Anthropic’s MCP Goes Stateless, Adds Security and Speed

The Model Context Protocol (MCP), developed by Anthropic, has transitioned to a stateless architecture as per its latest specification update on July 28, 2026. Key changes include the elimination of initialization handshakes and session IDs, leading to self-contained requests that carry protocol version and client details. A new Multi-Round Turn Request (MRTR) mechanism replaces server-initiated calls, allowing for interactive user confirmations.

HTTP header routing has been introduced for efficient request processing, along with enhanced caching capabilities. Additionally, security measures have been strengthened, especially in OAuth implementations, and some legacy features are set for deprecation. Developers are advised to consult migration documentation for adapting their systems accordingly.