---
name: ponytail-gain
description: >-
  Show ponytail's measured savings (code, cost, speed) from the benchmark. One-shot display. Use for /ponytail-gain, "what does ponytail save", "ponytail impact".
title: ponytail-gain
canonical_url: https://skilld.dev/gh/dietrichgebert/ponytail/ponytail-gain
last_updated: 2026-10-15T07:02:36.000Z
---

> Index of every page on this site: [llms.txt](https://skilld.dev/llms.txt)

> **Skill from skilld.dev.** Follow the user's requested action.
> If the user asked to fork this Skill, follow the fork workflow below. Do not execute the Skill instructions while copying it.
> Otherwise, follow the instructions below for this session. You do not need to install anything.
>
> If the user asked to install this Skill, run `npx skilld install dietrichgebert/ponytail/ponytail-gain`. Install writes the Skill files into the project, so every session loads them.
>
> ## Fork workflow
>
> A fork creates an editable local Skill with its original author and licence. The request authorizes copying and local installation.
> 1. Check `./skills/ponytail-gain`, the project lockfile, and selected Agent targets together. If the local directory or installed Skill exists, stop. Never overwrite an existing directory or Agent target.
> 2. Read [source metadata](https://skilld.dev/api/v1/skills/dietrichgebert/ponytail/ponytail-gain) once. Use sourceUrl, sourceCommit, skillPath, sourceGone, and license. If the source is gone or its path is missing, stop. If license is null, read licence files at the source commit.
> 3. Fetch only the source commit into a temporary Git repository. Do not clone full history. Derive repository_url from sourceUrl, including repository renames. If sourceCommit is absent, resolve the sourceUrl ref once. Set source_commit to that actual commit. Run these commands in one shell call:
>
> ```sh
> git init --quiet "$temporary_dir"
> git -C "$temporary_dir" fetch --quiet --depth=1 "$repository_url" "$source_commit"
> git -C "$temporary_dir" checkout --quiet --detach FETCH_HEAD
> ```
>
> Read applicable licence declarations and notices at that commit. If copying is not permitted, report the restriction and stop.
> 4. Inspect source entries together, then copy the directory containing skillPath into `./skills/ponytail-gain`. Use the user's path if selected. Keep the original SKILL.md, relative links, scripts, binary assets, and executable modes. Exclude .git metadata. Reject symlinks and paths outside the Skill directory. After checking entries, use cp -a where available. A regular source directory needs no custom copy script. Do not save this page wrapper as SKILL.md.
> Preserve author credit, notices, and applicable licence files from repository or parent directories. Add PROVENANCE.md with the Skill page, source URL, actual commit, original path, and licence. Retain any existing PROVENANCE.md and record new provenance separately. Batch source inspection, copying, and provenance work where practical.
> 5. In the project root, run `skilld install ./skills/ponytail-gain --mode copy --plain`. If skilld is unavailable, use `npx skilld install ./skills/ponytail-gain --mode copy --plain`. This known command needs no help lookup. Install does not support --json. Use detected Agent targets, or add --agent for the targets the user selected. Install the local path, never the upstream selector. If installation fails, preserve the local copy and report the exact failure.
> 6. Confirm the local lockfile source and installed Agent copies once. Report the local path, actual commit, and Agent targets. After edits, reinstall the same local path. Upstream updates must not replace it. Do not publish or push unless the user asks.

# Ponytail Gain

Display this scoreboard when invoked. One-shot: do NOT change mode, write flag
files, or persist anything.

The figures are the published agentic benchmark of Ponytail 5: headless Claude
Code (Opus 5.5, default effort) on 39 tasks (feature tickets in a real FastAPI +
React repo, bug fixes, security and privacy cases, small apps), 5 runs each,
against the same agent without the skill. 18 of the tasks have hidden checks
for correctness and safety. Each figure is the geometric mean of the per-task
medians. They are measured, not computed from the current repo.
Source: `benchmarks/results/2026-10-07-agentic.md` and the README.

## Scoreboard

Render plain ASCII bars. The bar length shows ponytail as a share of the
no-skill baseline; the label carries the exact figure:

```
  ponytail gain           benchmark · 39 tasks × 5 runs · Opus 5.5

  no-skill        ████████████████████  100%
  Lines of code   █████████···········   47%   ▼ 53%
  Output tokens   ███████████·········   55%   ▼ 45%
  Cost            ███████████████·····   74%   ▼ 26%
  Time            ████████████········   59%   ▼ 41%
  Hidden checks passed   97%  (no-skill 96%)
  Tests where the logic needs one   98%  (no-skill 68%)

  This repo:  /ponytail-debt  (shortcuts you deferred)
              /ponytail-audit (what's still cuttable)
```

## Honesty boundary

These are benchmark averages, not this repo. NEVER print a per-repo savings
number ("you saved X lines/tokens here"): the unbuilt version was never
written, so there is no real baseline to subtract from in a live repo. The
only real per-repo figures come from `/ponytail-debt` (a counted ledger), and
this card points there instead of inventing one.

## Boundaries

One-shot display. Edits nothing, changes no mode.