Beside those sits a labelled survey of 237 tools that contributed nothing and says so. The two sets are disjoint by construction, so they add rather than nest — a tool that gave a lesson is never counted twice.

Both halves are load-bearing, and they are doing different jobs. The settled results are what make the quality lens trustworthy: McCabe on complexity (1976), Halstead on volume (1977), Spärck Jones on term specificity (1972), Nagappan & Ball on churn. Fifty years of replication means those are not opinions, and a tool that measures your code should be built on the ones that survived.

The recent work is what makes it current: seventeen of the folded papers are from 2026, seven published in the last two months and three in the last thirty days (dates as of 2026-09-08; every row carries its arXiv id, so the claim is checkable rather than atmospheric). Retrieval for coding agents, context-compression cost, placebo-controlled localization — that literature is months old, not decades, and several rows were folded within weeks of the paper appearing.

Neither half alone would be enough. A tool built only on the classics would not know what an agent needs; one built only on last month's preprints would have nothing underneath it. And the newest row is a result that failed when it was tested here — which is the point of writing them down. All three counts are re-derived from that document's own tables by test/readmedriftcheck.sh on every run, which fails if this page and those tables disagree, so the claim cannot quietly drift. The row-by-row ledger is docs/LINEAGE.md.

Measured on 48 matched questions across django, webpack and this repository. Across all three, ripwire indexes in 0.25–0.45 s and 6.6–16.5 MB against that