Anthropic released Claude Fable 5.1 on September 1. It costs $10 per million input tokens and $50 per million output tokens, and the price of cache reads fell 75%, to $0.25 per million. Anthropic estimates typical workloads get about 25% cheaper and agent-style work up to 45% cheaper. A second model, Claude Mythos 5.1, is limited to vetted U.S. organizations. Enterprise Frontier Safeguards, which pair zero data retention with cloud infrastructure the customer controls, roll out in phases starting this fall. Agents reread the same files over and over, so the cache discount is where most of the savings land. That makes it realistic to leave an agent working on a contract archive, a support backlog, or a vendor review for days. The harder question is oversight. Someone who starts an agent on Friday and reads its output on Monday has handed off everything in between. Teams should agree on which tasks can run unattended and who checks the result before anyone relies on it. Pick the tasks your team may hand to an unattended agent, and name who checks the output.