npm-packages

WebMCP-org/npm-packages is an open-source project by WebMCP-org: NPM packages for MCP-B: Transport layers, React hooks, and browser tools for the Model Context Protocol. Indexed here so it can be found — not resold.

It is free. Get it from the upstream repository: https://github.com/WebMCP-org/npm-packages

From the project's own README (excerpt, reproduced for discovery under its MIT license):

@mcp-b

Polyfill and MCP bridge for the Web Model Context API (document.modelContext)

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The Web Standard

The Web Model Context API is a W3C Community Group draft spec. It makes every browser tab a tool source — web pages register tools that AI agents can discover and call:

MCP-b polyfills that API for all browsers today, and bridges it to the full Model Context Protocol — turning that tool source into a complete MCP server with prompts, resources, and browser transports.

> Built by MCP-b. Not an official W3C or MCP project.

Getting Started

1. Use the web standard directly

If you're running Chrome with --enable-experimental-web-platform-features, document.modelContext is already there. Just use it:

Add @mcp-b/webmcp-types (pnpm add -D @mcp-b/webmcp-types) for input schema inference:

2. Polyfill it

Want it to work in any browser without the Chrome flag? Add the polyfill — same API, same code:

Or with React: pnpm add usewebmcp

3. Full MCP server

Need the full Model Context Protocol — prompts, resources, transports, and interop with Claude Desktop, Cursor, or another MCP client? Use @mcp-b/global:

Or as a script tag (zero build step):

Or with React: pnpm add @mcp-b/global @mcp-b/react-webmcp

Call Those Tools

Three ways for AI agents to discover and call your tools:

MCP-B Extension — Install it from the Chrome Web Store. It discovers tools exposed by pages and connects them to extension-side agent experiences.

Chrome Native — Enable at chrome://flags → Experimental Web Platform features, or:

See Chromium flags reference for macOS / Windows / Linux commands.

Local Relay — Add to your MCP client config (Claude Desktop, Cursor, etc.):

Any website running @mcp-b/global becomes callable from your…