Migratoor

npm version License: MIT

Database migration safety checker MCP server. Catch dangerous migrations before they hit production.

Problem

Developers write migrations, deploy, and accidentally lock production tables for minutes. Or drop a column that running code still references. Or create an index that blocks all writes. These cause real outages.

migratoor checks your SQL migrations against 14 proven safety rules from Squawk and strong_migrations, explains why each pattern is dangerous, and suggests the safe alternative — all as MCP tools in your AI editor.

Quick Start

As MCP Server

Works with any MCP-compatible client — Claude Code, Claude Desktop, Cursor, Windsurf, VS Code (Copilot), Continue.dev, Zed, Cline, and more.

{
  "mcpServers": {
    "migratoor": {
      "command": "npx",
      "args": ["-y", "@mrzadexinho/migratoor"]
    }
  }
}

As Library

import { analyzeMigration, formatReport } from '@mrzadexinho/migratoor';

const result = analyzeMigration(`
  ALTER TABLE users ADD COLUMN email TEXT NOT NULL;
  CREATE INDEX idx_email ON users (email);
`);

console.log(formatReport(result));
// [CRITICAL] Adding NOT NULL column without default blocks reads/writes
// [CRITICAL] Creating index without CONCURRENTLY blocks all writes
// Safe alternatives provided for each finding

MCP Tools

Rules

Critical (blocks reads/writes, causes outages)

Warning (breaks running code, data risk)

Info (best practices)

Every critical and warning finding includes the safe alternative SQL — not just "this is wrong" but "here's exactly how to fix it."

Example Output

# Migration Safety Check

**3 statement(s) analyzed, 2 issue(s) found:**
- 2 critical

**This migration is NOT safe to run in production.**

## Critical

[CRITICAL] **Adding NOT NULL column without default blocks reads/writes**
Rule: `add-column-not-null-without-default` | Line: 1
```sql
ALTER TABLE users ADD COLUMN email TEXT NOT NULL

Safe alternative: Add column as nullable, backfill, then add NOT NULL constraint

ALTER TABLE users ADD COLUMN email TEXT;
ALTER TABLE users ALTER COLUMN email SET DEFAULT <value>;
UPDATE users SET email = <value> WHERE email IS NULL;
ALTER TABLE users ALTER COLUMN email SET NOT NULL;

## Architecture

migratoor/ src/ sql/ # SQL parsing layer types # Statement, ParsedMigration parser # Split SQL, classify DDL operations rules/ # Safety rules types # Rule, Finding, Severity postgres # 14 PostgreSQL safety rules registry # Rule lookup, list, filter engine/ # Analysis engine analyzer # Apply rules, collect findings, summarize reporter # Format results (structured + markdown) mcp/ # MCP server layer tools/ # 3 MCP tools tests/ # 93 tests mirroring src/ structure

## Prerequisites

- **Node.js** >= 20.0.0
- No other dependencies required — migratoor analyzes SQL statically

## Development

```bash
git clone https://github.com/mrzadexinho/migratoor.git
cd migratoor
npm install
npm run build
npm test

License

MIT