Onshape

io.github.gpambrozioPublished by GitHub account gpambroziov0.3.0Updated Oct 29, 2026

Drive Onshape CAD from an assistant: documents, sketches, solid features, assemblies and exports.

VerifiedSTDIODesktop onlyDeveloper ToolsMedia & Design

Overview

AI-generated overview

Connects an assistant to Onshape CAD so it can create documents, sketch and model parts, build assemblies, measure and export STL/STEP files.

What you can do
  • Sign in and manage Onshape credentials, including status and logout
  • List, search, create, update and delete documents, workspaces, elements and versions
  • Build part studios: sketches, extrudes, holes, fillets, patterns, variables, measurement and validation
  • Assemble parts with instances, mates, relations, BOM and mass properties
  • Export STL/STEP, drawings and shaded renders returned as images
  • Call any other Onshape REST endpoint through a generic request tool
When to use it
Useful when you want an assistant to design or modify Onshape CAD models conversationally, for example sketching a bracket, adding features, checking measurements, assembling parts or producing printable exports and renders.
Requirements
Runs locally via npx with Node 20 or newer. Needs an Onshape account and either a browser sign-in on first use, an API key pair (ONSHAPE_ACCESS_KEY and ONSHAPE_SECRET_KEY), or an OAuth app. Network access to the Onshape API host is required; output directory and other settings are optional.
Before you install
The API key pair grants access to your Onshape account; create it with Read, Write and Delete permissions only if you want delete tools to work. Credentials are stored in the OS keychain or a 0600 config file. Tools create, modify and delete documents, features and assemblies, and validation errors do not undo changes. Free accounts can only create public documents, so models may be visible to others.

Installation

In SourceWeft

  1. Open Onshape in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

Onshape MCP server

Drive Onshape CAD from an AI assistant. 93 tools for documents, part studios, sketching, solid features, assemblies, drawings, measurement and export — and no setup beyond installing it: the first tool call that needs Onshape opens a browser and asks you to connect.

[CI] [npm]

"Make a 60 × 40 × 10 mm bracket with 4 mm mounting holes and 2 mm fillets, then show me a render"

The assistant sketches it, extrudes it, fillets the edges, measures the result, renders it back into the conversation, and exports an STL you can print.

Install

Claude Code

bash
claude mcp add onshape -- npx -y @gpambrozio/onshape-mcp

Claude Desktop — download onshape-mcp-<version>.mcpb from the latest release and double-click it. Nothing else to install.

Cursor, VS Code, Windsurf, Zed and other MCP clients — add the server to the client's MCP config:

json
{  "mcpServers": {    "onshape": {      "command": "npx",      "args": ["-y", "@gpambrozio/onshape-mcp"]    }  }}

The file differs per client: ~/.cursor/mcp.json (Cursor), .vscode/mcp.json (VS Code), ~/.codeium/windsurf/mcp_config.json (Windsurf), ~/.config/zed/settings.json under context_servers (Zed).

Node 20 or newer is required. npx fetches the package on first run.

Signing in

Nothing to configure. The first tool call that needs Onshape starts a sign-in and asks your client to show you the link; clients that support MCP's URL elicitation render it as a prompt, and the rest get the URL in the reply. The page that opens links straight to the key page for your Onshape stack and takes the pasted pair; tick Read, Write and Delete when you create the key so every tool here works. Keys are verified against Onshape, then stored in your OS keychain.

Your credentials never pass through the assistant, the model or this project's authors — the exchange happens between your browser and a server bound to 127.0.0.1 in this process, which is exactly why MCP has URL elicitation.

Other ways in, if you prefer:

  • onshape_login — start the same flow deliberately.
  • onshape_set_api_key — paste a key pair you already have.
  • OAuth 2.0 — onshape_login with method: "oauth", for an app you registered at the Onshape developer portal with redirect URL http://localhost:8471/oauth/callback. Tokens refresh automatically.
  • Environment variables — set ONSHAPE_ACCESS_KEY and ONSHAPE_SECRET_KEY for unattended installs, and ONSHAPE_MCP_AUTO_LOGIN=0 to stop the server ever opening a browser.

An existing onshape-cli credential at ~/.onshape/credentials.json is picked up automatically.

onshape_auth_status shows what is in use (redacted); onshape_logout forgets it.

Tools

AreaTools
Sign-inlogin, login_status, set_api_key, auth_status, logout
Documentslist_documents, search_documents, get_document, get_document_summary, create_document, update_document, delete_document, get_workspaces, get_elements, find_part_studios, list_versions, create_version, delete_element
Part studioscreate_part_studio, get_features, get_feature_specs, get_sketch_info, get_body_details, get_parts, mass_properties, measure, clearance, validate_part_studio, add_feature, update_feature, delete_feature, rollback, eval_featurescript
Sketchingsketch_rectangle, sketch_circle, sketch_line, sketch_circle_axis, create_sketch, sketch_candy_cane_path
Solidsextrude, hole, thicken, revolve, sweep, fillet, chamfer, shell, draft, boolean, boolean_union, mirror, linear_pattern, circular_pattern, offset_plane
Geometryget_edges, find_circular_edges, find_edges_by_feature
Variablesget_variables, set_variable, get_configuration, encode_configuration
Exportexport_stl, export, shaded_view, get_thumbnail, thumbnail_info
Assembliescreate_assembly, get_assembly, insert_instance, delete_instance, transform_instance, get_assembly_features, assembly_mate_connector, assembly_mate, assembly_relation, assembly_group, assembly_add_feature, update_assembly_feature, delete_assembly_feature, get_mate_values, set_mate_values, get_bom, assembly_mass_properties
Drawingscreate_drawing, get_drawing_views, export_drawing
Feature studioscreate_feature_studio, get_feature_studio, set_feature_studio, get_feature_studio_specs
Metadataget_metadata, set_metadata
Escape hatchrequest

All names are prefixed onshape_, and every tool returns {"ok": true, "result": …} or {"ok": false, "error": …, "detail": …}.

Worth knowing:

  • Units are inches and degrees throughout, except STL exports, which are millimetres by default because that is what slicers assume.
  • Feature tools validate by default. Onshape answers 200 for a feature that fails to regenerate, so each tool re-reads the feature state and fails loudly instead. update_feature also fails when the edit puts another feature into ERROR; errors that were already there before the edit are listed in validation.preexistingErrors instead. Pass validate: false to skip it.
  • Assemblies: assembly_mate joins Part Studio mate connectors directly ({path: [instance id], connector: "FabC_0.mcPinion"}, as get_assembly lists them), insert_instance takes fixed: true to ground an instance, and assembly_relation couples mates as gear, rack and pinion, screw or linear. set_mate_values drives mates in inches and degrees and fails when Onshape ignores a value, which it does for mates with limits enabled.
  • Part Studio writes acknowledge applied changes. Creation replies include creationApplied: true; updates include updateApplied: true after the POST completes. Validation errors do not undo the change: inspect the model before retrying. A failed POST does not establish whether the server applied a change. Large replies retain the feature ID and validation outcome inline, with the full response in saved_to. If that file cannot be saved, responseStorageError reports the storage problem without changing the write/validation outcome. validate: false is reported as validationSkipped: true.
  • Renders come back as images. shaded_view and get_thumbnail return the PNG inline as well as writing it, so the model can see the part.
  • Big reads spill to disk. Anything over ONSHAPE_MCP_MAX_RESPONSE_BYTES (default 200 kB) is written to a file and summarised, keeping a feature tree from swallowing the context window.
  • onshape_request reaches any REST endpoint the dedicated tools miss.

Configuration

Every setting is optional.

VariableEffect
ONSHAPE_ACCESS_KEY, ONSHAPE_SECRET_KEYUse this key pair instead of signing in
ONSHAPE_BASE_URLOnshape API host (default https://cad.onshape.com)
ONSHAPE_OAUTH_CLIENT_ID, ONSHAPE_OAUTH_CLIENT_SECRETOAuth app to sign in with, instead of an API key
ONSHAPE_MCP_AUTO_LOGIN0 stops tool calls from starting a browser sign-in
ONSHAPE_MCP_NO_BROWSER1 never launches a browser; the URL is reported instead
ONSHAPE_MCP_SIGNIN_WAIT_MSHow long a call waits for sign-in (default 120000)
ONSHAPE_DOC, ONSHAPE_WS, ONSHAPE_ELEMDefault target; these arguments become optional when set
ONSHAPE_MCP_OUTPUT_DIRWhere relative export paths land (default: working directory)
ONSHAPE_MCP_MAX_RESPONSE_BYTESResponse size before spilling to a file (default 200000)
ONSHAPE_MCP_CONFIGCredential file path (default ~/.onshape-mcp/credentials.json)
ONSHAPE_TIMEOUT_MSPer-request timeout (default 120000)

Secrets go to the OS keychain (service onshape-mcp) when one is available, and the config file then holds only non-secret metadata. Without a keychain the file holds the secret and is written 0600 inside a 0700 directory.

Onshape account limits

These come from Onshape, not from this server:

  • Free accounts can only create public documents — pass public: true to onshape_create_document.
  • Deleting needs a key with delete permission. Without it Onshape answers 403 Invalid API key state; re-create the key at cad.onshape.com/user/developer/apiKeys with Delete ticked.
  • An instance can only be fixed when it is inserted. There is no public call to fix or unfix one later; insert it again with fixed and delete the old one.
  • Mate values need API version 10. Older versions accept a write and ignore it; get_mate_values and set_mate_values use v10.
  • The variable-table endpoint 404s on some accounts. onshape_set_variable and onshape_get_variables fall back to assignVariable features, which work everywhere; result.route / result.source says which path was taken. Setting a name that already has a Variable feature rewrites that feature in place.

Development

bash
npm installnpm run check     # type-checknpm test          # unit tests, no network and no browsernpm run buildnpm run bundle    # build the Claude Desktop .mcpb
node scripts/smoke.mjs           # live read-only check against your accountnode scripts/smoke.mjs --write   # also builds a throwaway partnode scripts/smoke.mjs --assembly <doc>   # rack and pinion assembly in a scratch document

Layout: src/auth (credential store, keychain, login flows, OAuth, elicitation), src/api (REST wrappers), src/builders (Onshape BTM feature payloads), src/tools (the MCP surface), src/server.ts (registration and the auth gate).

Contributions welcome — see CONTRIBUTING.md. Security reports: SECURITY.md.

Licence

MIT. Portions derived from onshape-cli — see NOTICE.

Not affiliated with, endorsed by, or supported by Onshape or PTC. "Onshape" is a trademark of PTC Inc.

Source: README.md at commit 63f39d1

Tools

0
SourceWeft has not started this package in its sandbox yet, so its tools are not known.

Version history

2
  1. v0.3.0LatestOct 29, 2026
  2. v0.1.2Sep 22, 2026

Score

50% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 days25 pts

    Keep the endpoint answering the MCP handshake; SourceWeft probes it every 30 days.

  • Auth declared10 pts

    Declare the credential headers in the registry entry, or keep the endpoint answering the probe so its auth can be classified.

  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts