Unverified50% confidenceFactExact time
Prompt Caching requires the prompt to meet a minimum cacheable length (typically 1024 tokens for Anthropic), and the prefix must be byte-for-byte identical for the cache to hit.
1
Sources
50%
Confidence
Medium-term (~90 days)
Relevance
10/15/2026
First Seen
Valid until: 1/13/2027
Sources
Related Entities
Related Claims
UnverifiedIn Anthropic's API billing system, prompt caching allows a stable prefix to be marked as cached content, and subsequent identical prefixes directly reuse the KV without recomputing attention, with these tokens recorded as "cache reads".75% similarUnverifiedWhether prompt caching hits depends on byte-for-byte consistency of the request prefix; if even one character at the beginning differs, the entire cache is invalidated.74% similarUnverifiedPrompt caching divides prefixes by 'breakpoints', and the prefix must be byte-for-byte identical to hit the cache, so it is critical to put unstable content such as timestamps and random IDs in the suffix.74% similarUnverifiedPrompt caching can avoid repeated charges for identical prefixes, because system prompts and retrieved document fragments tend to be highly repetitive across multiple conversation turns.72% similarUnverifiedPrefix caching improves inference efficiency by caching common prompt prefixes to reduce redundant computation.69% similar
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