Get Session Cost

Everything this session has cost so far, split by source.

A run's total_cost_usd is its LLM (and web-search) charge only. Browser time and proxy bandwidth are metered against the session's browser, which outlives any one run — so this is the endpoint for the session's full cost.

These are recorded usage costs, not an invoice total: promotional waivers and credits are applied downstream in billing, so a session run under a promotion can report cost here that was never charged.

Costs keep moving after a run reports finished: LLM calls settle up to about 90 seconds later, and the browser accrues time and proxy traffic until it stops.