jj

claude-plugin-jj

English | 日本語

A Claude Code plugin that helps users work with jj (Jujutsu VCS) managed projects.

Design Philosophy

3-Layer Architecture

Hook (Protection) → Skill (Guide) → Agent (Expert) provides progressive support.

Layer	Component	Role
Hook	jj-guard	Blocks Git command misuse before execution
Skill	jj-guide	Basic knowledge and daily operation reference
Agent	jj-expert	Agent with comprehensive advanced knowledge

Benefits of Integrated Plugin

The hook, skill, and agent are designed to work together, enabling each component to rely on the others.

• jj-guard deny messages are minimal — Instead of cramming command-specific alternatives into messages, it simply guides users to the skill. This centralizes information and reduces maintenance costs.
• jj-expert is an agent with more comprehensive jj knowledge — Provides expert assistance for advanced operations and troubleshooting.

Components

jj-guard Hook (PreToolUse)

Detects and blocks git command execution in jj-managed projects (where .jj directory exists). It's a guard for awareness, not absolute prohibition.

• Allows jj-mediated git operations like jj git push
• On denial, directs users to the skill for specific guidance
• Operations that can only be done with git (submodule, lfs, etc.) can be easily bypassed with :;git (intentional design)

jj-guide Skill

Provides basic jj concepts, Git→jj mapping table, and daily operation reference. Also serves as knowledge supplement when commands are denied.

jj-expert Agent

An agent with more comprehensive jj knowledge. Activated for complex inquiries and troubleshooting.

Installation

claude plugin marketplace add kawaz/claude-plugin-jj
claude plugin install jj@claude-plugin-jj

Usage

Once installed, the plugin automatically:

1. Prevents accidental git commands in jj repositories (via jj-guard hook)
2. Provides jj command references when needed (via jj-guide skill)
3. Offers expert assistance for advanced jj operations (via jj-expert agent)

Troubleshooting

When you need to run git commands

If you need to use Git features not yet supported by jj (submodules, lfs, etc.), use the :;git prefix:

:;git submodule update --init
:;git lfs pull

jj-guide skill not found

You can explicitly invoke the skill in Claude Code by typing jj:jj-guide.

License

MIT