Highlights
Prompt caching restored through the gateway (#703 — missed the v0.7.16 tag point): block-level cache markers (Claude Code marks system blocks and the trailing tool result) carry end to end on Anthropic rungs; gateway sessions previously ran fully uncached (~10× input billing, worse TTFT). cache_creation_input_tokens is now reported to callers; marked-system separator fidelity is byte-pinned.
Acceptance: real two-turn Claude Code session — turn 1 cache_creation=45,543, turn 2 cache_read=45,543, input_tokens=3.
Recorded owner follow-up: provider cache-write premium (1.25×) and read discount (0.1×) remain unmodeled in the price schema (same class as the per-search fee).
Ships experiential 0.7.17 + exp-gateway-native 0.3.13.