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.
Start at the file-format boundary
Claude Code and Codex do not write identical usage records. Claude can expose input, output, cache creation, and cache-read fields on assistant messages. Codex can separate model context from later token events, and cached input may be included inside total input.
