Add File Guard plugin - #430

File Guard

Protects files from agent-caused corruption by creating pre-write backups and blocking empty overwrites.

What it does

• Pre-write backups — Before every text_editor, text_editor_remote, or office_artifact write/patch/create/edit, creates a timestamped backup in .file_guard_backups/ (5-version rotation per file).
• Empty-overwrite blocking — If an agent attempts to write empty or whitespace-only content to a file that currently has data, the operation is blocked with a descriptive error. The original file is untouched.
• Agent-callable restore — Includes a file_guard_restore tool that lets agents list backups and restore files themselves.

Why

AI agents that edit files can accidentally destroy working content — empty overwrites, bad patches, malformed content. Once the write lands, the previous version is gone. File Guard prevents this at the interception layer, before the write executes.

Details

• Zero LLM calls — pure filesystem operations
• No configuration required — works out of the box
• Excludes caches/build artifacts (__pycache__/, .git/, node_modules/, venv/, .faiss/, *.pyc, *.pkl)
• MIT license

Plugin repo: https://github.com/wgnr-ai/a0-file-guard