AWS describes AgentCore as an agentic platform for building, deploying, and operating agents securely at scale with any framework and foundation model. It became generally available in October 2025 and is a set of modular services: Runtime, a managed harness, Gateway, Identity, Memory, Code Interpreter, Browser, Observability, Policy, and Evaluations, among others.
There are two ways to build. With the managed harness, generally available since June 2026, you declare the model, prompt, tools, and memory in configuration, and AgentCore runs the loop on Strands Agents at no separate harness charge. Or you write the loop yourself in a framework such as LangGraph, CrewAI, Google ADK, or the OpenAI Agents SDK, and deploy it to Runtime as a zip file or container. Each session runs in its own microVM for up to 8 hours.