Customaise MCP: your AI agent, in your real browser

Customaise MCP is a local bridge between any AI coding agent and your real, signed-in Chrome session. Add it to Cursor, Claude Code, Codex, Antigravity, or Kiro with one config line, or install the one-click bundle into Claude Desktop. Your agent gets 18 built-in tools plus every WebMCP tool your installed AgentScripts register, all running in the browser where you are already logged in.

How it connects

Three hops, no API keys and no headless browser. Your agent talks to a local server (run with npx, nothing to install). The server speaks the v2 bridge protocol to your Customaise extension over a WebSocket on your machine. The extension runs the tool in the tab you are already authenticated in.

What your agent can do

Eighteen built-in tools cover the browser itself: list, import, export, delete, and toggle scripts; read page DOM and console; list, open, close, focus, and reload tabs; read visually-selected elements; screenshot any tab as a viewport or full-page image; list and call the WebMCP tools your AgentScripts register; toggle the UI; and bulk-sync scripts to disk.

Conventions, read before building

The server exposes five MCP resources, two of which are full handbooks defining how Customaise expects UserScripts and AgentScripts to be written. A connected agent reads the relevant handbook before it touches a script, so it already knows how to build a UserScript, an AgentScript, or a CM_devtools script correctly.

Consent and plan tiers

Every WebMCP tool declares allow, prompt, or deny; prompt-gated calls block on an in-browser consent modal the agent cannot forge. The bridge is free up to 50 tool calls per day and 150 per rolling week, unlimited on Power User, and MCP calls never spend your in-browser AI token allowance. Requires the Customaise extension 1.2.3 or newer, signed in.