CrewAI is an open-source Python framework for building multi-agent systems where specialized AI agents collaborate to complete complex tasks. Each agent has a role, tools, and a goal — a Researcher agent finds information, an Analyst interprets it, a Writer drafts the output. CrewAI coordinates their interactions and manages the workflow. The framework supports sequential and parallel task execution, tool integration, and memory sharing between agents. It's model-agnostic — connect to GPT-4, Claude, Llama, or any provider via LiteLLM. The growing library of pre-built crews handles common use cases from competitive research to code generation. For developers building sophisticated AI applications that require coordinated multi-agent behavior, CrewAI provides structure and tooling that building from scratch would take weeks to replicate.