I tried Firefox’s new AI ‘Smart Window’ in a beta build

Firefox's upcoming Smart Window feature, tested in the v149.0b7 beta on macOS, makes AI the primary browsing interface. It offers three LLM options: Google Gemini Flash Lite, Alibaba Cloud's Qwen3-235B-A22B, and OpenAI's GPT-OSS 120B, plus a bring-your-own-LLM option. The feature replaces the new tab page with an AI prompt box that handles searches, content generation, and web page Q&A via a sidebar. A notable privacy concern emerged: Smart Window pre-populated its memory with months of prior browsing history without user consent upon activation — Mozilla acknowledged this as a bug and plans to fix onboarding. The author is skeptical of the feature's value, noting it largely rephrases Google search results and that user data flows to third-party AI infrastructure (Alibaba Cloud, OpenAI). The feature is not yet enabled by default and did not work on Linux during testing.