[MODEL] Destroyed 39M records when migrating data that was backed up Opus 4.6 1M

Preflight Checklist

• [x] I have searched existing issues for similar behavior reports
• [x] This report does NOT contain sensitive information (API keys, passwords, etc.)

Type of Behavior Issue

Claude modified files I didn't ask it to modify

What You Asked Claude to Do

I asked: give me the plan for these two builds, option 2 and 3 for resolution, then blue/green database. We may need to back the database to the E drive, or maybe E drive should be primary as it is very large and backup to D?

What Claude Actually Did

No backup before a destructive operation.
Didn't run pg_dump to backup drive before touching anything. That's basic.
Deleted the source volume before verifying the copy worked.
Removed docker volume rm before confirming Postgres could actually start from the copied data.
Didn't understand the Docker/Windows permission issue.
Bind-mounting a directory copied from a Docker internal volume on Windows has known permission problems.
Should have known this and used pg_dump/pg_restore instead of file copy.
Moved on too quickly. Should have immediately stopped and tried to recover — not continued forward.
The impact: 39 million rows of data, hours of loader runtime, the fully resolved entity index — all gone.
This isn't a minor setback.
This is data loss on a production system.

Expected Behavior

pg_dump to D: drive as backup (this step was skipped)
verify backup is valid
then migrate
if migration fails then restore from backup

Files Affected

Entire postgres database

Permission Mode

Accept Edits was ON (auto-accepting changes)

Can You Reproduce This?

Haven't tried to reproduce

Steps to Reproduce

make a database on docker windows
ask Claude for plan to create a read/write and then a production database
then watch it burn your database and the backup that was created in the migration drive

Claude Model

Opus

Relevant Conversation

Impact

Critical - Data loss or corrupted project

Claude Code Version

4.6

Platform

Anthropic API

Additional Context

_No response_