v0.5.0

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

What's new in v0.5.0

• Read a page as text. browser_snapshot accepts format:"text" to return the rendered text of the page main region (innerText) in one small payload, so an agent reads a text-heavy page directly instead of paying for a screenshot. format:"digest" also accepts includeText:true, and maxChars caps the length.
• Read a long text block in place. browser_snapshot accepts maxNameChars to raise the per-element name cap for one call (default 160), so a page whose whole body sits in one block element (main, article) is no longer truncated in compact.
• Screenshot is scoped to non-DOM content. Its description now steers the model to use it only for canvas, WebGL, image, or PDF content, and to read ordinary text pages with format:"text".
• browser_wait_for state digest-changes. Resolves when the AI-readable control digest changes, so an agent waits on state instead of a fixed sleep or a raw DOM settle.
• Workflow recording and replay. Any session driven through the MCP server can be recorded to a .jsonl run file (FASTMCP_RECORD) and replayed later through the bridge with no AI client (cli replay); cli export --script turns a run file into a runnable .mjs.
• Label-wrapped controls are visible again. A <label> that wraps or points to a visually-hidden <input> (DaisyUI radio tabs, custom checkboxes) is reported with the input's role and the label's text, so it appears in a snapshot and the digest and gets a ref.
• browser_evaluate is a gated last resort. It now requires a fallback reason and is refused until the tab has been read through the extension.
• Refs survive long-lived pages, and browser_inspect with a path no longer floods the context with React props.
• Content redaction for prompt-injection defense. User-configurable rules filter what the AI reads from a page, configured from the extension options page.

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.