Codex Diff Guard records an in-memory workspace snapshot before AI edits, then shows changed files with VS Code diff. It does not require Git and does not call the OpenAI API.
Use Cases
You asked Codex, Copilot Agent, or another AI tool to modify code and want to review exactly what changed.
You do not want to run git init for every temporary or small project.
You want a familiar red/green diff experience like Git diff, without depending on a Git repository.
How To Use
Open a project folder.
Codex Diff Guard starts recording automatically.
Ask Codex or another AI tool to modify code.
Save changed files.
Check M, N, and D markers in the Explorer.
Diffs open automatically when files change. You can also click Show Diffs.
Click a changed file to open the red/green diff again.
If you are satisfied with one file, run Codex Diff Guard: Accept Selected File.
If you want to accept everything, run Codex Diff Guard: Accept All Snapshot.
If you want a fresh baseline, run Codex Diff Guard: Start Recording again.
If you are not satisfied, run Codex Diff Guard: Revert Selected File.
Diff Colors
Red = code from the recorded snapshot was deleted.
Green = code in the current file was added.
Explorer Markers
M = modified file.
N = new file or new folder.
D = deleted file.
Commands
Codex Diff Guard: Start Recording
Codex Diff Guard: Show Changed Files
Codex Diff Guard: Show All Diffs
Codex Diff Guard: Accept Selected File
Codex Diff Guard: Accept All Snapshot
Codex Diff Guard: Revert Selected File
Codex Diff Guard: Clear Recording
Codex Diff Guard: Toggle Open Diff On File Open
Codex Diff Guard: Export Code as PNG
Export Code as PNG
Use Codex Diff Guard: Export Code as PNG from the command palette or the editor title button.
If text is selected, the selection is exported. Otherwise, the whole current file is exported.
The PNG uses Courier New as its code font.
Common syntax elements such as keywords, strings, comments, and numbers are exported with color.
Limits
The extension cannot prove that a change came from Codex.
It only detects which files changed after Start Recording.
Snapshots are stored in memory by default and are not written to disk.
It is not Git and does not replace Git.
Files larger than 1 MB are skipped by default to keep VS Code responsive.
Safety
No network requests.
No OpenAI API calls.
No code upload.
Snapshots are stored in memory by default.
Development
Install dependencies and compile:
npm install
npm run compile
Press F5 in VS Code to launch the Extension Development Host.
