Vercel — AI · · 1 min read

WebMCP support now available in mcp-handler

Mirrored from Vercel — AI for archival readability. Support the source by reading on the original site.

mcp-handler now has experimental support for WebMCP, the proposed web standard for exposing tools to in-browser agents. Add a single script tag to your site, and your existing MCP tools become available there too.

Opt tools in by adding them to the experimental_webMcp object:

app/api/mcp/route.ts
import { createMcpHandler } from "mcp-handler";
const handler = createMcpHandler(
(server) => {
server.registerTool("roll_dice", /* ... */);
experimental_webMcp: {
tools: ["roll_dice"],
export { handler as GET, handler as POST };

Then load the script from your MCP endpoint with the ?webmcp-script parameter:

<script src="/api/mcp?webmcp-script"></script>

The script registers those tools with the page and proxies each call back to your MCP server as the signed-in user, so authenticated tools work without a browser-side OAuth flow.

Upgrade to [email protected] and read the documentation to get started.

Contributors

Ben Sabic

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