You-AI is a client-side, privacy-first artificial intelligence application that operates entirely within a web browser. It functions as a synchronized swarm of five specialized AI agents, each routed through OpenRouter's free-tier models. The application processes all data locally, meaning user information never leaves the device. Knowledge is stored with AES-256 and SHA-256 encryption, and no account, tracking, or telemetry is required. The only external call is to OpenRouter's inference API, which receives only the current query without any identity data. The application's primary function is to provide a persistent, private AI assistant that compounds knowledge over time. It uses a five-agent pipeline coordinated behind a single consistent persona trained on the user's encrypted knowledge base. Features include real-time web retrieval, adversarial manipulation defense at the Validator layer, and optional cloud sync for backup. The architecture relies on browser technologies such as WebWorkers and WebAssembly to handle multi-model coordination. The zero-cloud design results in no per-query inference cost and no vendor lock-in. Typical use cases involve knowledge workers who need a private AI tool that remembers context across sessions without sharing data with third parties. The application addresses the cost-privacy-memory trilemma by combining persistent memory, local encryption, and free-tier frontier models. Users can interact with the swarm for reasoning, research, and task assistance, with all processing occurring in the browser. The system is designed for non-enterprise users who prioritize data sovereignty and zero marginal cost. Technical requirements include a modern browser capable of running WebWorkers and WebAssembly. The application is open source under an Apache 2.0 license. It targets the gap in the market for privacy-first, zero-marginal-cost personal AI, as noted in its reference to Y Combinator's funding criteria. The client-side architecture is a key differentiator, as it cannot be replicated by cloud-based incumbents without dismantling their data collection models.