ponytail
Ruleset that makes AI coding agents write the least code that works
ponytail is a ruleset for AI coding agents that pushes them to write the smallest working change. Version 5 is a rebuild, and its benchmark claims 53 percent less code, 41 percent faster runs, 26 percent lower cost, and 45 percent fewer tokens. It also requires a test for 98 percent of risky logic, according to the site.
Use it to stop an agent from over-building simple changes. Check the benchmark against your own tasks, because results vary by codebase.
Why it is here. It encodes restraint as rules an agent follows.
- Least code that works
- Benchmarked
- Version 5
Verified 2026-10-09. HTTP 200. https://ponytail.dev/ (HTTP 200, page fetched 2026-10-09), https://github.com/DietrichGebert/ponytail (GitHub API, 158492 stars), depo.zip listing https://www.depo.zip/tools/j578770nghjy4xbtsj1c51mzyx8da7pa
