Introduces LookupPricingAt() to resolve model pricing at a specific
timestamp instead of always using current prices. This is important
for accurate cost calculations when analyzing historical sessions
where pricing may have changed.
Changes:
- Add modelPricingVersion struct with EffectiveFrom timestamp
- Add defaultPricingHistory map for versioned pricing entries
- Update LookupPricing to delegate to LookupPricingAt(model, time.Now())
- Add comprehensive tests for time-windowed pricing lookup
The infrastructure supports future pricing changes by adding entries
to defaultPricingHistory with their effective dates.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Implement the configuration layer that supports the entire cost
estimation pipeline:
- config/config.go: TOML-based config at ~/.config/cburn/config.toml
(XDG-compliant) with sections for general preferences, Admin API
credentials, budget tracking, appearance, and per-model pricing
overrides. Supports Load/Save with sensible defaults (30-day
window, subagents included, Flexoki Dark theme). Admin API key
resolution checks ANTHROPIC_ADMIN_KEY env var first, falling back
to the config file.
- config/pricing.go: Hardcoded pricing table for 8 Claude model
variants (Opus 4/4.1/4.5/4.6, Sonnet 4/4.5/4.6, Haiku 3.5/4.5)
with per-million-token rates across 5 billing dimensions: input,
output, cache_write_5m, cache_write_1h, cache_read, plus long-
context overrides (>200K tokens). NormalizeModelName strips date
suffixes (e.g., "claude-opus-4-5-20251101" -> "claude-opus-4-5").
CalculateCost and CalculateCacheSavings compute per-call USD costs
by multiplying token counts against the pricing table.
- config/plan.go: DetectPlan reads ~/.claude/.claude.json to
determine the billing plan type. Maps "stripe_subscription" to
the Max plan ($200/mo ceiling), everything else to Pro ($100/mo).
Used by the budget tab for plan-relative spend visualization.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
