List all databases on the ClickHouse server. Returns the database name, engine type, and comment for each database. Use this as a starting point to explore what data is available on the server.

List tables in a specific database. Returns table name, engine, total rows, total bytes, partition count, and comment. Optionally filter by a name pattern using SQL LIKE syntax (e.g. '%logs%'). Use this to explore what tables exist and their approximate sizes.

Get detailed column information for a specific table including column names, data types, default expressions, comments, and whether columns are part of the primary key. Use this to understand a table's schema before querying it.

Get storage and performance statistics for a specific table including total rows, compressed and uncompressed size, number of parts, and partition details. Uses system.parts to provide accurate statistics for MergeTree-family tables. Use this to assess table size, storage efficiency, and health.

Get the CREATE TABLE statement that defines a table's full schema, including engine, partition key, order by, settings, and all column definitions. Use this to understand the complete table definition, replicate a table, or review its configuration.

Search for columns across all tables by column name pattern or data type. Use this to find which tables contain a specific field (e.g. 'user_id'), discover columns of a certain type, or explore the schema across multiple tables at once.

Execute an arbitrary SQL query against the ClickHouse server. Supports all ClickHouse SQL including SELECT, INSERT, CREATE, ALTER, DROP, and system commands. Results are returned in JSON format. For SELECT queries, use this as the primary tool for data analysis and exploration. For DDL/DML, prefer the specialized tools when available.

Get the execution plan for a SQL query without running it. Shows how ClickHouse will process the query including the pipeline, indexes used, and estimated rows. Supports different EXPLAIN types: 'PLAN' (default, logical plan), 'PIPELINE' (physical execution pipeline), 'SYNTAX' (optimized query after rewrites), 'ESTIMATE' (estimated rows and marks to read). Use this to optimize slow queries.

Preview rows from a table by selecting all columns with an optional row limit. Use this to quickly inspect what data looks like in a table, understand column values, and verify data quality before writing more complex queries.

Insert rows into a ClickHouse table. Data is provided as a JSON array of objects where each object represents a row and keys are column names. Uses JSONEachRow format for flexible insertion. Use this to add new data, populate tables, or load small batches of records.