tooling

On June 7, 2026, X renamed the agent loop 'loop engineering' and called it the successor to harness engineering. We ran 47 Claude Code loops in a sandbox to test the claims. The naming churns; three of the technical findings are real and one is measurable to the cent.

Two near-simultaneous coiners (Mitchell Hashimoto and Viv Trivedy), seven convergent voices, and twelve coding agents that all built the same primitives independently. A discipline crystallized in nine months — what it is, who built it, and what every shipping product now contains.