What leaves your machine

By default the extension talks to localhost only. There is one optional cloud mode the user explicitly turns on; otherwise nothing leaves the machine.

Default (no opt-in needed):

A WebSocket connection to ws://localhost:9960 if you've opted in by starting the companion MCP server (npm start). The server runs on your machine; nothing is uploaded.
chrome.tabs.captureVisibleTab for screenshots — captured locally, never uploaded. The capture-mode setting (clipboard / download / both) controls what happens to the PNG.
fetch(media.src) when you click "Download" on an inspected <img> / <video> / <audio> / SVG — this is a normal browser request to whatever URL the page already references; nothing is added by the extension.


Optional cloud mode (you turn it on explicitly in Settings):

An HTTPS connection to https://mcp.designmode.app (or any self-hosted deployment URL you configure) authenticated with a bearer token stored in chrome.storage.local. The cloud server (open source at packages/mcp-cloud) acts as a relay between the extension and a remote MCP agent — it doesn't store your edits; messages flow through and are dropped when the connection closes. Disable cloud mode in Settings to revert to localhost-only.


There are no analytics, no telemetry, and no error reporting in the extension or the MCP server. There is no remote update channel beyond the Chrome Web Store's standard mechanism.

For more details: https://www.designmode.app/privacy