The open source Model Context Protocol was just updated — here’s why it’s a big deal

The Model Context Protocol (MCP)—a rising open standard designed to help AI agents interact seamlessly with tools, data and interfaces—just hit a significant milestone. Today, developers behind the initiative finalized an updated version of the MCP spec, introducing key upgrades to make AI agents more secure, capable and interoperable.

In a very significant move, OpenAI, the industry leader in generative AI, followed the MCP announcement today by saying it is also adding support for MCP across its products. CEO Sam Altman said the support is available today in OpenAI’s Agents SDK and that support for ChatGPT’s desktop app and the Responses API would be coming soon.

Microsoft announced support for MCP alongside this release, including launching a new Playwright-MCP server that allows AI agents like Claude to browse the web and interact with sites using the Chrome accessibility tree.

“This new version is a major leap forward for agent-tool communication,” Alex Albert, a key contributor to the MCP project, said in a post on Twitter. “And having Microsoft building real-world infrastructure on top of it shows how quickly this ecosystem is evolving.”

What’s new in the updated MCP version?

The March 26 update brings several important protocol-level changes:

• OAuth 2.1-Based Authorization Framework: Adds a robust standard for securing agent-server communication, especially in HTTP-based transports.
• Streamable HTTP Transport: Replaces the older HTTP+SSE setup, enabling real-time, bidirectional data flow with better compatibility.
• JSON-RPC Batching: Allows clients to send multiple requests in one go, improving efficiency and reducing latency in agent-tool interactions.
• Tool Annotations: Adds rich metadata for describing tool behavior, enabling more imaginative discovery and reasoning by AI agents.

Figure 1: Claude Desktop using Playwright-MCP to navigate and describe datasette.io, demonstrating web automation powered by the Model Context Protocol.

The protocol uses a modular JSON-RPC 2.0 base, with a layered architecture separating core transport, lifecycle management, server features (like resources and prompts) and client features (like sampling or logging). Developers can pick and choose which components to implement, depending on their use case.

Microsoft’s contribution: Browser automation via MCP

Two days ago, Microsoft released Playwright-MCP, a server that wraps its powerful browser automation tool in the MCP standard. This means AI agents like Claude can now do more than talk—they can click, type, browse, and interact with the web like real users.

Built on the Chrome accessibility tree, the integration allows Claude to access and describe page contents in a human-readable form. The available toolset includes:

• Navigation: browser_navigate, go_back, go_forward
• Input: browser_type, browser_click, browser_press_key
• Snapshots: browser_snapshot, browser_screenshot
• Element-based interactions using accessibility descriptors

This turns any compliant AI agent into a test automation bot, QA assistant or data navigator.

people love MCP and we are excited to add support across our products.

available today in the agents SDK and support for chatgpt desktop app + responses api coming soon!

— Sam Altman (@sama) March 26, 2025

Setup is easy: users simply add Playwright as a command in claude_desktop_config.json, and the Claude Desktop app will recognize the tools at runtime.

The bigger picture: Interoperability at scale

Figure 2: The modular design of MCP enables developers to implement only the layers they need, while maintaining compatibility.

Anthropic first introduced MCP in late 2023 to solve a growing pain point: AI agents need to interact with real-world tools, but every app speaks a different “language.” MCP aims to fix that by providing a standard protocol for describing and using tools across ecosystems.

With backing from Anthropic, LangChain and now Microsoft, MCP is emerging as a serious contender for becoming the standard layer of agent interconnectivity. Since MCP was launched first by Anthropic, questions lingered whether Anthropic’s largest competitor, OpenAI, would support the protocol. And of course, Microsoft, a big ally of OpenAI, was another question mark. The fact that both players have supported the protocol shows momentum is building among enterprise and open-source communities. OpenAI itself has been opening its ecosystem around agents, including with its latest Agents SDK announced a week ago — and the move has solidified support around OpenAI’s API formats becoming a standard, given that others like Anthropic and Google have fallen in line. So with OpenAI’s API formats and MCP both seeing support, standardization has seen a big win over the past few weeks.

“We’re entering the protocol era of AI,” tweeted Alexander Doria, the co-founder of AI startup Pleias. “This is how agents will actually do things.”

What’s next?

With the release of MCP 0.2 and Microsoft’s tangible support, the groundwork is being laid for a new generation of agents who can think and act securely and flexibly across the stack.

Figure 3: OAuth 2.1 Authorization Flow in Model Context Protocol (MCP)

The big question now is: Will others follow? If Meta, Amazon, or Apple sign on, MCP could soon become the universal “language” of AI actions.

For now, it’s a big day for the agent ecosystem—one that brings the promise of AI interoperability closer to reality.

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