guidelines.md

guidelines.md is the project-level configuration file JetBrains Junie reads from a repository’s .junie/ directory to carry persistent context and coding conventions into every AI agent session. Instead of restating a project’s rules in each prompt, a team commits its expectations once as markdown, and Junie treats that file as standing guidance while it plans and edits code.

• A well-known location - Living in .junie/guidelines.md, it is discoverable to the agent and reviewable in version control like any other source file.
• Persistent project context - Architecture notes, naming conventions, testing expectations, and do-not-touch rules survive across sessions.
• Human-readable markdown - The format is plain prose, so the same file documents the project for people and steers the agent.
• Vendor-specific to Junie - It is JetBrains’ answer to agent guidance, parallel to conventions other coding assistants adopt.

In real API operations a guidelines.md file is where a team encodes the standards an AI coding agent must respect while touching an API codebase, from response conventions to how contracts are defined. It sits in the same emerging family as the various per-tool agent-instruction files, and as agentic coding spreads across the network I treat the presence of such a committed, reviewable rules file as a small but real signal that a team is governing how AI writes its code rather than leaving it unguided.