PI-Desktop is an open-source, local-first desktop workspace designed to provide AI agents with a persistent and extensible environment, independent of specific IDEs or terminals. Available for macOS, Windows, and Linux, the platform functions as an orchestration layer for agents, allowing users to manage complex workflows through three primary modes: standard execution, planning-based implementation, and goal-oriented autonomy. Technically, the system distinguishes itself through a sophisticated delegation architecture, where a main session can spawn independent Subagents with unique contexts or full Worker Sessions that operate as complete, inspectable desktop instances. The platform is highly model-agnostic, supporting OpenAI, Anthropic, Ollama, and custom gateways, allowing users to switch models (e.g., using a high-reasoning model for planning and a local model for private tasks) within a single session. Extensibility is achieved through a plugin system that supports commands, panels, floating widgets, MCP servers, and background services, all distributed via .piplug packages. Built on the pi-ai and pi-agent-core ecosystems, PI-Desktop prioritizes data privacy by keeping projects, sessions, and logs local, utilizing the OS Keychain for API credentials. The project's development was significantly aided by AI, utilizing over 27 billion tokens during construction.