vHal

You learn how to use the vHal MCP Server to explore vHAL properties, discover Android source implementations, and get guided implementation advice for climate control and related automotive features. This server provides structured tools to analyze properties, correlate their relationships, validate requests, and generate ready-to-use code and PR material for VHAL development.

How to use

You access the vHal MCP Server through a compatible MCP client. Use the server to discover HVAC and seat-related properties, inspect their dependencies, locate Android source implementations, and request step-by-step guidance on implementing climate control features. Start with simple property discovery, then move to advanced analyses that map property relationships and generate concrete implementation code and PR descriptions ready for review.

How to install

Prerequisites you need before installing: Python 3.12 or higher and an MCP-compatible client (for example Claude Desktop or a similar MCP client). An active internet connection is required for documentation scraping and remote lookups.

# Step 1: Install Python (ensure it's 3.12+)
# Step 2: Create and activate a virtual environment (optional but recommended)
python3 -m venv vhal-env
source vhal-env/bin/activate  # on macOS/Linux
# or
.
 vhal-env/bin/activate  # Windows
# Step 3: Install the MCP server in editable mode
pip install -e .

Configuration and usage notes

The vHal MCP Server configuration includes a local, stdio-based runtime command to launch the server through a MCP client. The client configuration snippet shows how to run the server using UV as the launcher and a Python entry point.

{
  "mcpServers": {
    "vhal-mcp-server": {
      "command": "/Users/youruser/.local/bin/uv",
      "args": ["run", "--directory", "/Users/youruser/vhal-mcp-server", "python", "main.py"],
      "env": {
        "PYTHONPATH": "/Users/youruser/vhal-mcp-server"
      }
    }
  }
}

Replace paths with your actual locations. After saving, quit and restart the MCP client to load the server. When you first ask questions that require analysis, you will be prompted to allow the MCP server to access its tools.

## Examples of common tasks

Basic property discovery helps you identify HVAC and SEAT related properties and their IDs. You can then request implementation guidance for a specific property to see recommended code patterns and usage.

## VHAL code generation workflow

When you need production-ready code for a new VHAL property, use the generate\_vhal\_implementation\_code tool to create the complete implementation, including HAL definitions, Java APIs, tests, and build configurations. You provide the property name, ID, type, group, access, change mode, description, and optional details like units, min/max values, areas, enum values, dependencies, and sample rate. The tool outputs all necessary files and an implementation guide.

## Pull request guidance

For VHAL changes, use generate\_vhal\_pr\_message to craft a detailed PR description that includes property metadata, dependencies, testing requirements, and a reviewer checklist. This ensures your changes are clear, testable, and ready for review in your Git hosting platform.

## Property validation

Use validate\_vhal\_property\_request to verify Android best practices for new properties. The tool checks for existing equivalents, suggests VENDOR\_ naming when needed, and provides guidance on compatibility with Android 16 and implementation approaches.

## Advanced usage

As you become more proficient, you can perform multi-phase workflows: discovery and research, dependency analysis, deep source code lookup, property validation, and finally custom implementation with accompanying PR materials. This enables a cohesive, production-ready climate control feature set with well-documented integration points.

## Available tools

### summarize\_vhal

Summarizes vHAL implementation questions by analyzing Android automotive documentation and providing contextual, implementation-focused answers.

### lookup\_android\_source\_code

Searches Android source code for vHAL properties and returns definitions with IDs and categories, plus direct links to source locations.

### discover\_related\_properties

Analyzes property relationships and dependencies, suggests an implementation order, and groups properties by functional categories.

### analyze\_vhal\_implementation

Provides detailed source code analysis for specific vHAL properties, with usage patterns and dependencies.

### generate\_vhal\_implementation\_code

Generates a complete VHAL property implementation, including all files, configurations, tests, and documentation for AAOS.

### generate\_vhal\_pr\_message

Creates comprehensive pull request messages with technical details, testing requirements, and checklists.

### validate\_vhal\_sources\_and\_enhance\_summary

Validates vHAL source accessibility, enhances summaries with citations, and exposes reliability scores.

### validate\_vhal\_property\_request

Validates a vHAL property request against Android best practices, including existence in Android releases and recommended naming conventions.