AgentFlow is a framework for building and training agentic LLM systems using reinforcement learning, specifically Flow-GRPO (Flow-based Group Refined Policy Optimization). It provides a modular architecture with four core roles—Planner, Executor, Verifier, and Generator—that coordinate via evolving memory and tool calls over multiple turns. The system supports both inference (via a Solver) and distributed RL training (via a Trainer/Client/Server architecture built on verl, vLLM, and Ray). It includes a multi-provider LLM engine abstraction (OpenAI, Anthropic, Gemini, DeepSeek, etc.), a tool system with metadata-driven discovery, and instrumentation for tracing and reward collection. The repository is heavily research-oriented, with benchmark datasets (AIME24, GPQA, GAIA, HotPotQA, etc.) and training pipelines for optimizing agent planners. While primarily an application framework, it has strong data/research components, making it a hybrid project with a focus on reproducible agentic reasoning experiments.