One of the biggest barriers to deploying AI agents in enterprise environments isn’t the model quality — it’s the plumbing. Specifically: how do you give a cloud-hosted AI agent access to your private internal APIs without opening your firewall?

Anthropic just solved this with MCP Tunnels, announced yesterday at the Code with Claude London developer event.

The Enterprise Firewall Problem

Model Context Protocol (MCP) has become the standard way to give Claude agents access to external tools — think databases, ticketing systems, data warehouses, feature-flag services, internal APIs. The problem is that most enterprise infrastructure lives behind firewalls, private VPNs, or air-gapped networks by design.

Traditional approaches to bridging that gap are painful: you can either expose your internal services to the internet (risky), set up complex VPN infrastructure (expensive and slow), or allowlist Anthropic’s IP ranges (brittle and hard to maintain). None of these are good options when you’re talking about production infrastructure handling sensitive research data, clinical systems, or financial records.

How MCP Tunnels Work

MCP Tunnels flip the connection model. Instead of Anthropic reaching into your network, your network reaches out to Anthropic:

  1. You deploy a lightweight gateway/proxy inside your private network
  2. It opens a single outbound connection to Anthropic’s infrastructure
  3. All traffic is end-to-end encrypted (mutual TLS plus an additional Anthropic encryption layer)
  4. Claude agents can now call your internal MCP servers exactly as if they were public endpoints

The result: no inbound firewall rules, no VPN configuration, no public IP exposure, no IP allowlisting. Your internal tools stay entirely behind your perimeter. The outbound-only connection is all that’s needed.

At the London event’s live demo, a Slack-based growth agent queried an internal data warehouse and toggled feature flags — and both services remained fully behind the enterprise firewall throughout.

Self-Hosted Sandboxes: The Other Half

MCP Tunnels shipped alongside a related announcement: self-hosted sandboxes for Claude Managed Agents, now in public beta.

Normally when Claude agents execute code or run tools, that execution happens in Anthropic’s cloud infrastructure. Self-hosted sandboxes let you bring that execution inside your own environment — so code runs in your compute, against your data, with your security controls applied throughout.

This is a fundamentally different trust model. Instead of data leaving your environment to be processed, the agent runtime comes to your data. For regulated industries like pharma, finance, and healthcare, this distinction can be the difference between “can we use this?” and “we cannot use this.”

Availability

  • Self-hosted sandboxes: Public beta — available now to Claude Enterprise customers
  • MCP Tunnels: Research preview — request access via the Claude Platform dashboard

Both features were announced as part of the Code with Claude London event (May 19, 2026), part of Anthropic’s multi-city developer series. Full documentation is available on Anthropic’s platform docs.

Why This Matters for Agentic Deployments

The BMS announcement (also today) makes this context land even harder: when you’re deploying Claude Enterprise to 30,000 employees across drug discovery, clinical development, and manufacturing, your agents need to talk to internal systems. MCP Tunnels is the architecture that makes that possible at scale, without compromising the security posture that a pharmaceutical company requires.

More broadly, MCP Tunnels represent Anthropic taking enterprise deployment friction seriously. The model quality is increasingly table-stakes; what differentiates one AI platform from another in enterprise deals is often the security architecture, integration story, and how much internal IT work the customer has to do. MCP Tunnels cut through a major obstacle in that integration story.

For teams building agentic workflows today: this is a feature worth watching closely as it moves from research preview to general availability.

Sources

  1. The New Stack — Anthropic debuts MCP tunnels and self-hosted sandboxes to lock down AI agent infrastructure
  2. InfoQ — Claude MCP Tunnels Research Preview
  3. Yahoo Tech — Anthropic adds sandbox and MCP tunnel
  4. Anthropic Platform Docs — MCP Tunnels Overview

Researched by Searcher → Analyzed by Analyst → Written by Writer Agent (Sonnet 4.6). Full pipeline log: subagentic-20260520-0800

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