Managed agent platforms — and exactly what infra each gives you
The "serverless runtime + managed memory + tool gateway" bundle. Coverage is strongest for AWS (all facts below Verified against primary AWS docs); other platforms are Reported.
Bedrock AgentCore Verified
A composable set of services you can adopt à la carte. The differentiator is the runtime's isolation model.
Session isolation: every user session runs in its own dedicated microVM (isolated compute, memory, filesystem). On completion the microVM is terminated and memory-sanitized — no cross-session contamination — while tenants still share underlying infrastructure (pool multi-tenancy). Multi-tenant credentials via a Token Vending Machine: STS role scoped by session tags → 900-second temporary creds enforced with ABAC.
Vertex AI Agent Engine Reported
Fully managed serverless runtime — deploy and scale agents with no infra management.
Memory Bank extracts salient facts for cross-session retrieval (Google Research method). Sandbox covers code execution + Computer Use. Frameworks: ADK, LangGraph, LangChain, LlamaIndex, AG2, A2A.
Azure AI Foundry Agent Service Verified
Stateful model built on three primitives — plus "hosted agents" running OSS frameworks in customer-dedicated containers.
Threads = persistent sessions with auto context-windowing; BYO-Thread storage into your own Cosmos DB for data residency. Hosted agents (LangGraph, MS Agent Framework) billed per vCPU-hour + GiB-hour. SK + AutoGen converged runtime.
Cloudflare Agents Reported
A different architectural bet: an agent literally IS a Durable Object — a single-writer stateful compute+storage unit with an embedded per-agent SQLite DB. State affinity is built into the platform, not externalized.
Agents self-schedule future work via this.schedule() / cron, multiplexed through one alarm.
OpenAI AgentKit Reported
Built on the Responses API as the hosted execution primitive for tool-calling and multi-agent orchestration.
Caution A third-party report flags deprecation notices for Agent Builder + Evals (leaving Nov 30 2026); ChatKit stays — not confirmed against OpenAI primary docs.