Glossary · term28 of 202
cache write
The cost of storing a prompt's context so later requests can read it from cache instead of reprocessing it. Billed above base input price, with the rate depending on how long the write stays valid.
also written as cache writes
Related terms
JSONLA text file format storing one JSON object per line rather than a single nested document, making it easy to append events without rewriting the whole file.view termTTLThe time a cached prompt stays valid before it expires and must be rewritten at full cost. Shortening it turns yesterday's cheap cache reads into today's expensive cache writes.view termcache hit ratioThe share of total tokens in a session that came from cache reads rather than fresh input, which matters because cached tokens bill far cheaper than uncached ones.view termcache missA request whose prompt prefix no longer matches what was cached, forcing the full prefix to be billed again at the cache-write rate instead of the cheaper cache-read rate.view termcache readA token served from a prior prompt's cached context instead of being processed fresh, billed at a fraction of the base input price. Most tokens in a long agent session are cache reads, not new context.view termccusageA community tool that estimates API-equivalent dollar costs from Claude Code transcript files by converting logged token counts using published pricing.view termmetered APIA pay-per-token pricing model, as opposed to a flat subscription, where usage is billed directly against a published rate card rather than drawn from a fixed weekly quota.view termprefix stabilityKeeping the leading portion of a prompt byte-identical across turns so it keeps qualifying for cheap cache reads instead of triggering an expensive cache rewrite.view termprompt cachingA billing mechanism where a stable, byte-identical prompt prefix gets reused across turns at a fraction of normal input cost, while any edit to that prefix forces a full-price rewrite.view term
At a glance
- cited by
- 2 posts
- categories
- 1
- first used
- jul 2026
Claude Code vs Codex Limits, Measured in the Same UnitClaude Code vs Codex limits, measured across 28 days and 56.8 billion tokens. Why token counts cannot predict quota burn, and what to read on each side instead.
Token-Compression Skills Do Not Survive MeasurementToken compression skills report savings the invoice never shows. Cache reads carry 87 percent of an agent bill, and cutting tokens can push the cost up.