Antigravity Manager is an Electron desktop application that serves as a multi-account manager and local API proxy gateway for AI models (Google Gemini, Claude, OpenAI-compatible). It allows users to pool multiple Google Cloud accounts, automatically rotates between them based on real-time quota and rate limits, and exposes a local proxy server that translates between OpenAI, Anthropic, and Gemini API protocols. The application handles OAuth token lifecycle, credential storage across OS keychains and encrypted files, and includes a React UI for account management, quota monitoring, and configuration. Architecturally, the app is a monolith with three major layers: an Electron main process that bootstraps a NestJS server (Fastify), a React renderer with TanStack Router and shadcn/ui, and a Python CLI for headless account operations. The proxy gateway is the most complex module, with controllers for OpenAI chat completions, Anthropic messages, Gemini models, batch jobs, file uploads, and WebSocket-based Responses API. Credential management is handled through a multi-provider master key system with migration paths, atomic file writes, and SQLite persistence via Drizzle ORM. The codebase also includes device identity profile manipulation (fingerprint spoofing) gated by environment variables, and binary patching of the agy CLI executable. The codebase demonstrates strong engineering practices with extensive Vitest unit tests (250+ test files), Playwright e2e tests, Zod schema validation at IPC boundaries, and structured error handling. However, it also carries risks: hardcoded model aliases and Google API endpoints, fragile binary patching logic, and a large surface area of credential storage strategies that may drift as OS APIs evolve. The repo is actively maintained with frequent commits and CI pipelines, but the complex fallback chains and security-sensitive code require careful ongoing maintenance.