Amazon Bedrock Prompt Caching for Claude: How It Works and How to Use It

Amazon Bedrock offers a prompt caching feature that stores pre-processed system instructions in GPU memory, avoiding redundant computation on repeated API calls. The mechanism works by generating a cryptographic hash of static prompt content and reusing the saved Key-Value cache state if the hash matches on subsequent requests. Cached content must meet minimum token thresholds — 1,024 tokens for Claude Sonnet 4.6 and 4,096 for Claude Opus 4.6 — and the cache remains active for a default five-minute TTL that resets with each cache hit. Developers must place static instructions before any dynamic content, as any change preceding the cache marker will invalidate the cache entirely. The feature can be implemented in Python using AWS's Boto3 library and the Bedrock Converse API by inserting a cachePoint marker after the fixed system prompt block.