fast-agent is an advanced, developer-friendly framework for building single reliable LLM-based autonomous agents, integrating task planning, evaluation, and execution into a seamless workflow. It abstracts complex aspects such as prompt engineering, multi-model coordination, and operational flow management—enabling developers to create powerful agents without being overwhelmed by technical intricacies. With a flexible design, it supports a wide range of use cases while allowing fine-grained control over each component.