W21 · May 18–24, 2026

Week 21 was an infrastructure week. The index now runs four category rankings side by side — model families, tokenized agents, service agents, and developer agents — covering 1,338 indexed agents, of which 138 are evidence-ranked (7 model families, 16 tokenized, 28 service, 87 developer). The shift this week wasn't a leaderboard shake-up; it was making each ranking explain itself.

Two things landed. First, the Agent Payments Stack index went live — a neutral six-layer map of who actually covers what in agent payments, from settlement to application. Coinbase and Stripe tie at five of six layers; Circle sits at four. Second, we shipped a confidence tier on scores: every ranked agent now carries a signal-coverage grade (high / medium / low / provisional), so a score built on five signals reads differently from one built on three. The principle is simple — a number without its sample size is a guess in a suit.