- Wednesday, November 11, 2026 · R1 Claude Fable 5.2 and Mythos 5.2 are out (the same model; Mythos is only for vetted cybersecurity and biomedical teams).…
- Wednesday, November 11, 2026 · K2 Which Claude model for what? Anthropic's official guide
The recommendation: start with Opus 5.5 at medium effort. Sonnet 5.5 suits narrowly scoped work, Haiku 5.5 simple high-volume tasks (classification, labeling, data extraction), and Fable 5.2 the…
- Thursday, November 12, 2026 · K3 An "audit" command for new models and Addy Osmani's 10 tips
If you build with Claude Code, save the audit prompt as an /audit command and run it on your existing projects now. It pairs well with the Fable 5.2 prompting guide in Nov 13 / K4; and make point (3)…
- Friday, November 13, 2026 · K4 Anthropic's official Fable 5.2 prompting guide
If you use Claude Code or your own system prompt, review your CLAUDE.md and prompts against K4d. The K4b block fits well into scheduled, unattended runs.