{"agent":"claude","input":"Review the Alembic migrations added by the open pull request in resources. Read alembic.ini, alembic/env.py, the prestart script, pyproject.toml and the models first, and confirm the new revisions attach to the current head with alembic heads and alembic history. Start the Postgres version the repository's compose file names in the sandbox with a fresh database and synthetic data only, never a production connection. Apply the chain up to the pull request's down_revision, load representative rows, then apply the new revisions while a second session holds a transaction on the affected tables and report any measured wait. Read the generated SQL with alembic upgrade --sql and flag NOT NULL without a default, dropped or narrowed columns, type changes that rewrite tables, backfills inside the DDL transaction, and indexes created without CONCURRENTLY. Run alembic downgrade and upgrade again and say what the downgrade discards, run alembic check against the models, and run the test suite. Comment on the changed lines with evidence and a safer staged alternative where one exists, and return migration-review.md with every command, its output and the limits of what a fresh database can show. Do not edit the migrations or open another pull request.","resources":[{"url":"https://github.com/your-org/your-app/pull/42"}]}