SolidworksMCP Local — 2026.10.18.6

Control an interactive SOLIDWORKS 2025 session from an MCP-capable AI client. This independent fork adds a durable shared queue, whole-operation locking and explicit recovery to the inherited modeling tools. Its date-based build number is independent of upstream: this is not upstream version 6.6.0.

Original project: alisamsam/Solidworks-MCP, by Samsaam Ali Baig. Immediate upstream: czuryk/SolidworksMCP, baseline 38468b3 (6.5.31). The original MIT license and copyright notice are preserved. This fork is not endorsed by either upstream or by Dassault Systèmes.

Verified scope

Build 2026.10.18.6 passed native acceptance on 2026-10-18 using SOLIDWORKS 2025 API 33.2.0. Two real MCP stdio clients operated on two disposable saved parts: six alternating whole operations, FIFO order, no native overlap or lost changes, two ordinary targeted CAD plans, and matching geometry after save/close/reopen. All 31 native qualification jobs and the final 18 upgrade checks passed. The existing Codex chat also passed reconnect verification after the user restarted the client application on 2026-10-18: its actual MCP tools connected to SW2025, reported build 2026.10.18.6 and confirmed an open, idle queue without recovery jobs. SolidWorks was left running. The earlier Transport closed probe is retained as history; this is one observed restart on the qualified workstation.

The complete offline suite passed 524 tests with one capability skip (525 collected, zero failures/errors); the separate broker suite passed 9/9. These results apply to the unchanged runtime at commit d0aa04ec84a501b7a2384bd734300bc615157960. Read release validation and limits or its machine-readable record. They also retain the failed .5 native attempt and its unresolved historical Windows test-cleanup incident.

The accepted mode is two chats, different saved parts, one SW instance. CAD operations run sequentially. Multi-instance execution and RAM/commit admission management remain future work; assembly/drawing switching is not natively qualified. The test began and ended with no working documents open. Qualification on this station does not certify every client, installation or model workflow.

The separately qualified predecessor has the following historical evidence. Build .4 passed a native two-process qualification on SW2025 API 33.2.0: six ordered changes to a synthetic solid, no overlap or lost updates, and matching geometry after save/close/reopen. Two real MCP stdio clients shared one broker. Cleanup and reconnect passed; the broker and SolidWorks survived a restart of the client application. These are results from one Windows workstation, not certification of every tool, CAD version or AI client. No user documents were initially open. Earlier failures remain recorded. See acceptance and limits.

Related MCP server: solidworks-mcp-pro

AI client compatibility

The server uses standard MCP over local stdio, not a model-specific API. Use a client that can launch a local MCP process and call tools. The model may be cloud-hosted or local; the MCP server and licensed SolidWorks run on the Windows CAD workstation in its interactive user session. An application without MCP support needs an adapter. No remote HTTP/SSE endpoint or browser-only connection is provided here.

Different compatible clients can share the queue. All must use the same activated source path, interpreter and Windows user/desktop session. Check the MCP initialization response for serverInfo.version = 2026.10.18.6. Compatibility with every client has not been independently tested.

Two chats and different models

Chats may prepare and submit jobs concurrently. One broker executes CAD operations one at a time, in FIFO admission order. Its lock covers the whole submitted tool, execute_cad_plan, run_transaction or trusted synchronous script, including supported verification, rollback and save/export steps.

In .6, opt in with coordination.target_document: after waiting, the executor selects the specified already open, saved model before preflight. A real switch requires both the current and target models to be clean and their edit states to be known and safe; unknown state, unsaved changes, active sketches or in-context edits prevent switching. The selector never opens, saves or closes models, changes configurations, or confirms dialogs. A target configuration is an assertion, not a request to change it.

Finish dependent steps, leave sketch/edit mode, verify and explicitly save within the submitted operation before yielding to another model. A dirty model left between requests prevents a switch; a same-model continuation may retain its sketch/dirty state subject to normal tool preflight. An assembly must always be editing itself, even when already active.

coordination.expected_document retains its compare-only behavior: it checks the active document after waiting and never activates it. Do not supply both fields. Pin document-specific reads as well as writes. There is no reservation between separate requests; submit dependent steps as one plan. Manual UI, external macros and other COM applications do not respect this lock. See the complete selection and recovery contract.

Example arguments for execute_cad_plan below modify and save the model. They are not an installation smoke test. The saved DemoA.SLDPRT must already be open and clean, and have one solid named Body1. Replace both IDs for each new operation; retain the request ID for transport retries/result lookup.

{
  "plan_id": "demo-a-rename-001",
  "operations": [
    {"op": "rename_body", "args": {"old_name": "Body1", "new_name": "Housing"}},
    {"op": "body_volume", "args": {"name": "Housing", "unit": "mm"}}
  ],
  "transaction": {"checkpoint_before": true, "rollback_on_failure": true},
  "invariants": {"solid_body_count": 1, "required_bodies": ["Housing"], "no_modal_dialog": true},
  "coordination": {
    "request_id": "demo-a-request-001",
    "target_document": {"path": "C:\\CAD-Test\\DemoA.SLDPRT", "document_type": 1},
    "wait_timeout_sec": 25
  }
}

The second chat supplies its own IDs and target path, for example C:\CAD-Test\DemoB.SLDPRT. Each whole plan waits for exclusive ownership, selects its model and completes before the next begins. Unsafe or ambiguous selection rejects before geometry; uncertain activation fences the queue for inspection. Rollback is operation-specific and may be refused before mutation when reliable undo or snapshots are unavailable. This is not a universal undo facility.

Install the queue/core runtime

Requirements: Windows 10/11 with an interactive Explorer desktop, licensed SolidWorks 2025, and Python 3.11+. Python 3.14 is the locally qualified runtime. SolidWorks installers, licenses and proprietary templates are excluded. Use a fixed local source directory outside cloud synchronization. Keep activated sources and their environment unchanged while clients are using them.

Clone the tagged source release from estasi/SolidworksMCP-Local. Optional model weights and their LFS pointers are excluded; Git LFS is not required for this queue/core installation.

git clone --branch v2026.10.18.6 https://github.com/estasi/SolidworksMCP-Local.git C:\MCP-Releases\2026.10.18.6
Set-Location C:\MCP-Releases\2026.10.18.6
py -3.14 -m venv C:\MCP-Runtime\sw2025-2026.10.18.6
$queuePython = 'C:\MCP-Runtime\sw2025-2026.10.18.6\Scripts\python.exe'
& $queuePython -m pip install -r requirements-queue.txt -c constraints-core-py314-win.txt
& $queuePython -m pip check

The direct core dependencies are pinned. See dependency notices for the tested transitive inventory. These constraints describe Windows/Python 3.14 only, not a cross-platform lock. Optional raster/vector dependencies are separate. Installing core packages does not qualify those backends.

Bind the intended SolidWorks process

Start SolidWorks manually. For an upgrade, finish CAD work, stop submissions, disconnect old MCP sessions normally and drain/stop the existing broker using the operations procedure. Do not mix old/new clients or delete state to bypass recovery.

& $queuePython -m solidworks_mcp.coordination.cli doctor
Get-Process SLDWORKS | Select-Object Id, ProcessName
& $queuePython -m solidworks_mcp.coordination.cli activate --target-pid <VERIFIED-PID> --expected-major 33 --acknowledge-idle-session

Replace <VERIFIED-PID> with the intended numeric PID after confirming the session is idle. Activation binds its generation and source path; it does not change client configuration, launch SolidWorks or reset the journal. Native API identity is checked when attaching. Multiple SolidWorks instances may make COM attachment ambiguous; a mismatch fails closed.

Configure a local MCP client

This is a common JSON configuration format; adapt its wrapper to your client's format. Keep absolute command, arguments and working directory consistent. Point every participating client at this same release.

{
  "mcpServers": {
    "SolidworksMCP": {
      "command": "C:\\MCP-Runtime\\sw2025-2026.10.18.6\\Scripts\\python.exe",
      "args": ["-u", "C:\\MCP-Releases\\2026.10.18.6\\solidworks_mcp_server.py"],
      "cwd": "C:\\MCP-Releases\\2026.10.18.6"
    }
  }
}

Reconnect through the client's supported lifecycle. Check the handshake version and call get_queue_status: an open, idle native queue is the expected control state. Status alone does not prove CAD correctness; qualify native operations on disposable synthetic models. Native clients auto-start the broker through the verified existing Explorer desktop. Optional operator prestart:

& $queuePython -m solidworks_mcp.coordination.launch --backend native --desktop
& $queuePython -m solidworks_mcp.coordination.cli status

Journal and recovery

The private SQLite WAL journal preserves FIFO sequence, request identities, outcomes and recovery evidence under %LOCALAPPDATA%\SolidworksMCP\coordination\v1\<sessionhash>. The broker outlives MCP frontends; this does not promise survival of Windows logoff/shutdown. Uncertain mutations are never automatically replayed.

• Keep a unique coordination.request_id until the outcome is known. After a lost response, call get_queue_request with that ID, instead of inventing a new ID for a possibly completed change.

• A client wait timeout does not stop CAD. An execution overrun fences the queue; it does not interrupt COM or release ownership while that call can still act.

• cancel_queued_job only cancels waiting jobs. queue_events and get_queue_status read control state without COM.

• Recovery requires inspecting CAD/files, proving execution returned or the old CAD generation ended, and explicitly acknowledging the affected jobs. Follow recovery and rollback.

Do not publish journals, endpoint credentials, client configuration, recovery bundles, logs, screenshots or working models. AI clients may send returned tool data to their chosen model provider; this server does not control that provider's retention policy.

Other tools and optional models

Inherited tools cover sketches, features, bodies, references, dimensions, transactions, views, exports and vectorization. Live MCP discovery provides the schemas. Raw Python requires coordination.trusted_python=true and reviewed synchronous code; static checks are not a sandbox. No detached CAD work or independent COM connections are allowed. Automatic dialog confirmation and automatic recovery are disabled in the queued executor.

Native tool dimensions normally use millimetres; raw COM uses metres. Verify body count, dimensions and volume rather than relying only on a success flag.

This source distribution excludes optional line-art weight binaries and their Git LFS pointers. Their original paths, pointer hashes and expected object identities are recorded in publication-manifest.json and the model notices. Do not replace missing weights or disable hash checks. Exact export provenance and redistribution rights require separate review: code and training-data terms are distinct. See model notices and third-party notices. CUDA/vectorization and SW2026/2027 are outside this queue qualification.

Development, attribution and publication

Run offline tests in an isolated checkout/environment, never against working CAD models. The CI/core route uses requirements-queue.txt and tests named test_queue_*.py. The complete inherited suite additionally needs the five scientific packages in requirements-testextras.txt, not GPU packages or weights:

# In a separate test environment, from the source root:
python -m pip install -r requirements-queue.txt -r requirements-testextras.txt -c constraints-testextras-py314-win.txt
python -m pip check
python -m unittest discover -s tests -p "test_*.py"

Historical .4 fresh Windows/Python 3.14 qualification: 423 passed and one explicit Windows-job capability skip, plus 9 separate broker tests passed. The native entry points were blocked by the retained offline qualification runner; no CAD was contacted. Earlier failed core-only/full-suite and station TEMP runs remain recorded in validation. The constraints capture this platform; they are not a universal Python/OS lock. See publication review.

SolidworksMCP remains the MCP server name, solidworks_mcp the Python package; existing tool/protocol identifiers are retained. Local queue/reliability work is independent of upstream. The MIT license does not grant a SolidWorks license or replace third-party asset terms. Runtime data and local Git history are not part of this source-only GitHub distribution.