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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 withreadonly = 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 usingchDB's embedded ClickHouse 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:

• Returns200 OK with the ClickHouse version if the server is healthy and can connect to ClickHouse
• Returns503 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.

1. 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

2. Add the following:

{"mcpServers": {"mcp-clickhouse": {"command":"uv","args": ["run","--with","mcp-clickhouse","--python","3.10","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 theClickHouse SQL Playground, you can use the following config:

{"mcpServers": {"mcp-clickhouse": {"command":"uv","args": ["run","--with","mcp-clickhouse","--python","3.10","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 ClickHouse engine), add the following configuration:

{"mcpServers": {"mcp-clickhouse": {"command":"uv","args": ["run","--with","mcp-clickhouse","--python","3.10","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","3.10","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"      }    }  }}

3. Locate the command entry foruv 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.

4. Restart Claude Desktop to apply the changes.

If you prefer to use the system Python installation instead of uv, you can install the package from PyPI and run it directly:

1. Install the package using pip:

   python3 -m pip install mcp-clickhouse

   To upgrade to the latest version:

   python3 -m pip install --upgrade mcp-clickhouse

2. Update your Claude Desktop configuration to use Python directly:

{"mcpServers": {"mcp-clickhouse": {"command":"python3","args": ["-m","mcp_clickhouse.main"      ],"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"      }    }  }}

Alternatively, you can use the installed script directly:

{"mcpServers": {"mcp-clickhouse": {"command":"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"      }    }  }}

Note: Make sure to use the full path to the Python executable or themcp-clickhouse script if they are not in your system PATH. You can find the paths using:

• which python3 for the Python executable
• which mcp-clickhouse for the installed script

1. Intest-services directory rundocker compose up -d to start the ClickHouse cluster.

2. Add the following variables to a.env file in the root of the repository.

Note: The use of thedefault user in this context is intended solely for local development purposes.

CLICKHOUSE_HOST=localhostCLICKHOUSE_PORT=8123CLICKHOUSE_USER=defaultCLICKHOUSE_PASSWORD=clickhouse

3. Runuv sync to install the dependencies. To installuv follow the instructionshere. Then dosource .venv/bin/activate.

4. For easy testing with the MCP Inspector, runfastmcp dev mcp_clickhouse/mcp_server.py to start the MCP server.

5. To test with HTTP transport and the health check endpoint:

   # Using default port 8000CLICKHOUSE_MCP_SERVER_TRANSPORT=http python -m mcp_clickhouse.main# Or with a custom portCLICKHOUSE_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 server
• CLICKHOUSE_USER: The username for authentication
• CLICKHOUSE_PASSWORD: The password for authentication

• 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
• CLICKHOUSE_SECURE: Enable/disable HTTPS connection
  • Default:"true"
  • Set to"false" for non-secure connections
• CLICKHOUSE_VERIFY: Enable/disable SSL certificate verification
  • Default:"true"
  • Set to"false" to disable certificate verification (not recommended for production)
  • TLS certificates: The package uses your operating system trust store for TLS certificate verification viatruststore. We calltruststore.inject_into_ssl() at startup to ensure proper certificate handling. Python’s default SSL behavior is used as a fallback only if an unexpected error occurs.
• CLICKHOUSE_CONNECT_TIMEOUT: Connection timeout in seconds
  • Default:"30"
  • Increase this value if you experience connection timeouts
• CLICKHOUSE_SEND_RECEIVE_TIMEOUT: Send/receive timeout in seconds
  • Default:"300"
  • Increase this value for long-running queries
• 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.
• 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"
• 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"
• CLICKHOUSE_MCP_QUERY_TIMEOUT: Timeout in seconds for SELECT tools
  • Default:"30"
  • Increase this if you seeQuery timed out after ... errors for heavy queries
• CLICKHOUSE_ENABLED: Enable/disable ClickHouse functionality
  • Default:"true"
  • Set to"false" to disable ClickHouse tools when using chDB only

• CHDB_ENABLED: Enable/disable chDB functionality
  • Default:"false"
  • Set to"true" to enable chDB tools
• 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)

For local development with Docker:

# Required variablesCLICKHOUSE_HOST=localhostCLICKHOUSE_USER=defaultCLICKHOUSE_PASSWORD=clickhouse# Optional: Override defaults for local developmentCLICKHOUSE_SECURE=false# Uses port 8123 automaticallyCLICKHOUSE_VERIFY=false

For ClickHouse Cloud:

# Required variablesCLICKHOUSE_HOST=your-instance.clickhouse.cloudCLICKHOUSE_USER=defaultCLICKHOUSE_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.comCLICKHOUSE_USER=demoCLICKHOUSE_PASSWORD=# Uses secure defaults (HTTPS on port 8443)

For chDB only (in-memory):

# chDB configurationCHDB_ENABLED=trueCLICKHOUSE_ENABLED=false# CHDB_DATA_PATH defaults to :memory:

For chDB with persistent storage:

# chDB configurationCHDB_ENABLED=trueCLICKHOUSE_ENABLED=falseCHDB_DATA_PATH=/path/to/chdb/data

For MCP Inspector or remote access with HTTP transport:

CLICKHOUSE_HOST=localhostCLICKHOUSE_USER=defaultCLICKHOUSE_PASSWORD=clickhouseCLICKHOUSE_MCP_SERVER_TRANSPORT=httpCLICKHOUSE_MCP_BIND_HOST=0.0.0.0# Bind to all interfacesCLICKHOUSE_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","3.10","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 dependenciesuv run ruff check.# run lintingdocker compose up -d test_services# start ClickHouseuv run pytest -v testsuv run pytest -v tests/test_tool.py# ClickHouse onlyuv run pytest -v tests/test_chdb_tool.py# chDB only