---
title: "Scaling AI Agent Infrastructure with the MCP Stateless updates"
description: "The 2026-07-28 Model Context Protocol specification release candidate addresses production bottlenecks caused by the earlier session-oriented HTTP model, including session pinning, sticky routing, lost state, and Redis-backed infrastructure. It removes the initialize/initialized handshake and Mcp-Session-Id, carrying protocol version, client information, and capabilities in _meta on each request while exposing method and name through HTTP headers. The update also introduces ttlMs/cacheScope caching, Multi Round-Trip Requests for elicitations and task progress, issuer and resource-indicator verification, and full JSON Schema 2020-12 support. The post says the stateless core enables ordinary load balancing, serverless deployment, and transparent failover, while SDK beta releases for TypeScript, Python, Go, and C# support migration."
---

# Scaling AI Agent Infrastructure with the MCP Stateless updates

[Google](https://yomu.fyi/company/google) · Kurtis Van Gent, Alan Blount · Aug 5, 2026

**Type:** Explainer

## Summary

The 2026-07-28 Model Context Protocol specification release candidate addresses production bottlenecks caused by the earlier session-oriented HTTP model, including session pinning, sticky routing, lost state, and Redis-backed infrastructure. It removes the initialize/initialized handshake and Mcp-Session-Id, carrying protocol version, client information, and capabilities in \_meta on each request while exposing method and name through HTTP headers. The update also introduces ttlMs/cacheScope caching, Multi Round-Trip Requests for elicitations and task progress, issuer and resource-indicator verification, and full JSON Schema 2020-12 support. The post says the stateless core enables ordinary load balancing, serverless deployment, and transparent failover, while SDK beta releases for TypeScript, Python, Go, and C# support migration.

## Context

The original MCP HTTP model required persistent session state, initialization handshakes, and session pinning. The post describes resulting problems with round-robin load balancing, sticky routing, pod failures, autoscaling, and shared Redis session stores when deploying MCP servers across cloud-native infrastructure.

## Approach / What changed

The update removes transport-level session management and makes requests self-describing. Protocol metadata travels in each request’s \_meta field, while protocol version, method, and name are exposed through HTTP headers; Multi Round-Trip Requests, caching fields, security enhancements, and SDK beta releases address stateless interaction, governance, and migration.

## Takeaways

- The legacy HTTP flow returned an Mcp-Session-Id that clients had to resend, pinning requests to in-memory state and causing failures when traffic reached another pod.
- New requests carry protocol metadata in \_meta and expose protocol version, method, and name through HTTP headers; disagreements between headers and the JSON-RPC body produce a -32020 header mismatch error.
- Multi Round-Trip Requests returns an InputRequiredResult with requestState for elicitations, allowing clients to continue the interaction and use tasks/get or tasks/update to monitor progress.

**Tags:** [Architecture](https://yomu.fyi/topic/architecture), [Load Balancing](https://yomu.fyi/topic/load-balancing), [MCP](https://yomu.fyi/topic/mcp), [Serverless](https://yomu.fyi/topic/serverless)

- Source: [Google](https://developers.googleblog.com/scaling-ai-agent-infrastructure-with-the-mcp-stateless-updates)
- Source URL: https://developers.googleblog.com/scaling-ai-agent-infrastructure-with-the-mcp-stateless-updates
- Ingested by Yomu: 2026-09-09T14:27:59.288Z

[Read original post](https://developers.googleblog.com/scaling-ai-agent-infrastructure-with-the-mcp-stateless-updates)