FAgent offers a modular architecture for constructing AI agents, including environment abstractions, policy interfaces, and tool connectors. It supports integration with popular LLM services, implements memory management for context retention, and provides an observability layer for logging and monitoring agent actions. Developers can define custom tools and actions, orchestrate multi-step workflows, and run simulation-based evaluations. FAgent also includes plugins for data collection, performance metrics, and automated testing, making it suitable for research, prototyping, and production deployments of autonomous agents in various domains.