/project-setup

Your Task

Bootstrap jj (Jujutsu) workflow enforcement for the current project. This sets up a SessionStart hook, a PreToolUse guard hook, permissions, and CLAUDE.md instructions so that every Claude Code session in this project uses jj properly.

CRITICAL: This is a jj (Jujutsu) plugin. You MUST NOT use ANY raw git commands — not even for context discovery. Always use jj equivalents. The only exceptions are jj git subcommands and gh CLI.

Steps

Step 1: Detect context

1. Verify this is a jj repo by running jj root. If it fails, tell the user this command requires a jj repository and stop.
2. Find the plugin's templates/scripts directory. Look for the directory containing this command file — it will be something like ~/.claude/plugins/cache/muloka-claude-plugins/project-setup-jj/<hash>/. The templates are in templates/ and scripts in scripts/ relative to the plugin root.
3. Determine the project root using jj root.
4. Ensure .claude/ and .claude/scripts/ directories exist in the project root:

   mkdir -p "$(jj root)/.claude/scripts"
   

Step 2: Copy SessionStart hook script

Copy jj-session-start.sh from the plugin's scripts/ directory to the project's .claude/scripts/:

cp <plugin-scripts-dir>/jj-session-start.sh "$(jj root)/.claude/scripts/"
chmod +x "$(jj root)/.claude/scripts/jj-session-start.sh"

Step 3: Update .claude/settings.local.json

Read the current .claude/settings.local.json (may not exist). Deep-merge the following configuration using jq, preserving all existing keys and deduplicating entries:

SessionStart hook:

{
  "hooks": {
    "SessionStart": [
      {
        "matcher": "startup|resume|clear|compact",
        "hooks": [
          {
            "type": "command",
            "command": "<project-root>/.claude/scripts/jj-session-start.sh",
            "async": false
          }
        ]
      }
    ]
  }
}

Permissions:

{
  "permissions": {
    "allow": [
      "Bash(jj status*)", "Bash(jj diff*)", "Bash(jj log*)",
      "Bash(jj new*)", "Bash(jj commit*)", "Bash(jj describe*)",
      "Bash(jj bookmark*)", "Bash(jj git push*)", "Bash(jj git fetch*)",
      "Bash(jj rebase*)", "Bash(jj squash*)", "Bash(jj edit*)",
      "Bash(jj abandon*)", "Bash(jj undo*)", "Bash(jj op log*)",
      "Bash(jj resolve*)", "Bash(jj root*)", "Bash(jj file*)",
      "Bash(jj split*)", "Bash(jj config*)", "Bash(jj git remote*)",
      "Bash(gh *)"
    ],
    "deny": ["Bash(git *)"]
  }
}

Replace <project-root> with the actual absolute path from jj root.

Merge strategy: Use jq to deep-merge. For array fields (allow, deny, hook arrays), concatenate and deduplicate. For object fields, merge recursively. Preserve any existing settings not related to jj.

Step 4: Copy require-jj-new hook script

Copy require-jj-new.sh from the plugin's scripts/ directory to the project's .claude/scripts/:

cp <plugin-scripts-dir>/require-jj-new.sh "$(jj root)/.claude/scripts/"
chmod +x "$(jj root)/.claude/scripts/require-jj-new.sh"

Then merge a PreToolUse hook entry into .claude/settings.local.json (using the same deep-merge strategy as Step 3):

{
  "hooks": {
    "PreToolUse": [
      {
        "matcher": "Edit|Write|NotebookEdit",
        "hooks": [
          {
            "type": "command",
            "command": "<project-root>/.claude/scripts/require-jj-new.sh"
          }
        ]
      }
    ]
  }
}

Replace <project-root> with the actual absolute path from jj root.

Step 5: Copy workspace hook scripts

Copy workspace scripts from the plugin's scripts/ directory to the project's .claude/scripts/:

cp <plugin-scripts-dir>/jj-workspace-create.sh "$(jj root)/.claude/scripts/"
cp <plugin-scripts-dir>/jj-workspace-remove.sh "$(jj root)/.claude/scripts/"
chmod +x "$(jj root)/.claude/scripts/jj-workspace-create.sh"
chmod +x "$(jj root)/.claude/scripts/jj-workspace-remove.sh"

Then merge WorktreeCreate and WorktreeRemove hook entries into .claude/settings.local.json (using the same deep-merge strategy as Steps 3 and 4):

{
  "hooks": {
    "WorktreeCreate": [
      {
        "hooks": [
          {
            "type": "command",
            "command": "<project-root>/.claude/scripts/jj-workspace-create.sh"
          }
        ]
      }
    ],
    "WorktreeRemove": [
      {
        "hooks": [
          {
            "type": "command",
            "command": "<project-root>/.claude/scripts/jj-workspace-remove.sh"
          }
        ]
      }
    ]
  }
}

Replace <project-root> with the actual absolute path from jj root.

Step 6: Create or update CLAUDE.md

Read the CLAUDE.md template from the plugin's templates/CLAUDE.md.template. The template includes a content hash in its start marker (<!-- jj-project-setup:start hash:<hex> -->) for version tracking. It uses an ## VCS heading (h2) so it fits naturally into any existing CLAUDE.md heading hierarchy.

Then handle four cases:

1. No CLAUDE.md exists: Create it from the template.
2. CLAUDE.md exists with <!-- jj-project-setup:start hash:<hex> --> marker: Extract the hash from the installed marker and compare it to the hash in the template. If they match, the section is up to date — skip (report "CLAUDE.md already up to date"). If they differ, replace the section between the start and <!-- jj-project-setup:end --> markers (inclusive) with the template content.
3. CLAUDE.md exists with <!-- jj-project-setup:start --> (no hash — legacy): Replace the section between markers with the template content (upgrades to the hashed format).
4. CLAUDE.md exists without any marker: Prepend the template content followed by a blank line, preserving all existing content.

The CLAUDE.md file is at the project root (from jj root).

Step 7: Confirm to user

Show a summary of what was set up:

• SessionStart hook script copied to .claude/scripts/jj-session-start.sh
• PreToolUse guard hook copied to .claude/scripts/require-jj-new.sh
• WorktreeCreate hook script copied to .claude/scripts/jj-workspace-create.sh
• WorktreeRemove hook script copied to .claude/scripts/jj-workspace-remove.sh
• Settings updated in .claude/settings.local.json (SessionStart + PreToolUse + WorktreeCreate + WorktreeRemove hooks + permissions)
• CLAUDE.md created/updated with jj workflow instructions (or "already up to date" if hash matches)

Remind the user to:

• Restart Claude Code for the hooks to take effect
• Optionally add .claude/scripts/ to their ignore patterns if they don't want to track these in version control