v0.4.8

WebExtension builds of FastMCP Browser — the MCP bridge that drives Chrome/Firefox over a loopback WebSocket (33 MCP browser tools).

What's new in v0.4.8

• Lightweight page digest. browser_snapshot now accepts format:"digest" to return actionable controls with refs, values, and checked/disabled state without a full accessibility tree. The digest stays warm as the DOM settles, invalidates promptly on relevant mutations, scopes to the top visible modal, and supports browser_act.refresh:"digest" for post-action state.
• Nested modal targeting. Dialog-scoped snapshots now select the last visible dialog, including alertdialog, so nested modal actions target the active dialog rather than an underlying one.
• Bundle parsing regression fixed. The digest role set uses a distinct identifier so the concatenated Chromium/Firefox content bundle parses and the page engine can inject successfully.
• Retained v0.4.7 guidance. Tool descriptions continue to discourage click-then-type for form fields; browser_fill and browser_fill_form set values directly and avoid an unnecessary click round-trip.

Install

Unzip an archive and load it unpacked:

• Chromium (fastmcp-browser-extension-chromium.zip) → chrome://extensions → Load unpacked → the chromium folder
• Firefox (fastmcp-browser-extension-firefox.zip) → about:debugging → Load Temporary Add-on → firefox/manifest.json

The Firefox .xpi has manifest.json at the archive root. It is unsigned; standard Firefox release builds require a Mozilla-signed add-on for permanent installation. LibreWolf and Firefox Developer Edition/Nightly may allow unsigned add-ons when signature enforcement is disabled.