This server allows you to interact with a ClickHouse database cluster through the following features:
Execute read-only SQL queries with
run_select_query
, ensuring all queries are run withreadonly = 1
List all databases on your ClickHouse cluster using
list_databases
List all tables within a specified database using
list_tables
, with optional filtering usingLIKE
syntax
Connection details can be configured via environment variables or Claude Desktop configuration, including support for HTTPS, SSL verification, and timeouts.
Allows executing SQL queries on a ClickHouse cluster and retrieving information about databases and tables. It provides tools to run SELECT queries, list databases, and list tables in a database.
ClickHouse MCP Server
An MCP server for ClickHouse.
Features
ClickHouse Tools
run_select_query
- Execute SQL queries on your ClickHouse cluster.
- Input:
sql
(string): The SQL query to execute. - All ClickHouse queries are run with
readonly = 1
to ensure they are safe.
list_databases
- List all databases on your ClickHouse cluster.
list_tables
- List all tables in a database.
- Input:
database
(string): The name of the database.
chDB Tools
run_chdb_select_query
- Execute SQL queries using chDB's embedded ClickHouse engine.
- Input:
sql
(string): The SQL query to execute. - Query data directly from various sources (files, URLs, databases) without ETL processes.
Health Check Endpoint
When running with HTTP or SSE transport, a health check endpoint is available at /health
. This endpoint:
- Returns
200 OK
with the ClickHouse version if the server is healthy and can connect to ClickHouse - Returns
503 Service Unavailable
if the server cannot connect to ClickHouse
Example:
Configuration
This MCP server supports both ClickHouse and chDB. You can enable either or both depending on your needs.
- Open the Claude Desktop configuration file located at:
- On macOS:
~/Library/Application Support/Claude/claude_desktop_config.json
- On Windows:
%APPDATA%/Claude/claude_desktop_config.json
- On macOS:
- Add the following:
Update the environment variables to point to your own ClickHouse service.
Or, if you'd like to try it out with the ClickHouse SQL Playground, you can use the following config:
For chDB (embedded ClickHouse engine), add the following configuration:
You can also enable both ClickHouse and chDB simultaneously:
- Locate the command entry for
uv
and replace it with the absolute path to theuv
executable. This ensures that the correct version ofuv
is used when starting the server. On a mac, you can find this path usingwhich uv
. - Restart Claude Desktop to apply the changes.
Running Without uv (Using System Python)
If you prefer to use the system Python installation instead of uv, you can install the package from PyPI and run it directly:
- Install the package using pip:To upgrade to the latest version:
- Update your Claude Desktop configuration to use Python directly:
Alternatively, you can use the installed script directly:
Note: Make sure to use the full path to the Python executable or the mcp-clickhouse
script if they are not in your system PATH. You can find the paths using:
which python3
for the Python executablewhich mcp-clickhouse
for the installed script
Development
- In
test-services
directory rundocker compose up -d
to start the ClickHouse cluster. - Add the following variables to a
.env
file in the root of the repository.
Note: The use of the default
user in this context is intended solely for local development purposes.
- Run
uv sync
to install the dependencies. To installuv
follow the instructions here. Then dosource .venv/bin/activate
. - For easy testing with the MCP Inspector, run
fastmcp dev mcp_clickhouse/mcp_server.py
to start the MCP server. - To test with HTTP transport and the health check endpoint:
Environment Variables
The following environment variables are used to configure the ClickHouse and chDB connections:
ClickHouse Variables
Required Variables
CLICKHOUSE_HOST
: The hostname of your ClickHouse serverCLICKHOUSE_USER
: The username for authenticationCLICKHOUSE_PASSWORD
: The password for authentication
Caution
It is important to treat your MCP database user as you would any external client connecting to your database, granting only the minimum necessary privileges required for its operation. The use of default or administrative users should be strictly avoided at all times.
Optional Variables
CLICKHOUSE_PORT
: The port number of your ClickHouse server- Default:
8443
if HTTPS is enabled,8123
if disabled - Usually doesn't need to be set unless using a non-standard port
- Default:
CLICKHOUSE_SECURE
: Enable/disable HTTPS connection- Default:
"true"
- Set to
"false"
for non-secure connections
- Default:
CLICKHOUSE_VERIFY
: Enable/disable SSL certificate verification- Default:
"true"
- Set to
"false"
to disable certificate verification (not recommended for production)
- Default:
CLICKHOUSE_CONNECT_TIMEOUT
: Connection timeout in seconds- Default:
"30"
- Increase this value if you experience connection timeouts
- Default:
CLICKHOUSE_SEND_RECEIVE_TIMEOUT
: Send/receive timeout in seconds- Default:
"300"
- Increase this value for long-running queries
- Default:
CLICKHOUSE_DATABASE
: Default database to use- Default: None (uses server default)
- Set this to automatically connect to a specific database
CLICKHOUSE_MCP_SERVER_TRANSPORT
: Sets the transport method for the MCP server.- Default:
"stdio"
- Valid options:
"stdio"
,"http"
,"sse"
. This is useful for local development with tools like MCP Inspector.
- Default:
CLICKHOUSE_MCP_BIND_HOST
: Host to bind the MCP server to when using HTTP or SSE transport- Default:
"127.0.0.1"
- Set to
"0.0.0.0"
to bind to all network interfaces (useful for Docker or remote access) - Only used when transport is
"http"
or"sse"
- Default:
CLICKHOUSE_MCP_BIND_PORT
: Port to bind the MCP server to when using HTTP or SSE transport- Default:
"8000"
- Only used when transport is
"http"
or"sse"
- Default:
CLICKHOUSE_ENABLED
: Enable/disable ClickHouse functionality- Default:
"true"
- Set to
"false"
to disable ClickHouse tools when using chDB only
- Default:
chDB Variables
CHDB_ENABLED
: Enable/disable chDB functionality- Default:
"false"
- Set to
"true"
to enable chDB tools
- Default:
CHDB_DATA_PATH
: The path to the chDB data directory- Default:
":memory:"
(in-memory database) - Use
:memory:
for in-memory database - Use a file path for persistent storage (e.g.,
/path/to/chdb/data
)
- Default:
Example Configurations
For local development with Docker:
For ClickHouse Cloud:
For ClickHouse SQL Playground:
For chDB only (in-memory):
For chDB with persistent storage:
For MCP Inspector or remote access with HTTP transport:
When using HTTP transport, the server will run on the configured port (default 8000). For example, with the above configuration:
- MCP endpoint:
http://localhost:4200/mcp
- Health check:
http://localhost:4200/health
You can set these variables in your environment, in a .env
file, or in the Claude Desktop configuration:
Note: The bind host and port settings are only used when transport is set to "http" or "sse".
Running tests
YouTube Overview
remote-capable server
The server can be hosted and run remotely because it primarily relies on remote services or has no dependency on the local environment.
ClickHouse database integration with schema inspection and query capabilities
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