A tool for managing Git hooks, which are commands that run during actions such as committing or pushing code. Lefthook supports hooks such as pre-commit and commit-message checks, including parallel execution and file filters.

Use it to configure formatting, tests, linting, commit-message validation, staged-file checks, and related Git workflow commands, including in CI.

It makes repository checks repeatable for the whole team and can run several checks efficiently before changes are committed or pushed.

lefthook — Skill for Claude Code by Fandhe-AI

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent

npx skills add Fandhe-AI/agent-reference-skills --skill lefthook

Clone the repo

git clone --depth 1 https://github.com/Fandhe-AI/agent-reference-skills

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/fandhe-ai/agent-reference-skills/lefthook/github.svg)](https://agentmods.dev/skills/fandhe-ai/agent-reference-skills/lefthook)

Your own site

<a href="https://agentmods.dev/skills/fandhe-ai/agent-reference-skills/lefthook"><img src="https://agentmods.dev/badge/skills/fandhe-ai/agent-reference-skills/lefthook/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/fandhe-ai/agent-reference-skills/lefthook"><img src="https://agentmods.dev/badge/skills/fandhe-ai/agent-reference-skills/lefthook.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 84 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,122 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits

Socket pass 10 May 2026
Snyk warn 10 May 2026

How audits are shown

Origin unknown No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00084	$0.01122
Opus 5	$0.00042	$0.00561
Sonnet 5	$0.00017	$0.00224
Haiku 4.5	$0.00008	$0.00112

Measured 9d ago against content hash 03dd38ebe19a, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

lefthook scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/lefthook/SKILL.md · 109 lines

The source is not reproduced here

No licence file

Read it on GitHub

Files

What ships with it

50 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

9d ago First seen · 109 lines · 84 tokens per session scan A 03dd38ebe19a

Subscribe to this mod's changes

lefthook is a skill published in the GitHub repository Fandhe-AI/agent-reference-skills (3 stars, last pushed yesterday), with no licence file. It adds 84 tokens to every session and 1,122 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

Commits Git and workflow Testing

github-copilot-upgrader

Use this to update the Github Copilot CLI/SDK.

microsoft/vscode · 18 tokens

workflow-patterns

Use this skill when implementing tasks according to Conductor's TDD workflow, handling phase checkpoints, managing git commits for tasks, or understanding the verification protocol.

wshobson/agents · 35 tokens

meta-pre-commit-quality-gate

Run three quality gates (ruff + mypy + pytest) in parallel over the staged diff, then arbitrate a single BLOCK/APPROVE verdict. Use before committing changes locally when you want a comprehensive pre-commit gate beyond per-file linting — exactly the same gate set CI enforces.

opensquilla/opensquilla · 68 tokens

lefthook