v0.4.5

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

What's new in v0.4.5

• Screenshots capture the right tab. browser_screenshot (viewport, full page, and the visual-mode overlay) now brings the requested tab to the front before captureVisibleTab and restores the tab you were on, so a background Automation tab no longer returns an image of an unrelated foreground tab.
• dom_stable / network_idle actually settle. The wait slice now always outlasts the requested quiet window, and an omitted stableMs no longer produces a NaN slice that hangs until the deadline.
• Documented tool params now reach the extension. goal, keywords, relevantOnly (snapshot/find/inventory), filter (inventory), and refresh (act) were documented but missing from the schemas, so zod silently stripped them; they are wired end to end.
• Tighter sandbox. The authorized tab set follows group membership, so a tab dragged out of the Automation group immediately loses authorization, and auto-resolved tabs reconcile first.
• More fixes. Structured removed diff entries, position:fixed elements accepted by the actionability check, browser_open reuses any live grouped tab instead of opening a duplicate, the CLI honors per-tool timeouts, and non-idempotent actions are no longer auto-retried.
• Housekeeping — MCP server version bumped to 0.4.5; README test counts corrected (55 server, 151 extension).

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.