Provider Cache Notes

This reference keeps the public skill package grounded in first-party cache guidance without copying provider documentation into the repo.

OpenAI

• Official guide: OpenAI prompt caching
• The main structural rule is exact prefix reuse: keep stable instructions and tool definitions at the beginning, move dynamic user-specific content later, and watch cached_tokens in usage metadata.
• OpenAI also documents prompt_cache_key as a routing aid when many requests share a long common prefix.

Anthropic

• Official guide: Anthropic prompt caching
• Anthropic frames prompt caching as reusing specific prompt prefixes to reduce processing time and cost for repeated workloads.
• The public lesson for this skill is the same: benchmark stable prefixes, treat tool or instruction changes as likely cache-break events, and keep runtime reports local unless the user explicitly exports them.

Repo Boundary

• This skill package uses those official docs as source input, not as imported copy.
• The benchmark helper stays provider-agnostic and only reads user-supplied run artifacts.