Explainer
What is WebMCP?
WebMCP is a proposed web standard. A page calls document.modelContext.registerTool so an agent can discover actions the site already knows how to do.
Agent
Asks for an action
- Claude
- ChatGPT
- Cursor
PlugMCP Browser
Runs in your tab- Discover tools
- Allow
- Run in tab
Waiting for an agent0/3
The site
registerTool in the page
- search_serversSearch
- open_serverNavigate
- filter_directoryFilter
- copy_install_snippetClipboard
How the pieces fit
Three layers
- Layer 01
The site exposes named tools (or you save a proposal on a silent page).
- Layer 02
PlugMCP Browser runs those tools in the tab you are logged into, with Allow before pay, send, or delete.
- Layer 03
PlugMCP hosted servers are remote MCP endpoints at /s/{slug} — APIs, wraps, and bundles. They do not see your browser cookies.
On this site
PlugMCP speaks WebMCP too
This website also registers search and copy-install tools for in-page agents. That is not the same as Browser.
- search_servers
- open_server
- filter_directory
- copy_install_snippet
tswebmcp.ts
document.modelContext.registerTool({
name: "search_servers",
description: "Search the PlugMCP MCP directory by name, category, or client.",
inputSchema: {
type: "object",
properties: {
query: { type: "string", description: "Free-text search" },
category: { type: "string" },
client: { type: "string" },
},
},
async execute(args) {
const data = await json(`/api/v1/servers?q=${args.query}`);
return ok(JSON.stringify(data));
},
});
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