Git MCP Assistant Tool

A production-ready Git MCP tool for Kamiwaza that exposes Git operations through FastMCP/HTTP transport. Enables AI models to perform comprehensive Git repository management including cloning, file operations, branching, committing, and pushing changes.

Features

File Operations (4 tools)

• clone_repository - Clone repositories into isolated workspace
• read_file - Read file contents from repository
• write_file - Write content to files with automatic directory creation
• list_files - List files and directories (with recursive option)

Git Status & Inspection (4 tools)

• git_status - Get working tree status (branch, modified, staged, untracked)
• git_diff_unstaged - View unstaged changes with context
• git_diff_staged - View staged changes with context
• git_log - Get commit history with configurable depth

Git Write Operations (5 tools)

• git_add - Stage specific files for commit
• create_branch - Create new branches from base branch
• commit_changes - Stage and commit changes with message
• git_checkout - Switch between branches
• push_changes - Push commits to remote repositories

Security Model

Workspace Isolation

• All operations scoped to /app/workspace container directory
• Path traversal prevention with multiple validation layers
• No access to files outside workspace boundaries

Input Validation

• URLs: Only https:// and git:// protocols allowed
• Git References: Alphanumeric, dots, underscores, slashes, hyphens only
• Branch Names: Additional validation (no leading hyphen, no .lock suffix)
• File Paths: Relative paths within repository, no ../ allowed
• Shell Safety: Blocks all shell metacharacters (;&| `$(){}[]<>`)

Container Security

• Runs as non-root user (appuser)
• Named volume (no host bind mounts)
• Resource limits: 2 CPU, 2G memory
• Health checks every 30 seconds

Installation

Prerequisites

• Docker and Docker Compose
• Git (installed in container)
• Python 3.11+ (for development)

Build and Run

# Build the Docker image
cd tools/tool-git-mcp
docker-compose build

# Start the service
docker-compose up -d

# Check health
curl http://localhost:8000/health

Using Kamiwaza Build System

# Build using Kamiwaza tooling
make build TYPE=tool NAME=tool-git-mcp

# Sync App Garden compose files
make sync-compose

# Validate configuration
make validate

# Run tests
make test TYPE=tool NAME=tool-git-mcp

Configuration

Environment Variables

Custom Configuration

Create a .env file:

GIT_AUTHOR_NAME=Your Name
GIT_AUTHOR_EMAIL=your.email@example.com

Usage Examples

Clone Repository

{
  "tool": "clone_repository",
  "arguments": {
    "url": "https://github.com/username/repo.git",
    "path": "my-repo",
    "branch": "main"
  }
}

Response:

{
  "success": true,
  "repo_path": "my-repo",
  "branch": "main",
  "commit": "a1b2c3d4"
}

Read File

{
  "tool": "read_file",
  "arguments": {
    "repo_path": "my-repo",
    "file_path": "README.md"
  }
}

Response:

{
  "success": true,
  "content": "# Project Title\n...",
  "path": "README.md"
}

Write File

{
  "tool": "write_file",
  "arguments": {
    "repo_path": "my-repo",
    "file_path": "src/main.py",
    "content": "print('Hello, World!')"
  }
}

Response:

{
  "success": true,
  "path": "src/main.py",
  "bytes": 22
}

Check Status

{
  "tool": "git_status",
  "arguments": {
    "repo_path": "my-repo"
  }
}

Response:

{
  "success": true,
  "branch": "main",
  "commit": "a1b2c3d4",
  "modified": ["src/main.py"],
  "staged": [],
  "untracked": ["new-file.txt"]
}

Create Branch

{
  "tool": "create_branch",
  "arguments": {
    "repo_path": "my-repo",
    "branch_name": "feature-xyz",
    "base_branch": "main"
  }
}

Commit Changes

{
  "tool": "commit_changes",
  "arguments": {
    "repo_path": "my-repo",
    "message": "Add new feature",
    "files": ["src/main.py", "src/utils.py"]
  }
}

Response:

{
  "success": true,
  "commit": "b2c3d4e5",
  "message": "Add new feature",
  "branch": "feature-xyz"
}

Push Changes

{
  "tool": "push_changes",
  "arguments": {
    "repo_path": "my-repo",
    "remote": "origin",
    "branch": "feature-xyz"
  }
}

MCP Protocol

Endpoint

• Base URL: http://localhost:8000
• MCP Path: /mcp
• Health Check: /health

Request Format

POST /mcp HTTP/1.1
Content-Type: application/json

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "clone_repository",
    "arguments": {
      "url": "https://github.com/example/repo.git"
    }
  }
}

Response Format

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "success": true,
    "repo_path": "repo",
    "branch": "main",
    "commit": "a1b2c3d4"
  }
}

Testing

Run Tests

# Install dependencies
pip install -r requirements.txt

# Run all tests
pytest tests/ -v

# Run specific test file
pytest tests/test_security.py -v

# Run with coverage
pytest tests/ --cov=src/tool_git_mcp --cov-report=html

Test Categories

• Security Tests (tests/test_security.py) - Path traversal, injection prevention
• Git Operations Tests (tests/test_git_operations.py) - All 13 Git operations
• Server Tests (tests/test_server.py) - Health check, tool registration

Known Limitations

1. No SSH Authentication - Only HTTPS cloning supported (SSH planned for future)
2. Single Workspace - One workspace per container instance
3. No Concurrent Operations - No locking for parallel Git operations
4. ASCII/UTF-8 Files Only - Binary files not supported for read/write operations
5. No Interactive Operations - No merge conflict resolution or interactive rebases
6. No Git Hooks - Hooks are not executed (security feature)

Architecture

tool-git-mcp/
├── src/tool_git_mcp/
│   ├── __init__.py          # Package initialization
│   ├── server.py            # FastMCP server with 13 tools
│   ├── security.py          # SecurityManager for validation
│   └── git_operations.py    # GitOperations wrapper
├── tests/
│   ├── test_server.py       # Server and registration tests
│   ├── test_security.py     # Security validation tests
│   └── test_git_operations.py  # Git operation tests
├── Dockerfile               # Container with git + Python
├── docker-compose.yml       # Local development setup
├── requirements.txt         # Python dependencies
├── kamiwaza.json           # Tool metadata
└── README.md               # This file

Security Guarantees

1. ✅ Workspace Isolation - All operations within /app/workspace
2. ✅ Path Traversal Prevention - Multiple validation layers
3. ✅ Command Injection Prevention - Regex validation + GitPython parameterization
4. ✅ Protocol Whitelist - Only HTTPS and git:// allowed
5. ✅ Non-Root Container - Runs as appuser
6. ✅ Structured Errors - No sensitive path leakage

Troubleshooting

Container Won't Start

# Check logs
docker-compose logs tool-git-mcp

# Verify health check
docker-compose ps

Tool Registration Issues

# Access MCP endpoint directly
curl http://localhost:8000/mcp

# Check tool list
curl -X POST http://localhost:8000/mcp \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}'

Permission Errors

Ensure the workspace volume has correct permissions:

docker-compose exec tool-git-mcp ls -la /app/workspace

Git Authentication

For private repositories, use HTTPS URLs with tokens:

https://username:token@github.com/owner/repo.git

Contributing

1. Follow the security model strictly
2. Add tests for all new operations
3. Validate against the security test suite
4. Update documentation for new features

License

MIT License - See LICENSE file for details

Support

For issues and questions:

• GitHub Issues: kamiwaza-extensions
• Documentation: Kamiwaza Docs