Installation

Install the WebMCP Kit plugin in Claude Code or Codex, and set up a browser that can run WebMCP tools.

Prerequisites

• Claude Code 2.1.220 or newer (claude --version) — or Codex.
• Your website’s repo, cloned locally, with a dev server you can run.
• A WebMCP-capable browser for the verification step — see Browser setup below. Not needed to install the plugin.

Claude Code

Inside a Claude Code session:

/plugin marketplace add nekuda-ai/webmcp-kit
/plugin install webmcp-kit@nekuda

Or from your terminal — same result:

claude plugin marketplace add nekuda-ai/webmcp-kit
claude plugin install webmcp-kit@nekuda

Confirm it worked:

claude plugin details webmcp-kit@nekuda

Expect Skills (2): implement, verify. The skills load as /webmcp-kit:implement and /webmcp-kit:verify.

Codex

The plugin ships in the Agent Plugins open format, which Codex supports natively. In a Codex session:

1. Run /plugins to open the plugin directory.
2. Add nekuda-ai/webmcp-kit as a marketplace source.
3. Install webmcp-kit.

Browser setup

WebMCP is a young standard, so the browser surface (document.modelContext) is behind a flag today. You only need it to test tools — visitors with unsupported browsers are unaffected, because the SDK quietly does nothing there.

Pick one:

• Chrome 150+ — open chrome://flags, enable the WebMCP flag for localhost. This exposes document.modelContext.
• Chrome 149 — exposes only the older navigator.modelContext; the SDK handles both.

Quick check in devtools:

typeof document.modelContext   // "object" when WebMCP is active

Updating

/plugin marketplace update