Card #2857 · OpenAI Platform & APIs
Prompt cache misses caused by volatile tail content
The prompt cache is frequently voided when volatile data is present at the end of the context window, leading to 100% cache misses. This forces expensive full-context window rewrites to resolve the issue, resulting in significant costs per write.
Pain score
0.49/ 1.00 · weighted product of four components
Reach0.32distinct authors (log-normalized)
Recency0.85freshness decay, half-life months
Engagement0.25upvotes + comments, normalized
Monetization1.00willingness-to-pay cues in evidence
§ Evidence — 3 verified quotes
if I have a cache write that includes some unique data that changes from turn to turn, that also must be preserved exactly, otherwise I get a 100% cache miss.
the only solution to that is to deliberately bust the cache, which is a full-context window rewrite, each costing ~$3.50 per write
Everything so far seems to be pointing towards no resilience against volatile tail materials.
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