Skills
Claude Code Adds 1-Hour Prompt Cache Opt-In After Silent TTL Regression from 1 Hour to 5 Minutes in March 2026 — Set ENABLE_PROMPT_CACHING_1H to Restore
Anthropic silently changed Claude Code's default prompt cache TTL from 1 hour to 5 minutes on March 6, 2026, causing cost inflation for API-key and cloud users. A new ENABLE_PROMPT_CACHING_1H environment variable lets users opt back into the 1-hour TTL on API key, Bedrock, Vertex, and Foundry. A separate bug was also fixed where setting DISABLE_TELEMETRY accidentally forced the 5-minute TTL, meaning privacy-conscious users were paying more without knowing.
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