TypeScript Agent Frameworks in 2026: Loop, Runtime, Sandbox

Most TypeScript teams shopping for an agent framework don't need one. A single generateObject call covers classification, extraction, summarization, tagging — the 80% case for production LLM work in TS right now. But once the model starts deciding what to do next, surviving deploys, or coordinating with other agents, you start shopping. And the moment you do, you discover the TS agent ecosystem is not one market but three. Three layers Loop — wraps the agent loop so you don't write while (!done)