Are you getting the AI you paid for? Anthropic’s new AI verification tool has a costly catch

When you pay for access to a named AI model, identifying it from its answers alone remains unreliable. A convincing reply can show that a service works, while leaving a more basic purchase question unresolved: did the model you selected actually do the work?Anthropic's FlashProve research release, published Nov. 2, offers a way to check model computation without exposing the model's private weights. The catch is the work required to produce that assurance: roughly 70 to 95 times the GPU time of ordinary inference in the company's benchmark.That makes FlashProve a potential safeguard for buyers using third-party AI services, with substantial distance still to travel before routine use. The demonstration uses Meta's Llama 4 Maverick, not a verification feature being switched on for Claude customers.The process begins before a response is checked. A provider publishes a cryptographic commitment to its model weights, the numerical parameters that determine how the model computes an answer. Think of it as a fingerprint that fixes which weights subsequent proofs must match, while keeping those weights hidden.The provider then produces a proof that the committed model, given the specified...