An MCP server for ClickHouse.
-
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.
run_chdb_select_query
- Execute SQL queries using chDB's embedded OLAP engine.
- Input:
sql
(string): The SQL query to execute. - Query data directly from various sources (files, URLs, databases) without ETL processes.
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:
curl http://localhost:8000/health
# Response: OK - Connected to ClickHouse 24.3.1
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:
{
"mcpServers": {
"mcp-clickhouse": {
"command": "uv",
"args": [
"run",
"--with",
"mcp-clickhouse",
"--python",
"3.13",
"mcp-clickhouse"
],
"env": {
"CLICKHOUSE_HOST": "<clickhouse-host>",
"CLICKHOUSE_PORT": "<clickhouse-port>",
"CLICKHOUSE_USER": "<clickhouse-user>",
"CLICKHOUSE_PASSWORD": "<clickhouse-password>",
"CLICKHOUSE_SECURE": "true",
"CLICKHOUSE_VERIFY": "true",
"CLICKHOUSE_CONNECT_TIMEOUT": "30",
"CLICKHOUSE_SEND_RECEIVE_TIMEOUT": "30"
}
}
}
}
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:
{
"mcpServers": {
"mcp-clickhouse": {
"command": "uv",
"args": [
"run",
"--with",
"mcp-clickhouse",
"--python",
"3.13",
"mcp-clickhouse"
],
"env": {
"CLICKHOUSE_HOST": "sql-clickhouse.clickhouse.com",
"CLICKHOUSE_PORT": "8443",
"CLICKHOUSE_USER": "demo",
"CLICKHOUSE_PASSWORD": "",
"CLICKHOUSE_SECURE": "true",
"CLICKHOUSE_VERIFY": "true",
"CLICKHOUSE_CONNECT_TIMEOUT": "30",
"CLICKHOUSE_SEND_RECEIVE_TIMEOUT": "30"
}
}
}
}
For chDB (embedded OLAP engine), add the following configuration:
{
"mcpServers": {
"mcp-clickhouse": {
"command": "uv",
"args": [
"run",
"--with",
"mcp-clickhouse",
"--python",
"3.13",
"mcp-clickhouse"
],
"env": {
"CHDB_ENABLED": "true",
"CLICKHOUSE_ENABLED": "false",
"CHDB_DATA_PATH": "/path/to/chdb/data"
}
}
}
}
You can also enable both ClickHouse and chDB simultaneously:
{
"mcpServers": {
"mcp-clickhouse": {
"command": "uv",
"args": [
"run",
"--with",
"mcp-clickhouse",
"--python",
"3.13",
"mcp-clickhouse"
],
"env": {
"CLICKHOUSE_HOST": "<clickhouse-host>",
"CLICKHOUSE_PORT": "<clickhouse-port>",
"CLICKHOUSE_USER": "<clickhouse-user>",
"CLICKHOUSE_PASSWORD": "<clickhouse-password>",
"CLICKHOUSE_SECURE": "true",
"CLICKHOUSE_VERIFY": "true",
"CLICKHOUSE_CONNECT_TIMEOUT": "30",
"CLICKHOUSE_SEND_RECEIVE_TIMEOUT": "30",
"CHDB_ENABLED": "true",
"CHDB_DATA_PATH": "/path/to/chdb/data"
}
}
}
}
-
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.
-
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.
CLICKHOUSE_HOST=localhost
CLICKHOUSE_PORT=8123
CLICKHOUSE_USER=default
CLICKHOUSE_PASSWORD=clickhouse
-
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:
# Using default port 8000 CLICKHOUSE_MCP_SERVER_TRANSPORT=http python -m mcp_clickhouse.main # Or with a custom port CLICKHOUSE_MCP_SERVER_TRANSPORT=http CLICKHOUSE_MCP_BIND_PORT=4200 python -m mcp_clickhouse.main # Then in another terminal: curl http://localhost:8000/health # or http://localhost:4200/health for custom port
The following environment variables are used to configure the ClickHouse and chDB connections:
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.
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_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:
For local development with Docker:
# Required variables
CLICKHOUSE_HOST=localhost
CLICKHOUSE_USER=default
CLICKHOUSE_PASSWORD=clickhouse
# Optional: Override defaults for local development
CLICKHOUSE_SECURE=false # Uses port 8123 automatically
CLICKHOUSE_VERIFY=false
For ClickHouse Cloud:
# Required variables
CLICKHOUSE_HOST=your-instance.clickhouse.cloud
CLICKHOUSE_USER=default
CLICKHOUSE_PASSWORD=your-password
# Optional: These use secure defaults
# CLICKHOUSE_SECURE=true # Uses port 8443 automatically
# CLICKHOUSE_DATABASE=your_database
For ClickHouse SQL Playground:
CLICKHOUSE_HOST=sql-clickhouse.clickhouse.com
CLICKHOUSE_USER=demo
CLICKHOUSE_PASSWORD=
# Uses secure defaults (HTTPS on port 8443)
For chDB only (in-memory):
# chDB configuration
CHDB_ENABLED=true
CLICKHOUSE_ENABLED=false
# CHDB_DATA_PATH defaults to :memory:
For chDB with persistent storage:
# chDB configuration
CHDB_ENABLED=true
CLICKHOUSE_ENABLED=false
CHDB_DATA_PATH=/path/to/chdb/data
For MCP Inspector or remote access with HTTP transport:
CLICKHOUSE_HOST=localhost
CLICKHOUSE_USER=default
CLICKHOUSE_PASSWORD=clickhouse
CLICKHOUSE_MCP_SERVER_TRANSPORT=http
CLICKHOUSE_MCP_BIND_HOST=0.0.0.0 # Bind to all interfaces
CLICKHOUSE_MCP_BIND_PORT=4200 # Custom port (default: 8000)
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:
{
"mcpServers": {
"mcp-clickhouse": {
"command": "uv",
"args": [
"run",
"--with",
"mcp-clickhouse",
"--python",
"3.13",
"mcp-clickhouse"
],
"env": {
"CLICKHOUSE_HOST": "<clickhouse-host>",
"CLICKHOUSE_USER": "<clickhouse-user>",
"CLICKHOUSE_PASSWORD": "<clickhouse-password>",
"CLICKHOUSE_DATABASE": "<optional-database>",
"CLICKHOUSE_MCP_SERVER_TRANSPORT": "stdio",
"CLICKHOUSE_MCP_BIND_HOST": "127.0.0.1",
"CLICKHOUSE_MCP_BIND_PORT": "8000"
}
}
}
}
Note: The bind host and port settings are only used when transport is set to "http" or "sse".
uv sync --all-extras --dev # install dev dependencies
uv run ruff check . # run linting
docker compose up -d test_services # start ClickHouse
uv run pytest -v tests
uv run pytest -v tests/test_tool.py # ClickHouse only
uv run pytest -v tests/test_chdb_tool.py # chDB only