Content
# CodeSafer (cleaner-code)
> **AI code security scanner as a Model Context Protocol (MCP) server.**
> Detects hidden threats in AI-generated code that traditional linters miss.
[](https://modelcontextprotocol.io)
[](#license)
[](https://nodejs.org)
**Website:** [codesafer.org](https://codesafer.org/) · **MCP Clients:** Claude Code, Cursor, VS Code + Copilot, Cline
---
## Why CodeSafer?
AI coding assistants generate code fast — but who's checking it for hidden threats?
Recent supply-chain attacks show that malicious code can hide in ways human reviewers and traditional linters routinely miss:
- **Invisible Unicode characters** injected into identifiers (30+ variants)
- **BiDi / Trojan Source** attacks that reorder how code is displayed vs. executed (CVE-2021-42574)
- **Homoglyphs** — Cyrillic characters masquerading as Latin (CVE-2021-42694)
- **Glassworm-style Unicode steganography** hiding payloads in whitespace
- **Rules file backdoors** planted in `.cursorrules`, `CLAUDE.md`, and other AI config files
- **Typosquatted dependencies** in `package.json`
- **Obfuscation patterns** — `eval` + base64, reverse shells, packed payloads
CodeSafer scans for all of these before the code runs on your machine.
---
## How it works
CodeSafer runs as a local MCP server. Your AI client (Claude Code, Cursor, etc.) calls its tools when reviewing or generating code, and findings are returned inline.
**Hybrid detection:**
1. **8 static analysis scanners** — deterministic rules for known attack categories (fast, zero false-negatives on the patterns they cover).
2. **CodeBERT deep analysis** — transformer model classifies code chunks as malicious/benign with confidence scores. Catches obfuscated or novel patterns that static rules miss.
Nothing leaves your machine. The AI analysis runs locally against a tokenizer server.
---
## Features
| Capability | Details |
|---|---|
| Invisible character detection | 30+ Unicode variants including Zero-Width Space, Mongolian Vowel Separator |
| BiDi / Trojan Source | Full CVE-2021-42574 coverage |
| Homoglyph detection | Cyrillic/Greek/Latin confusables (CVE-2021-42694) |
| Unicode steganography | Glassworm-style whitespace payloads |
| Rules file backdoors | Scans `.cursorrules`, `CLAUDE.md`, `.claude/`, Cursor rules |
| Dependency scanning | Typosquatting + suspicious install scripts in `package.json` |
| Obfuscation detection | `eval` + base64, reverse shells, packed payloads |
| AI deep analysis | CodeBERT transformer classifier with confidence scores |
| MCP native | 6 MCP tools, stdio transport |
| Local-first | No code uploaded — runs entirely on your machine |
---
## MCP Tools
CodeSafer exposes six tools to your MCP client:
| Tool | Purpose |
|---|---|
| `scan_file` | Scan a single file for hidden malicious code patterns |
| `scan_directory` | Recursively scan a directory across all source files |
| `scan_rules_file` | Scan an AI configuration/rules file for prompt injection and Rules File Backdoor attacks |
| `check_dependencies` | Check `package.json` for typosquatting, suspicious install scripts, and dependency risks |
| `ai_analyze` | Deep AI analysis using the trained CodeBERT model (classifies chunks as malicious/benign with confidence) |
| `explain_finding` | Get detailed explanation of a specific threat category, with attack scenarios and remediation |
---
## Installation
### Prerequisites
- Node.js 18 or later
- An MCP-compatible client (Claude Code, Cursor, VS Code + Copilot, Cline)
### From source
```bash
git clone https://github.com/goldmembrane/cleaner-code.git
cd cleaner-code
npm install
npm run build
```
### Configure your MCP client
**Claude Code** (`~/.claude.json` or project `.mcp.json`):
```json
{
"mcpServers": {
"codesafer": {
"command": "node",
"args": ["/absolute/path/to/cleaner-code/dist/index.js"]
}
}
}
```
**Cursor** (`.cursor/mcp.json`):
```json
{
"mcpServers": {
"codesafer": {
"command": "node",
"args": ["/absolute/path/to/cleaner-code/dist/index.js"]
}
}
}
```
Restart your client, and CodeSafer tools will appear in the tool picker.
---
## Usage
Once configured, ask your AI client things like:
- *"Scan this file for hidden security issues."*
- *"Check the dependencies in package.json for typosquatting."*
- *"Scan `.cursorrules` for a rules-file backdoor."*
- *"Run a deep AI analysis of `src/auth.ts`."*
- *"Explain what a Trojan Source attack is and how to fix the finding above."*
The client will call the appropriate MCP tool and return findings with severity, line numbers, and remediation guidance.
---
## Free tier & Plans
CodeSafer is free to use. Static analysis (`scan_file`, `scan_directory`, `scan_rules_file`, `check_dependencies`, `explain_finding`) has no limits.
AI deep analysis (`ai_analyze`) includes **10 free runs per session**. Paid plans for higher AI quotas are available at [codesafer.org](https://codesafer.org/).
---
## Detection categories
CodeSafer detects threats across **9 categories**:
1. **Invisible Unicode characters** — 30+ variants including Zero-Width Space, Zero-Width Joiner
2. **BiDi / Trojan Source attacks** — CVE-2021-42574
3. **Homoglyphs** — Cyrillic/Greek characters masquerading as Latin (CVE-2021-42694)
4. **Unicode steganography** — Glassworm patterns in whitespace
5. **Rules file backdoors** — malicious instructions in `.cursorrules`, `CLAUDE.md`, etc.
6. **Dependency risks** — typosquatting and suspicious install scripts
7. **Obfuscation patterns** — `eval` + base64, packed payloads, reverse shells
8. **Static analysis findings** — 8 deterministic scanners
9. **AI deep analysis** — CodeBERT transformer for novel and obfuscated threats
---
## Project structure
```
cleaner-code/
├── src/
│ ├── index.ts # MCP server entry point
│ ├── api-server.ts # Optional HTTP API server
│ ├── types.ts # Scanner interfaces
│ ├── utils.ts # File collection, summary formatting
│ └── scanner/
│ ├── invisible.ts # Invisible Unicode scanner
│ ├── bidi.ts # BiDi / Trojan Source scanner
│ ├── homoglyph.ts # Homoglyph scanner
│ ├── encoding.ts # Encoding / charset scanner
│ ├── obfuscation.ts # Obfuscation pattern scanner
│ ├── steganography.ts # Unicode steganography scanner
│ ├── rules-backdoor.ts # Rules file backdoor scanner
│ ├── dependency.ts # Dependency risk scanner
│ └── ai-analyzer.ts # CodeBERT deep analyzer
├── ml/ # ML model assets and tokenizer
├── functions/ # Cloud function deployments
├── deploy/ # Deployment manifests
└── web/ # Landing page assets
```
---
## License
ISC — see the `LICENSE` file for details.
---
## Links
- **Website:** [codesafer.org](https://codesafer.org/)
- **Model Context Protocol:** [modelcontextprotocol.io](https://modelcontextprotocol.io/)
- **Report issues:** [GitHub Issues](https://github.com/goldmembrane/cleaner-code/issues)
