dryrun

The Offline-First PostgreSQL MCP That Won't Ruin Your Production

Schema linting, migration safety checks, query validation, and 17 MCP tools for your AI assistant, all working from a JSON snapshot. No production credentials needed.

Get dryrun GitHub Repository

How It Works

# Dump schema from production (once)
dryrun --db "$DATABASE_URL" dump-schema -o schema.json

# Import into your project
dryrun import schema.json

# Lint naming conventions, PK types, missing indexes...
dryrun lint

# Detect drift between saved snapshot and live database
dryrun --db "$DATABASE_URL" drift

# Serve as MCP server for Claude or other AI assistants
dryrun mcp-serve

Features

Schema Linting

21 rules covering naming conventions, primary key types, varchar vs text, missing timestamps, FK indexes, and partition health. Configurable severity and rule disabling.

Migration Safety

Analyzes DDL statements for lock types, table rewrite risks, and index build impact. Suggests safe alternatives for every dangerous operation.

Query Validation

Parses SQL against your actual schema. Catches non-existent columns, detects anti-patterns, and suggests missing indexes, all without hitting the database.

Schema Audit

Deep audit for duplicate indexes, foreign key coverage gaps, unused indexes, and stale statistics. Goes beyond linting to find structural issues in your schema.

MCP Server for AI

17 tools that give Claude and other AI assistants full schema awareness. Your assistant stops guessing column names and starts writing correct SQL.

Offline-First

Dump the schema once, commit the JSON, and everyone works offline. No production credentials on developer machines or CI runners.

Installation

Homebrew

brew install boringsql/tap/dryrun

go install github.com/boringsql/dryrun/cmd/dry-run@latest

Why dryrun?

AI coding assistants write SQL blind. They don't know your schema, your indexes, or your constraints, so they generate migrations that take ACCESS EXCLUSIVE locks on busy tables, add varchar(255) columns when you use text, or create indexes that already exist.

dryrun makes your database schema portable:

Capture once, use everywhere. One dump-schema command produces a JSON file that contains your tables, columns, indexes, constraints, functions, and per-table statistics. Commit it, share it, CI it.
Lint before you ship. 21 convention rules catch naming violations, missing timestamps, serial vs identity, and more, all from the JSON file, no database connection needed.
Check before you migrate. Every DDL statement gets a lock type, rewrite risk, and safe alternative. Know whether ALTER TABLE will lock your busiest table before you find out in production.

Use Cases

AI-assisted database development

Install dryrun as an MCP server and your AI assistant gains full schema awareness. It stops hallucinating column names, suggests proper indexes, and warns you when a migration will rewrite the table.

Pre-deploy migration review

The check_migration MCP tool analyzes every DDL statement for lock types and rewrite risks. Wire it into your AI-assisted workflow or CI pipeline.

Schema governance across teams

Enforce naming conventions, require timestamps, ban varchar in favor of text, and flag tables without primary keys. One dryrun.toml config keeps the whole team aligned.