Windsurf Rules: A Technical Deep Dive

Windsurf is an AI-first code editor that takes a radically simple approach to configuration: a single .windsurf/rules file containing plain markdown. No frontmatter, no special syntax, no configuration files - just markdown with a 12,000 character limit.

Introduction

Windsurf's minimalist philosophy makes rules zero-configuration, git-friendly, universal, and approachable. The core principle: Maximum impact with minimum syntax.

Format Specification

Windsurf uses a hierarchical rules system with files named .windsurf/rules that can be placed in:

•Current workspace directory
•Workspace sub-directories
•Parent directories up to the git root (for git repositories)

your-project/

├── .windsurf/

│ └── rules ← Main configuration

├── src/

│ └── .windsurf/

│ └── rules ← Optional: sub-directory rules

├── tests/

└── package.json

File Format

Pure markdown without frontmatter. No YAML frontmatter. No special directives. Just markdown with optional XML tags for grouping.

Format Guidelines

•12,000 character limit per rules file
•Keep rules simple, concise, and specific
•Use bullet points, numbered lists, and markdown formatting
•Optional XML tags can help group similar rules

Simplicity as Design

Windsurf's minimalism is intentional design, not a limitation.

Advantages of Simplicity

1.Zero Learning Curve: Just write markdown. That's it.
2.No Configuration Overhead: No frontmatter fields, glob syntax, or inclusion modes to learn
3.Universal Compatibility: Renders perfectly on GitHub, works in any markdown editor
4.Git-Friendly: Simple, clear diffs with no frontmatter noise

Trade-offs of Simplicity

•No Conditional Application: All rules apply to entire project, always
•No Metadata: No author, version, tags storage
•No Format-Specific Features: Pure markdown content only

Mitigation: Use section headers to organize by context, store metadata externally (e.g., in prpm.json)

PRPM's Implementation

Windsurf's simplicity means minimal parsing logic. PRPM preserves content as-is with a single instructions section containing the entire file content.

Best Practices

Use Clear Section Headers

Organize by domain/concern rather than file type. Use sections like "Language & Type Safety", "Testing", "Code Quality" rather than a flat list of rules.

Include Context with Rules

Provide rationale for rules. Use the pattern: rule followed by indented *Rationale: explanation*.

Keep It Concise

Write scannable points rather than novel-length rules. Aim for clarity and brevity.

Conclusion

Windsurf's single-file, plain-markdown approach represents simplicity as a feature. PRPM respects this simplicity with minimal parsing, lossless roundtrip for simple content, clear warnings when features are lost, and quality scoring that reflects conversion fidelity.