Anthropic's Stealth Cache Downgrade Drives 30% Cost Increase

Anthropic silently reduced Prompt Cache TTL from 1 hour to 5 minutes on March 6th, significantly diminishing cache hit rates and increasing API costs for developers. This undisclosed breaking change directly impacts cost optimization strategies for applications relying on prompt caching, potentially triggering unexpected cost spikes. The lack of communication underscores the importance of developers actively monitoring their API usage and cache performance metrics.