Amazon Bedrock AgentCore Runtime V2 now prepares an agent environment once, saves a snapshot and restores that state into a new isolated microVM for each session. The change makes startup less dependent on container-image size and can produce faster, more consistent first responses.
Under the earlier design, every session pulled an image, started the container and repeated initialization. V2 performs those steps when a runtime is created or updated, waits for a healthy response, clears the operating system file cache and freezes memory and disk state. New sessions resume from that point with initialized objects and clients already in memory.
The architecture changes familiar cold-start advice. Static imports, clients and objects should be initialized before the snapshot instead of deferred to the first request. File data is different: the cache is cleared before freezing, so image files are fetched when first read. Separate binaries and command-line tools may still need build hooks or other preparation.
AWS recommends measuring platform OverheadLatency separately from application work and testing at realistic new-session rates. V2 does not eliminate model calls, tool latency or dynamic data loading, and creating or updating a runtime now takes longer while the snapshot is built. For chat and voice applications, developers may still need to start sessions before users arrive if even a roughly two-second delay is too high.