Compares two document versions and produces AI-powered redline analysis with structured change summaries, risk flags, and clause-by-clause breakdowns. Use when the user mentions "redline", "compare documents", "what changed", "version comparison", "contract diff", "track changes", or needs to understand differences between document versions.
Scanned 9/12/2026
Install to Claude Code
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---
name: redline
language: en
description: Compares two document versions and produces AI-powered redline analysis with structured change summaries, risk flags, and clause-by-clause breakdowns. Use when the user mentions "redline", "compare documents", "what changed", "version comparison", "contract diff", "track changes", or needs to understand differences between document versions.
---
# case.dev Redline Comparison
AI-powered document comparison that goes beyond visual diffs. Upload two versions of a contract or legal document, get a structured analysis of what changed, what it means, and what to watch out for.
Requires the `casedev` CLI. See `setup` skill for installation and auth.
## Quick Start
```bash
# Compare two local files
casedev redline compare ./contract-v1.pdf ./contract-v2.docx --json
# Compare two vault objects
casedev redline compare \
--vault VAULT_ID \
--base OBJECT_ID_V1 \
--target OBJECT_ID_V2 \
--json
```
## Compare Documents
### Local files
```bash
casedev redline compare ./old-version.pdf ./new-version.docx --json
```
Accepts PDF, DOCX, DOC, and TXT. Mixed formats supported (e.g., PDF vs DOCX).
### Vault objects
```bash
casedev redline compare \
--vault VAULT_ID \
--base OBJECT_ID \
--target OBJECT_ID \
--json
```
### URL sources
```bash
casedev redline compare \
--base-url "https://example.com/v1.pdf" \
--target-url "https://example.com/v2.pdf" \
--json
```
## Output Structure
The default JSON output contains:
```json
{
"summary": "Plain-English narrative of key changes",
"riskFlags": [
{
"severity": "high",
"clause": "Indemnification (Section 8.2)",
"change": "Cap reduced from $5M to $1M",
"impact": "Significantly increases exposure for indemnifying party"
}
],
"changes": [
{
"section": "Section 3.1 — Payment Terms",
"type": "modified",
"before": "Net 30 from invoice date",
"after": "Net 60 from invoice date",
"significance": "medium"
}
],
"stats": {
"sectionsModified": 12,
"sectionsAdded": 2,
"sectionsRemoved": 1,
"riskFlagsHigh": 1,
"riskFlagsMedium": 3
}
}
```
## Options
| Flag | Description |
|------|-------------|
| `--format` | Output format: `json` (default), `markdown`, `text` |
| `--detail` | Detail level: `summary`, `standard` (default), `detailed` |
| `--focus` | Comma-separated clause types to prioritize (e.g., `indemnification,termination,liability`) |
| `--perspective` | Analysis perspective: `neutral` (default), `drafter`, `reviewer` |
| `--json` | Shorthand for `--format json` |
### Detail levels
- **`summary`** — Executive overview only. Key changes and high-severity risk flags. Fast.
- **`standard`** — Full clause-by-clause breakdown with all risk flags. Default.
- **`detailed`** — Everything in standard plus original/modified text excerpts, suggested responses, and negotiation context.
### Perspective
- **`neutral`** — Objective analysis of changes.
- **`drafter`** — Flags changes that weaken your position (you drafted the original).
- **`reviewer`** — Flags changes you should push back on (you're reviewing incoming edits).
## Common Workflows
### Quick contract review
A partner sends back a marked-up contract. See what changed and whether to worry:
```bash
casedev redline compare ./our-draft.docx ./their-markup.docx \
--perspective reviewer \
--detail summary \
--json
```
### Deep-dive on specific clauses
Focus analysis on the clauses that matter most:
```bash
casedev redline compare ./v3.pdf ./v4.pdf \
--focus "indemnification,limitation-of-liability,termination,governing-law" \
--detail detailed \
--json
```
### Vault-based comparison
Compare two versions already stored in a vault:
```bash
casedev redline compare \
--vault VAULT_ID \
--base OBJECT_ID_V1 \
--target OBJECT_ID_V2 \
--format markdown
```
### Multi-version negotiation tracking
Compare across multiple rounds to see the negotiation arc:
```bash
# Compare each consecutive pair
casedev redline compare --vault VAULT_ID --base V1_ID --target V2_ID --json > round1.json
casedev redline compare --vault VAULT_ID --base V2_ID --target V3_ID --json > round2.json
casedev redline compare --vault VAULT_ID --base V3_ID --target V4_ID --json > round3.json
```
## Supported Formats
| Format | Input | Notes |
|--------|-------|-------|
| PDF | ✅ | OCR applied automatically for scanned documents |
| DOCX | ✅ | Preserves section/heading structure |
| DOC | ✅ | Converted to DOCX internally |
| TXT | ✅ | Plain text comparison |
Cross-format comparison is supported (e.g., compare a PDF against a DOCX).
## Troubleshooting
**"Unable to extract text"**: Document may be a scanned image without OCR text layer. Re-upload to a vault (automatic OCR) or use `casedev ocr process` first.
**Large documents timeout**: Documents over 200 pages may need `--detail summary` for faster processing.
**"No significant changes found"**: Documents may be identical or near-identical. Check you're comparing the right versions.
**Risk flags seem off**: Use `--perspective` to align analysis with your role in the negotiation. Default `neutral` perspective doesn't assume a side.
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