An AI Coding Cost Tracker Needs a Measurement Contract
The most dangerous number in an AI coding dashboard is the one labeled cost without a definition. A local tool can reconstruct token activity from Claude Code and Codex session records. It can apply a dated model-price table. That produces an estimate with a clear use: comparing periods and understanding the shape of local activity. It does not produce an invoice. Claude Code and Codex do not write identical usage records. Claude can expose input, output, cache creation, and cache-read fields on
