How we contain Claude across products

Twelve months ago, we'd have rejected out of hand the idea of granting Claude access sufficient to take down an internal Anthropic service. Today that level of access is routine, and Anthropic developers are more productive for it. The risk of these deployments has two components: how likely a failure is, and how much damage one could do. Progress on safeguards and model training has steadily driven down the first; the second—the theoretical blast radius—only grows as capabilities and access expand. Yet as agents become capable of doing work that once required a person or even a team, the cost of not deploying grows large enough that the risk-reward calculation tips heavily toward adoption, as long as products can be made safe. The engineering question becomes how to cap the blast radius.When bounds can be placed on the relative damage of an autonomous agent—such as through control over its environment—high-utility capabilities can motivate deployment. Claude Mythos Preview is an example of a model whose blast radius was deemed too high to ship in April 2026. However, we expect broader release of models with similar levels of capability to become appropriate as defenders harden critical systems and safeguards mature—even though some risk will always remain. Model capability is an important factor in the total risk of an agent’s deployment.There are broadly two ways to do this.The first is to supervise the agent’s behavior via a human-in-the-loop. Claude Code previously protected against agents taking unintended actions by asking users for permission at each turn. Theoretically that works, but we’ve found the approach to be fallible. Our telemetry showed users approved roughly 93% of permission prompts. The more approvals a user sees, the less attention they pay to each, becoming over time much less diligent in their supervision. We recently built Claude Code auto mode, which automates safer approvals in order to reduce this approval fatigue. Still, vulnerabilities remain—any probabilistic defense has a non-zero miss rate.1The second approach to capping the blast radius—and the focus of much of this post—is containment. Rather than supervising what the agent does, we supervise what it’s able to do by enforcing access boundaries through, for example, sandboxes, virtual machines, and egress controls. This is where Anthropic engineering has devoted the most effort, and also where many of the most surprising security failures have occurred.Over the past two …