Bedrock AgentCore Runtime, the Agent Runtime
Updated
AWS announced the next generation of AgentCore Runtime, the serverless microVM compute in Amazon Bedrock AgentCore.
Bedrock Agent Runtime in the agents directory
AgentCore Runtime is the Bedrock agent runtime: the serverless microVM compute within Amazon Bedrock AgentCore. On September 18, 2026, AWS announced that the next generation of that runtime is available.
AWS says the new runtime reclaims unused memory throughout a session, so you pay for actual usage rather than the peak, and it keeps cold-start times consistent regardless of container image size or concurrency. The same post says there is no pre-provisioning, it scales to zero, sessions have hardware-enforced isolation, and you pay only for what you use. It is available in us-east-1, us-east-2, us-west-2, eu-west-1, and ap-northeast-1. Set platformVersion to V2 when creating or updating a runtime.
AWS docs describe AgentCore Runtime as a secure, serverless hosting environment for deploying and running AI agents or tools, with each user session in a dedicated microVM. That is separate from the Bedrock Agent Runtime API: the bedrock-agent-runtime endpoint, whose data plane invokes agents and flows and queries knowledge bases.
Key facts
- AWS says the new Runtime reclaims unused memory during a session, so customers pay for actual usage rather than the peak.
- Cold starts restore each new instance from a snapshot, which AWS says keeps start times consistent regardless of container image size or concurrency.
- In AWS testing, P75 cold start was 1.9 to 2.0 seconds for images from 200 MB to 2 GB, compared with 5.4–30 seconds on V1.
- AWS lists availability in us-east-1, us-east-2, us-west-2, eu-west-1, and ap-northeast-1. Set platformVersion to V2 when creating or updating a runtime.
Source: The new AgentCore Runtime is now available in Amazon Bedrock AgentCore · Amazon Web Services