redlines

redlines — Word Document Redlining Library

When to Use

• Converting AI-generated edits into Word tracked changes
• Applying diff output to DOCX files with native revision markup
• Building legal tools that produce redlined documents
• Automated document comparison with Word-compatible output
• "Draft by exception" workflows where you track exceptions to standard clauses

How It Works

Takes diff output (from any source) and applies it to a DOCX as native Word tracked changes. Built by a practising Singapore counsel who needed deterministic document transformation.

Input

• Original DOCX
• Modified text or diff output

Output

DOCX with Word native tracked changes (insertions in blue, deletions in strikethrough)

Usage

import { applyRedlines } from '@houfu/redlines';

const result = applyRedlines({
  originalDoc: './contract.docx',
  modifiedText: 'modified contract text here',
  author: 'LQClaw'
});

result.toDocx('./contract-redlined.docx');

Key Design Decisions

• Deterministic — Same input produces identical output
• Format preservation — Headers, lists, tables survive transformation
• Standard-compliant — Output is valid DOCX that Word renders correctly
• No round-trip through Word — Works headlessly, no Office install required

Audience and Work Shape

Audience: legal engineers and counsel comfortable invoking a JavaScript library from a workflow. Not a self-service tool for a reviewing partner and not intended for non-technical users. The judgment as to which edits to apply sits upstream of this skill; this skill only carries them into the DOCX.

Work shape: Bounded Transactional primitive. Text-in (or diff-in) → DOCX-out. The transform is mechanical. It is not a redline reviewer, not a redline generator, and not a substantive review step.

Scope and Legal Use

This skill provides legal support, not legal advice. Producing a tracked-changes DOCX is mechanical document processing; the redlined output is a draft, not a vetted lawyer redline and not signed-off work product. A successful run means "the supplied edits were carried into the file as Word revisions" — not "these edits are correct" and not "this draft is fit to send."