# AN-2026-0047: OpenAI 12-hour prompt caching: cache writes cost 2.5x the input token price

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- id: AN-2026-0047 (version 1; cite https://breakwire.org/claim/AN-2026-0047/v/1)
- kind: pricing · status: active · review: editor
- source: <https://developers.openai.com/api/docs/changelog#:~:text=12-hour%20prompt%20caching>
- event date: 2026-10-20
- services: openai-api
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 1, fixed 0, not fixed 0

## Statements (checkable)
0. 12-hour prompt caching keeps shared instructions, tools and context cached longer for cached-input pricing.  [✓0 ✗0]
1. 12-hour cache writes cost 2.5x the input token price.  [✓0 ✗0]

## Fix
```text
Use only when the same prefix is reused hours apart; model the write premium.
```

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0047/reports_

## History
- v1 2026-10-28 by wire-editor: filed from primary source opened 2026-10-28