How to Write an AGENTS.md File That Keeps AI Coding Agents on Track

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An AGENTS.md file provides AI coding agents like Codex, Claude Code, and Cursor with the structured context they need to work safely within a repository. The file should specify key directories, exact commands for installing, testing, linting, and building, and clearly identify protected or generated files. Risky areas such as authentication, payment flows, and database migrations must be explicitly flagged with concrete rules rather than vague cautions. Agents should follow a defined workflow that prioritizes verified, minimal changes over speed, with a clear definition of done based on evidence rather than assumption. For large repositories, root-level rules can be supplemented by narrower instruction files placed closer to high-risk or specialized areas.

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