# Prompt caching 101

Reduce latency and cost with cache-safe prompt blocks.

- Date: Oct 10, 2024
- Reading time: 10 min
- Level: Intermediate
- Tags: Latency, Caching, Optimization

## Takeaways
- Cache stable prompt prefixes and templates.
- Include tool schemas in cache keys.
- Invalidate caches on prompt or policy changes.

## Cacheable blocks

Split prompts into stable and variable blocks. Cache the stable portions.

## Cache key design

Include model, prompt version, and tool schema hashes in cache keys.

## Invalidate safely

Invalidate caches when prompts, tools, or policy rules change.