Eidolon is an open-source framework for building, deploying, and managing multi-agent AI applications. It provides a Python SDK with abstractions for LLM integration (OpenAI, Anthropic, Mistral, Ollama, Azure), retrieval-augmented generation (RAG) pipelines, memory systems (vector stores, symbolic memory, file storage), and document processing (loaders, parsers, splitters). Agents are configured declaratively via YAML and can communicate with each other, use tools, and stream responses. The framework includes a Kubernetes operator for production deployment, a web UI built with Next.js and React for chatbot interaction and developer tooling, and a TypeScript client library. It also features built-in agent types like SimpleAgent, RetrieverAgent, SQLAgent, and a Tree-of-Thought agent, along with logic units for web search, browser automation, and API integration.