Sumanshu Arora

# Environment Variables **Comprehensive reference for all environment variables that configure MCP Template behavior.** ## Overview MCP Templates supports various environment variables to configure system behavior, set defaults, and customize operations. This document provides a complete reference for all available environment variables. ## Discovery and Tool Management ### MCP_DISCOVERY_TIMEOUT - **Description**: Maximum time (in seconds) to wait for tool discovery operations - **Default**: `60` - **Type**: Integer - **Usage**: Controls timeout for both Docker and Kubernetes probe operations - **Example**: ```bash export MCP_DISCOVERY_TIMEOUT=120 ``` ### MCP_DISCOVERY_RETRIES - **Description**: Number of retry attempts for failed discovery operations - **Default**: `3` - **Type**: Integer - **Usage**: Uses tenacity library for retry logic on subprocess errors, timeouts, and OS errors - **Example**: ```bash export MCP_DISCOVERY_RETRIES=5 ``` ### MCP_DISCOVERY_RETRY_SLEEP - **Description**: Sleep time (in seconds) between discovery retry attempts - **Default**: `5` - **Type**: Integer - **Usage**: Fixed wait time between retries using tenacity's wait_fixed strategy - **Example**: ```bash export MCP_DISCOVERY_RETRY_SLEEP=10 ``` ## Backend Configuration ### MCP_BACKEND - **Description**: Default backend type for deployments - **Default**: `docker` - **Type**: String - **Valid Values**: `docker`, `kubernetes`, `podman` - **Usage**: Sets the default backend when not explicitly specified in commands - **Example**: ```bash export MCP_BACKEND=kubernetes ``` ### MCP_STDIO_TIMEOUT - **Description**: Timeout (in seconds) for stdio-based MCP server communications - **Default**: `30` - **Type**: Integer - **Usage**: Used by Docker and Podman backends for stdio protocol timeout - **Example**: ```bash export MCP_STDIO_TIMEOUT=60 ``` ## Caching Configuration ### MCP_DEFAULT_CACHE_MAX_AGE_HOURS - **Description**: Maximum age (in hours) for cached tool discovery results - **Default**: `24.0` - **Type**: Float - **Usage**: Controls persistent cache expiration for discovered tools - **Example**: ```bash export MCP_DEFAULT_CACHE_MAX_AGE_HOURS=48.0 ``` ### MCP_CACHE_FILE_PATTERN - **Description**: File pattern for tool cache files - **Default**: `*.tools.json` - **Type**: String - **Usage**: Glob pattern used to identify cache files for cleanup operations - **Example**: ```bash export MCP_CACHE_FILE_PATTERN="*_tools_*.json" ``` ## CLI Behavior ### MCP_VERBOSE - **Description**: Enable verbose output by default - **Default**: `false` - **Type**: Boolean (string) - **Valid Values**: `true`, `false` - **Usage**: Sets default verbosity level for CLI operations - **Example**: ```bash export MCP_VERBOSE=true ``` ### MCP_DRY_RUN - **Description**: Enable dry-run mode by default - **Default**: `false` - **Type**: Boolean (string) - **Valid Values**: `true`, `false` - **Usage**: Makes CLI commands show what would be done without executing - **Example**: ```bash export MCP_DRY_RUN=true ``` ## Container Registry ### MCP_DEFAULT_REGISTRY - **Description**: Default Docker registry for image operations - **Default**: `docker.io` - **Type**: String - **Usage**: Used when pulling or referencing container images without explicit registry - **Example**: ```bash export MCP_DEFAULT_REGISTRY=ghcr.io ``` ## Template Configuration ### MCP_TRANSPORT - **Description**: Default transport protocol for MCP servers - **Default**: Server-specific (usually `http`) - **Type**: String - **Valid Values**: `stdio`, `http` - **Usage**: Controls how MCP servers communicate with clients - **Example**: ```bash export MCP_TRANSPORT=stdio ``` ### MCP_LOG_LEVEL - **Description**: Default logging level for MCP servers and CLI - **Default**: `info` - **Type**: String - **Valid Values**: `debug`, `info`, `warning`, `error`, `critical` - **Usage**: Controls verbosity of log output across the system - **Example**: ```bash export MCP_LOG_LEVEL=debug ``` ### MCP_CONFIG_FILE - **Description**: Path to custom configuration file - **Default**: Server/template specific - **Type**: String (file path) - **Usage**: Allows overriding default config file locations - **Example**: ```bash export MCP_CONFIG_FILE=/app/config/custom.json ``` ## Template Creation Variables ### MCP_TEMPLATE_DEFAULT_TRANSPORT - **Description**: Default transport for newly created templates - **Default**: `http` - **Type**: String - **Valid Values**: `stdio`, `http` - **Usage**: Used during template creation process - **Example**: ```bash export MCP_TEMPLATE_DEFAULT_TRANSPORT=stdio ``` ### MCP_TEMPLATE_DEFAULT_PYTHON_IMAGE - **Description**: Default Python base image for template creation - **Default**: `python:3.10-slim` - **Type**: String - **Usage**: Sets the base image for Python-based MCP server templates - **Example**: ```bash export MCP_TEMPLATE_DEFAULT_PYTHON_IMAGE=python:3.11-alpine ``` ## System Environment Variables ### SHELL - **Description**: User's shell for interactive CLI operations - **Default**: System default - **Type**: String - **Usage**: Used by interactive CLI to provide shell-specific completion and formatting - **Note**: Standard Unix environment variable, not MCP-specific ## Template-Specific Variables Templates may define their own environment variables for configuration. Common patterns include: ### Configuration Override Pattern Templates often support environment variables that override config values: ```bash export CUSTOM_API_KEY=your-api-key export CUSTOM_BASE_URL=https://api.example.com export CUSTOM_FEATURES=feature1,feature2 export CUSTOM_ADVANCED__TIMEOUT=30 export CUSTOM_ADVANCED__RETRY_ATTEMPTS=3 ``` ### Runtime Behavior Templates may use environment variables for runtime behavior: ```bash export DATA_DIR=/custom/data/path export ENABLED_FEATURES=auth,logging,metrics ``` ## Configuration Precedence Environment variables are processed with the following precedence (highest to lowest): 1. **Command-line arguments** - Explicit flags and options 2. **Environment variables** - System or user-defined variables 3. **Configuration files** - Template or user config files 4. **Template defaults** - Built-in template defaults ## Best Practices ### Development - Use `.env` files for local development environment variables - Set `MCP_DRY_RUN=true` for testing configuration changes - Enable `MCP_VERBOSE=true` for debugging deployment issues ### Production - Set appropriate timeouts for your infrastructure: ```bash export MCP_DISCOVERY_TIMEOUT=120 export MCP_STDIO_TIMEOUT=60 ``` - Configure caching for better performance: ```bash export MCP_DEFAULT_CACHE_MAX_AGE_HOURS=72.0 ``` - Use appropriate backend for your environment: ```bash export MCP_BACKEND=kubernetes # For K8s environments ``` ### Security - Avoid setting sensitive values directly in environment variables - Use secure configuration management for API keys and credentials - Consider using template-specific config files for sensitive data ## Validation You can verify environment variable configuration using: ```bash # Check current backend mcpt config show | grep backend # Test discovery settings mcpt tools list --template demo --verbose # Verify cache settings mcpt cache status ``` ## Related Documentation - [Configuration](../getting-started/configuration.md) - General configuration guide - [CLI Deploy](../cli/deploy.md) - Command-line deployment options - [Template Creation](../templates/creating.md) - Creating custom templates