pi-webmcp

A Pi extension that connects Pi to webpages that register WebMCP tools.

Packages

Package details

extension

Install pi-webmcp from npm and Pi will load the resources declared by the package manifest.

npm repohome report
$ pi install npm:pi-webmcp
Package
pi-webmcp
Version
0.1.2
Published
Jun 21, 2026
Downloads
not available
Author
nickbreaton
License
MIT
Types
extension
Size
71 KB
Dependencies
4 dependencies · 3 peers
Pi manifest JSON
{
  "extensions": [
    ".pi/extensions/pi-webmcp.ts"
  ]
}

Security note

Pi packages can execute code and influence agent behavior. Review the source before installing third-party packages.

README

pi-webmcp

A Pi extension that connects Pi to webpages that register WebMCP tools.

[!IMPORTANT]

Both the WebMCP specification and Chrome’s implementation are in active development. Anticipate breaking changes that affect this extension.

[!CAUTION]

This extension can pose a security risk in its default operating mode once the /webmcp command is run. A malicious webpage could poison the running Pi session’s context via its WebMCP tool instructions.

Use at your own risk. Consider setting allowedOrigins to restrict which webpages Pi can connect to.

First-time Setup

  1. Install this extension via npm.

    pi install npm:pi-webmcp

  2. Enable Chrome remote debugging by visiting chrome://inspect/#remote-debugging.

Chrome remote debugging settings

  1. Enable the relevant Chrome flags for WebMCP.

    • chrome://flags/#devtools-webmcp-support
    • chrome://flags/#enable-webmcp-testing

Chrome WebMCP flags

Usage

  1. Run /webmcp and accept the once-per-session confirmation prompt in Chrome.

Chrome remote debugging permission prompt

  1. Navigate to a WebMCP-capable page, such as Chrome Lab’s WebMCP Travel demo.

    More can be found here.

Commands

  • /webmcp or /webmcp connect — Connect to Chrome and discover WebMCP tools.
  • /webmcp disconnect — Disconnect from Chrome WebMCP.
  • /webmcp list — Show active WebMCP tools.

Options

Configure WebMCP options under the webmcp key in Pi settings, either globally in ~/.pi/agent/settings.json or per trusted project in .pi/settings.json:

{
  "webmcp": {
    "allowedOrigins": ["googlechromelabs.github.io"]
  }
}
Option Description
webmcp.allowedOrigins When specified, Pi will only discover and connect to WebMCP tools from these origins.
webmcp.disallowedOrigins When specified, Pi will not discover or connect to WebMCP tools from these origins.

Browser Support

WebMCP is currently only implemented in Chrome, so this extension is scoped to Chromium-based browsers for now. We plan to support additional browsers if / when they implement WebMCP.