Git Bash Prevention

Purpose

Prevent direct bash git commands and guide users to use git MCP instead. This skill automatically detects when bash is used for git operations and provides equivalent MCP alternatives, ensuring consistent tool usage and policy compliance.

When to Use

• User attempts git commit, git push, git pull, etc. via bash
• User writes bash script containing git commands
• Claude detects git command in bash execution
• User asks about running git from terminal
• PreToolUse hook detects bash tool with git commands

How to Use This Skill

Step 1: Detect Git Commands in Bash

Monitor for git commands in bash execution:

# Detected patterns:
git commit
git push
git pull
git branch
git merge
git status
git log
git add
git checkout
git reset
git revert
git clean
git restore
[any other git command]

Detection triggers when:

• User calls Bash tool
• Command contains git as a command (any context):
  • Direct: git status
  • Piped: cat file | git apply
  • Chained: cd repo; git push
  • Substituted: $(git status) or `git log`
  • Subshell: (git commit) or { git status; }

Step 2: Classify Command Type

Determine if command is:

Allowed (query-only):

• git status
• git log
• git diff
• git blame
• git show
• git branch -l (list only)

Actionable (requires MCP):

• git add
• git commit
• git push
• git pull
• git merge
• git rebase
• git reset
• git checkout
• git stash
• git branch (create/delete)
• git tag
• git worktree
• Any destructive operation

Forbidden (always block):

• git reset --hard
• git clean -f
• git revert
• git restore (not --staged)
• Operations that risk data loss

Step 3: Provide MCP Alternative

When actionable git command detected:

1. Acknowledge the intent

   Detected: git commit -m "Fix bug"
   

2. Explain why MCP is better

   Git MCP provides:
   - Policy enforcement (commit messages, confirmations)
   - Automatic attribution (Co-Authored-By)
   - Ticket tracking integration
   - Safety checks and validations
   

3. Show MCP equivalent

   Instead of:
   $ git commit -m "Fix bug"
   
   Use git MCP:
   > Call Bash tool? No, use Git MCP tool instead
   

4. Execute via MCP (if appropriate)

   Using git MCP commit tool with:
   - Message: "Fix bug"
   - Apply policies
   - Enforce format rules
   

Step 4: Handle Special Cases

Case 1: Git config commands

git config user.name "Name"

Action: Suggest configuring via project setup instead of bash

Case 2: Piped git commands

echo "message" | git commit -F -

Action: Use git MCP directly, avoid pipes

Case 3: Git in scripts

#!/bin/bash
git commit -m "Auto commit"

Action: Convert script to use git MCP or execute commands directly

Case 4: Complex git workflows

git log --oneline | grep "feat:" | head -5

Action: Use git MCP query tools directly

Enforcement Strategy

Level 1: Warning (Informational)

For query-only commands (status, log, diff):

ℹ️  Using bash for git queries
You can use git MCP for better integration:
  $ git-mcp status (Shows formatted output)

Action: Suggest but allow

Level 2: Guidance (Actionable)

For actionable commands (commit, push, branch):

⚠️  Bash git command detected: git commit
This bypasses:
  - Commit confirmation checks
  - Message format validation
  - Automatic attribution
  - Policy enforcement

Use git MCP instead for:
  - Safety checks
  - Policy compliance
  - Automatic formatting

Action: Redirect to MCP, don't execute bash

Level 3: Block (Destructive)

For forbidden operations (reset --hard, clean -f, revert):

❌ Destructive git operation blocked: git reset --hard

This command is forbidden because:
  - Irreversible data loss risk
  - No recovery mechanism
  - Destructive operations not supported

Use git MCP safely or alternative approach.

Action: Block execution entirely, no override available

MCP Tool Mapping

Common git commands mapped to MCP equivalents:

Bash Command	MCP Tool	Notes
git status	query status	Query only
git log	query log	Query only
git diff	query diff	Query only
git commit	execute commit	Applies policies
git add	execute stage	Applies policy checks
git push	execute push	Requires confirmation
git pull	execute pull	Updates working tree
git branch	execute branch	Create/delete
git checkout	execute checkout	Switch branch
git stash	execute stash	Temporary storage
git tag	execute tag	Create/delete tags
git reset --hard	BLOCKED	Destructive
git clean -f	BLOCKED	Destructive

Implementation via Hook

This skill is typically triggered by PreToolUse hook:

Event: PreToolUse
Condition: tool === "Bash" AND command contains "git "
Action: Invoke git-bash-prevention skill

Hook can:

1. Detect git command in bash
2. Load this skill
3. Check command type
4. Allow/warn/block
5. Provide MCP alternative

User Guidance

For Query Operations

You're running: git log --oneline

This works fine in bash! If you want:
  • Formatted output: Use git MCP
  • Integration with workflow: Use git MCP
  • Otherwise: This bash command is OK

For Actionable Operations

You're running: git commit -m "Fix bug"

⚠️  This bypasses git policies!

Better approach:
  1. Use git MCP commit tool
  2. Policies enforced automatically
  3. Message validated
  4. Attribution added

Should I use git MCP instead? (Yes/No)

For Forbidden Operations

You're running: git reset --hard origin/main

❌ This is blocked!

Reason: Irreversible data loss risk - not supported

Your options:
  1. Use git MCP safe alternatives
  2. Use git revert (creates new commit)
  3. Contact team lead for override

Additional Resources

Reference Files

For detailed bash prevention rules:

• references/git-bash-rules.md - Complete bash git detection patterns