Culprit SQL Studio

Culprit SQL Studio helps developers identify and optimize slow SQL queries across SQL Server, PostgreSQL, MySQL, and MariaDB databases. Simply analyze your queries and receive one-sentence fixes to improve performance. Available as a free, open-source desktop application, command-line interface (CLI), and Model Context Protocol (MCP) server, it integrates seamlessly into your development workflow.

Culprit SQL Studio reads database statistics and catalog information to identify performance problems and explain them in plain language. It ranks findings by their share of database time and covers slow queries, plan regressions, missing indexes, blocking, and unsafe migrations. Each finding includes supporting evidence, a suggested production-safe fix, and a way to verify the result. The product is an investigation tool for understanding database performance issues, rather than a monitoring service that collects data continuously. Users connect Culprit to a supported database or open a SQLite file, then inspect a dashboard and findings based on available statistics and catalog views. The app can explain and compare execution plans, show changes between periods, and present blocking sessions as a tree. Users can test virtual indexes or lint migration SQL with the CLI. Coding agents can use its MCP server and tools; database access can be limited to statistics and plans, or approved read-only queries. Suggested fixes are shown, not applied. Culprit is for people investigating performance issues across SQL Server, PostgreSQL, TimescaleDB, YugabyteDB, MySQL, MariaDB, and SQLite. The page describes a shared workflow for database developers and teams using coding agents or CI. It emphasizes read-only operation, local data, no account or cloud service, and no server-side agent or collector. The app, CLI, and MCP server are free and open source under the MIT license.