advanced tools
MCP server that drives a local SolidWorks instance over COM for parametric part modelling.
Let an AI agent (Claude, or any other MCP client) model real parametric parts and assemblies in your own SolidWorks — and check its own work. Every modelling call returns the measured volume, mass and bounding box, so the agent can compare the result with the spec and correct itself instead of guessing that it "looks about right".
Built by the tools themselves: a mounting bracket (every step checked against a hand calculation), an M10 bolt with a real thread, a revolved + shelled vase, a swept pipe, a lofted + shelled horn.
width@Sketch1), so the part stays editable, in SolidWorks or
through the agent.{ok: false, error} with the cause, never silently wrong geometry.Install uv.
Start SolidWorks and leave it open (the server attaches to the running instance — it does not launch one).
Register the server with your MCP client.
Claude Code:
claude mcp add solidworks -- uvx solidworks-mcp
Claude Desktop (claude_desktop_config.json) or any other client:
{
"mcpServers": {
"solidworks": {
"command": "uvx",
"args": ["solidworks-mcp"]
}
}
}
It is also listed in the official
MCP Registry
as io.github.hjbaard/solidworks-mcp.
Ask for a part, for example:
Design a 100 × 80 × 8 mm mounting plate with a Ø16 mm centre bore, four counterbored M5 holes 12 mm from the corners and R5 corners. Check the volume against your own calculation, then export a fine STL.
The server hands every MCP client short modelling guidelines when it connects
(conventions, verify each step, known pitfalls). The full guide is the resource
solidworks://guide: recipes for holes, ribs, threads and assemblies, 3D-print
advice, and how to reverse-engineer a part from a mesh (STL/3MF). The same text
is in src/solidworks_mcp/guide.md.
Windows, with SolidWorks installed, licensed and running.
Python 3.11+ (uv fetches one if needed).
Tested on SOLIDWORKS 2026 (3DEXPERIENCE R2026x). The API calls it uses exist since SOLIDWORKS 2020 SP2, so 2020–2025 should work, but that is untested. To check your installation, run this with SolidWorks open:
uvx solidworks-mcp --selftest
It builds a few small parts, compares each with a hand calculation and closes them unsaved. Please paste its output in a compatibility report, whether it worked or not.
Status: early (0.x). It works end-to-end, but tool names and conventions may still change. See CHANGELOG.md.
uvx solidworks-mcp --selftest shows your
SolidWorks release, language and templates, and which tool areas work. Add
its output to a bug report.GetActiveObject and does not launch one.EnsureModule errors — the first COM call generates the
makepy typelib wrappers under your temp gen_py folder. Let it finish; if it gets
into a bad state, delete the gen_py cache and retry. Early binding is mandatory on
this build (see Architecture).{ok: false, error: ...} — that is by design: every tool
fails loud with a readable message rather than silently producing wrong
geometry. Read the message; it names the likely cause.scripts/introspect_api.py to inspect your installed typelib.Clone the repository, then install it editable into a venv:
python -m venv .venv
.\.venv\Scripts\python.exe -m pip install -e .[dev]
To run the MCP server from this checkout instead of via uvx, point your client at the venv's Python:
{
"mcpServers": {
"solidworks": {
"command": "C:\\path\\to\\SolidWorks-MCP\\.venv\\Scripts\\python.exe",
"args": ["-m", "solidworks_mcp.server"]
}
}
}
With SolidWorks open:
.\.venv\Scripts\python.exe scripts\probe_connection.py # M0
.\.venv\Scripts\python.exe scripts\m1_block.py # M1
.\.venv\Scripts\python.exe scripts\m2_parametric.py # M2
.\.venv\Scripts\python.exe scripts\test_mcp_server.py # M3 (full MCP loop over stdio)
.\.venv\Scripts\python.exe scripts\m5_demo_bracket.py # M5 (3D-print bracket, every step verified)
scripts/introspect_api.py regenerates/inspects the installed typelib and prints
verified enum values — run it if SolidWorks is upgraded and signatures change.
.\.venv\Scripts\python.exe -m pytest # all tests
.\.venv\Scripts\python.exe -m pytest -m "not solidworks" # fast unit layer, no SolidWorks
Two layers: pure unit tests (units, selector/direction parsing, polygon
cleaning, the component-placement maths, and that every MCP tool forwards its
arguments to the right session method) run anywhere; integration tests
(solidworks marker) drive a running SolidWorks and verify each feature's
volume — or each component's placement — against a hand calc. They auto-skip if
SolidWorks isn't reachable.
The server speaks MCP over stdio.
| Tool | Purpose |
|---|---|
get_status | Is SolidWorks reachable? revision, server version, active/current part |
new_part | Create a new empty part (becomes current) |
add_box(width_mm, height_mm, depth_mm, name) | Sketch rectangle + extrude; returns mass properties |
add_cylinder(diameter_mm, height_mm, name) | Cylinder by revolving a profile 360° about an axis (Y axis) |
add_disc(diameter_mm, thickness_mm, name, x_mm, y_mm) | Disc/puck/flange: circle extruded along +Z, centred at (x, y) (holes/patterns compose) |
add_cone(bottom_diameter_mm, top_diameter_mm, height_mm, name) | Cone/frustum by revolve (top Ø = 0 → full cone) |
add_revolved_profile(profile_mm, angle_deg, name, corner_radii_mm, axis_mm) | Revolve any closed (radius, height) profile about the Y axis (shafts, vases, rings), or [x, y] points about any line axis_mm on the Front plane; corner_radii_mm rounds its edges |
add_swept_pipe(path_mm, diameter_mm, bend_radius_mm, name, smooth) | Sweep a round profile along a 2D path with rounded bends (pipes, tubes, rods), or along a spline through the points with smooth=True |
add_swept_profile(profile_mm, path_mm, bend_radius_mm, name, corner_radii_mm) | Sweep any closed cross-section along a 2D path (rails, gaskets, trim, channels); corner_radii_mm rounds the cross-section |
add_lofted_solid(profiles_mm, heights_mm, name) | Loft/blend 2+ polygon or round profiles on stacked parallel planes (transitions, adapters, a leg thick at the knee) |
add_rib(start_mm, end_mm, toward_mm, thickness_mm, z_mm, name) | Straight rib / gusset in a plane parallel to Front at z_mm, grown toward toward_mm until it meets the part (L-bracket gussets) |
add_extruded_profile(points_mm, depth_mm, name, corner_radii_mm, rotate_deg, about_mm, draft_deg, merge) | Extrude any closed polygon [[x,y],…] (brackets, sections); corner_radii_mm rounds its corners with real sketch fillets, each radius a dimension; rotate_deg turns it about a pivot; draft_deg tapers its walls; merge=False keeps a separate body |
add_plane(base, offset_mm, angle_deg, about, name) | A reference plane offset from a plane, or turned about a model axis; its offset or angle a dimension; gives its origin and axes |
add_extruded_profile_on_plane(points_mm, plane, depth_mm, reverse, name, corner_radii_mm, draft_deg, merge) | Extrude a polygon drawn on any plane (3D points on it), merged with the part |
list_bodies() | The part's solid bodies: name, volume, bounding box |
combine_bodies(operation, main, tools, name) | Add, subtract or intersect bodies of the part (add / subtract / common) |
split_body(plane, name) | Split the part into two bodies along a plane |
add_extruded_spline(points_mm, depth_mm, name) | Extrude a smooth closed spline through points (free-form/organic outlines) |
add_hole(diameter_mm, x_mm, y_mm, name) | Cut a circular through-hole at (x, y) through the depth axis |
add_counterbore_hole(clearance_diameter_mm, cbore_diameter_mm, cbore_depth_mm, x_mm, y_mm, name) | Counterbored screw hole (flush cap-head / heat-set insert) on +Z |
add_thread(size, x_mm, y_mm, z_mm, length_mm, internal, name) | Real, printable ISO metric thread (e.g. M10x1.5) from a rod's end edge or a hole's mouth, via SolidWorks' Thread feature; the size is checked against the thread profiles. Internal: drill the basic minor diameter first (M10x1.5 → Ø8.376) |
add_hole_on_face(diameter_mm, face, x_mm, y_mm, z_mm, depth_mm, name) | Round hole on ANY planar face at a 3D point, through or blind (side holes, heat-set insert holes); the face through the point is used |
add_hole_wizard(kind, size, face, x_mm, y_mm, z_mm, depth_mm, fit, thread, name) | ISO hole from SolidWorks' Hole Wizard tables: clearance (ISO 273 fits), counterbore, countersink or tapped; thread="modeled" cuts a real, printable thread |
add_boss_on_face(diameter_mm, face, x_mm, y_mm, z_mm, height_mm, name) | Round boss (standoff, peg) grown out of ANY planar face |
add_extruded_profile_on_face(points_mm, face, depth_mm, name, corner_radii_mm) | Polygon pad/ledge grown out of ANY planar face (3D points on the face) |
add_text_on_face(text, face, x_mm, y_mm, z_mm, height_mm, depth_mm, emboss, font, name) | Engrave text into ANY planar face, or emboss it: labels, version numbers; the position is two dimensions |
cut_profile(points_mm, depth_mm, name, corner_radii_mm, rotate_deg, about_mm) | Cut a polygon pocket/slot from the +Z face (blind or through), optionally turned about a pivot |
cut_profile_on_face(points_mm, face, depth_mm, name, corner_radii_mm) | Cut a polygon pocket on ANY face (3D points on the face) |
cut_profile_through_plane(points_mm, plane, depth_mm, name, corner_radii_mm) | Cut a polygon drawn on the Front/Top/Right plane or a plane by name, through all both ways or depth_mm centred on the plane (wedges, side windows, symmetric recesses); keep_inside keeps the profile instead, so two views make a 3D shape |
cut_offset_pocket(face, x_mm, y_mm, z_mm, rim_mm, depth_mm, name) | Pocket a face leaving a rim along its outline (I-beam web, tray, frame); rim and depth are dimensions |
cut_slot(length_mm, width_mm, x_mm, y_mm, angle_deg, depth_mm, name) | Cut a straight slotted hole (obround) on the +Z face at any angle |
add_extruded_slot(start_mm, end_mm, width_mm, depth_mm, name) | Extrude a stadium (rounded tab, lug, link) between two points, the round ends centred on them |
add_fillet(radius_mm, edges, name, radii_at_mm) | Round edges (edges: all, axis x/y/z, a face outline "+z:outline", one feature's edges "feature:Boss", or indices "2,5"); radii_at_mm varies the radius from end to end |
add_full_round(face, x_mm, y_mm, z_mm, name) | Round a rib's top off completely between its two closest opposite sides |
add_chamfer(distance_mm, edges, name) | Chamfer edges at 45° (edges: all, axis, a face outline, a feature's edges, or indices) |
add_shell(thickness_mm, open_face) | Hollow to a wall thickness; open a face (+z/…) or none |
add_linear_pattern(count, spacing_mm, direction, feature_name) | Repeat a feature N times along +x/-x/… |
add_circular_pattern(count, center_x_mm, center_y_mm, feature_name) | Repeat a feature N times around an axis (bolt circle) |
add_mirror(plane, offset_mm, features, name) | Mirror features (copies follow their seeds) or the whole body about the Front/Top/Right plane, or a plane by name, moved offset_mm; fails when a copy would land outside the part |
set_dimension(dimension_name, value_mm) | Change a named driving dim (e.g. D1@BlockExtrude, or any name a tool returned in dimensions), rebuild, remeasure; an angle in degrees |
set_equation(equation) | Add a global equation or variable linking dims (e.g. "W" = 40, then "width@Sketch1" = "W") |
slice_mesh(path, axis, heights_mm, frame) | Cross-sections of an STL/3MF mesh as polygon loops, ready to use as profiles |
compare_with_mesh(path, axis, heights_mm, frame, offset_mm) | Compare the part's cross-sections with a reference mesh (area and extent differences) |
read_sketch(name) | A sketch read back in model coordinates: lines, arcs, circles, splines, its dimensions, fully defined or not |
add_sketch(plane, start_mm, segments, name) | Sketch an outline of lines, arcs and splines on any plane, fully defined: tangent where it flows, dimensioned from the origin |
extrude_sketch(sketch, depth_mm, reverse, name) / cut_sketch(sketch, depth_mm, reverse, name) | Build on an existing sketch by name (one a person drew): extrude it, or cut it blind or through all |
list_dimensions() | Every dimension in the part: name (for set_dimension), feature, value, unit |
list_features() | The part's history in tree order (name, type, suppressed); flags features that fail to rebuild and sketches that are not fully defined |
delete_feature(name, with_children) | Undo a step: delete a feature with its sketch; refuses (and names them) while other features depend on it, unless with_children |
suppress_feature(name, suppress) | Take a feature out but keep it and its dimensions (try a variant); suppress=False brings it back with its dependents |
set_material(name, database) | Assign a material (e.g. 6061 Alloy) so mass/density are real |
rebuild(top_only) | Force rebuild, report errors |
get_mass_properties | Volume, mass, density, surface area, centre of mass, bounding box |
get_bounding_box | Tight part bounding box (min/max/size, mm) |
list_faces(component) / list_edges | Inspect faces (normal/area/centre; a cylinder's axis, radius and centre, also of a component in an assembly) and edges (type/ends/axis/length) by index |
check_printability(up, overhang_deg, min_wall_mm) | For a print direction: overhanging faces (area, worst lean, centre), bed contact, height; with min_wall_mm the walls thinner than that |
export(path, file_format, quality, deviation_mm, angle_deg) | STEP/STL/IGES/Parasolid/3MF (silent; verifies file). STL/3MF tessellation: quality coarse/fine, or explicit deviation_mm+angle_deg |
screenshot(path, view, zoom_mm) | PNG/BMP/JPG from a standard view (iso, front, top, …), zoomed to fit or onto a region |
make_drawing(path) | 2D drawing as PDF or editable .slddrw: front, top, right (first angle) and isometric views on A4 with the model's own dimensions, each once |
save_part(path) / open_part(path) | Save to / open a native .sldprt; open_part also imports STEP, IGES and Parasolid files as a part to build on |
close_part(save) | Close the current part or assembly; without one, SolidWorks' active document if it is saved |
| Tool | Purpose |
|---|---|
new_assembly | Create a new empty assembly (becomes the current document) |
open_assembly(path) / save_assembly(path) | Open / save a native .sldasm; open_assembly also imports STEP, IGES and Parasolid assemblies, parts as components in place |
insert_component(path, x_mm, y_mm, z_mm, fixed) | Insert a part, or a .sldasm as a sub-assembly, with its origin at (x, y, z); the first component is fixed by default |
list_components | Name, path, fixed, position, rotation and bounding box of every component (its own extent, also when turned), and the mates with their dimensions and errors |
set_component_transform(name, x_mm, y_mm, z_mm, rx_deg, ry_deg, rz_deg) | Move/rotate a component; the transform is read back and verified |
add_mate(comp_a, face_a, comp_b, face_b, mate_type, distance_mm, angle_deg, flip) | Mate two faces (by direction, or #index from list_faces): coincident, distance, parallel, perpendicular, angle, or concentric between cylinders — measured back afterwards; a refused mate is removed. A distance or angle mate returns its dimension: a joint angle as one number |
check_motion(dimension_name, values, distances) | Step a joint through its range: overlapping pairs and chosen distances per step, the smallest distance and where it occurs |
check_interference | Component pairs whose solids overlap, with the volume in mm³ (touching faces don't count) |
measure_distance(component_a, component_b, point_mm, axis_mm) | Smallest distance between two components, to a point (with the nearest point, and whether the point is in the material), or to an axis |
get_assembly_bounding_box | Tight bounding box of the whole assembly (min/max/size, mm) |
export and screenshot work on assemblies too.
Faces are selected by direction in the component's own frame (+x, -z, …),
so a selector keeps meaning the same face however the component is turned. Add
:inner (e.g. +y:inner) for the cavity side of a hollow part — the inside of a
room wall instead of its outer skin.
All linear dimensions are millimetres; the server converts to/from the SolidWorks-internal metre/radian units at the boundary.
src/solidworks_mcp/
binding.py early-binding plumbing (wrap raw dispatches in generated classes)
com_worker.py one dedicated STA thread; all COM calls serialised through it
session.py SolidWorks operations (must run on the COM thread)
server.py FastMCP tools that delegate to session via the worker
constants.py enum values read from the installed typelib (verified)
units.py mm<->m, deg<->rad
errors.py SolidWorksError -> agent-facing {ok:false,error}
Two non-obvious design decisions, both load-bearing:
Early binding is mandatory. On this build GetActiveObject returns a
dispatch whose GetTypeInfo() fails, so EnsureDispatch/CastTo cannot infer
types and pure late binding breaks (IModelDoc2.FirstFeature →
DISP_E_MEMBERNOTFOUND). We generate makepy wrappers from the installed
typelib and wrap each raw dispatch in the right interface class; calls then go
by dispid via InvokeTypes, bypassing name resolution. See binding.py.
A dedicated COM thread. COM is STA and thread-affine. The MCP server runs
on asyncio, so all COM work is pinned to one worker thread (com_worker.py)
that handlers post to and await — actively enforcing the "one COM session,
single-threaded" rule that does not hold automatically in an async server.
Proven end-to-end against SOLIDWORKS 2026 (3DEXPERIENCE R2026x):
| Milestone | What it proves | State |
|---|---|---|
| M0 | COM connection to a running SolidWorks | ✅ |
| M1 | new part → sketch rectangle → extrude → mass properties (volume matches hand calc) | ✅ |
| M2 | change a named dimension → rebuild → volume changes predictably | ✅ |
| M3 | full agent loop via the MCP server: build → measure → correct → export STEP/STL + screenshot | ✅ |
| M4 | revolve, sweep, loft, profiles, holes/pockets/counterbores, slots, fillet/chamfer, shell, patterns, equations, materials, save/open | 🚧 ongoing |
| M5 | end-to-end 3D-print part: build a functional mounting bracket through the full loop → verify every dimension → export a fine STL (scripts/m5_demo_bracket.py) | ✅ |
| M6 | assemblies: insert and position components, mate them, check interference — every placement and mate measured back (tests/test_assembly.py) | ✅ |
See Docs/PROGRESS.md for the detailed log and roadmap. Feedback and contributions are welcome.
cut_profile),
fillets, chamfers, shells, linear + circular patterns (bolt
circles); plus equations, materials, geometry inspection, and
save/open of .sldprt, holes + pockets on any planar face
(model→sketch transform), round flanges (disc + bore + bolt circle), and
slotted holes (cut_slot, obround at any angle — the first arc-based sketch),
general revolves (add_revolved_profile: any (r,z) profile → shafts,
vases, rings), swept pipes/tubes (add_swept_pipe: a round profile along
a rounded 2D path), and lofts (add_lofted_solid: blend stacked polygon
profiles → transitions/adapters), free-form extrusions
(add_extruded_spline: a smooth closed spline → organic/aesthetic outlines), and
non-circular sweeps (add_swept_profile: any cross-section along a path →
rails, gaskets, trim), and mirrors (add_mirror: features or the whole
body about a plane through the part)._planar_face_by_normal,
+z/…, with :inner for the cavity side of a hollow part), and edge selection
by axis or explicit index (_select_edges). list_faces/list_edges let
an agent inspect geometry before selecting.FAQs
MCP server that drives a local SolidWorks instance over COM for parametric part modelling.
We found that solidworks-mcp demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
Research
/Security News
Socket uncovered two malicious VS Code themes in a GlassWorm-linked cluster with thousands of installs across VS Code Marketplace and Open VSX.
Security News
/Company News
Capital One is partnering with Socket to proactively secure its open source supply chain.
Security News
Socket CTO Ahmad Nassri discusses how to keep AI agents from bypassing package blocks, limit credential access, and monitor their actions.