Cryo MCP 🧊

A Model Completion Protocol (MCP) server for the Cryo blockchain data extraction tool.

Cryo MCP allows you to access Cryo's powerful blockchain data extraction capabilities via an API server that implements the MCP protocol, making it easy to query blockchain data from any MCP-compatible client.

Features

• Full Cryo Dataset Access: Query any Cryo dataset through an API server
• MCP Integration: Works seamlessly with MCP clients
• Flexible Query Options: Support for all major Cryo filtering and output options
• Block Range Options: Query specific blocks, latest block, or relative ranges
• Contract Filtering: Filter data by contract address
• Latest Block Access: Easy access to the latest Ethereum block data
• Multiple Output Formats: JSON and CSV support
• Schema Information: Get detailed dataset schemas and sample data

Installation (Optional)

This is not required if you will run the tool with uvx directly.

# install with UV (recommended)
uv tool install cryo-mcp

Requirements

• Python 3.8+
• uv
• A working installation of Cryo
• Access to an Ethereum RPC endpoint

Quick Start

Usage with Claude Code

1. Run claude mcp add for an interactive prompt.
2. Enter uvx as the command to run.
3. Enter cryo-mcp -r <ETH_RPC_URL> as the args
4. Alternatively, provide ETH_RPC_URL as an environment variable instead.

New instances of claude will now have access to cryo as configured to hit your RPC endpoint.

Available Tools

Cryo MCP exposes the following MCP tools:

list_datasets()

Returns a list of all available Cryo datasets.

Example:

client.list_datasets()

query_dataset()

Query a Cryo dataset with various filtering options.

Parameters:

• dataset (str): The name of the dataset to query (e.g., 'blocks', 'transactions', 'logs')
• blocks (str, optional): Block range specification (e.g., '1000:1010')
• start_block (int, optional): Start block number (alternative to blocks)
• end_block (int, optional): End block number (alternative to blocks)
• use_latest (bool, optional): If True, query the latest block
• blocks_from_latest (int, optional): Number of blocks from latest to include
• contract (str, optional): Contract address to filter by
• output_format (str, optional): Output format ('json', 'csv')
• include_columns (list, optional): Columns to include alongside defaults
• exclude_columns (list, optional): Columns to exclude from defaults

Example:

# Get transactions from blocks 15M to 15.01M
client.query_dataset('transactions', blocks='15M:15.01M')

# Get logs for a specific contract from the latest 100 blocks
client.query_dataset('logs', blocks_from_latest=100, contract='0x1234...')

# Get just the latest block
client.query_dataset('blocks', use_latest=True)

lookup_dataset()

Get detailed information about a specific dataset, including schema and sample data.

Parameters:

• name (str): The name of the dataset to look up
• sample_start_block (int, optional): Start block for sample data
• sample_end_block (int, optional): End block for sample data
• use_latest_sample (bool, optional): Use latest block for sample
• sample_blocks_from_latest (int, optional): Number of blocks from latest for sample

Example:

client.lookup_dataset('logs')

get_latest_ethereum_block()

Returns information about the latest Ethereum block.

Example:

client.get_latest_ethereum_block()

Configuration Options

When starting the Cryo MCP server, you can use these command-line options:

• --rpc-url URL: Ethereum RPC URL (overrides ETH_RPC_URL environment variable)

Environment Variables

• ETH_RPC_URL: Default Ethereum RPC URL to use when not specified via command line

Advanced Usage

Querying with Block Ranges

Cryo MCP supports the full range of Cryo's block specification syntax:

# Using block numbers
client.query_dataset('transactions', blocks='15000000:15001000')

# Using K/M notation
client.query_dataset('logs', blocks='15M:15.01M')

# Using offsets from latest 
client.query_dataset('blocks', blocks_from_latest=100)

Contract Filtering

Filter logs and other data by contract address:

# Get all logs for USDC contract
client.query_dataset('logs', 
                    blocks='16M:16.1M', 
                    contract='0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48')

Column Selection

Include only the columns you need:

# Get just block numbers and timestamps
client.query_dataset('blocks', 
                    blocks='16M:16.1M', 
                    include_columns=['number', 'timestamp'])

Development

Project Structure

cryo-mcp/
├── cryo_mcp/           # Main package directory
│   ├── __init__.py     # Package initialization
│   ├── server.py       # Main MCP server implementation
├── tests/              # Test directory
│   ├── test_*.py       # Test files
├── pyproject.toml      # Project configuration
├── README.md           # Project documentation

Run Tests

uv run pytest

License

MIT

Credits

• Built on top of the amazing Cryo tool by Paradigm
• Uses the MCP protocol for API communication