Prompt Caching: Reuse Context, Measure the Benefit

Many AI requests repeat the same instructions, reference material, or tool definitions. Prompt caching can reuse a stable prefix instead of processing it from scratch each time. Benefits depend on actual reuse, cache lifetime, and provider rules; changing content on every request can defeat the intended saving.

What matters

• Place genuinely stable instructions and reference material before request-specific content.
• Track cache reads, writes, latency, and total spend instead of assuming every request benefits.
• Review the provider’s current retention and isolation behaviour before caching sensitive context.

Practical example: An internal writing assistant reuses an approved style guide while each request contains a different document.

One action today: Measure how much context your application repeats before enabling a caching strategy.