head to head · open source
ponytail vs agent-rules-books
ponytail has 141,465 GitHub stars, 7,581 forks, 270 open issues and last shipped 5 days ago. agent-rules-books has 2,816 stars, 499 forks, 5 open issues and last shipped 9 days ago. ponytail leads on adoption by 4,924% (141,465 vs 2,816 stars). ponytail is written in JavaScript under MIT; agent-rules-books is written in various languages under MIT. ponytail has attracted 5% as many forks as stars, agent-rules-books 18%. ponytail was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 3 topic tags (agent-skills, claude-code, cursor-rules), so they are genuine substitutes rather than adjacent tools.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| ponytail | agent-rules-books | |
|---|---|---|
| GitHub stars | ★ 141K | ★ 2.8K |
| License | MIT | MIT |
| Written in | JavaScript | — |
| Last push | 2026-09-14 | 2026-09-10 |
| Forks | ⑂ 7.6K | ⑂ 499 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick ponytail if
- You weight community size — 141K stars and counting
- You want the MIT license terms
- Your stack matches JavaScript
- You value the larger contributor base for long-term maintenance
pick agent-rules-books if
- You want the agent-rules-books feature set and don't need the biggest community
- You prefer the MIT license terms
- You evaluated both and agent-rules-books fits your workflow better
About ponytail
Ponytail is an open source agent skill for JavaScript and LLM based coding tools that makes an AI agent write the minimum working code for a task, and it is built for developers and teams running agents such as Claude Code, Codex, or Cursor against real repositories.
read the full ponytail overview →
About agent-rules-books
agent rules books is an MIT licensed, tool agnostic collection of AGENTS.md rules and agent skills, distilled from classic software engineering books, that installs into AI coding agents such as Codex, Cursor and Claude Code to steer them toward better refactoring, architecture, domain driven design and code quality.
read the full agent-rules-books overview →
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Frequently asked questions
Is ponytail or agent-rules-books more popular?
ponytail has 141,465 GitHub stars and agent-rules-books has 2,816. ponytail has the larger community by that measure.
Are ponytail and agent-rules-books free?
Both are open source. ponytail is licensed under MIT and agent-rules-books under MIT. Neither carries a licence fee.
What is the difference between ponytail and agent-rules-books?
ponytail is written in JavaScript and agent-rules-books in various languages. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, ponytail or agent-rules-books?
Choose ponytail if you want the larger community (141,465 stars) or its MIT licence terms. Choose agent-rules-books if its feature set, stack or MIT licence fits better. Both are self-hostable.