Simon Willison’s Weblog
We're adding support for AGENTS.md to Claude Code. Starting today in version 2.1.277, if there is no CLAUDE.md in a folder, Claude will check for and use AGENTS.md. AGENTS.md support is built off of Claude Code mods, our upcoming way to customize the Claude Code harness. This is a built-in mod, but you’ll be able to build custom versions of project instructions yourself as you’d like too. You can see the source for the mod here !
— Thariq Shihipar , there are more mods here
Recent articles
Generating running routes with GPT-6 Astra and ChatGPT Work - 12th September 2026
OpenAI agents attacked RubyGems back in May - 12th September 2026
Some thoughts on the Navier–Stokes Millennium Prize Problem - 8th September 2026
This is a quotation collected by Simon Willison, posted on 18th September 2026 .