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MCP tool annotations were introduced nearly a year ago as a way for servers to describe the behavior of their tools — whether they’re read-only, destructive, idempotent, or reach outside their local environment. Since then, the community has filed five independent Specification Enhancement Proposals (SEPs) proposing new annotations, driven in part by a sharper collective understanding of where risk actually lives in agentic workflows. This post recaps where tool annotations are today, what they can and can’t realistically do, and offers a framework for evaluating new proposals. ...

You’ve built an MCP server that works quite well, but now you’re wondering: How do I add richer UI elements? Custom auth flows? What about domain-specific conventions, like those for finance or healthcare? This is where extensions come in. They let developers layer new capabilities on top of the baseline MCP implementation without touching the core protocol. This allows us to keep things stable while also opening up room to experiment, learn, and build with the community’s needs in mind. ...

MCP’s current spec release came out in November 2025. We haven’t cut a new version since, but the project hasn’t stood still. Over the past year MCP has moved well past its origins as a way to wire up local tools. It now runs in production at companies large and small, powers agent workflows, and is shaped by a growing community through Working Groups, Spec Enhancement Proposals (SEPs), and a formal governance process. None of that is news, but it’s the foundation we’re building on. ...

Today, we’re announcing that MCP Apps are now live as an official MCP extension. Tools can now return interactive UI components that render directly in the conversation: dashboards, forms, visualizations, multi-step workflows, and more. This is the first official MCP extension, and it’s ready for production. We proposed MCP Apps last November, building on the amazing work of MCP-UI and the OpenAI Apps SDK. We were excited to partner with both OpenAI and MCP-UI to create a shared open standard for providing affordances for developers to include UI components in their MCP clients. ...

A lot has happened since we first released MCP. We wrapped up 2025 with a major spec update and the momentum hasn’t slowed down. None of it would have happened without the community: every PR, every issue filed, every server and client built. That energy is what keeps MCP moving forward. To keep that momentum going, the Core Maintainer team is evolving as well. Departing Core Maintainers First, some news. Inna Harper and Basil Hosmer will be stepping away from the Core Maintainer team to focus on other projects. ...

When MCP first launched in November of 2024, quite a few of its users relied on local environments, connecting clients to servers over STDIO. As MCP became the go-to standard for LLM integrations, community needs evolved, leading to the build-out of infrastructure around remote servers. There’s now growing demand for distributed deployments that can operate at scale. The Streamable HTTP transport was a significant step forward, enabling remote MCP deployments and unlocking new use cases. However, as enterprise deployments scale to millions of daily requests, early adopters have encountered practical challenges that make it difficult to leverage existing infrastructure patterns. The friction of stateful connections has become a bottleneck for managed services and load balancing. ...

Today marks a major milestone for the Model Context Protocol. Anthropic is donating MCP to the Agentic AI Foundation, a directed fund under the Linux Foundation. MCP will become a founding project of the newly created foundation. In one year, MCP has become one of the fastest-growing and widely-adopted open-source projects in AI: Over 97 million monthly SDK downloads, 10,000 active servers and first-class client support across major AI platforms like ChatGPT, Claude, Cursor, Gemini, Microsoft Copilot, Visual Studio Code and many more. ...

We’re updating how Specification Enhancement Proposals (SEPs) are submitted and managed. Starting today, SEPs will be created as pull requests to the seps/ directory instead of GitHub issues. Why the Change? When we introduced SEPs in July, we chose GitHub Issues as our starting point. Issues are familiar to developers, low-friction, and got us up and running quickly. But as more proposals have come through the process, we’ve identified some key pain points: ...

Today, MCP turns one year old. You can check out the original announcement blog post if you don’t believe us. It’s hard to imagine that a little open-source experiment, a protocol to provide context to models, became the de-facto standard for this very scenario in less than twelve months. But not only do we hit the first anniversary milestone today - we’re also releasing a brand-new MCP specification version. Before we get to the details of what’s new, let’s do a bit of a retrospective. ...

Today we’re introducing the proposal for the MCP Apps Extension (SEP-1865) to standardize support for interactive user interfaces in the Model Context Protocol. This extension addresses one of the most requested features from the MCP community and builds on proven work from MCP-UI and OpenAI Apps SDK - the ability for MCP servers to deliver interactive user interfaces to hosts. MCP Apps Extension introduces a standardized pattern for declaring UI resources, linking them to tools, and enabling bidirectional communication between embedded interfaces and the host application. ...