Module usage 

Structs

HookExecution

A single hook execution event from a type: "attachment" JSONL record where attachment.type == "hook_success".

ModelPricing

Pricing per 1M tokens (USD) by model family.

ParsedJsonl

Combined result from parsing a single JSONL file.

SessionUsage

Usage summary for a single session, returned to the frontend status bar.

UsageEntry

Flat row representing a single completed assistant turn.

Constants

WEB_SEARCH_COST_PER_REQUEST

Flat fee per Anthropic web-search server-tool request ($10 per 1,000 = $0.01).

Functions

context_window_for_model

Fable, Haiku 5.5+, Opus 5+ and Sonnet 5+ run a 1M window natively: JSONL strips the [1m] tag, yet 74 bare claude-opus-5*/claude-sonnet-5 sessions were observed sending requests over 200K. Opus/Sonnet 4.x stay 200K unless tagged [1m].

cost_for_entry

Single source of truth for per-turn cost (USD), used by both the live status bar (reduce_session) and the Usage page (commands::usage).

encode_project_path

Encode a project path the same way Claude Code does.

fast_multiplier_for_model

Fast-mode (research preview) cost multiplier, applied to the entire token cost line when usage.speed == "fast". Fast mode is Opus-only and its premium varies by version (confirmed Anthropic pricing, 2026-09):

find_current_session_jsonl

Find the JSONL file for the current session by looking up Claude Code’s active sessions directory, matching on project path. Falls back to finding the newest JSONL created after spawned_at.

parse_jsonl_entries

Parse a single JSONL file into one UsageEntry per unique message.id.

pricing_for_entry

Per-turn rates: pricing_for_model, except Haiku 5.5+ turns whose prompt (input + cache reads + cache writes) exceeds 100k tokens, which bill the long-prompt tier. Unverified: Anthropic’s pricing page doesn’t say which token classes count toward the threshold.

pricing_for_model

Hardcoded as of 2026-10. Requires a code change + release when Anthropic updates pricing.

reduce_session

Reduce a list of UsageEntry for a single session into a SessionUsage.