Pi Web Agent is a lightweight, extensible framework for building AI chat agents on the web. It leverages Python FastAPI on the backend and a React frontend to deliver interactive conversations powered by OpenAI, Cohere, or local LLMs. Users can upload documents or connect external databases for semantic search via vector stores. A plugin architecture allows custom tools, function calls, and third-party API integrations locally, it offers full source code access, role-based prompt templates, and configurable memory storage to create customized AI assistants.