Automatic file backup before any modification. Use when a file is about to be edited, modified, or transformed. Creates timestamped backup copies in a _backups/ folder, manages backup rotation (max 3 per file), and provides post-task summaries of all modifications and backups created.

Backup First

No file should ever be changed without a backup existing first.

Rules

1. Create Backup Before Every Edit

Before editing any file, create a backup copy in a _backups/ subfolder inside the current working folder.
The backup must be created and confirmed before any modifications begin on the original file.

2. Backup Naming Format

Use this exact format: originalname_backup_YYYYMMDD_HHMM.ext

Examples:

index.html → _backups/index_backup_20260209_1430.html
styles.css → _backups/styles_backup_20260209_1430.css
report.docx → _backups/report_backup_20260209_1430.docx

3. Maximum 3 Backups Per File

Keep a maximum of 3 backups per original file.
When creating a 4th backup, delete only the oldest backup for that specific file.
Do not delete backups belonging to other files.

4. Session Startup Check

At the start of every session, check if the _backups/ folder exists in the working directory.
If it does not exist, create it immediately.
This check should happen before any file work begins.

5. Post-Task Summary

After completing any task that involved file modifications, show the user a summary:

✅ Task complete
─────────────────────────────
Files modified:    X
Backups created:   X
Backup location:   _backups/
─────────────────────────────

Activation

This skill activates when:

A file is about to be edited or modified
A new session begins (for the startup check)
A task involving file changes is completed (for the summary)

backup-first