Copy/paste detector for programming source code, supports 223 formats. AI-ready with token-efficient reporter, skill and MCP server.
jscpd is a copy-paste detection tool that scans source code for duplicated blocks across 223 to 224 language formats, using the Rabin-Karp algorithm to identify clones. It ships in two variants: a TypeScript engine (v4) with 13 reporters, LevelDB store support, and a Node.js programming API, and a ground-up Rust rewrite (v5) that runs as a self-contained binary with no Node.js dependency, delivering 24 to 37 times faster detection on real codebases. The MCP server integration allows Claude Code and other MCP-compatible agents to invoke duplicate detection directly as a tool call during code review or refactoring tasks. An AI reporter outputs results in a token-efficient format roughly 79 percent leaner than standard console output, making it practical for LLM pipelines where context budgets matter. The v5 Rust engine also adds git blame with side-by-side author comparison via gitoxide, and parallel file tokenization controlled through a workers flag. Developers, CI pipelines, and AI coding agents working across large polyglot repositories are the primary audience.
- ✓Open-source license (MIT)
- ✓Actively maintained (<30d)
- ✓Clear description
- ✓Topics declared
- ✓Mature repo (>1y old)
- ✓Documented (README)
claude mcp add jscpd -- npx -y jscpd{
"mcpServers": {
"jscpd": {
"command": "npx",
"args": ["-y", "jscpd"]
}
}
}MCP Servers overview
# jscpd
[](https://www.npmjs.com/package/jscpd)
[](https://github.com/kucherenko/jscpd/blob/master/LICENSE)
[](https://www.npmjs.com/package/jscpd)
[](https://github.com/kucherenko/jscpd/actions/workflows/nodejs.yml)
[](https://codecov.io/gh/kucherenko/jscpd)
[](https://app.fossa.io/projects/git%2Bgithub.com%2Fkucherenko%2Fjscpd?ref=badge_shield)
[](#backers)
[](#sponsors)
[](https://nodei.co/npm/jscpd/)
> Copy/paste detector for programming source code. Supports 224+ formats. AI-ready with MCP server and token-efficient reporter. Now with a Rust-powered engine — 24-37x faster.
jscpd implements the [Rabin-Karp](https://en.wikipedia.org/wiki/Rabin%E2%80%93Karp_algorithm) algorithm to find duplicated code blocks across files.
## Quick Start
```bash
# TypeScript engine (Node.js, v4.x)
npm install -g jscpd@4
jscpd /path/to/code
# or use without installing
npx jscpd@4 /path/to/code
# Rust engine (v5.x, 24-37x faster) — both jscpd and cpd commands
npm install -g jscpd@5
jscpd /path/to/code
cpd /path/to/code
# Rust engine — cpd command only
npm install -g cpd
cpd /path/to/code
# Rust-native install (exposes both jscpd and cpd)
cargo install jscpd
```
## Documentation
| Document | Description |
|----------|-------------|
| [TypeScript (v4.x)](docs/typescript.md) | Node.js engine — CLI, reporters, config, detection modes |
| [Rust (v5.x)](docs/rust.md) | Rust engine — installation, CLI, reporters, blame, Rust API |
| [AI-Ready](docs/ai-ready.md) | AI reporter, agent skills, MCP server |
| [Programming API](docs/api.md) | TypeScript and Rust programmatic APIs |
| [Packages](docs/packages.md) | Monorepo package and crate overview |
## Two Engines
| | TypeScript (v4) | Rust (v5) |
|---|---|---|
| **npm package** | [`jscpd@4`](https://www.npmjs.com/package/jscpd) | [`jscpd@5`](https://www.npmjs.com/package/jscpd) or [`cpd`](https://www.npmjs.com/package/cpd) |
| **CLI command** | `jscpd` | `jscpd` and `cpd` (both available) |
| **Speed** | Baseline | 24-37x faster |
| **Formats** | 224 | 223 |
| **Node.js required** | Yes | No (self-contained binary) |
| **Programming API** | TypeScript (`jscpd()`, `detectClones()`) | Rust (`cpd-finder` crate) |
| **LevelDB store** | Yes | No |
| **Reporters** | 13 | 13 |
`jscpd@5` installs both `jscpd` and `cpd` commands. The `cpd` npm package installs only the `cpd` command. Both contain the same Rust binary.
## What's New
### v5.0.x — Rust Engine
jscpd v5 is a ground-up Rust rewrite that ships as [`jscpd@5`](https://www.npmjs.com/package/jscpd) (installs both `jscpd` and `cpd` commands) or [`cpd`](https://www.npmjs.com/package/cpd) (installs the `cpd` command only). Self-contained binary — no Node.js runtime required.
**Same interface, 24-37x faster:**
- All CLI options from v4 are preserved — drop-in replacement: `jscpd` → `jscpd@5`
- Same `.jscpd.json` config file, same detection algorithm, same reporters
- 223 language formats with cross-format detection (Vue SFC, Svelte, Astro, Markdown)
**New in v5:**
- **24-37x faster** detection on real projects (see [benchmark](docs/performance-comparison.md))
- Small codebases (548 files): 34x faster
- Medium codebases (9K files): 37x faster
- Large codebases (17K files, 900 MB): 24x faster
- **Git blame** with side-by-side author comparison (`--blame --reporters console-full`) — uses [gitoxide](https://github.com/GitoxideLabs/gitoxide) instead of shelling out to `git`, making blame significantly faster
- **`--workers`** — control parallelism for file tokenization and detection (default: auto, uses all CPU cores; not available in v4)
- **13 reporters**: `console`, `console-full`, `json`, `xml`, `csv`, `html`, `markdown`, `badge`, `sarif`, `ai`, `xcode`, `threshold`, `silent`
- **AI reporter** — token-efficient output for LLM pipelines (~79% fewer tokens than console)
- **Self-contained binary** — prebuilt for 6 platforms (macOS arm64/x64, Linux arm64/x64, Windows x64)
**Not yet in v5** (use v4 for these):
- LevelDB/Redis stores (`--store leveldb`)
- Node.js programming API (`jscpd()`, `detectClones()`)
See [Rust docs](docs/rust.md) for the full CLI reference and differences from v4.
### v4.2.x — TypeScript Engine
- **Custom tokenizer backend** — replaced `prismjs` with own backend built on [reprism](https://github.com/tannerlinsley/reprism). ~11.5% faster tokenization on real projects
- **Cross-format detection** — Vue SFC, Svelte, Astro, and Markdown tokenized per-block, enabling detection across file types
- **New formats**: Apex, CFML/ColdFusion, GDScript, and 70+ additional formats (224 total, up from 152)
- **Shebang detection** — auto-detect language for extensionless scripts
- **`--store-path`** — configure LevelDB cache directory for parallel runs
- **`--skipComments`** — shorthand for `--mode weak`
- **`--formats-names`** — map filenames (e.g. `Makefile`, `Dockerfile`) to formats
- **`--noTips`** — suppress tip output in CI
- **Bug fixes**: entire-file duplicates silently dropped (#728), ReDoS on Lisp/Elisp files (#737), process crash on malformed `package.json` (#739), Vue SFC cross-file detection (#737), Vue SFC column numbers (#737), 50 dependency security vulnerabilities
See [TypeScript docs](docs/typescript.md) for the full CLI reference.
## Packages
| Package | Description |
|---------|-------------|
| [jscpd](apps/jscpd) | CLI and Node.js API (v4.x) |
| [jscpd-server](apps/jscpd-server) | REST API + MCP server |
| [@jscpd/core](packages/core) | Core detection algorithm |
| [@jscpd/finder](packages/finder) | File detection, reporters |
| [@jscpd/tokenizer](packages/tokenizer) | Source code tokenization |
| [@jscpd/html-reporter](packages/html-reporter) | HTML report |
| [@jscpd/badge-reporter](packages/badge-reporter) | SVG badge |
| [jscpd-sarif-reporter](packages/sarif-reporter) | SARIF (GitHub Code Scanning) |
| [@jscpd/leveldb-store](packages/leveldb-store) | LevelDB persistent store |
| [@jscpd/redis-store](packages/redis-store) | Redis distributed store |
| [cpd](rust) (Rust engine) | Rust-powered engine (v5.x) — also available as `jscpd@5` |
## Who Uses jscpd
- [GitHub Super Linter](https://github.com/github/super-linter) — linter aggregator as a GitHub Action
- [Code-Inspector](https://www.code-inspector.com/) — code analysis and technical debt management
- [Mega-Linter](https://nvuillam.github.io/mega-linter/) — 100% open-source linters aggregator for CI
- [Codacy](https://docs.codacy.com/) — automated source code analysis
- [Natural](https://github.com/NaturalNode/natural) — NLP facility for Node.js
- [OpenClaw](https://github.com/openclaw/openclaw) — personal AI assistant for self-hosted devices
## Performance
Benchmarked on macOS (Apple Silicon), 10 runs per target (3 for CopilotKit). v4 ran with `--no-gitignore -i "node_modules"` to ensure comparable file scanning.
| Target | Files | Size | jscpd v4 | jscpd v5 | Speedup |
|--------|-------|------|----------|----------|---------|
| fixtures | 548 | 1.5 MB | 1.03s | 0.03s | **34.3x** |
| svelte | 9K | 38 MB | 15.80s | 0.43s | **36.9x** |
| CopilotKit | 17K | 159 MB | 82.89s | 3.44s | **24.1x** |
See [performance-comparison.md](docs/performance-comparison.md) for full methodology and raw data.
## Contributing
1. Fork the repo [kucherenko/jscpd](https://github.com/kucherenko/jscpd/)
2. Clone forked version (`git clone https://github.com/{your-id}/jscpd`)
3. Install dependencies (`pnpm install`)
4. Run in dev mode: `pnpm dev`
5. Add your changes
6. Add tests and check: `pnpm test`
7. Build: `pnpm build`
8. Create PR
## Backers
Thank you to all our backers! 🙏 [[Become a backer](https://opencollective.com/jscpd#backer)]
<a href="https://opencollective.com/jscpd#backers" target="_blank"><img src="https://opencollective.com/jscpd/backers.svg?width=890"></a>
## Sponsors
Support this project by becoming a sponsor. Your logo will show up here with a link to your website. [[Become a sponsor](https://opencollective.com/jscpd#sponsor)]
<a href="https://opencollective.com/jscpd/sponsor/0/website" target="_blank"><img src="https://opencollective.com/jscpd/sponsor/0/avatar.svg"></a>
<a href="https://opencollective.com/jscpd/sponsor/1/website" target="_blank"><img src="https://opencollective.com/jscpd/sponsor/1/avatar.svg"></a>
<a href="https://opencollective.com/jscpd/sponsor/2/website" target="_blank"><img src="https://opencollective.com/jscpd/sponsor/2/avatar.svg"></a>
<a href="https://opencollective.com/jscpd/sponsor/3/website" target="_blank"><img src="https://opencollective.com/jscpd/sponsor/3/avatar.svg"></a>
<a href="https://opencollective.com/jscpd/sponsor/4/website" target="_blank"><img src="https://opencollective.com/jscpd/sponsor/4/avatar.svg"></a>
<a href="https://opencollective.com/jscpd/sponsor/5/website" target="_blank"><img src="https://opencollective.com/jscpd/sponsor/5/avatar.svg"></a>
<a href="https://opencollective.com/jscpd/sponsor/6/website" target="_blank"><img src="https://opencollective.com/jscpd/sponsor/6/avatar.svg"></a>
<a href="https://opencollective.com/jscpd/sponsor/7/website" target="_blank"><img src="https://opencollective.comWhat people ask about jscpd
What is kucherenko/jscpd?
+
kucherenko/jscpd is mcp servers for the Claude AI ecosystem. Copy/paste detector for programming source code, supports 223 formats. AI-ready with token-efficient reporter, skill and MCP server. It has 5.8k GitHub stars and was last updated today.
How do I install jscpd?
+
You can install jscpd by cloning the repository (https://github.com/kucherenko/jscpd) or following the README instructions on GitHub. ClaudeWave also provides quick install blocks on this page.
Is kucherenko/jscpd safe to use?
+
Our security agent has analyzed kucherenko/jscpd and assigned a Trust Score of 100/100 (tier: Verified). See the full breakdown of passed checks and flags on this page.
Who maintains kucherenko/jscpd?
+
kucherenko/jscpd is maintained by kucherenko. The last recorded GitHub activity is from today, with 47 open issues.
Are there alternatives to jscpd?
+
Yes. On ClaudeWave you can browse similar mcp servers at /categories/mcp, sorted by popularity or recent activity.
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