Ponytail Lazy Developer Mode
DietrichGebert/ponytail
Makes the agent pick the laziest solution that works: skip unneeded work, reuse what exists, prefer the standard library and platform features, and keep diffs small.
Review a branch or PR's diff against main and report opportunities to subtract — simplify, delete, and reduce the number of concepts a reader has to hold in their head.
Install Lean Review
$ npx skills add geanlabs/gean --skill lean-review -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install geanlabs/gean lean-review --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/geanlabs/gean.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.agents/skills/lean-review .claude/skills/lean-review && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "lean-review" agent skill from https://github.com/geanlabs/gean/tree/main/.agents/skills/lean-review into .claude/skills/lean-review/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "lean-review", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/geanlabs/gean/tree/main/.agents/skills/lean-reviewType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add geanlabs/gean --skill lean-review -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install geanlabs/gean lean-review --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/geanlabs/gean.git skills-src && mkdir -p .agents/skills && cp -r skills-src/.agents/skills/lean-review .agents/skills/lean-review && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "lean-review" agent skill from https://github.com/geanlabs/gean/tree/main/.agents/skills/lean-review into .agents/skills/lean-review/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "lean-review", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add geanlabs/gean --skill lean-review -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install geanlabs/gean lean-review --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/geanlabs/gean.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/.agents/skills/lean-review .cursor/skills/lean-review && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "lean-review" agent skill from https://github.com/geanlabs/gean/tree/main/.agents/skills/lean-review into .cursor/skills/lean-review/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "lean-review", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/geanlabs/gean.git --path .agents/skills/lean-review--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add geanlabs/gean --skill lean-review -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install geanlabs/gean lean-review --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/geanlabs/gean.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/.agents/skills/lean-review .gemini/skills/lean-review && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "lean-review" agent skill from https://github.com/geanlabs/gean/tree/main/.agents/skills/lean-review into .gemini/skills/lean-review/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "lean-review", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install geanlabs/gean lean-reviewInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add geanlabs/gean --skill lean-review -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/geanlabs/gean.git skills-src && mkdir -p .github/skills && cp -r skills-src/.agents/skills/lean-review .github/skills/lean-review && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "lean-review" agent skill from https://github.com/geanlabs/gean/tree/main/.agents/skills/lean-review into .github/skills/lean-review/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "lean-review", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add geanlabs/gean --skill lean-review -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install geanlabs/gean lean-review --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/geanlabs/gean.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/.agents/skills/lean-review .opencode/skills/lean-review && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "lean-review" agent skill from https://github.com/geanlabs/gean/tree/main/.agents/skills/lean-review into .opencode/skills/lean-review/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "lean-review", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
lean-review- GitHub stars
- 177
- Token cost
- ~1.5k tokens
- SKILL.md length
- 666 words
- Files
- 5 (incl. scripts, references)
- Skills in repo
- 2
- Repo updated
- First seen
- Licence
- None found
At a glance
Review a branch or PR's diff against main and report opportunities to subtract — simplify, delete, and reduce the number of concepts a reader has to hold in their head.
- Works in 5 steps: Collect the scope → Drop don't-touch paths → Classify each addition → …
- Review a branch before merge for bloat
- SKILL.md covers Rules, Workflow, Fix mode and Out of scope, plus 1 more section
- Runs Shell scripts from its folder; calls make and go
What it does
Lean Review is an agent skill from geanlabs/gean. Review a branch or PR's diff against main and report opportunities to subtract — simplify, delete, and reduce the number of concepts a reader has to hold in their head. Use when users want to (1) review a branch before merge for bloat, (2) find dead code or premature abstractions, (3) identify duplication of existing utilities, (4) audit AI-generated code for over-engineering, or (5) reduce LOC without changing behavior. Report-only by default; only applies fixes when the user explicitly says so.
Its SKILL.md is about 1.5k tokens, which your agent loads only when the skill is triggered. The skill folder holds 6 other files, including scripts and reference files (for example `references/dont-touch.md`, `references/finding-categories.md` and `scripts/collect-diff.sh`).
It sits in Development, covering Code simplification. It works with Ethereum and Go. The repository describes itself as: Lean consensus client for Ethereum node operators.
When your agent uses it
- Review a branch before merge for bloat
- Premature abstractions
- Identify duplication of existing utilities
- Audit AI-generated code for over-engineering
Example prompts
- “/lean-review”
Requirements
- A Bash shell
Workflow steps
5 steps, taken from the step headings in SKILL.md.
- Collect the scope
- Drop don't-touch paths
- Classify each addition
- Assign a risk class
- Report
What it can do on your machine
Read from SKILL.md and the folder at commit cb1ed81. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
Ships 2 files in scripts/ (Shell), which the agent can run.
Shell commands in SKILL.md call:
makego
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Lean Review loads about 1.5k tokens when it runs, and up to ~3.3k if it reads all its reference files. Until then it costs about 128 tokens; SKILL.md has 666 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); the scripts in this folder are not scanned.
SKILL.md
Without a licence we can't republish the file, so here is its outline and opening line. It has 666 words (~1,509 tokens).
“Find what can come out of a change before merge: dead code, premature abstractions, defensive filler, duplicated utilities, comment bloat.”
- name
- lean-review
Files
SKILL.md and 4 other files (scripts, references) in .agents/skills/lean-review of geanlabs/gean.
- SKILL.md
- references/dont-touch.md
- references/finding-categories.md
- scripts/collect-diff.sh
- scripts/test-collect-diff.sh
Open the folder on GitHubat commit cb1ed81
Compare with similar skills
Lean Review next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Lean Review this skillgeanlabs/gean | 177 | — | ~1.5k | Automated safety check: Pass | None | |
| Ponytail Lazy Developer ModeDietrichGebert/ponytail | 160k | 1 repos | ~873 | Automated safety check: Pass | MIT | |
| Ponytail Reviewkortix-ai/suna | 20k | 4 repos | ~593 | Automated safety check: Pass | Custom licence | |
| PonytailDavidObando/gsharp | 565 | 7 repos | ~1.7k | Automated safety check: Pass | MIT | |
| Add Redis Command to go-redisredis/go-redis | 22k | — | ~1.4k | Automated safety check: Pass | BSD-2-Clause | |
| Go Pedantrychromedp/chromedp | 13k | — | ~3.7k | Automated safety check: Pass | MIT |
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Categories
Questions about Lean Review
What does Lean Review do?
Review a branch or PR's diff against main and report opportunities to subtract — simplify, delete, and reduce the number of concepts a reader has to hold in their head. Lean Review is an agent skill from geanlabs/gean. Review a branch or PR's diff against main and report opportunities to subtract — simplify, delete, and reduce the number of concepts a reader has to hold in their head.
When should I use Lean Review?
Lean Review fits situations like: review a branch before merge for bloat; premature abstractions; identify duplication of existing utilities; audit AI-generated code for over-engineering.
How do I install Lean Review in Claude Code?
Run `npx skills add geanlabs/gean --skill lean-review -a claude-code`. Or copy the skill folder (.agents/skills/lean-review in geanlabs/gean) into .claude/skills/lean-review in your project. Claude Code loads it when a task matches its description.
How do I install Lean Review in Codex?
Run `npx skills add geanlabs/gean --skill lean-review -a codex`. Or copy the skill folder (.agents/skills/lean-review in geanlabs/gean) into .agents/skills/lean-review in your project. Codex loads it when a task matches its description.
Can I use Lean Review in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add geanlabs/gean --skill lean-review -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/lean-review, .gemini/skills/lean-review, .github/skills/lean-review and .opencode/skills/lean-review in your project.
What does Lean Review need to run?
Going by SKILL.md and its folder, Lean Review needs a shell for the scripts in its folder and the command-line tools its instructions call (make and go). Our summary lists: A Bash shell.
Does Lean Review access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is Lean Review safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. The check reads SKILL.md only: the scripts in the folder are not scanned, so read them before running anything.
What licence does Lean Review use?
No licence was found for Lean Review or its repository. Without one, default copyright applies: ask the author before reusing or redistributing it.
How many tokens does Lean Review use?
About 1.5k tokens (SKILL.md is roughly 6k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 1.8k tokens, read only when the agent opens those files.
What are the alternatives to Lean Review?
Skills that share tags, products or a category with Lean Review: Ponytail Lazy Developer Mode (DietrichGebert/ponytail, 160k stars), Ponytail Review (kortix-ai/suna, 20k stars), Ponytail (DavidObando/gsharp, 565 stars) and Add Redis Command to go-redis (redis/go-redis, 22k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Lean Review?
geanlabs (a GitHub organization) maintains it in geanlabs/gean, which has 177 GitHub stars. The repository holds 2 skills in this directory. The repository was last updated on October 10, 2026.
Source: geanlabs/gean on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.