dev.bitbybitPublished by bitbybit.devOfficial publisherv1.6.0Updated Oct 29, 2026
Bitbybit 3D parametric CAD API, version-exact, for coding agents: search, describe, examples, guide
Documents the Bitbybit 3D CAD API for coding agents: look up members, signatures, examples and guides for one exact API version.
Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.
Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.
Read https://sourceweft.com/mcp/dev.bitbybit%2Fcad/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.Add this to your client's mcpServers config.
{
"mcpServers": {
"bitbybit-cad": {
"type": "http",
"url": "https://mcp.bitbybit.dev/mcp"
}
}
}An MCP server that documents the Bitbybit 3D CAD API for AI coding agents: every function, its parameters, defaults, return type and examples, for the exact version your project uses. Bitbybit has 2205 functions across three CAD kernels - more than any model holds in memory - so an agent working from memory invents plausible names that do not exist. An agent with this server looks each one up instead, and writes code that compiles the first time.
It answers from the API index Bitbybit publishes with every release (https://git-cdn.bitbybit.dev/v<version>/ai-context/index.json), never from memory, and never from a moving "latest".
The diagram shows what an agent is writing code for. The MIT-licensed npm packages run the CAD kernels in your users' browsers or in your own Node process; script runners load the same engine from one file; the CAD Cloud REST API runs the work on managed servers. This server knows all of them, and every answer carries a tier - oss, platform-pro or cloud-pro - so an agent never sends you to a paid service for something the free packages already do.
The same server runs two ways. Hosted at https://mcp.bitbybit.dev/mcp over Streamable HTTP, which needs nothing installed and serves the newest release; or locally over stdio with npx, which needs Node 20 and serves the version your project has installed. Start with the remote.
[Add to Cursor] [Install in VS Code] [Install in VS Code Insiders]
Claude Code
or the local server:
For a project, commit a .mcp.json at its root so every collaborator's Claude Code finds it:
Cursor (.cursor/mcp.json)
VS Code (.vscode/mcp.json) - the type is required, or VS Code tries to start the URL as a program:
Either form takes the local server instead: { "command": "npx", "args": ["-y", "@bitbybit-dev/mcp"] }, with "type": "stdio" in VS Code.
Codex
or codex mcp add bitbybit -- npx -y @bitbybit-dev/mcp for the local server. In ~/.codex/config.toml that is [mcp_servers.bitbybit] with url = "https://mcp.bitbybit.dev/mcp".
Gemini CLI (gemini mcp add -t http bitbybit https://mcp.bitbybit.dev/mcp), Windsurf (serverUrl in ~/.codeium/windsurf/mcp_config.json), Zed (context_servers in its settings) and the JetBrains IDEs (AI Assistant, MCP, a JSON entry with url) take the same address. claude.ai, ChatGPT and the Claude API connect to the remote as a custom connector - every configuration is documented here.
The server documents one exact version of the API. It picks it in this order:
--version <version> on the command line;BITBYBIT_VERSION=<version> in the environment;@bitbybit-dev packages installed around the working directory (core, then the renderer packages, then occt); packages that disagree are reported on stderr and the first wins;Indexes are cached in $XDG_CACHE_HOME/bitbybit-mcp (or ~/.cache/bitbybit-mcp); --no-cache skips the cache. Everything the program prints goes to stderr; stdout is the protocol.
Every tool is read-only. Tiers in the answers: oss (in the npm packages, MIT), platform-pro (only when scripting inside bitbybit.dev), cloud-pro (only on CAD Cloud, with an API key).
This server answers questions; it never runs geometry. When you want the agent to produce geometry - measure a STEP file, run a pipeline, unfold a sheet-metal part, convert to glTF - connect the Bitbybit CAD Cloud MCP alongside it, with a CAD Cloud API key:
In Codex the same is [mcp_servers.bitbybit-cloud] with url = "https://api.bitbybit.dev/mcp" and env_http_headers = { "X-API-Key" = "BITBYBIT_API_KEY" }, the key read from the environment.
The two are designed to work together: the agent learns a member here and calls it there with the same dotted path and the same argument object.
The package exports the tool registry and the index reader, so another server can serve the same tools:
toHttp(registry, context) renders the same tools for a plain HTTP endpoint, and guarded(registry, report) is the error boundary every server puts around a registry: a handler that throws answers a generic error result and the throw goes to report, so no internal message reaches a client. Registry.map(wrap) re-wraps every handler for such concerns of your own. The package root imports no Node built-in, so a bundler can take it into an edge runtime; the loader and the version detector, which read the file system, are the separate index-loader and installed-version entries, and the $ref inliner the tool schemas go through is the dependency-free json-schema entry.
The stdio server sends nothing anywhere except one request to the CDN for the index of the version it serves.
Beyond NPM packages, Bitbybit offers:
This package is part of the open-source Bitbybit ecosystem. Your subscription helps fund continued development.
⭐ Subscribe - Silver or Gold plan | Get API Key for CAD Cloud
MIT © Bit By Bit Developers
Source: packages/dev/mcp/README.md at commit 2ab11c8
Search the Bitbybit API
Find Bitbybit API members (methods, namespaces, cloud operations) by keywords, for example "box solid" or "fillet edges". Returns dotted paths with a one-line summary, the tier (oss on npm, platform-pro only at bitbybit.dev, cloud-pro only on CAD Cloud) and the engines each is published for. Call describe with a path before writing code that uses it.
limitqueryrequiredengineversionDescribe an API member
The exact contract of one member by dotted path, for example occt.shapes.solid.createBox: signature, every parameter with its type, default and range, the return type, the documentation, examples and where it runs. Answers are for the API version the server holds. It also describes the types a member returns or takes by their name, for example Inputs.IFC.SpaceInfoDto, field by field, and a member's answer lists those types. An unknown path is reported as not found together with the nearest existing paths; nothing is guessed.
pathrequiredversionList a namespace
The members one level below a namespace path, for example occt.shapes, each with its kind and summary. Without a path, the top-level namespaces. Use it to discover what exists before searching for details.
pathversionGet code examples
Working TypeScript examples for a member path, for a namespace, or for a topic given as keywords. Each example names the member it belongs to and links its reference page. Examples are written for the API version the server holds.
pathlimittopicengineversionRead the guides
Sections of the public guides: building with Bitbybit (what runs in the browser, on a server, on a lightweight backend, and what needs CAD Cloud), writing geometry with the kernels (which kernel to use, the order to build a part in, choosing edges, checking and exporting shapes), writing design documents (parametric models as JSON: parameters, sketches, features, references, parts and assemblies), and writing IFC building models (storeys, walls and their joins, doors, windows, slabs, roofs, rooms, properties and quantities). Without a topic it lists the sections. Read "integrate" before recommending where geometry should run: the npm packages are the default, and CAD Cloud is for algorithms that exist only there or compute the caller cannot provide. Read "geometry" before writing geometry code, "design" before writing a design document, and "ifc" before writing an IFC model.
topicSearch
Searches the Bitbybit API documentation and returns a list of results with id, title and url. Each id is a dotted API path that fetch accepts.
queryrequiredFetch
Fetches the full documentation of one Bitbybit API member by id (a dotted path returned by search) as text, with its title, url and metadata.
idrequired100% 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.
claude mcp add --transport http bitbybit https://mcp.bitbybit.dev/mcpclaude mcp add --transport stdio bitbybit -- npx -y @bitbybit-dev/mcp{ "mcpServers": { "bitbybit": { "type": "http", "url": "https://mcp.bitbybit.dev/mcp" } } }{ "mcpServers": { "bitbybit": { "url": "https://mcp.bitbybit.dev/mcp" } } }{ "servers": { "bitbybit": { "type": "http", "url": "https://mcp.bitbybit.dev/mcp" } } }codex mcp add bitbybit --url https://mcp.bitbybit.dev/mcpclaude mcp add --transport http bitbybit-cloud https://api.bitbybit.dev/mcp --header "X-API-Key: <your key>"import { createDocsRegistry, contextForIndex, GUIDES, GUIDE_PAGE_URL } from "@bitbybit-dev/mcp";import { loadIndex } from "@bitbybit-dev/mcp/index-loader";import { createMcpServer } from "@bitbybit-dev/mcp/server";
const version = "<a released version>";const index = await loadIndex({ version });const context = contextForIndex(index, GUIDES, GUIDE_PAGE_URL);const server = createMcpServer(createDocsRegistry(), context, { name: "bitbybit", version });