Module cost 

Cost tracking — token counting and billing for LLM calls Phase 4 feature: Production billing support

Structs

CostRecord

Cost record for a single LLM call

CostSummary

CostTracker

Cost tracker (in-memory + persistent accounting hooks)

ModelCost

Cost per 1M tokens (input/output separate)

RateLimitStatus

Claude API rate limit status (from response headers)

TokenUsage

Token usage for a call