AI browser assistants and extensions embed conversational and task-focused AI directly into users’ web workflows. As of 2025-12-20 this category spans large-model integrations, web-grounded answer engines, and lightweight browser/iOS extensions that automate browsing tasks and research. Key product approaches include Anthropic’s Claude family (conversational and developer assistants used for writing, analysis and code), Perplexity AI (real-time, source-cited answers and developer APIs), Google Gemini (multimodal models and enterprise/developer APIs), and smaller, extension-first offerings such as Minion AI. Vertical or operational solutions like Kay AI show how agentic assistants are being packaged for domain-specific automation (insurance workflows). This space is timely because users increasingly expect contextual, sourced assistance without leaving the browser: search and research workflows now prioritize web-grounded citations, multimodal inputs (text, images), and fast developer integrations. Browser extensions act as the primary delivery mechanism for lightweight assistants (Minion), while large-model platforms (Claude, Gemini) and answer engines (Perplexity) compete on model capabilities, grounding, and API access. Important considerations include accuracy and citation, latency when fetching live web data, privacy and extension permissions, and enterprise integration for compliance and scalability. For buyers and users, evaluate whether you need a general conversational model integrated into dev workflows (Claude, Gemini), a real-time sourced answer engine (Perplexity), a browser-first productivity assistant (Minion), or a domain agent (Kay AI). The right choice balances grounding, multimodality, privacy controls, and how tightly the assistant must integrate with web apps and enterprise systems.