A Firefox sidebar where Claude (Anthropic's AI) interacts with web pages on your behalf — clicking elements, reading content, filling forms, extracting data, and navigating sites through natural conversation. Key features: - 63 browser automation tools (DOM, navigation, network, cookies, storage, screenshots) - Persistent site knowledge — Claude remembers working selectors, API endpoints, and interaction patterns per domain - Site profiles — detects whether a site is UI-driven, API-driven, or hybrid - Prompt injection defense — page content is sanitized before Claude sees it - Context compression — long conversations stay within token limits - Two autonomy modes: confirm risky actions (default) or skip confirmations Requires your own Anthropic API key. All data stays local — the only external call is to Anthropic's API.