JAI: Diff Editor (lite-diff)

100% AI Code · Human Reviewed

Working with AI assistants like Claude, Cursor, or ChatGPT? Tired of manually applying code patches?

This extension bridges unified diff format and your IDE. Apply AI-generated patches with preview, selective hunk application, automatic backups, and drift detection.

Two ways to work:

Manual — Paste a lite-diff patch into the editor panel, preview in VS Code diff viewer, apply with one click
AI-assisted (MCP) — Your AI agent reads code, generates patches, previews, and applies — all through MCP tools, no copy-paste needed

Based on the lite-diff specification.

Features

In-file edits — Replace, delete, insert with familiar unified diff syntax
Insert at file start/end — Use @@ BOF and @@ EOF for file start/end
Boundary blocks — Delete ranges between two marker lines using ...
Global options — Ignore whitespace, blank lines, apply to all matches
Preview mode — See exact changes in VS Code diff viewer before applying
Multi-file support — Process multiple files in a single patch
Automatic backups — Every change creates a backup in .ldiff/ directory
MCP Server — Integrate with Claude and Cursor IDE for AI-assisted patching

Tutorial Videos

Overview Demo	Claude Desktop — Chat	Claude Desktop — Code
Claude Code (VS Code)	Cursor IDE

Quick Start

Open Command Palette (Ctrl/Cmd+Shift+P)
Run JAI: Diff Editor (lite-diff)
Paste your lite-diff patch
Review changes in diff viewer, then apply

Syntax Guide

Basic Edit

--- file.txt
+++ file.txt
@@
 context line (unchanged)
-old line
+new line

Insert at File Start

--- file.txt
+++ file.txt
@@ BOF
+first line
+second line

Insert at File End

--- file.txt
+++ file.txt
@@ EOF
+last line

Note: After @@ BOF and @@ EOF only + lines are allowed. Context ( ) or deletion (-) lines will cause error E411.

Delete Range (Boundary Block)

--- file.txt
+++ file.txt
@@
-start boundary
...
-end boundary
+replacement

Deletes everything from "start boundary" to "end boundary" inclusive, then inserts replacement.

Rules for boundary blocks:

... cannot appear at the start or end of the block
Two ... in a row without - line between them are forbidden
Each boundary must have - lines on both sides

Global Options

Add at the beginning of your patch, before any diff block:

--ignore-space-at-eol
--ignore-blank-lines

--- file.txt
+++ file.txt
@@
 context line
-old line
+new line

Option	Description
`--ignore-space-at-eol`	Ignore trailing whitespace at end of lines
`--ignore-space-change`	Ignore changes in whitespace quantity (but not presence)
`--ignore-blank-lines`	Ignore blank lines when matching context
`--ignore-all-space`	Ignore all whitespace differences
`--apply-all-matches`	Apply hunk to all occurrences (single hunk only)

Important Rules

All structural elements must begin at the first position (no indentation): ---, +++, @@, -, +, (context), ..., #, --
No blank lines allowed inside hunk body (from @@ to the next @@ or end of diff block)
Comments start with # at the first position on a separate line
Preview creates directories .ldiff/<TIMESTAMP>/original/ and .ldiff/<TIMESTAMP>/preview/

Configuration

Setting	Default	Description
`diffEditor.verboseLogging`	`false`	Enable verbose logging for debugging
`diffEditor.backupLimit`	`5`	Max backup packages to keep (0 = only active)

Telemetry

This extension collects minimal anonymous telemetry (feature usage counts, no personal data) to help prioritize development. Telemetry respects the VS Code telemetry.telemetryLevel setting — set it to "off" to disable. See PRIVACY.md for full details.

Contributing

Found a bug or have a feature request? Please open an issue on GitHub.

For other inquiries: JeenyJAI@gmail.com

License

This extension is proprietary software. See LICENSE for details.

The lite-diff specification is licensed under CC BY 4.0. This license applies to the specification only and does not grant any rights to this extension's source code or binaries — you're free to create your own implementations of the spec.

🚀 Created with Claude Opus 4.6 · Early contributions by ChatGPT 5 Pro