Claude Opus 4.8

Two weeks before the Fable 5 release, Claude Opus 4.8 had landed 41 days after Opus 4.7, same pricing: SWE-bench Pro up from 64.3% to 69.2%, #1 on GDPval-AA at 1890 Elo, fast mode at 2.5x speed for a third of the old price, and dynamic workflows in Claude Code for orchestrating hundreds of parallel subagents.

Bun's Jarred Sumner used dynamic workflows to port Bun from Zig to Rust, ~750,000 lines in eleven days with 99.8% of the test suite passing. Not in production yet, and he was clear about that, but the dev-X discourse ran for days anyway.

Sources: official announcement, dynamic workflows + Bun case study, Simon Willison