dshworks/dsh-solidworks

   ___ _      __     dsh-solidworks
  / __| \    / /
  \__ \\ \/\/ /      SOLIDWORKS for DeepSeek Harness:
  |___/ \_/\_/       model, assemble, check, draw and export, in the SOLIDWORKS on your desk

21 tools · verified on SOLIDWORKS 2016 SP1 and 2019 SP0 · one bridge exe, no runtime to install, no admin · your files read-only by default · MIT

Watch it · Get started · Tools · What it will not do · How it works · Proof · When to skip it · llms.txt · 中文

One paragraph in, a flange out. You describe the part; dsh models it in the SOLIDWORKS on your desk, checks the volume against its own arithmetic (158,983.493 mm³ both ways), and looks at it from four sides. It can also put parts together, check them for collisions, count a bill of materials, make the drawing, and work on the files you already have, read-only unless you say otherwise.

Watch it

Every clip is a real session: dsh 0.2.0-rc.2 with deepseek-flash, SOLIDWORKS 2019 SP0 in a Parallels VM, recorded from the SOLIDWORKS window. The captions are the session's own tool calls and results, and its own closing words. Time spent thinking is fast-forwarded; nothing is cut or reordered. How the clips are made.

Point at it

You select a face in SOLIDWORKS and say what to do with it. dsh reads your selection (the flange's top face, 8 edges), rounds every edge of it at 2 mm, and explains why the volume went down by 360.218 mm³ even though one fillet adds material.

Put parts together, check they fit

A shaft is modeled, both parts saved, and assembled with the shaft through the bore and the flange 40 mm up. Interference: 0 pairs. dsh also counts faces that only touch, and points out that a 30 mm shaft in a 30 mm bore is a line-to-line fit. Then the bill of materials.

Draw it

The drawing lays its views out in projection at the largest standard scale that fits, brings in the model's dimensions, and comes back to your workspace as a PDF.

_{Left: the PDF as exported. Right: sw_view, four views on one picture, which is how dsh looks at what it made.}

Get started

You need dsh 0.2.0-rc.2 or later (its dsh plugin add uses pnpm, so pnpm on the PATH) and a running SOLIDWORKS 2016 or later.

dsh and SOLIDWORKS on the same Windows PC

dsh plugin --profile web add @dshworks/dsh-solidworks

Start SOLIDWORKS, start dsh, ask. The plugin runs its bundled swbridge.exe on the first SOLIDWORKS question; there is nothing to pair or install.

dsh on a Mac, SOLIDWORKS in a Windows VM

1. On the Mac: dsh plugin --profile web add @dshworks/dsh-solidworks, then start dsh once. It listens for the bridge and writes a pairing kit.
2. In the VM, signed in as the person who uses SOLIDWORKS, open \\Mac\Home\.dsh\dsh-solidworks\windows\ (Parallels shares your Mac home folder there) and double-click pair.cmd.

That installs the bridge for that Windows user, connects it to dsh, and starts it at every sign-in. No administrator, no firewall rule: the bridge dials out to dsh, so Windows never opens a port. If you ask dsh before pairing, the answer says where the kit is.

On VMware, another PC, or a Mac without Parallels sharing, copy the ~/.dsh/dsh-solidworks/windows/ folder to the Windows machine and run pair.cmd there. If the VM reaches your Mac on an address the kit did not list, set it:

# ~/.dsh/profiles/web/cordis.patch.yml
- id: dsh-solidworks
  config:
    advertise: ['10.211.55.2']   # Parallels' usual host address

Undo it in the VM with %LOCALAPPDATA%\dsh-solidworks\swbridge.exe uninstall.

Any other MCP client, on the Windows PC

swbridge.exe mcp is a plain stdio MCP server with the same 21 tools:

claude mcp add solidworks -- C:\tools\swbridge.exe mcp

The exe is in this package at bin/swbridge.exe and on every GitHub release with its SHA-256.

Tools

Lengths are millimetres, angles degrees, mass kilograms, whatever units the document uses; field names say so (value_mm, mass_kg). Geometry is addressed in one space everywhere: model-space points [x, y, z] in mm, Y up, the front plane at z = 0, top at y = 0, right at x = 0. Faces and edges are picked by a point on them. doc is a path, file name or title of an open document and defaults to the active one.

What it will not do

The rules are enforced on the Windows side, where the files are. dsh can ask for anything; only the bridge decides.

• Change your file without being told to. Documents open read-only by default; sw_edit, sw_build, sw_study and sw_assemble work in memory; sw_save writes a new file into an allowed folder, and over a source file only if the bridge was started with --allow-save.
• Delete your work. sw_build deletes only features it built in this bridge session, and a sketch of yours that one of them consumed stays; your features can be suppressed, not removed. It refuses to build while the rollback bar is above the end of the tree, where new features would land among yours. sw_study puts every value back and checks that it did.
• Write outside its folders. Exports, saved copies and BOM files go to Documents\dsh-solidworks, or a folder you allowed with --allow-write. An existing file is replaced only when asked.
• Throw away someone's work. It closes a document with unsaved changes only if this bridge opened or made that document and the call says discard.
• Start, close or click SOLIDWORKS. It attaches to the SOLIDWORKS in front of you, never starts or quits one, and never answers a dialog: it tells you the dialog's text instead, because answering is your decision.
• Run code. No macro, script or "invoke any API" tool. Every SOLIDWORKS call it can make is in bridge/compat/members.tsv.
• Put the pairing token in the model's context. The "not connected" answer says where the kit is, never the token, so transcripts do not carry it.

The link between dsh and a bridge on another machine is authenticated both ways (each side proves the token with HMAC-SHA256 over fresh nonces before a single call crosses) but not encrypted. It is meant for a host-only VM network or a local one; across anything else, carry it through SSH or a VPN. See SECURITY.md.

How it works

 dsh (Windows, macOS, Linux)                        Windows, the user's desktop session
 +-------------------------------+                  +----------------------------------+
 | @dshworks/dsh-solidworks      |   same PC:       | swbridge.exe  (.NET Framework 4.8)|
 |  21 sw_* tools, built with    |   stdio MCP      |  MCP server, protocol/tools.json  |
 |  dsh's own MCP tool factory   | <--------------> |  one STA thread + OLE msg filter  |
 |  spawn | listen                |   VM / other PC: |  IDispatch late binding           |
 +-------------------------------+   the bridge     |        |                          |
              ^                      dials dsh       |        v  COM, out of process     |
              |  protocol/tools.json  (HMAC pairing) |  SOLIDWORKS 2016 ... current      |
              +----- one contract, both halves ----- +----------------------------------+

• One space for geometry. Sketch points, picks, probes, component origins and bounding boxes are all model-space millimetres. The bridge maps each sketch point through the sketch's own transform, so a circle on a face goes where the model said, whatever axes SOLIDWORKS gave that face's sketch. A pick asks every face or edge for its closest point to the target, so it does not depend on the view, the zoom or what is in front, and it never touches your selection.
• Checks against intent. sw_build answers with the part's volume and box, sw_probe with areas and distances, sw_interference with overlap volumes: numbers the model compares with what it meant to make. A build that fails halfway removes what it made, so the part is either built or as it was.
• One exe for every release. The bridge references no SOLIDWORKS interop assembly. Every call goes through IDispatch by name, so the build that drives 2016 drives 2019 and later, and builds on Linux CI. dynamic and PowerShell's COM adapter both fail on SOLIDWORKS objects out of process (TYPE_E_ELEMENTNOTFOUND, measured); Type.InvokeMember does not.
• 2016 is checked, not assumed. bridge/compat/members.tsv lists the 200 members the bridge calls, each with its interface. A test fails if the bridge calls anything not listed, names a member any way but as a literal, or if a listed member is missing from the SOLIDWORKS 2016 SP1 interop. It is how SaveAs2 (2019 SP1+), Get6 (2018+) and IEquationMgr.GlobalVariable (2016 SP4+) stay out.
• The instance you are looking at. Every SOLIDWORKS registers SolidWorks_PID_<pid> in the desktop's Running Object Table. The bridge picks the visible one highest in the window Z-order instead of whatever GetActiveObject returns. We found machines with four instances, three of them invisible and stuck on a startup dialog.
• Busy, not hung. All calls run on one STA thread with an OLE message filter that retries while SOLIDWORKS is busy. A call that outlives its budget returns TIMEOUT and says whether it may still complete; later calls fail fast with SW_BUSY instead of queueing behind it, and sw_status still answers and names the dialog SOLIDWORKS is waiting on.
• Dial out, not listen. On another machine the bridge connects to dsh. Windows Firewall blocks inbound by default and opening a port takes an administrator; an outbound connection takes neither and works from behind the VM's NAT. The first bridge keeps the link; a heartbeat frees it within seconds when that bridge goes away.
• One contract. protocol/tools.json holds the names, schemas, budgets and error codes. The bridge embeds it; the plugin builds dsh tools from it with dsh's own createMcpToolDefinition, so validation, error results and image admission behave as for any MCP server.

Proof

Every claim on this page was run, against real SOLIDWORKS, on 2026-10-18.

The end-to-end checks test each answer against something the tool did not say about itself. The modelling ones compute it from the geometry asked for: the plate above must come to 6000·20 − π·10²·20 − 4·25·(1 − π/4)·20 mm³ and its top face to that area over 20; a 50 mm cube shelled at 2 mm with one face open to 50³ − 46²·48 = 23,432 mm³; a revolved 10/20 mm tube 30 mm long with a 1 mm chamfer to π(20² − 10²)·30 − π·(20 − 1/3); a design study at 10 and 40 mm to that area times 10 and 40, and the plate back at 20 afterwards; two plates mated face to face must not interfere and a third pushed 10 mm into both must overlap each by exactly the top face area times 10; the BOM must count 3; the drawing must have its four views at the sheet's scale and export as %PDF-. The ownership checks build on a sketch the bridge did not make (saved, closed and reopened, so it is forgotten): a failed build and a delete of what was built on it must leave that sketch in place, and a sketch that fails on its second entity must leave the feature tree exactly as it was. A blind cut sketched on a plane under the body must reverse itself and remove exactly π·5²·4 mm³, and a drawing saved next to its part must be the document its .slddrw name exports. The reading ones from 0.1.0 still run: the stock box.sldprt must reach 325,500 mm³ after sw_edit sets its depth to 150 mm, the fetched STEP must hash to the bridge's SHA-256, the refusals must return their codes. On 2016 the run used a SOLIDWORKS that someone else had a 58-document assembly open in; a check confirms their documents, dirty flags, active document and the 57 parts their assembly had loaded came back unchanged.

Measured through the link in the 0.2.1 runs, SOLIDWORKS under x64 emulation on Windows 11 ARM64 (the slower end is the 2016 SOLIDWORKS that also holds the 58-document assembly): the five-step plate build 3.2-4.3 s, a probe 0.3-0.9 s, a four-view picture 2.5-3.4 s, a drawing 1.9-3.9 s, interference on a three-part assembly 1.1-3.2 s, open a part 1.3-1.5 s, export STEP 0.4-0.5 s.

Not verified yet: SOLIDWORKS 2020 and later, Windows 10, x64 hardware. Reports welcome: open an issue with swbridge status pasted in.

When to skip it

• You need lofts, sweeps, patterns, the Hole Wizard or sheet metal. sw_build covers sketch, extrude, cut, revolve, fillet, chamfer, shell and planes. Sketches are exact but carry no sketch dimensions or relations; the features' own dimensions (depths, radii, angles) are named and drivable.
• Your files are STEP or IGES. sw_open opens SOLIDWORKS documents; import them in SOLIDWORKS first.
• You need it in the SOLIDWORKS window. There is no task pane; the conversation is in dsh.
• You want to walk 50,000 faces. Out-of-process COM costs a round trip per call, and a probe asks every face near the point. The tools return summaries; geometry-heavy work belongs in an add-in or on an exported STEP.
• You run several SOLIDWORKS machines into one dsh at once. One bridge holds the link at a time.

Troubleshooting

Configuration

The plugin row, id: dsh-solidworks:

The bridge, swbridge.exe: mcp, connect, status, uninstall, with --out, --allow-write, --allow-save, --pid. swbridge help has the rest.

Prior art

• wzyn20051216/solidworks-automation-skill (MIT): the broadest open SOLIDWORKS MCP server, a 61-tool Python server with a careful authenticated HTTP transport. Python plus pywin32 on the CAD machine, every tool in every turn.
• eyfel/mcp-server-solidworks (SolidPilot, AGPL-3.0) and tian-yu200/dsh-solidworks (AGPL-3.0): the best modelling ideas, targeting SOLIDWORKS 2026 with an interop built per release.
• Slacker-LLC/solidworks-mcp (Apache-2.0): clean code; uses members that 2016 lacks.

What this one does differently: one model-space coordinate system for every tool, builds that undo themselves when a step fails, a 2016 floor that a test enforces, one exe with no runtime to install, a link that needs no open port, and dsh's own tool plumbing instead of a parallel one. No code was copied from any of them.

Development

npm install && npm test              # plugin + contract + 2016 member check, no Windows needed
npm run build:bridge                 # .NET 8 SDK; builds bin/swbridge.exe for net48
SW_LINK_TOKEN=... node tests/live/e2e.mjs   # live run against a bridge that dials this machine

CONTRIBUTING.md has the rest, including how to run the live checks against your own SOLIDWORKS. bridge/compat/README.md explains how sw2016.tsv is regenerated from an installed interop. node scripts/format-contract.mjs keeps protocol/tools.json in its layout. MIT, see LICENSE.