mcp-clickhouse
Execute SQL queries on ClickHouse clusters, list databases and tables with enhanced filtering capabilities using LIKE/NOT LIKE patterns.
Click on "Install Server".
Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state.
In the chat, type
@followed by the MCP server name and your instructions, e.g., "@mcp-clickhouselist tables in my_db matching user_% or order_%"
That's it! The server will respond to your query, and you can continue using it as needed.
Here is a step-by-step guide with screenshots.
ClickHouse MCP Server (Enhanced)
An MCP server for ClickHouse with enhanced filtering capabilities for database and table discovery.
Note: This is a fork of ClickHouse/mcp-clickhouse with added filtering support for
list_databasesandlist_tablestools. Both functions now support single or multiple LIKE/NOT LIKE patterns for flexible database and table discovery.
What's New in This Fork
✨ Multiple Pattern Support: Filter databases and tables using multiple LIKE patterns with OR logic
✨ Advanced Exclusions: Exclude using multiple NOT LIKE patterns with AND logic
✨ Backward Compatible: Single string patterns still work exactly as before
✨ Pagination Aware: Multiple patterns work seamlessly with table pagination
Features
ClickHouse Tools
run_select_queryExecute SQL queries on your ClickHouse cluster.
Input:
sql(string): The SQL query to execute.All ClickHouse queries are run with
readonly = 1to ensure they are safe.
list_databasesList databases on your ClickHouse cluster.
Optional inputs:
like(string or list of strings): ApplyLIKEfilter(s) to database names. Multiple patterns are combined with OR logic.not_like(string or list of strings): ApplyNOT LIKEfilter(s) to exclude database names. Multiple patterns are combined with AND logic.
Examples:
like="prod_%"- Single patternlike=["prod_%", "staging_%"]- Multiple patterns (matches either)not_like=["test_%", "temp_%"]- Exclude multiple patterns (excludes both)
list_tablesList tables in a database with pagination.
Required input:
database(string).Optional inputs:
like(string or list of strings): ApplyLIKEfilter(s) to table names. Multiple patterns are combined with OR logic.not_like(string or list of strings): ApplyNOT LIKEfilter(s) to exclude table names. Multiple patterns are combined with AND logic.page_token(string): Token returned by a previous call for fetching the next page.page_size(int, default50): Number of tables returned per page.include_detailed_columns(bool, defaulttrue): Whenfalse, omits column metadata for lighter responses while keeping the fullcreate_table_query.
Examples:
like="user_%"- Single patternlike=["user_%", "order_%"]- Multiple patterns (matches either)not_like=["temp_%", "backup_%"]- Exclude multiple patterns (excludes both)
Response shape:
tables: Array of table objects for the current page.next_page_token: Pass this value back to fetch the next page, ornullwhen there are no more tables.total_tables: Total count of tables that match the supplied filters.
chDB Tools
run_chdb_select_queryExecute 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.
Enhanced Filtering Capabilities
This fork adds powerful filtering capabilities to both list_databases and list_tables tools, allowing you to efficiently discover and filter databases and tables using SQL LIKE patterns.
Key Features
Single Pattern Filtering
Filter with a single LIKE pattern:
like="prod_%"matches all databases/tables starting with "prod_"Exclude with a single NOT LIKE pattern:
not_like="test_%"excludes all starting with "test_"
Multiple Pattern Filtering
OR logic for
like:like=["user_%", "order_%"]matches tables starting with "user_" OR "order_"AND logic for
not_like:not_like=["temp_%", "backup_%"]excludes tables starting with "temp_" AND tables starting with "backup_"
Combined Filtering
Mix both:
like=["prod_%", "staging_%"], not_like=["_backup"]includes prod/staging but excludes any ending with "_backup"
Use Cases
Scenario 1: Multi-environment Database Discovery
# Find all production and staging databases
list_databases(like=["prod_%", "staging_%"])Scenario 2: Clean Table Listing
# List all user and order tables, but exclude temporary and backup tables
list_tables(
database="mydb",
like=["user_%", "order_%"],
not_like=["temp_%", "backup_%"]
)Scenario 3: Development Environment Cleanup
# Find all test/temp/dev databases for cleanup
list_databases(like=["test_%", "temp_%", "dev_%"])Health Check Endpoint
When running with HTTP or SSE transport, a health check endpoint is available at /health. This endpoint:
Returns
200 OKwith the ClickHouse version if the server is healthy and can connect to ClickHouseReturns
503 Service Unavailableif the server cannot connect to ClickHouse
Example:
curl http://localhost:8000/health
# Response: OK - Connected to ClickHouse 24.3.1Configuration
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.jsonOn Windows:
%APPDATA%/Claude/claude_desktop_config.json
Add the following:
{
"mcpServers": {
"mcp-clickhouse": {
"command": "uv",
"args": [
"run",
"--with",
"mcp-clickhouse-like",
"--python",
"3.10",
"mcp-clickhouse"
],
"env": {
"CLICKHOUSE_HOST": "<clickhouse-host>",
"CLICKHOUSE_PORT": "<clickhouse-port>",
"CLICKHOUSE_USER": "<clickhouse-user>",
"CLICKHOUSE_PASSWORD": "<clickhouse-password>",
"CLICKHOUSE_ROLE": "<clickhouse-role>",
"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-like",
"--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-like",
"--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-like",
"--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"
}
}
}
}Locate the command entry for
uvand replace it with the absolute path to theuvexecutable. This ensures that the correct version ofuvis 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:
python3 -m pip install mcp-clickhouse-likeTo upgrade to the latest version:
python3 -m pip install --upgrade mcp-clickhouse-likeOptional chDB Support: If you want to use chDB features (embedded ClickHouse engine), install with the chdb extra:
python3 -m pip install mcp-clickhouse-like[chdb]Note: chDB is not available on Windows. If you're on Windows, use the standard ClickHouse tools instead.
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 the mcp-clickhouse script if they are not in your system PATH. You can find the paths using:
which python3for the Python executablewhich mcp-clickhousefor the installed script
Development
In
test-servicesdirectory rundocker compose up -dto start the ClickHouse cluster.Add the following variables to a
.envfile 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=clickhouseRun
uv syncto install the dependencies. To installuvfollow the instructions here. Then dosource .venv/bin/activate.For easy testing with the MCP Inspector, run
fastmcp dev mcp_clickhouse/mcp_server.pyto 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
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
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 serverDefault:
8443if HTTPS is enabled,8123if disabledUsually doesn't need to be set unless using a non-standard port
CLICKHOUSE_ROLE: The role to use for authenticationDefault: None
Set this if your user requires a specific role
CLICKHOUSE_SECURE: Enable/disable HTTPS connectionDefault:
"true"Set to
"false"for non-secure connections
CLICKHOUSE_VERIFY: Enable/disable SSL certificate verificationDefault:
"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 via
truststore. 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 secondsDefault:
"30"Increase this value if you experience connection timeouts
CLICKHOUSE_SEND_RECEIVE_TIMEOUT: Send/receive timeout in secondsDefault:
"300"Increase this value for long-running queries
CLICKHOUSE_DATABASE: Default database to useDefault: 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 transportDefault:
"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 transportDefault:
"8000"Only used when transport is
"http"or"sse"
CLICKHOUSE_MCP_QUERY_TIMEOUT: Timeout in seconds for SELECT toolsDefault:
"30"Increase this if you see
Query timed out after ...errors for heavy queries
CLICKHOUSE_ENABLED: Enable/disable ClickHouse functionalityDefault:
"true"Set to
"false"to disable ClickHouse tools when using chDB only
chDB Variables
CHDB_ENABLED: Enable/disable chDB functionalityDefault:
"false"Set to
"true"to enable chDB tools
CHDB_DATA_PATH: The path to the chDB data directoryDefault:
":memory:"(in-memory database)Use
:memory:for in-memory databaseUse a file path for persistent storage (e.g.,
/path/to/chdb/data)
Example Configurations
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=falseFor 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_databaseFor 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/dataFor 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/mcpHealth 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-like",
"--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".
Running tests
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 onlyComparison with Upstream
This fork maintains full compatibility with the upstream project while adding enhanced filtering capabilities:
Feature | Upstream | This Fork |
Single LIKE pattern | ✅ | ✅ |
Single NOT LIKE pattern | ✅ | ✅ |
Multiple LIKE patterns | ❌ | ✅ (OR logic) |
Multiple NOT LIKE patterns | ❌ | ✅ (AND logic) |
Pagination support | ✅ | ✅ (with patterns) |
Backward compatible | - | ✅ |
Implementation Details
Type Safety: Uses
Union[str, List[str]]for pattern parametersSQL Generation: Patterns are properly escaped using
format_query_value()to prevent SQL injectionPagination: Multiple patterns are stored in the pagination cache and validated across pages
Performance: Generates optimized SQL with parenthesized conditions for efficient query execution
YouTube Overview (Upstream Project)

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