How to rewrite `Claude.md` and install the skill for Opus5 and Fable5

Question

Anthropic has released the new Opus 5 and Fable 5 models. Many existing resources&mdash;such as `claude.md` files and custom skills&mdash;are no longer compatible with these new models. How should one rewrite or adjust `claude.md`, or develop skills better suited to these models?

alvis · Accepted Answer

These models don't take claude.md, Claude Code does, and claude.md still get fed to these models if you're using Claude Code.That said, prompting on opus 5 needs new technique: https://platform.claude.com/docs/en/build-with-claude/prompt...

gojkoa · Answer

where did you get the "are no longer compatible" part? we moved from opus 4 to opus 5 without changing anything and no specific conflicts. used fable for a while, also did not have to change anything. I read some advice on the anthropic website that opus 5 doesn't require as many examples as before, but this was a recommendation how to make things shorter, not a backwards compatibility issue.

How to rewrite `Claude.md` and install the skill for Opus5 and Fable5

Anthropic has released the new Opus 5 and Fable 5 models. Many existing resources—such as `claude.md` files and custom skills—are no longer compatible with these new models. How should one rewrite or adjust `claude.md`, or develop skills better suited to these models?

These models don't take claude.md, Claude Code does, and claude.md still get fed to these models if you're using Claude Code.
That said, prompting on opus 5 needs new technique: https://platform.claude.com/docs/en/build-with-claude/prompt...