What is Malloy Mcp Server

malloy-mcp-server is an MCP Server implementation designed for executing Malloy queries and managing Malloy resources, enabling interaction with Malloy data models through the Malloy Publisher.

Use cases

Use cases include executing complex queries on user data, accessing metadata for projects and packages, and integrating with other systems that utilize Malloy data models.

How to use

To use malloy-mcp-server, install it via pip or uv, configure environment variables for the Malloy Publisher API, and run the server. You can execute queries using the provided MCP tool and access various resource endpoints.

Key features

Key features include the ability to execute Malloy queries via MCP, access to Malloy project, package, and model metadata, robust error handling with detailed context, comprehensive test coverage, and a type-safe implementation.

Where to use

malloy-mcp-server can be used in data analytics, business intelligence, and any application requiring interaction with Malloy data models for querying and resource management.

Malloy MCP Server

An MCP server implementation for executing Malloy queries and managing Malloy resources.

Features

• Execute Malloy queries via MCP
• Access Malloy project, package, and model metadata
• Robust error handling with detailed context
• Comprehensive test coverage
• Type-safe implementation

Installation

# Install using uv (recommended)
uv pip install malloy-mcp-server

# Or using pip
pip install malloy-mcp-server

Usage

Starting the Server

from malloy_mcp_server import mcp

# Run the server
if __name__ == "__main__":
    mcp.serve()

Configuration

The server can be configured using environment variables:

Example:

# Set the publisher URL
export MALLOY_PUBLISHER_ROOT_URL="http://malloy-publisher:4000"

# Run with custom configuration
python -m malloy_mcp_server

Executing Queries

The server provides an MCP tool for executing Malloy queries:

from malloy_mcp_server import ExecuteMalloyQueryTool

# Example query execution
result = await ExecuteMalloyQueryTool(
    query="select * from users",
    model_path="my_package/users"
)

Accessing Resources

The server provides the following resource endpoints:

• malloy://project/home/metadata - Project metadata
• malloy://project/home/package/{package_name} - Package metadata
• malloy://project/home/model/{model_path} - Model metadata

Development

Setup

1. Clone the repository:

git clone https://github.com/namabile/malloy-mcp-server.git
cd malloy-mcp-server

2. Install dependencies:

uv pip install -e ".[dev]"

Running Tests

# Run all tests
pytest

# Run with coverage
pytest --cov=malloy_mcp_server

Code Quality

The project uses:

• black for code formatting
• mypy for type checking
• ruff for linting

Run quality checks:

black .
mypy .
ruff check .

Error Handling

The server provides detailed error handling with context:

from malloy_mcp_server.errors import QueryExecutionError

try:
    result = await ExecuteMalloyQueryTool(...)
except QueryExecutionError as e:
    print(f"Error: {e.message}")
    print("Context:", e.context)

Architecture

The server is built on:

• FastMCP for the MCP server implementation
• Malloy Publisher Client for Malloy interactions
• Pydantic for data validation

Key components:

• server.py - Core server implementation
• tools/query_executor.py - Query execution tool
• errors.py - Error handling utilities

Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests for new functionality
5. Submit a pull request

License

MIT License - see LICENSE file for details