Games made with Claude Fable 5.1

Fable 5.1 is Anthropic's model for demanding reasoning and long-horizon agentic work, released September 1, 2026. It extends Claude Fable 5 at the same prices, with stronger long-running agentic coding, multistep research, and document, spreadsheet and slide work. Claude Mythos 5.1 has the same capabilities but is open only to Project Glasswing participants.

Anthropic suggests starting most work on Opus and moving to Fable when results at higher Opus effort still fall short. Fable is the slowest and most expensive current Claude model, at $10 per million input tokens and $50 per million output. It reads text and images, writes text, has a 1M-token context window, and is on claude.ai, in Claude Code and through the API and major clouds.

Canva's head of AI, quoted in the announcement, says it built a rhythm game in Canva Code with real music and on-beat gameplay matched to the level it generated. As of September 2026 it's the newest Fable model, with retirement not sooner than September 1, 2027.