Workflow SDK vs AWS Bedrock AgentCore
How the Workflow SDK compares to AWS Bedrock AgentCore, a durable-execution framework versus an AI-agent hosting platform. They solve different problems.
Amazon Bedrock AgentCore is AWS's platform for hosting and operating AI agents, with a secure microVM runtime and building blocks for Memory, tool Gateways, and Identity. AgentCore is not a durable-execution engine, so it addresses a different part of the AI agent stack.
These solve different problems. AgentCore answers "where do I securely run and operate an agent on AWS?" The Workflow SDK answers "how do I make a multi-step, tool-calling agent loop durable, resumable, and streamable?" AWS itself pairs AgentCore with a durable layer (Step Functions, or Temporal) for resumability. The Workflow SDK provides that durable layer natively, in your own app.
At a glance
| Workflow SDK | AWS Bedrock AgentCore | |
|---|---|---|
| Category | Open-source durable-functions SDK | AI-agent hosting & operations platform |
| Durable execution? | ✅ Event-log replay; the agent loop resumes from its last checkpoint after a crash | ❌ Not built-in: sessions are ephemeral microVMs; durability is opt-in via Memory or a framework checkpointer |
| What it gives you | Durable orchestration, steps, hooks, streaming, observability | Runtime (microVM hosting), Harness (managed agent loop), Memory, Gateway (tools/MCP), Identity, Browser, Code Interpreter, Observability, Policy, Evaluations |
| Languages | TypeScript / JavaScript (Python beta) | Python-first for authoring; TypeScript or Python project scaffolding via the @aws/agentcore command-line interface (CLI); framework-agnostic (LangGraph, CrewAI, Strands, and others) |
| Isolation | VM-sandboxed workflow code + full-Node steps | Dedicated Firecracker microVM per session (strong hardware isolation) |
| Max duration | No limit (Vercel World limits) | 8-hour hard cap per session |
| AI streaming | Native durable, resumable streaming (survives reconnect, cold start, replay) | Live server-sent events (SSE) / WebSocket only: no buffering or replay of missed tokens |
| Versioning | Runs pinned to immutable deployment | Immutable runtime versions + endpoints; in-flight sessions stay on their launch version (deployment/rollback only, no replay) |
| Portability | Apache-2.0; runs anywhere Node runs; World abstraction | AWS-only; agent code is portable, the operating platform is not |
| Compliance | Inherits your platform | HIPAA-eligible; SOC, PCI, and ISO not third-party certified; not FedRAMP-authorized |
| Pricing | SDK free; pay your platform | Per-module consumption (vCPU-hr / GB-hr, etc.) + model inference billed via Bedrock; no minimums |
What the limits mean in practice: AgentCore's 8-hour session cap means an agent that waits on a human, a long-running job, or a slow external system can't span that wait in one session. Workflow SDK runs have no duration cap: they suspend durably at sleep() and hooks for hours or weeks.
The core distinction: durability
AgentCore Runtime gives each session an isolated microVM with up to 8 hours of runtime, but the compute is ephemeral: on a crash or stop, the next invocation gets a fresh microVM with no automatic replay of the agent loop. AWS's own guidance is to use AgentCore Memory or a framework checkpointer for state durability, and to layer a workflow engine (Step Functions or Temporal) on top when you need durable orchestration.
The Workflow SDK is that durable layer. With WorkflowAgent (in the AI SDK), the agent loop becomes a durable workflow: each model call and tool execution is a checkpointed step, the run resumes mid-loop after a failure, and partial output streams to the client through resumable streams that survive disconnects and cold starts.
Where AgentCore leads
AgentCore is purpose-built for operating agents on AWS, and brings things the Workflow SDK doesn't try to be:
- MicroVM isolation per session: the strongest hardware isolation among the tools in this section.
- Managed agent infrastructure: Memory, a tool Gateway (turn APIs/Lambda/MCP servers into tools), and Identity (credential vaulting, OAuth) as first-class managed services.
- Enterprise/AWS compliance breadth and Virtual Private Cloud (VPC)/PrivateLink networking.
AgentCore fits applications that run agents inside AWS with managed memory, tools, and identity. The Workflow SDK fits durable, resumable, streamable agent execution in your own TypeScript app without an AWS dependency. You can also combine them by hosting on AgentCore and orchestrating durably with the Workflow SDK.
Compiled from public documentation. AgentCore cold-start figures are community-sourced (no published service-level agreement). Verify against the AgentCore docs. Not based on head-to-head benchmarks.