Anthropic Rolls Out MCP 2026-07-28 With a Stateless Core for Claude

Anthropic updates Claude for the latest MCP specification

Anthropic has announced that support for the Model Context Protocol (MCP) 2026-07-28 specification is rolling out across Claude products. The release is the fifth MCP specification update and changes the protocol’s core architecture, authorization model, and approach to optional capabilities.

According to Anthropic’s announcement, the most consequential change is a move from a bidirectional, stateful protocol to a stateless request/response core. The Model Context Protocol project’s release notes add that the finalized specification removes protocol sessions and the initialize handshake.

That redesign is intended to make MCP servers easier to run on serverless and edge infrastructure. For developers building integrations for Claude and other AI applications, stateless interactions can reduce the operational need to maintain persistent connections between clients and servers.

Extensions formalize apps and long-running work

The new release also introduces a versioned extensions framework. Anthropic says MCP Apps and Tasks are now standardized through that mechanism, rather than requiring changes to the core protocol.

MCP Apps are intended to support interactive user interfaces within an MCP-enabled experience, while Tasks provide a model for work that may take longer than a single request. The Model Context Protocol Blog says the specification also adds routing headers alongside these extension and authorization changes.

The separation between a smaller core protocol and formal extensions could allow implementations to adopt capabilities selectively. A client or server that does not need interactive UI support or asynchronous task handling can remain focused on the request/response foundation, while products that need those functions can implement the relevant extension.

Authorization changes target enterprise deployments

Authorization is another focus of MCP 2026-07-28. Anthropic says the updated specification aligns authorization with production OAuth 2.0 and OpenID Connect (OIDC) deployments. The company specifically cites enterprise identity systems such as Microsoft Entra and Okta as examples of environments that MCP servers can connect to without workarounds.

OAuth 2.0 is widely used to delegate application access, while OIDC layers identity information on top of OAuth-based flows. Aligning MCP’s authorization requirements with those established standards is significant for organizations that need AI-connected tools to work with existing identity and access-management systems.

A protocol change with implementation implications

Anthropic reports that MCP recently exceeded 400 million monthly SDK downloads, which it says represents a fourfold increase during the year. That figure is the company’s own measurement, but it underscores why changes to the specification may matter beyond Claude.

For MCP server operators, the 2026-07-28 release means reviewing assumptions tied to sessions and initialization. For client developers, it creates a defined path to support optional features such as apps and tasks. And for enterprise deployments, the revised authorization model offers a standards-based route for connecting MCP services to established identity providers.

Anthropic has not detailed a product-by-product rollout schedule in the announcement, saying only that support is being rolled out across Claude products. The finalized specification and its release notes are available from the Model Context Protocol project.