# Multi-agent frameworks converge: Microsoft's 1.0 and OpenAI's SDK overhaul

- **Published:** 2026-04-16
- **Updated:** 2026-10-12
- **Category:** Harnesses & Tooling
- **Author:** Sinthetix
- **URL:** https://sinthetix.com/blog/multi-agent-frameworks-converge-on-sandboxes

> Microsoft Agent Framework 1.0 and OpenAI's Agents SDK update landed within two weeks. What they share, where they differ, and what to ask before you commit.

In the first half of April, two of the most widely used agent-building toolkits shipped major releases. Microsoft declared Agent Framework 1.0 stable on April 3 [1]. OpenAI published a large update to its Agents SDK on April 15, covered by GIGAZINE the next day [2]. Anthropic, meanwhile, published an engineering write-up on April 8 describing how it separates the pieces of its hosted agent service [3]. Read together, they show where multi-agent tooling is settling.

**Key takeaways**

- Microsoft Agent Framework 1.0 stabilizes five multi-agent orchestration patterns and graph-based workflows for .NET and Python.
- OpenAI's SDK update adds native sandbox execution and separates the harness from the sandbox; subagents and code mode are still planned.
- Anthropic's design splits model loop, execution environment and session log, so each can fail or be replaced independently.
- The common direction: durable state, isolated execution, and standard tool protocols such as MCP.

## Microsoft Agent Framework 1.0

Version 1.0 is available for .NET and Python. Microsoft lists as stable: single agents with connectors to Microsoft Foundry, Azure OpenAI, OpenAI, Anthropic Claude, Amazon Bedrock, Google Gemini and Ollama; middleware hooks for content safety, logging and compliance; memory and context providers; graph-based workflows with branching, parallel steps and checkpointing; and declarative agents and workflows defined in YAML [1].

For multi-agent work, the release names five orchestration patterns: sequential, concurrent, handoff, group chat and Magentic-One. Microsoft says these support streaming, checkpointing, human-in-the-loop approvals and pause and resume [1]. It also supports MCP for discovering and calling tools on compliant servers, and A2A for coordinating with agents built in other frameworks, with A2A 1.0 support described as coming soon [1]. Migration assistants are provided for projects built on AutoGen and Semantic Kernel [1].

## OpenAI's Agents SDK update

The April 15 update centers on running agents safely over long tasks. As reported by GIGAZINE:

- **Sandboxes:** built-in support for Blaxel, Cloudflare, Daytona, E2B, Modal, Runloop and Vercel, or your own, with a manifest abstraction intended to keep environments portable from prototype to production [2].
- **Harness separated from execution:** the control loop now lives apart from the sandbox, which OpenAI says is meant to protect the harness if prompt injection leads to problematic generated code [2].
- **Resumability:** sandbox state can be saved and work resumed after an interruption, and several sandboxes can be created for one harness to run work in parallel [2].
- **Availability:** Python first, with TypeScript planned; code mode and subagents are described as future releases. The SDK is free, with standard fees for the tokens and tools agents use [2].

Note that subagents, the feature closest to hierarchical multi-agent delegation, are not yet shipped in this release [2].

## The convergence

| Concern | Microsoft Agent Framework 1.0 | OpenAI Agents SDK update |
| --- | --- | --- |
| Coordination | Five orchestration patterns, graph workflows [1] | Parallel sandboxes for one harness; subagents planned [2] |
| Durability | Checkpointing, pause and resume [1] | Saved sandbox state, resume after interruption [2] |
| Isolation | Middleware hooks for safety and compliance [1] | Harness separated from sandbox [2] |
| Model choice | Seven listed provider connectors [1] | Not covered in the source; check SDK docs |
| Tools | MCP and A2A [1] | Tool and environment management handled by the harness [2] |

Anthropic's engineering post reaches the same architecture from a different direction. It splits an agent into a brain (model plus harness), hands (sandboxes and tools behind one `execute` interface) and a session (an append-only event log kept outside both). It says this makes containers disposable, lets a crashed harness resume from the log, and keeps credentials out of the sandbox [3]. Its sharpest line applies to every framework: "Harnesses encode assumptions that go stale as models improve" [3].

## What differs

Frameworks still differ in practical ways that matter more than feature lists:

- **Model neutrality.** Microsoft's connectors span seven named providers [1]. Confirm how freely each framework lets you switch models, since agents often outlive the model they were built on.
- **Maturity.** Microsoft labels its core APIs stable at 1.0 [1]. OpenAI's sandbox features are new and some announced pieces are not yet released [2].
- **Where the state lives.** Each framework stores checkpoints or sessions somewhere. Know where, and who can read them.

## Questions before you commit

1. Can an agent run be killed and resumed from stored state?
2. Do model-written scripts execute in an isolated environment without access to credentials?
3. Can you swap the model without rewriting orchestration?
4. Which announced features are shipped, and which are on a roadmap?

For businesses, pick a framework on durability, isolation and exit options rather than on the number of orchestration patterns, and build a small proof of concept that deliberately kills a run midway to see whether it recovers.

## Sources

1. [Microsoft Agent Framework Version 1.0](https://devblogs.microsoft.com/agent-framework/microsoft-agent-framework-version-1-0/), Microsoft Agent Framework Blog, 2026-04-03
2. [OpenAI upgrades Agents SDK with sandbox execution and a model-native harness](https://www.gigazine.net/gsc_news/en/20260416-openai-agent-sdk), GIGAZINE, 2026-04-16
3. [Scaling Managed Agents: Decoupling the brain from the hands](https://www.anthropic.com/engineering/managed-agents), Anthropic Engineering, 2026-04-08

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