CrateDB MCP sandbox

A little walkthrough to get you started using CrateDB and MCP.

Prerequisites

You will need CrateDB, CrateDB Toolkit, mcptools, a Swiss Army Knife for MCP Servers, and the uv package manager. CrateDB will be invoked using Docker, but you can also use Podman or CrateDB Cloud.

Install

Run a single instance of CrateDB for evaluation purposes.

docker run --rm --name=cratedb \
  --publish=4200:4200 --publish=5432:5432 \
  --env=CRATE_HEAP_SIZE=2g crate/crate:latest \
  -Cdiscovery.type=single-node

Install software packages.

brew tap f/mcptools
brew install mcp uv
brew install --cask docker-desktop

Install the CrateDB Toolkit package with MCP support.

uv tool install --upgrade 'cratedb-toolkit[mcp]'

Usage

CLI

Two examples that make the MCP server submit SQL statements to the database, by invoking the corresponding MCP tool of the MCP server.

Using cratedb-mcp.

export CRATEDB_MCP_HTTP_URL=http://localhost:4200
mcpt call query_sql --params '{"query":"SELECT * FROM sys.summits LIMIT 3"}' \
  uvx 'cratedb-mcp @ git+https://github.com/crate/cratedb-mcp@packaging-adjustments' \
  | jq

Using mcp-alchemy.

export DB_URL=crate://crate@localhost:4200/?schema=testdrive
mcpt call execute_query --params '{"query":"SELECT * FROM sys.summits LIMIT 3"}' \
  uvx --with='sqlalchemy-cratedb>=0.42.0.dev2' mcp-alchemy

Landscape API documentation

The MCP server landscape for PostgreSQL and CrateDB page provides an overview of a portion of the MCP server landscape, focusing on the most popular ones that can connect to both PostgreSQL and CrateDB databases.

Note

The page can be generated using this command:

uvx 'cratedb-toolkit[mcp]' query mcp inquire --format=markdown | sponge mcp-cratedb-landscape.md

Looking glass

CTK includes a subsystem that provides a wrapper around the Model Context Protocol Python SDK, including inquiry and launcher utilities, i.e. to start MCP servers and hold conversations with them, with a focus on MCP servers that wrap database access.

In order to get an idea about a fragment of the MCP server landscape, focusing on those that are talking to PostgreSQL and CrateDB databases, and their detailed capabilities, this subsystem also provides a little MCP database server registry which can render its ingredients into JSON, YAML, and Markdown formats.

Enumerate registered MCP servers. All of them have been validated to work well with CrateDB.

ctk query mcp list

[
  "cratedb-mcp",
  "dbhub",
  "mcp-alchemy",
  "pg-mcp",
  "postgres-basic",
  "quarkus"
]

Inquire all registered MCP servers, and report about their capabilities.

ctk query mcp inquire

Inquire specific registered MCP server.

ctk query mcp --server-name=postgres-basic inquire

Todo

Launch registered MCP server.

ctk query mcp --server-name=postgres-basic launch