Autonomous agent frameworks and platforms encompass the tools, SDKs, and marketplaces used to design, run, and govern goal‑directed AI “agents” that orchestrate multi‑step workflows. Since 2023 this space has moved from proofs of concept to production‑grade stacks: developer‑first SDKs for orchestration, no‑code visual builders for rapid composition, IDE‑centric agentic coding, and marketplaces for sharing and deploying agent templates. Key players reflect these roles: AutoGPT provides a self‑hosted or cloud option to run automated agents and workflows; LangChain supplies a standards‑oriented SDK and commercial platform for building, testing, and deploying reliable agents; LlamaIndex focuses on building document agents and scaling retrieval‑augmented generation (RAG) in enterprise settings; Windsurf (formerly Codeium) and Replit embed agent features into developer IDEs to keep coding “in flow”; AgentGPT offers a browser‑based, no‑code entry point with goal templates; and MindStudio targets rapid visual design and enterprise controls for deployment and operations. Current trends include composable multi‑model pipelines, RAG as a core capability for knowledge‑driven agents, tighter IDE and hosting integration, and growing emphasis on observability, governance, and abuse‑detection when moving agents into production. Marketplaces and template libraries are emerging to accelerate reuse and standardize best practices, while platforms differentiate on deployment options (self‑hosted vs cloud), enterprise controls, and testing/monitoring features. For teams evaluating this space in 2026, the practical tradeoffs are integration with existing retrieval and data stacks, model and hosting governance, developer ergonomics versus no‑code accessibility, and the ability to monitor, audit, and safely scale autonomous behaviors.