# VS Code MCP Environment Variable Configuration Guide
## Current Configuration Analysis
Looking at your `.vscode/mcp.json` file, the current environment variable configuration is as follows:
```json
"env": {
"mcp_name": "ZephyrMcpServer"
}
```
## How to Add Git Authentication Environment Variables
### Method 1: Direct Addition in mcp.json
Modify the `.vscode/mcp.json` file to add Git authentication variables in the `env` section:
```json
{
"name": "Zephyr MCP Server",
"description": "Model Context Protocol server for Zephyr RTOS development workflows",
"version": "1.0.0",
"mcp": {
"servers": {
"zephyr-mcp": {
"command": "python",
"args": ["${workspaceFolder}/src/mcp_server.py"],
"env": {
"mcp_name": "ZephyrMcpServer",
"GIT_USERNAME": "your_git_username",
"GIT_PASSWORD": "your_git_token_or_password"
},
"capabilities": {
// ... other configurations remain unchanged
}
}
}
}
}
```
### Method 2: Using More Secure Methods
#### Option A: Using Environment Variables in VS Code Settings
1. Open VS Code settings (Ctrl+,)
2. Search for `terminal.integrated.env.windows`
3. Add user settings:
```json
{
"terminal.integrated.env.windows": {
"GIT_USERNAME": "your_git_username",
"GIT_PASSWORD": "your_git_token_or_password"
}
}
```
#### Option B: Using System Environment Variables
Set user-level environment variables in Windows system:
```powershell
# Set user environment variables
[Environment]::SetEnvironmentVariable('GIT_USERNAME', 'your_git_username', 'User')
[Environment]::SetEnvironmentVariable('GIT_PASSWORD', 'your_git_token', 'User')
```
#### Option C: Using .env File (Recommended)
1. Create a `.env` file in the project root directory:
```env
# .env file
GIT_USERNAME=your_git_username
GIT_PASSWORD=your_git_token_or_password
MCP_NAME=ZephyrMcpServer
```
2. Modify MCP server code to load the .env file (add at the beginning of mcp_server.py):
```python
import os
from pathlib import Path
# Load .env file
env_path = Path(__file__).parent.parent / '.env'
if env_path.exists():
with open(env_path, 'r') as f:
for line in f:
line = line.strip()
if line and not line.startswith('#') and '=' in line:
key, value = line.split('=', 1)
os.environ[key.strip()] = value.strip()
```
## Configuration Priority
Environment variable priority (from highest to lowest):
1. **Direct parameter passing**: username/token parameters directly provided when calling functions
2. **env settings in mcp.json**: Environment variables set in VS Code MCP configuration
3. **VS Code terminal environment variables**: Environment variables configured in VS Code settings
4. **System environment variables**: Operating system-level environment variables
5. **Default values**: If none of the above are set, use the default value "None"
## Security Best Practices
### 1. Do Not Hardcode Credentials in Code
```json
// ❌ Incorrect approach
"env": {
"GIT_USERNAME": "my_real_username",
"GIT_PASSWORD": "my_real_password123"
}
```
### 2. Use Placeholders and Documentation
```json
// ✅ Correct approach
"env": {
"mcp_name": "ZephyrMcpServer",
"GIT_USERNAME": "${GIT_USERNAME}",
"GIT_PASSWORD": "${GIT_PASSWORD}"
}
```
### 3. Use VS Code's Variable Substitution
VS Code supports several predefined variables:
- `${env:GIT_USERNAME}` - Reference system environment variables
- `${workspaceFolder}` - Workspace folder path
- `${userHome}` - User home directory
### 4. Create Configuration Templates
Create an `mcp.json.template` file:
```json
{
"name": "Zephyr MCP Server",
"env": {
"mcp_name": "ZephyrMcpServer",
"GIT_USERNAME": "YOUR_GIT_USERNAME_HERE",
"GIT_PASSWORD": "YOUR_GIT_TOKEN_HERE"
}
}
```
Then copy it to `mcp.json` and fill in actual values before use.
## Verifying Configuration
### Method 1: Using MCP Tools for Verification
```python
# Verify if environment variables are set correctly
import os
print(f"GIT_USERNAME: {os.environ.get('GIT_USERNAME', 'Not set')}")
print(f"GIT_PASSWORD: {'Set' if os.environ.get('GIT_PASSWORD') else 'Not set'}")
```
### Method 2: Testing with west_init
```python
# Test west_init function
result = west_init(
repo_url="https://github.com/zephyrproject-rtos/zephyr",
branch="main",
project_dir="test-project",
auth_method="env" # Use environment variable authentication
)
print(result)
```
## Common Issues
### Q1: Environment Variables Not Taking Effect
**Solution:**
1. Restart VS Code
2. Check if environment variable names are correct (case-sensitive)
3. Verify that the MCP server correctly reads the environment variables
### Q2: Security Warnings
**Solution:**
1. Use Personal Access Tokens (PAT) instead of passwords
2. Regularly rotate tokens
3. Use system environment variables instead of hardcoding in files
### Q3: Multi-user Shared Configuration
**Solution:**
1. Use system environment variables
2. Create user-specific configuration files
3. Use `.env` files and add to `.gitignore`
## Recommended Configuration
**Most secure configuration method:**
1. **Do not** store real credentials in `mcp.json`
2. Use system environment variables
3. Document the required environment variables
**Final recommended mcp.json:**
```json
{
"name": "Zephyr MCP Server",
"description": "Model Context Protocol server for Zephyr RTOS development workflows",
"env": {
"mcp_name": "ZephyrMcpServer"
}
}
```
**What users need to do:**
Set environment variables at the system level:
```powershell
# Windows
[Environment]::SetEnvironmentVariable('GIT_USERNAME', 'your_username', 'User')
[Environment]::SetEnvironmentVariable('GIT_PASSWORD', 'your_token', 'User')
# Linux/Mac
export GIT_USERNAME="your_username"
export GIT_PASSWORD="your_token"
```
