XP-002: AGENTS.md Platform Compatibility - Cross-Platform

Summary

• Rule ID: XP-002
• Severity: MEDIUM
• Category: Cross-Platform
• Normative Level: SHOULD
• Auto-Fix: No
• Verified On: 2026-02-09

Applicability

• Tool: all
• Version Range: unspecified
• Spec Revision: unspecified

Evidence Sources

• https://developers.openai.com/codex/guides/agents-md
• https://opencode.ai/docs/rules
• https://docs.cursor.com/en/context
• https://docs.cline.bot/prompting/cline-memory-bank#cline-memory-bank-custom-instructions-[copy-this]
• https://github.blog/changelog/2025-08-28-copilot-coding-agent-now-supports-agents-md-custom-instructions/

Test Coverage Metadata

• Unit tests: true
• Fixture tests: true
• E2E tests: false

Examples

The following examples demonstrate what triggers this rule and how to fix it.

Invalid

Just plain text without any markdown headers or structure.

Valid

# Project Memory

## Build Commands

### Testing

Run tests with npm test.