Crate tt_preview 

tt-preview — pure cost preview engine.

See docs/superpowers/specs/2026-05-28-trackC-cost-preview-api-design.md.

Re-exports

pub use error::PreviewError;

pub use types::CacheProjections;

pub use types::CurrentEstimate;

pub use types::EstimationConfidence;

pub use types::PreviewRequest;

pub use types::PreviewResponse;

pub use types::QualityRiskBand;

pub use types::RouteSuggestion;

pub use types::Suggestion;

Modules

cache_projection

Cache hit-rate projection.

classifier

Cheap regex-based task classifier. Pattern-matches the last user message against indicators of: classification, extraction, code, agent, generic chat. The same patterns inform output-no-max-tokens Inspect rule fix hints.

error

Preview engine errors. Designed so the HTTP handler can always emit a valid PreviewResponse with warnings[], never a 5xx.

pricing

Wrapper over per-provider pricing tables.

route_suggestions

Cheaper-equivalent route suggestions.

token_estimator

Per-model token estimation.

types

Request + response shapes for the preview engine.

Functions

preview

Top-level entry point. Returns a complete PreviewResponse. The only way this returns Err is if the model is unknown AND the optional fallback heuristic also fails — in practice the handler converts that into a 400 with a clear message.