Anthropic shipped Sonnet 5.5 on September 28, 2026 — same $2/$10 as Sonnet 5, same 1M context, 30%+ faster, up to 30% cheaper per task, and on GDPval-AA it sits two Elo points under Opus 5.5. Five jobs Sonnet 5.5 already replaced in its first day on real marketing work, three where Opus 5.5 or Sonnet 5 still wins, and the routing principle that matters now that the Sonnet tier can carry real marketing work.
OpenAI shipped GPT-6 Sol and GPT-6 Luna on September 22, 2026 — three weeks after GPT-6 Astra, at half the per-token price of GPT-5.6 Sol and Luna. Sol ($2/$10) is the workhorse, Luna ($0.10/$0.50) is the budget engine, and Terra is gone. Five jobs to give Sol, three to keep on Astra or peers, and the routing principle that falls out once you stop chasing the flagship.
OpenAI shipped GPT-5.6 in three flavors (Sol, Terra, Luna) on June 26, 2026 — but only to a small invitee list, pending US government review. Here's the practitioner's read: what the 1.5M context window actually unlocks for marketers, the pricing reality (Terra is the real story, not Sol), and the four workflows I'll route to it the day it opens up.
Anthropic's first public Mythos-class model is fast, opinionated, and 2× the price of Opus 4.8. After a week of running real marketing jobs through it, here's the actual breakdown — capabilities, costs, the 30-day data retention rule that affects agencies, and the marketer use cases where Fable 5 actually wins.
