fenix-skills/skills/git-guardrails/SKILL.md

name	description
git-guardrails	Set up git safety guardrails for Claude Code — block dangerous commands (push, reset --hard, clean, branch -D, checkout .) via settings.json deny/ask rules or PreToolUse hooks. Use when user wants to prevent destructive git operations or review their git safety setup.

Git Guardrails for Claude Code

Prevent Claude from executing destructive git commands. Two enforcement strategies available — choose one or combine both.

What Gets Blocked

• git push (all variants including --force)
• git push --force (force push — data loss risk)
• git reset --hard (discards uncommitted work)
• git clean -f / git clean -fd (deletes untracked files)
• git branch -D (force-delete branch)
• git checkout . / git restore . (discards all working changes)
• rm -rf /* / sudo rm (filesystem destruction)

Strategy A: settings.json deny/ask rules (Fénix default)

This is the simpler approach — no scripts needed. Rules go in ~/.claude/settings.json:

{
  "permissions": {
    "deny": [
      "Bash(rm -rf /*)",
      "Bash(sudo rm:*)",
      "Bash(git reset --hard:*)",
      "Bash(git push --force:*)"
    ],
    "ask": [
      "Bash(git push:*)",
      "Bash(git clean:*)",
      "Bash(git branch -D:*)",
      "Bash(git checkout .:*)",
      "Bash(git restore .:*)",
      "Bash(pkill:*)",
      "Bash(kill:*)"
    ]
  }
}

deny = hard block, Claude cannot execute even if asked. ask = Claude must get user confirmation before executing.

When to use

• Simple setups, single machine
• When you want some commands to be confirmable (ask) rather than fully blocked (deny)
• Already configured in ~/.claude/settings.json — just merge the rules

Strategy B: PreToolUse hook script

A shell script that intercepts Bash tool calls and blocks dangerous patterns before execution. More flexible — can use regex, log attempts, etc.

Setup

1. Copy the bundled script:

cp scripts/block-dangerous-git.sh ~/.claude/hooks/block-dangerous-git.sh
chmod +x ~/.claude/hooks/block-dangerous-git.sh

2. Add to ~/.claude/settings.json:

{
  "hooks": {
    "PreToolUse": [
      {
        "matcher": "Bash",
        "hooks": [
          {
            "type": "command",
            "command": "~/.claude/hooks/block-dangerous-git.sh"
          }
        ]
      }
    ]
  }
}

When to use

• When you need regex-based pattern matching
• When you want to log blocked attempts
• When deny/ask rules are too coarse

Verify

Test the hook script:

echo '{"tool_input":{"command":"git push origin main"}}' | ~/.claude/hooks/block-dangerous-git.sh

Should exit code 2 and print BLOCKED to stderr.

Fénix's current setup

Already configured in ~/.claude/settings.json:

• deny: rm -rf /*, sudo rm, git reset --hard, git push --force
• ask: pkill, kill, ssh
• CLAUDE.md: Documents git permissions (read freely, write when asked, destructive = confirm first)

Recommended additions to ask rules

Consider adding these to the ask array if not already present:

• Bash(git clean:*) — prevents accidental deletion of untracked files
• Bash(git branch -D:*) — prevents force-deleting branches
• Bash(git checkout .:*) — prevents discarding all working changes
• Bash(git restore .:*) — same as above, modern syntax

Attribution

Adapted from mattpocock/skills git-guardrails-claude-code.