SolidWorks API MCP Server

TypeScript MCP server that gives an AI assistant search and lookup access to the SolidWorks API documentation corpus in this repository: about 14,000 documented interfaces, methods, properties, enums and programming-guide examples.

Features

• Relevance-ranked search over the whole corpus. Understands API names (SelectByID2, IModelDocExtension.SelectByID2), descriptions (how do I create an extrusion feature) and word variants. See Search.

• Exact lookup of interface members, enum values, related members and examples, with case-insensitive names.

• Helpful failures: a miss returns "did you mean" suggestions and, for members, the interfaces that actually declare them.

• Discovery tools to list docsets and interface/enum names.

• Compact responses: search hits omit noisy keyword lists unless asked (verbose), and every limit is capped so one call can't flood the client's context.

• Stdio transport (stdin/stdout), MCP protocol versions 2025-06-18, 2025-03-26 and 2024-11-05 negotiated automatically (JSON-RPC batches accepted for the older versions).

Related MCP server: Fluent MCP Server

Runtime and Tooling

• Runtime: Bun + TypeScript

• Tests: Vitest; type checking: tsc

• Bun-only JavaScript tooling: bun install, bun run <script>, bunx <tool>

Quick Start

bun install
bun run start

Data Root

By default the server reads from <repo>/solidworks-api. Override with SW_API_DATA_ROOT:

$env:SW_API_DATA_ROOT = "C:\path\to\solidworks-api"
bun run start

The server exits with an error if the data root does not exist.

Client Configuration

Claude Desktop (claude_desktop_config.json), Windows example:

{
  "mcpServers": {
    "solidworks-api": {
      "command": "bun",
      "args": ["run", "C:\\path\\to\\solidworks-api-mcp\\server\\solidworks_mcp_server.ts"]
    }
  }
}

Claude Code:

claude mcp add solidworks-api -- bun run C:\path\to\solidworks-api-mcp\server\solidworks_mcp_server.ts

Restart the client after changing its configuration.

Tools

All tools are read-only. Names are case-insensitive. Bad arguments are reported as tool errors (isError) that name the offending field.

Failed lookups return { "error": "Not found", "message": ..., "suggestions": [...] }, plus declared_on when the member exists on other interfaces. Unknown docsets return { "error": "Unknown docset", "available": [...] }; a search that comes back empty because of one carries a note saying so. Document paths in results are relative to the data root.

Search

Ranking is a field-weighted BM25 over identifier-aware terms (server/search.ts):

• Identifiers are split on case and digit boundaries (SelectByID2 becomes select, id, 2) and also kept whole, so exact API names outrank their fragments.

• Filler words are ignored, words are lightly stemmed, and longer words and a few domain synonyms (extrusion/extrude, document/doc, save/export, ...) match at reduced weight.

• An identifier also matches its numbered versions (FeatureExtrusion finds FeatureExtrusion3), and stopwords next to a word are tried as part of an identifier, so save as finds SaveAs3.

• Members whose documentation marks them obsolete (about a fifth of the corpus) rank below current ones.

• A one-word query that is a member name ranks exact matches first (current before obsolete); one that names a concept (sketch) ranks its interface (ISketch) first.

The index is built in memory from _search_index.json right after the client's initialized notification, so the first query does not pay for it.

Development

bun run test        # vitest
bun run typecheck   # tsc --noEmit

Ranking is regression-tested against the real corpus in tests/search.test.ts; tests/protocol.test.ts also drives the server over stdio.

Project Structure

solidworks-api-mcp/
|- server/
|  |- solidworks_mcp_server.ts   JSON-RPC/MCP protocol, entry point
|  |- tools.ts                   tool definitions and handlers
|  |- schema.ts                  tool argument validation
|  |- search.ts                  ranking engine
|  |- store.ts                   data store (indexes, paths, search)
|  |- catalog.ts                 docset/interface/member/enum name resolution
|  |- suggest.ts                 "did you mean" suggestions
|  |- outbox.ts                  ordered, backpressure-safe stdout writer
|  |- util.ts                    shared helpers
|  `- types.ts
|- solidworks-api/               documentation corpus (markdown + JSON)
|- tests/
|- bin/solidworks-mcp
`- package.json