Claude Code

The pgdeadbolt plugin puts the checker inside Claude Code’s loop. Every time Claude writes or edits a migration, the plugin checks it. If the migration would lock a table, Claude is blocked and handed the safe rewrite, so it fixes the migration before moving on.

Install

/plugin install pgdeadbolt --marketplace aryan-tah/pgdeadbolt

Or add the marketplace first and pick the plugin from the list:

/plugin marketplace add aryan-tah/pgdeadbolt
/plugin install pgdeadbolt@pgdeadbolt

What it adds

• A skill with the zero-downtime patterns (concurrent indexes, NOT VALID constraints, backfilling instead of volatile defaults, expand and contract) and framework notes. Claude reads it when it’s working on a migration.
• A hook that runs after Claude’s Write, Edit and MultiEdit calls on .sql files in migration folders:
  • errors block, and Claude gets the lock, the reason and the safe SQL;
  • warnings (renames, drops) are added to Claude’s context without blocking;
  • if pgdeadbolt itself can’t run, the hook never blocks.

Settings

Set these environment variables where you run Claude Code:

Variable	Default	Meaning
PGDEADBOLT_PATHS	(migrat|/db/|/sql/)	Regex for which .sql paths count as migrations
PGDEADBOLT_PG_VERSION	16	Postgres major version
PGDEADBOLT_IN_TRANSACTION	unset	Set to 1 if your tool wraps files in a transaction

ORM migrations

The hook checks SQL. Prisma, Drizzle and Supabase generate SQL files, so they’re covered. For Rails, Django or Knex migrations written in Ruby, Python or JavaScript, the skill still teaches Claude the safe patterns. To check a Django migration, print its SQL and pipe it in: python manage.py sqlmigrate app 0042 | npx pgdeadbolt check - --in-transaction.