The extension

Run it from source.

It isn't in the Chrome Web Store yet, so building it yourself is the install. It's the part that does the work. It registers tools from packages you've installed on the page you're on, so an agent can call them. You'll need Bun and Chrome 149+.

1. Clone and install

   git clone https://github.com/robertn702/webmcp-cafe
   cd webmcp-cafe && bun install

2. Build it against the live registry

   WXT_REGISTRY_API_URL=https://webmcp.cafe bun run build --filter=@webmcp-cafe/extension

   That variable controls where the extension polls for the revocation feed and the domain list. Page loads never hit the network — they read from chrome.storage.local — so leaving it off just means those polls target localhost:3000. Leave it set to the live registry in production.

3. Load it

   chrome://extensions → Developer mode → Load unpacked → apps/extension/.output/chrome-mv3

4. Turn WebMCP on

   Enable chrome://flags/#enable-webmcp-testing and restart. Chrome 149+. Sites we inject into don't serve an origin-trial token on our behalf, so anyone running the extension has to turn it on.

5. Check it worked

   Open a page one of your installed packages matches and look at the page console. [webmcp-cafe] N installed package(s) matched this URL means a match registered. With nothing installed, every page logs 0 installed package(s) — that is the expected empty state, not a failure.

In the meantime, browse the registry to see what packages exist, or publish one.