AGENTS.md vs CLAUDE.md: Where Agent Context Actually Lives

AI coding agents like Claude Code, Cursor, and Copilot often rely on fragmented context files, leading to inconsistencies across repositories. While CLAUDE.md remains common, AGENTS.md has emerged as an open, vendor neutral standard proposed by Sourcegraph's Amp team. This markdown file, committed to the repo root, provides essential commands, conventions, and architecture details. Adopting AGENTS.md prevents agent drift and ensures consistent behavior, replacing the mess of multiple, out-of-sync instruction files across different development environments.