Claude Code v2.1.277 Adds Native Support for AGENTS.md Standard
On September 19, Anthropic announced that Claude Code CLI supports the AGENTS.md standard starting with v2.1.277, a release that includes 87 CLI changes in total. Several developers (@pvncher, @trq212, @petergyang, @zeeg, @altryne and others) relayed and confirmed the news the same day.
Confirmed
- Trigger logic: when there is no CLAUDE.md in the project folder, Claude automatically looks for and uses AGENTS.md in that directory as the project instructions file
- This behavior can be modified or toggled under Project instructions in /config
- AGENTS.md is a cross-agent standard for project documentation files, used to describe project conventions and context to agents
- The community views this update as Anthropic officially adopting the AGENTS.md community standard
Why it matters
AGENTS.md is a cross-tool configuration standard; previously, each coding agent used its own private config file (such as CLAUDE.md for Claude Code). Official support means developers only need to maintain a single project instructions file that can be read by multiple coding agents, reducing configuration overhead in multi-tool workflows. @iannuttall also expressed the hope that Claude Code would in the future more proactively discover and use such standard configuration files.
2026-09-19 ~ 2026-09-19 · 16 related posts
Primary sources
- Claude Code 2.1.277 adds native AGENTS.md support as first built-in 'mod' — trq212 · 2026-09-19
- Claude Code v2.1.277 adds AGENTS.md support when CLAUDE.md is missing — altryne · 2026-09-19
- [source] Claude Code is getting native AGENTS.md support, spotted on GitHub — jevans102 · 2026-09-19
- Anthropic finally adds AGENTS.md support to Claude Code — iannuttall · 2026-09-19
- [source] Claude Code 2.1.277 ships 87 CLI changes, adds AGENTS.md support — ClaudeCodeLog · 2026-09-19
- Claude Code 2.1.277 adds AGENTS.md support, falling back when CLAUDE.md is missing — romainhuet · 2026-09-19
10 near-duplicate retellings: pvncher · petergyang · zeeg · AlexandrePesant · jasonkneen · mobav0 · MaziyarPanahi · JoshKale · Saboo_Shubham_ · jarrodwatts