pricing

name	pricing
description	Guide for updating model pricing in Splitrail. Use when adding new AI model costs or updating existing pricing data.

Pricing Model Updates

Token pricing is defined in src/models.rs. Built-in models are populated by populate_defaults() into the runtime model registry, and user/config models can be merged with init_external_models().

Adding a New Model

1. Add a ModelInfo entry in populate_defaults() with:
   • pricing: Use PricingStructure::Flat { input_per_1m, output_per_1m } for flat-rate models, or PricingStructure::Tiered for threshold-based pricing.
   • caching: Use the appropriate CachingSupport variant (None, OpenAI, Anthropic, OpenAIWithWrites, or Tiered).
   • service_tiers: Leave empty unless the provider has distinct priority/flex/batch rates.
   • dated_pricing: Leave empty unless pricing changes by usage date.
   • is_estimated: Set to true only when pricing is not confirmed by a provider/tool source.
   • input_token_semantics: Auto-derived for built-in models (defaults to ExcludesCache); only GPT/o-series models typically need IncludesCacheRead. External model configs should set this explicitly if it affects cache-read counting.
2. If the model has aliases (date suffixes, provider-prefixed names, regional names, etc.), add entries to the alias section mapping each observed name to the canonical model name.
3. Add or update tests in src/models.rs for canonical pricing, aliases, caching, and estimated/non-estimated status.

Dated Pricing Overrides

Use dated_pricing when a model has temporary promotional pricing, launch pricing, or another time-bounded rate that should apply based on the original usage timestamp.

The default pricing and caching fields should represent the durable/current sticker price. Each DatedPricing override has a valid_until: NaiveDate exclusive end date and applies when usage_date < valid_until. For example, an introductory rate that applies through 2026-08-31 should use valid_until = NaiveDate::from_ymd_opt(2026, 9, 1).expect("valid date").

When adding a dated override:

• Keep the model's default pricing/caching at the post-promo or durable rate.
• Add the temporary rate with add_dated_pricing!() after add_model!().
• Add boundary tests for the final day of the temporary rate and the first day after it ends.
• Prefer dated calculator functions in analyzers that know the usage timestamp.

Price Calculation

Use models::calculate_total_cost_for_service_tier_at() when an analyzer has a message or event timestamp. This preserves historical costs across dated pricing windows.

Use the undated compatibility helpers, such as models::calculate_total_cost(), only for tests, config-like calculations, or call sites that truly do not know the usage date. Undated helpers use the model's default pricing/caching, not temporary dated overrides.

Common Pricing Sources

• Anthropic pricing
• OpenAI pricing
• Google AI pricing