How Ponytail Rules Are Adapted for Cursor, Windsurf, and Other AI Agents

Ponytail adapts its core rule set for specific AI agents by shipping pre-configured rule files in agent-specific directories—simply copy .cursor/rules/ponytail.mdc for Cursor or .windsurf/rules/ponytail.md for Windsurf to activate the guidelines.

The Ponytail project (DietrichGebert/ponytail) maintains a standardized set of coding guidelines that must be adapted to the unique configuration formats of different AI coding agents. Rather than requiring users to manually translate rules, the repository provides agent-specific rule files that map the core Ponytail policy to each tool's expected location and syntax.

Core Rule Architecture

The source of truth for all agent adaptations resides in .agents/rules/ponytail.md at the repository root. This file contains the canonical rule set written in Markdown-compatible syntax.

According to the DietrichGebert/ponytail source code, agent-specific directories contain copies or reformatted versions of this core file. This architecture ensures consistency across platforms while respecting each agent's unique file path and extension requirements.

Agent-Specific Rule Locations

Different agents expect rule files in specific locations with specific extensions. Ponytail accommodates these requirements through dedicated directories.

Cursor Integration

Cursor loads always-on project rules from the .cursor/rules/ directory. Ponytail provides .cursor/rules/ponytail.mdc, which contains the same guidelines as the core file but uses the .mdc extension required by Cursor's rule engine.

When placed in the user's ~/.cursor/rules/ directory or the project's .cursor/rules/ directory, Cursor automatically ingests these instructions on startup and enforces them during coding sessions.

Windsurf Configuration

Windsurf expects rule files at /.windsurf/rules/. The repository includes .windsurf/rules/ponytail.md, which places the canonical rules in Windsurf's expected location.

The file uses standard Markdown format, allowing Windsurf to read and enforce the guidelines without additional configuration or syntax conversion.

Enabling Ponytail for Your Agent

To activate Ponytail rules, copy the appropriate agent-specific file from the repository to your local configuration directory. No code changes or modifications to the rule content are necessary.

Enable for Cursor:

# Copy Cursor-specific rules to global config

cp .cursor/rules/ponytail.mdc ~/.cursor/rules/ponytail.mdc

Enable for Windsurf:

# Copy Windsurf-specific rules to global config

cp .windsurf/rules/ponytail.md ~/.windsurf/rules/ponytail.md

You can also copy these to individual project directories (e.g., ./.cursor/rules/ponytail.mdc) for project-specific enforcement rather than global application.

Disabling or Removing Rules

To deactivate Ponytail guidelines, remove the rule files from the agent's configuration directory:

# Remove Cursor rules

rm ~/.cursor/rules/ponytail.mdc

# Remove Windsurf rules

rm ~/.windsurf/rules/ponytail.md

The agents will stop loading these rules on the next startup.

Configuration File Reference

The following files control how Ponytail rules are mapped to specific agents:

• .agents/rules/ponytail.md — Core rule set (source of truth)
• .cursor/rules/ponytail.mdc — Cursor-compatible rule file with .mdc extension
• .windsurf/rules/ponytail.md — Windsurf-compatible rule file
• docs/agent-portability.md — Documentation mapping agents to file paths and formats
• README.md — High-level integration instructions for all supported agents

Summary

• Ponytail maintains a canonical rule set in .agents/rules/ponytail.md that serves as the source of truth for all agent adaptations.
• Cursor uses .cursor/rules/ponytail.mdc, which must be copied to ~/.cursor/rules/ or your project directory to enable always-on guidance.
• Windsurf reads rules from .windsurf/rules/ponytail.md, requiring the file to be placed at ~/.windsurf/rules/ or the project root.
• Adaptation requires no code modification—simply copy the pre-configured agent file to the appropriate location.
• The docs/agent-portability.md file provides the complete mapping matrix for all supported agents.

Frequently Asked Questions

Where are the canonical Ponytail rules stored?

The canonical rule set lives in .agents/rules/ponytail.md at the repository root. This file contains the master copy of all guidelines, which is then adapted into agent-specific formats for Cursor, Windsurf, and other supported tools.

Do I need to modify the rule files to use them with different agents?

No modifications are necessary. The repository provides pre-adapted copies in agent-specific directories (such as .cursor/rules/ and .windsurf/rules/) that use the correct file extensions and locations expected by each agent. Simply copy the file to your configuration directory.

How do I disable Ponytail rules after enabling them?

Delete the rule file from your agent's configuration directory. For Cursor, remove ~/.cursor/rules/ponytail.mdc. For Windsurf, remove ~/.windsurf/rules/ponytail.md. The agent will stop loading these rules on the next startup.

Does Ponytail support agents other than Cursor and Windsurf?

Yes. According to the repository's docs/agent-portability.md and README, Ponytail provides adaptations for multiple agents including Cline and others. Each agent receives a rule file placed in its expected configuration directory, following the same copy-and-use workflow described for Cursor and Windsurf.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}