Auto-Rollback Generation

Derives inverse SQL from a forward migration and enumerates operations that cannot be reversed rather than fabricating a fake rollback.

Reversibility rules

• DROP TABLE, recoverable only if the original CREATE is present in the script; otherwise irreversible.
• DELETE without backup, irreversible.
• TRUNCATE, irreversible.
• ADD COLUMN ↔ DROP COLUMN, reversible forward, irreversible back (data is lost).
• CREATE INDEX ↔ DROP INDEX, reversible.
• ALTER COLUMN type change, inverse attempted, with a warning when the original type would lose data.

Output

{
  rollbackSql: 'SQL that reverses the forward script',
  irreversible: ['operation 1 that cannot be reversed'...],
  notes: 'explanation of choices and caveats'
}

The agent is constrained to never invent DDL for tables/columns the forward script doesn't reference.