git-guardrails

Setup Git Guardrails

Sets up guards that intercept and block dangerous git commands before they execute.

What Gets Blocked

• git push (all variants including --force)
• git reset --hard
• git clean -f / git clean -fd
• git branch -D
• git checkout . / git restore .

When blocked, the agent sees a message telling it that it does not have authority to access these commands.

Steps

1. Ask platform

Ask the user: which platform are you using — Claude Code or opencode?

2. Ask scope

Ask the user: install for this project only or all projects?

Scope paths per platform:

	Project	Global
Claude Code	.claude/settings.json	~/.claude/settings.json
opencode	./opencode.json	~/.config/opencode/opencode.json

3. Claude Code setup

3a. Copy the hook script

The bundled script is at: scripts/block-dangerous-git.sh

Copy it to the target location based on scope:

• Project: .claude/hooks/block-dangerous-git.sh
• Global: ~/.claude/hooks/block-dangerous-git.sh

Make it executable with chmod +x.

3b. Add hook to settings

Add to the appropriate settings file:

Project (.claude/settings.json):

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

Global (~/.claude/settings.json):

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

If the settings file already exists, merge the hook into existing hooks.PreToolUse array — don't overwrite other settings.

3c. Verify

Run a quick test:

echo '{"tool_input":{"command":"git push origin main"}}' | <path-to-script>

Should exit with code 2 and print a BLOCKED message to stderr.

4. opencode setup

4a. Add permission rules

Add the following to the appropriate config file (project opencode.json or global ~/.config/opencode/opencode.json):

{
  "permission": {
    "bash": {
      "*": "ask",
      "git push": "deny",
      "git push *": "deny",
      "git reset --hard *": "deny",
      "git clean -f*": "deny",
      "git clean -fd*": "deny",
      "git branch -D *": "deny",
      "git checkout .": "deny",
      "git restore .": "deny"
    }
  }
}

Important: opencode evaluates the LAST matching rule. The broad catch-all ("*": "ask") must come first, and the specific deny rules must come last. If the catch-all were last, it would override all deny rules.

If the config file already exists, merge the permission.bash rules into the existing config. Prepend any new deny rules before the existing catch-all (if present), keeping the catch-all as the first entry.

4b. Remind user to restart

opencode loads config once at startup. Tell the user to quit and restart opencode for the changes to take effect.

5. Ask about customization

Ask if the user wants to add or remove any patterns from the blocked list.

For Claude Code: edit the copied block-dangerous-git.sh script. For opencode: add or remove entries from the permission.bash rules in opencode.json.